Stability and Control characteristics of the Early Mark Spitfires [Archive] - Page 4

NZtyphoon

08-03-2012, 11:35 PM

To reiterate: From http://www.spitfires.ukf.net/ which is well researched and more accessible than M & S:

Mk Is less than 1 year old lost through structural failure in flight:

K9977 Ia 191 EA MII FF 16-5-39 602S 18-5-39 lost wing during aerobatics crashed Haddington CE Lothian 30-12-39 Sgt Bailey killed SOC 11-2-40

N3120 Ia 391 EA MIII FF 29-10-39 6MU 3-11-39 266S 20-1-40 broke up in test flight to alt Pilot Gleed thrown out crashed 14.40hrs Littleport Cambs 18-2-40 SOC 22-2-40

X4613 Ia 1233 EA MIII FF 15-10-40 6MU 15-10-40 ? 603S 17-10-40 266S 24-10-40 Lost wing and crashed Gedney Hill Lincs CE 2-3-41 SOC 20-3-41

R6692 Ia 746 EA MIII FF 3-6-40 6MU 5-6-40 609S 7-6-40 Overstressed attacking Ju88 CE 12-8-40 SOC 2-9-40

Mk Is - older airframes on OTUs lost through structural failure in flight:

R6777 Ia 803 EA MIII FF 21-6-40 8MU 22-6-40 65S 12-7-40 C2 ops 30-7-40 GAL 616S 20-8-40 72S 2-9-40 92S 3-11-40 145S 4-2-41 AFDU 6-3-41 152S 13-3-41 SF H 10-4-41 57OTU 4-8-41 61OTU 3-1-42 Broke up in air and crashed Blackbill Glam FAC3 8-7-42

R6882 Ia 840 EA MIII FF 1-7-40 (CMG) 6MU Brize Norton 28-7-40 cannon wing fitt 7OTU 3-9-40 AFDU Duxford 11-1-41 R-RH 10-2-41 Cv Vb M45 92S 'QJ-N' 9-3-41 609S 30-8-41 Broke up in air and abandoned 2.5m NE of East Stoke Notts FACE 10-1-42 SOC 17-1-42

R7064 Ia 1431 EA MIII FF 5-2-41 9MU 6-2-41 411S 5-7-41 52OTU 23-11-41 struct damaged in spin crashed and hit fence nr Aston Down CE 25-3-42 SOC 3-4-42

X4234 Ia 1031 EA MIII FF 15-8-40 8MU 16-8-40 609S 24-8-40 damaged combat P/O Staples safe 27-9-40 AST 66S 13-10-40 57OTU 1-11-40 FACB 27-6-42 ros wing fail in spin crashed Alsager Cheshire CE 25-9-42

X4854 Ia 1351 EA MIII FF 14-12-40 MU 16-12-42 53OTU into sea nr Dunraven Castle Thought struct fail of stbd wing 2-1-43

Less than 1 year old lost through structural failure in dive:

K9838 Ia FF 6-1-39 41S 11-1-39 struct fail in dive Eryholme Yorks 16-3-39 SOC FH21.25 pilot killed

X4056 Ia 972 EA MIII FF 1-8-40 39MU 2-8-40 616S 30-8-40 Wing came off during dive 8m SE of Kirton-in-Lindsey FAC3 8-11-40 SOC 11-11-40

X4421 Ia 1138 EA MIII FF 12-9-40 8MU 13-9-40 66S 16-9-40 57OTU 21-10-40 steep dive from low cloud violent pull out high speed stall spun wing fail Pilot thrown clear but killed 15.15hrs crashed Northrop Flints 27-3-41 SOC cancel RAE 8-4-41 AST 13-5-41 rebuilt as Va M45 164S 29-4-42 FACE 18-8-42 (Rebuild suspect)

X4662 Ia 1260 EA MIII FF 1-11-40 9MU 8-11-40 485S 15-3-41 61OTU 25-6-41 131S 17-7-41 pull out steep dive stbd wing broke away crashed dbf pilot killed 12.07hrs Northallerton 27-7-41 SOC 1-8-41

X4680 Ia 1264 EA MIII FF 2-11-40 12MU 5-11-40 72S 17-1-41 CB ops 9-4-41 Scottish Aviation 123S 3-6-41 steep dive and pull out from cloud wings and tailplane broke off fus hit ground Kirknewton pilot killed 16.00hrs 15-6-41 SOC 1-7-41 FH77.50 RAE accident invest 20-8-41

Older airframes lost in dive:

N3191 Ia 432 EA MIII FF 23-11-39 24MU 2-12-39 234S 22-3-40 lost wings in dive crashed nr Truro Cornwall CE 16-1-41 AST 14-2-41 SOC 23-4-41

X4381 Ia 1122 EA MIII FF 6-9-40 6MU 10-9-40 152S 13-9-40 501S 'SD-J' 5-11-40 53OTU 7-7-41 stbd wing broke off after high speed dive out of cloud Tonpentre nr Pontypridd dbf CE 16.30hrs 6-8-41 SOC 21-8-41 RAE 30-1-42

Overstressed in storm at high altitude:

R7033 PRIV 1738 HEA M45 HAL 8-6-41 Cv PRIII Type C 1PRU Benson 7-8-41 loss of control in storm at high alt pilot thrown clear at 1000ft landed safe total wreck nr Bishops Stortford 5-10-41 remains to RAE for accident invest 1-42

17 with structural or wing failure, seven of which occurred during a dive or pulling out of a dive: See Henshaw

Six - N3191, R6777, R6882, R7064, X4234, X4854 - old, retired Spitfire Is in OTUs. One, R7033, was a PRU aircraft caught in a storm at high altitude.

Out of 17 structural failures three were recently delivered Spitfires: two, K9977 and N3120 had structural or wing failures before the Pilot's Notes were printed in July 1940 while K9838 broke up in a dive in early 1939 - it might well have been these three incidents which prompted the warnings to be printed.

Now let's see Crumpp's serial numbers and comments.

Crumpp

08-03-2012, 11:35 PM

In the Thomas/Shore book on the Typhoon/Tempest there is 18 losses listed as 'sf' (structural failure) of which 14 were over Britain and only 2 of these past Jan 1944.

What a shame the Air Ministry did not have stability and control standards in place.

They would have realized something was not kosher when the aircraft motion did not align with predicted results.

Crumpp

08-03-2012, 11:36 PM

which is well researched and more accessible than M & S:

And obviously not as in-depth as M&S.

NZtyphoon

08-03-2012, 11:37 PM

And obviously not as in-depth as M&S.

Prove it - scan and post the relevant pages instead of making useless comments.

Al Schlageter

08-03-2012, 11:42 PM

What a shame the Air Ministry did not have stability and control standards in place.

They would have realized something was not kosher when the aircraft motion did not align with predicted results.

UGH!!!?

The s/fs had nothing to do with 'stability and control standards'. To bad the Americans didn't have S&CS for the P-51 when they were loosing wings.

NZtyphoon

08-03-2012, 11:48 PM

UGH!!!?

The s/fs had nothing to do with 'stability and control standards'. To bad the Americans didn't have S&CS for the P-51 when they were loosing wings.

Just another one of Crumpp's diversions - I'm waiting for his list of Mk Is destroyed through structural failure, along with scans of the relevant pages from Morgan and Shacklady.

Al Schlageter

08-03-2012, 11:56 PM

Just another one of Crumpp's diversions - I'm waiting for his list of Mk Is destroyed through structural failure, along with scans of the relevant pages from Morgan and Shacklady.

Not likely to happen, as you, and others, know so well.

Crumpp

08-04-2012, 12:05 AM

1567MkI produced/17 structural failures = 92

About the same as the Beechcraft Bonanza.......

No wonder the RAF wanted to solve the issue.

http://img37.imageshack.us/img37/1149/spitfireserials.jpg (http://imageshack.us/photo/my-images/37/spitfireserials.jpg/)

http://img33.imageshack.us/img33/5568/spitfireserials2.jpg (http://imageshack.us/photo/my-images/33/spitfireserials2.jpg/)

I just thought this one was very interesting.....

http://img838.imageshack.us/img838/6144/spitfireserial100octane.jpg (http://imageshack.us/photo/my-images/838/spitfireserial100octane.jpg/)

Crumpp

08-04-2012, 12:11 AM

X4268 went in July 41 to figure out why all the Early Mark Spitfire wings were breaking.

NZtyphoon

08-04-2012, 12:47 AM

1567MkI produced/17 structural failures = 92

About the same as the Beechcraft Bonanza.......

No wonder the RAF wanted to solve the issue.

Thanks for the scans.
Structural failure through what causes? You count dives as structural failure but this is not the same as structural failure through poor longitudinal stability - Henshaw notes that no aircraft could withstand a sudden dive while the aircraft was still trimmed to climb, or with a poorly fitted tailplane fairing shroud, nor do the bare listings say anything about the circumstances.

http://i91.photobucket.com/albums/k304/Major_Sharpe/Henshaw13-page-001a.jpg

Spitfire II Pilot's Notes on diving:

DIVING
21. The Maximum permissible diving speed is 450 m.p.h. A.S.I.
Note the following:

(iii) The aeroplane should be trimmed in the dive, i.e. the trimming tab control should be set to give no load on the elevator. This will lessen the possibility of excessive "g" being induced in easing out of the dive particularly if the pilot should ease his hold on the stick owing to "blacking out" or any other reasons. No difficulty in easing out of the dive will be experienced even if the aircraft is trimmed in the dive as the elevator control is comparatively light and recovery from the dive is not resisted by excessive stability in pitch. Elevator tabs may be used, very carefully, as in para. 14.

(Note Henshaw's comments on diving a correctly trimmed Mk V well beyond 450 mph.)

The Pilot's Notes don't warn about longitudinal stability in the dive, and before claiming they do, read the comments properly: They discuss imposing loads during aerobatics, part of which involves a dive. In rough weather it says the pilot could suddenly jerk the stick unless bracing his arm

http://i91.photobucket.com/albums/k304/Major_Sharpe/page12dh.jpg

The NACA report does not mention elevator control or longitudinal stability in the dive.

Ergo, structural failure in dives cannot be attributed to longitudinal instability, there could be all sorts of reasons for such failure to occur, including badly trimmed control surfaces.

So, omitting dive failures we have:

Mk Is less than 1 year old lost through structural failure in flight:

K9977 Ia 191 EA MII FF 16-5-39 602S 18-5-39 lost wing during aerobatics crashed Haddington CE Lothian 30-12-39 Sgt Bailey killed SOC 11-2-40

N3120 Ia 391 EA MIII FF 29-10-39 6MU 3-11-39 266S 20-1-40 broke up in test flight to alt Pilot Gleed thrown out crashed 14.40hrs Littleport Cambs 18-2-40 SOC 22-2-40

X4613 Ia 1233 EA MIII FF 15-10-40 6MU 15-10-40 ? 603S 17-10-40 266S 24-10-40 Lost wing and crashed Gedney Hill Lincs CE 2-3-41 SOC 20-3-41

R6692 Ia 746 EA MIII FF 3-6-40 6MU 5-6-40 609S 7-6-40 Overstressed attacking Ju88 CE 12-8-40 SOC 2-9-40

(R6692 was "overstressed" - without knowing how this occurred this cannot be attributed to poor longitudinal stability.)

Mk Is - older airframes on OTUs lost through structural failure in flight:

R6777 Ia 803 EA MIII FF 21-6-40 8MU 22-6-40 65S 12-7-40 C2 ops 30-7-40 GAL 616S 20-8-40 72S 2-9-40 92S 3-11-40 145S 4-2-41 AFDU 6-3-41 152S 13-3-41 SF H 10-4-41 57OTU 4-8-41 61OTU 3-1-42 Broke up in air and crashed Blackbill Glam FAC3 8-7-42

R6882 Ia 840 EA MIII FF 1-7-40 (CMG) 6MU Brize Norton 28-7-40 cannon wing fitt 7OTU 3-9-40 AFDU Duxford 11-1-41 R-RH 10-2-41 Cv Vb M45 92S 'QJ-N' 9-3-41 609S 30-8-41 Broke up in air and abandoned 2.5m NE of East Stoke Notts FACE 10-1-42 SOC 17-1-42

R7064 Ia 1431 EA MIII FF 5-2-41 9MU 6-2-41 411S 5-7-41 52OTU 23-11-41 struct damaged in spin crashed and hit fence nr Aston Down CE 25-3-42 SOC 3-4-42

X4234 Ia 1031 EA MIII FF 15-8-40 8MU 16-8-40 609S 24-8-40 damaged combat P/O Staples safe 27-9-40 AST 66S 13-10-40 57OTU 1-11-40 FACB 27-6-42 ros wing fail in spin crashed Alsager Cheshire CE 25-9-42

X4854 Ia 1351 EA MIII FF 14-12-40 MU 16-12-42 53OTU into sea nr Dunraven Castle Thought struct fail of stbd wing 2-1-43

Three failures before early 1941 which might be attributed to longitudinal instability, plus 5 older airframes four of which were on OTUs - who knows what stresses and strains these older aircraft went through before ending up in the hands of trainee pilots?

Al Schlageter

08-04-2012, 12:53 AM

Ergo, structural failure in dives cannot be attributed to longitudinal instability.

Sure you can NZ if that is what your agenda is.;);) It doesn't matter even if the a/c was exceeding it dive limit speed.

MiG-3U

08-04-2012, 04:56 AM

Again, the failures were notable enough for the RAF to send the plane to be tested to discover why the wings were failing in August of 1940.
...

It was serious enough that X4228 went to Farnborough on 24-8-40 to be used in testing to discover the cause of wing structure failures.

Hm... so it was the X4268 which went to Farnborough for aileron testing Aug 40, the tests for wing failures were July 41.

Interesting interpretation :)

Glider

08-04-2012, 06:19 AM

First of all, credit where its due, Crump has produced the copies with details and for that I thank him.

So we have 4 losses in the front line which are obviously caused by something.
One of these made it home and was probably a bent wing as the aircraft is designated as overstressed. I don't see any other examples so there is no case for saying that this was a significant problem.
The otthers we do not know the details of but the reasons could be many. This is far from proving that the Spit structural limits were easily reached.

What I also find interesting is that none seem to have been lost to spinning which rules that out as a weakness

NZtyphoon

08-04-2012, 06:22 AM

Hm... so it was the X4268 which went to Farnborough for aileron testing Aug 40, the tests for wing failures were July 41.

Interesting interpretation :)

This is clearer http://www.spitfires.ukf.net/p014.htm

X4268 Ia 1066 EA MIII FF 24-8-40 AMDP VA 24-8-40 RAE 9-40 aileron trials pilot J Quill. RAE 7-41 flight measurements of wing internal pressure for invest into struct fail of Spit wings. returned VAWD for continuation of trials.
ASTH for flaps mods. CRD AAEE 8-9-41 M45 install. Strengthened flaps tested as air brakes. 18-10-41 trials with thermostatically operated rad shutter ros VA 18-10-41 CRD DeH 23-11-41 39MU 18-2-42 3SGR 10-3-42 CF PRU engine failed wheels up landing nr Weeton Lancs CE 21-4-42 SOC 30-4-42

Opinions of an aerodynamicist:
http://i91.photobucket.com/albums/k304/Major_Sharpe/Morgan1a.jpg
http://i91.photobucket.com/albums/k304/Major_Sharpe/Morgan2a.jpg
http://i91.photobucket.com/albums/k304/Major_Sharpe/Morgan3a.jpg

No mention of longitudinal instability being a problem...
and an accident inspector:

http://i91.photobucket.com/albums/k304/Major_Sharpe/Newton1a.jpg
http://i91.photobucket.com/albums/k304/Major_Sharpe/Newton2a.jpg
http://i91.photobucket.com/albums/k304/Major_Sharpe/Newton3a.jpg

http://i91.photobucket.com/albums/k304/Major_Sharpe/Newton4a.jpg (X4421 Ia 1138 EA MIII FF 12-9-40 8MU 13-9-40 66S 16-9-40 57OTU 21-10-40 steep dive from low cloud violent pull out high speed stall spun wing fail Pilot thrown clear but killed 15.15hrs crashed Northrop Flints 27-3-41 SOC cancel RAE 8-4-41 AST 13-5-41 rebuilt as Va M45 164S 29-4-42 FACE 18-8-42 (Rebuild suspect) )

One of the major causes - aileron instability caused by stretching cable - again no mention of longitudinal instability.

robtek

08-04-2012, 08:49 AM

bongodriver

08-04-2012, 08:59 AM

Isn't the instability the fact that the Spitfire tightens its turn by itself without further control input???
The pilot has to stabilize the plane by countersteering.
Like a rear wheel driven car in a power slide around a turn, working, but stable is different.

It's not an effect that has ever got much mention, pilots are often quite candid about the quirks of aircraft they fly, and this thread is the first place I ever heard of it, it may have happened under certain conditions but I don't think it was a common feature of Spitfire handling.

robtek

08-04-2012, 09:15 AM

Still the "pro Spitfire faction" is trying to push the dispute to a black and white scenario and concentrate to steer the thread to sections where they believe to have valid counter-documentation.

The truth is always grey!

Undisputed should still be the sensitivity and lightness of the longitudal control of the Spitfire.

Also proven is the fact that the longitudal control isn't stable, as it increases the g-load without further pilot input.

Those things should be implemented in game.

If now a player pulls his joystick all the way back in a cruise speed turn, the plane should react accordingly as the resulting g-forces would be way above the structural limits.

The player should be forced to use a small input to initialisize the turn and the to almost neutralize the controls to hold that turn, as the pilots had to to in RL.

In a tightening turn there should be signals (i.e. vibrations) to indicate the beginning of the pre stall buffet, followed by shaking and the loss of energy and increasing turn radius when the turn is further tightened and the buffet is fully entered.

Further tighteneing the turn should lead to a flick-roll.

The disharmony between ailerons and elevators should also be there.

Imo that is a summary that should please any rational view on this thread.

Crumpp

08-04-2012, 09:20 AM

No mention of longitudinal instability being a problem...
and an accident inspector:

:rolleyes:

Really? It was the second major problem he mentions out of the 68 structural failures.

Isn't the instability the fact that the Spitfire tightens its turn by itself without further control input???
The pilot has to stabilize the plane by countersteering.
Like a rear wheel driven car in a power slide around a turn, working, but stable is different.
Today 02:22 AM

Correct. You have to apply a push force when should be applying a pull force. It is called a force reversal.

So a small input becomes an ever increasing acceleration until arrested by a push force. It is a symptom of the instability.

This is a measured by the NACA and a function of the divergent oscillation stick free measured by the RAE.

At high speed, the aircraft acceleration can overcome the airframe's limits to destruction.

Crumpp

08-04-2012, 09:22 AM

bongodriver

08-04-2012, 09:37 AM

Just need to bear in mind that the effects being called for are 'not' conducive to qualities noted for being 'easy to fly', so how do we meet half way on this? how are we going to recreate an alleged instability in an aircraft but retain the ease of flying qualities? or are we really saying that one NACA report on a MkV Spitfire outweighs the accounts of every Spitfire pilot of any Marque that ever lived?

When are we getting the 109 thread?

NZtyphoon

08-04-2012, 09:53 AM

:rolleyes:

Really? It was the second major problem he mentions out of the 68 structural failures.

Wrong: 20 case of pilots losing control in cloud, 13 structural failures due to oxygen starvation, three due to pilot black-out - in none of these cases is longitudinal instability mentioned as a major or causative factor.

Still the "pro Spitfire faction" is trying to push the dispute to a black and white scenario and concentrate to steer the thread to sections where they believe to have valid counter-documentation.

The truth is always grey!

The anti-Spitfire, bad longitudinal instability faction can only see a cloudy, murky-grey, glass half empty scenario where there is no clear evidence that longitudinal instability actually caused in flight structural failure and they don't like valid black and white documentary evidence being posted to show how doubtful their case is. :rolleyes:

Crumpp

08-04-2012, 09:54 AM

When are we getting the 109 thread?

You guys want to do the Bf-109 next?

I was going to do the Hurricane next.

Crumpp

08-04-2012, 10:01 AM

The anti-Spitfire, bad longitudinal instability faction can only see a cloudy, murky-grey, glass half empty scenario where there is no clear evidence that longitudinal instability actually caused in flight structural failure and they don't like black and white evidence being posted to show how doubtful their case is.

But it is not that way.

First, the anti-Spitfire faction exist's only in your mind.

Second, anybody who knows stability and control can read the article to see the characteristics clearly.

The gentleman who was interviewed for the article points out the fact they did not have a good understanding of stability and control engineering at the time.

The article is most interesting because it shows the thought process of the day and not for its engineering conclusions.

You however, take those engineering conclusions as proof. By that thinking, we should be doing meta-center calculations to prove the airplane was stable!!

:grin:

bongodriver

08-04-2012, 10:05 AM

You guys want to do the Bf-109 next?

I was going to do the Hurricane next.

Why didn't you start threads concurrently?

NZtyphoon

08-04-2012, 10:29 AM

But it is not that way.

First, the anti-Spitfire faction exist's only in your mind.

That's reassuring - you all can stop the "pro-Spitfire faction" nonsense then.

Second, anybody who knows stability and control can read the article to see the characteristics clearly.

You mean poor longitudinal stability? By all means point it out to the ignoramus' surrounding you.

The gentleman who was interviewed for the article points out the fact they did not have a good understanding of stability and control engineering at the time.

What he does point out is that it was extremely difficult visualising the type of combat likely to be faced in a future war - he does not point "out the fact they did not have a good understanding of stability and control engineering at the time."

Jeffrey Quill Supermarine Chief test Pilot:
http://i91.photobucket.com/albums/k304/Major_Sharpe/Quill2-001.jpg

http://i91.photobucket.com/albums/k304/Major_Sharpe/Quill3-001.jpg

The bob weights introduced in 1942:

http://i91.photobucket.com/albums/k304/Major_Sharpe/Quill3-002.jpg
http://i91.photobucket.com/albums/k304/Major_Sharpe/Quill4a.jpg
http://i91.photobucket.com/albums/k304/Major_Sharpe/Quill5-003.jpg

No stability problems Mk I & II, although borderline; Spitfire Vs incorrectly loaded at a squadron level in 1942, so bob-weights fitted in a "crash" (sic!) program before elevators modified with a larger mass balance.

Glider

08-04-2012, 12:33 PM

Crump

Before you start everything I would much prefer it if you used a more complete and modern set of standards for the calculations.

The most recent ones that I had any dealings with were

MIL - STD - 1797A

The fundamental problem that I believe you have, is that something is either stable or unstable. These standards give levels of accaptable stability for different types of combat aircraft. For instance you would expect what is acceptable for a C17 to differ from an F15 or you end up with an F15 which is a sitting duck or a lot of airsick troops in the C17.

I last used these in the late 1980's and there is a better than average chance that they may have changed in that time, so you may want to look into it.

However to carry on with the black and white process that you have is foolish and totally out of kilter with the real world. In the real world its a mixture of theory your preferred approach, how they actually feel to fly which is my approach, plus what are they desinged to do. These are normally combined and we used to refer to the flying qualities.

If I go back to the three gliders I mentioned an age ago.
The Twin Astir was very heavy and as far as aerobatics was only really good in the vertical, but it was excellent for training people to go cross country as it had less need to thermal but was fast.
The K21 was a much better all round glider good at most aerobatics and for training. However it was almost impossible to spin, a major problem in a trainer. So much so we use an old K13 for Spin Training which I loved to fly. The K21 was also good for training all types of flying thermalling and cross country
The Fox was a dedicated aerobatic machine. You certainly didn't want to go cross country or thermal but if you wanted to learn the fine points of aerobatics, this was the machine to use. Excellent roll rate for a glider and very precise in the control.

All design is a balance and as I write this the BOB Lancaster and a Spit have just flown very low over my house at about 5-700 ft

Back to the topic the term we use is the flying quality of the machine, which has to take in the task in mind, how it feels and the theory. These standards cover this combination
The

6S.Manu

08-04-2012, 01:02 PM

I do consider myself to be an amature historian, which is why I always have some substance behind my theory and statement. It may not be everything everyone want but there is something.

"Some substance" is not a fact. "Researching for the detail and mandatory verification of the source are the primary rules of an historian", it's been said by one of my friends (historian).

Until there're unanswered questions then there's no fact. If have the right to doubt of it if it's not clear and so I ask you for detail.

Can I? Or I have been labled as naysayer? Or a Blue pilot who want to pork the Spitfire?
Don't worry... when we'll be talking about the 109 I'll post questions about that too if the "fact" are not detailed.

Please focus on the fact that I questioned also the pilots' experience and the airplane's conditions during the RAF mockfight.

I don't know your opionion about that, but it state that some pilots were not using the plane at it's full performance because they were afraid.

Now why should them be afraid if the plane was easy to fly? Could it be that those planes where not good as the others, or maybe the plane has a characteristic that they wanted to avoid. The author seems to claim the latter, but he says "probably" (IIRC)...

Of course the poster who want to picture they favourite plane as the better had claimed that the pilot's on the 109 was high skilled (and I can't doubt it, by logic) and the outturned ones were worser... Now please tell me why I'm the bad guy formaking questions while the "it's so because I tell it" guys are the good one?

As opinion the one about "easy to fly" means that it was easy to take in combat... no proof about that but people, you too, keep claiming it as gospel truth.
This "can" easily be the reason of that statement: http://www.bbc.co.uk/news/uk-11004370

So many extreme manouvres... note that I've written "can"... it's a theory but not less meaningful as the "easy to take in combat" one.

Lets take the example of the bending of the wings. Crumps says this happened a lot and there were piles of wings to be repaired. My belief is that this happened in late 1944 when Spitfires were being used for tassks way beyond what they were designed for. I produced two different sources both of which are very clear and invite Crumpp to supply his evidence that this happened in the BOB. Result silence.

I've not the responsibility of that claim, why should I find a source?

Anyway you keep missing the point: it's not "how many times it happened", it's "if it can happen".

Do I need a document to state that in most of the fights the victim was unaware of the enemy? Many reports seem to prove it. Of course we'll never have the right number but using "logic" we can define that most of the time the pilots didn't use their plane at its structural limits.

Now I ask to you: do you think they fought as the players are used to do in this sim?

Take the doc about the mock fight in which some RAF pilots could not outturn the 109 becouse of the fear to spin. Now reproduce the same mock fight in sim: experience makes me say that an average pilot (one who actually understood the limits of the plane) will always outturn the 109.

In this sim most pilots fly as there is no tomorrow (since they are allowed to do it, as to fly at 7km with the open cockpit): logically they do critical manouvres far more than the real pilots, so the issue of a plane has to be more evident...

So do you see why I claim that your document (Mr.Newton's interview) is not helpful here? First it's incomplete since it's the number of reported accidents, not all the accidents

Its more than you have put forward. You have a theory but nothing behind it

Ah! It's called intellectual honesty!

You posted that interview claiming this: "To get a feel for how fragile the SPitfire was the following is a posting I found which breaks the losses bytype. Remembering that 20,000+ Spts were built during WW2 the numbers are pretty low".

You were stating that only 46 spitifires were lost for structural failure on more than 22000!!!

Not knowing if the accidents over the sea were to be investigated by the AAIB (as I honestly and correctly asked), but it's easy to think they weren't (as other thinks it's a logic thing)... so 46 on 22000 is not an attendible number, while you stated it was the true one.

This is the reason I posted that it as small sample of the total Spitfire lost. And I remain with this convinction.

Possible but very unlikely. The reports are procduced during the war, the book many years later.

And on what are based the books? Does the author invent the numbers or he did a research for documents like we do?

You stated that 2 books reported the same numbers for which reason? Nobody here claimed you to be a liar, you had not to defend yourself.

If the source is about a small sample of accidents (as this one) or unattendible (and this's not the case) you can report it in 20 books... it remains about a small sample of accidents.

Why did you not quoted the part about the different numbers on the other book?
I report it again: "3 books: one has different numbers... Which ones are the corrected numbers?"

Can you answer? Do you still claim the 46/22000?

I hope you can anwser, or I start thinking that you can be one of those amatour historian (luckly) expert on spreading disinformation bacause of a personale agenda: I hope you are not, at first you impressed me as an nice honest guy.

There is no way they can know for certainty as to what happened in some cases over german held areas. However you accuse them of ignoring accidents which is insulting and you do it without evidence which compounds the insult.
You are also factually wrong. The vast majority of Typhoon losses due to the loss of the tail happened over Germany areas but this wasn't ignored. The pilots were aware of what was going on, it was reported and the issue was addressed. To pretend that Spits breaking up would be ignored is clearly wrong and without evidence again insulting.
You may well question my approach to historical facts but I would never, ever, say such a thing without something to support what I said.
I await your supporting evidence with some interest, note evidence not theory. It shouldn't be difficult as you believe it happended so often finding an unexplained loss that was put forward and then ignored should be straight forward.

Accusing what? I only asked if those accidents were ignored by the AAIB (not reported to them by the RAF).. some other posters honestly claimed that it's very probable that those accidents were not reported to AAIB since without wreckage were could not be an investigation.
I asked for it before and you, as the claimer of the AAIB's 46/22000 should have given an answer, researching instead of quoting a text without asking yourself the accuracy of the data (not on AAIB reported accidents, but on all the entire picture of the Spitfire lost in an accident).

Insulting? I'm starting to losing my patience with these accusations... please, Glider, remove them.

Did the Typhoon's issue have been reported to the AAIB? Do you know it? Where's the evidence?
I honestly asked if the wreckages were necessary to the AAIB: nobody said "yes, look at this document". So, until then, it's really probably that Typhoon's issue oversea were not investigated by the AAIB.

I'm questioning your evidences, I've not to prove anything that I've not questioned before. I'm playing the devil's advocate.

If you want that then I suggest you go and look for it. Of course you can have a theory but a theory it remains unless and until you can support it. The AAAIB can only look at things that are referred to them, it always was and should always be that any unexplained accident should be reported to them. You forget that its in the interest of the pilots and crew to report these incidents as their lives are on the line

I don't forget anything!... I asked for it before BECAUSE OF this matter!

Its not a small sample it all the incidents that were reported to them. If you believe that there were others that were ignored then support that statement. Again without evidence its a theory without support

I've never stated it.. please don't turn around putting words in my mouth. I've never

I'm claiming that it's a small sample compared to all the Spitfires lost for accident during the WW2 since all the things covered before. I'm not the one who claimed the 46/22000

The only real insulting thing it's you asking for evidence to the others when they actually question yours.
I don't have to proof anything, it's you who has to answer.

Yours it's a nice way to support facts: "if I have a little evidence than it's as I say".

Or is that pilot reports, test pilot reports, test establishments reports and official accidents reports that are to be ignored because they are inconvenient?

As I said before you miss the point of the thread... sure reports are usefull to understand some issues, but the clear evidences of that issues are more difficult to be found since those pilots have care of their life and it's not really probable that they flew in the way most of IL2's players do.

Look, before the implementation of the structural damage in IL2 1946 I used to dive at 900km/h pulling up very sharply... It's irrealistic and I'm happy that DT developed this feature.

It's so wrong to have also the elevator sensibility as an plane's issue as clearly warned in the pilot's note?

I don't hear Crumpp, yourself or anyone else demanding that the Spitfire be easy to land, easy to take off, be faultless in a turn and always turning inside the Me109 as did the German pilots and test establishments or are you in favour of such realistic factors

And here we go with the accusation of be Pro-Blue and Anti-Red!!! Good job! Glider, I thought you were different... In this message board it's impossible to be objective.

It so sad that many fans have to be always the ones against the others...

Your question: IMO the Spitfire landing is good as is it since ALL the plane in IL2 are easy to land.

Do I want a 109 difficult to land? As I stated before, many times, in other threads, I DO!!!
As I do a 190 that flips for a the accellerated stall...

Have I to put it under my sig?

MiG-3U

08-04-2012, 01:19 PM

Isn't the instability the fact that the Spitfire tightens its turn by itself without further control input???

So you mean that all the early Spitfire's had the control reversal at turn?

And do you mean that longitudinally instable aircraft has also the control reversal?

The problem here is that you extend a phenomena found on the worst case for all the early Spitfires.

MiG-3U

08-04-2012, 01:35 PM

Can I? Or I have been labled as naysayer? Or a Blue pilot who want to pork the Spitfire?

Well, as you seem to be so productive text wise today, could you explain me why it's only the blue side who want's to model the longitudal stability and elevator control after the worst case scenario (Rotol propeller and the CoG beyond the limits) for all the early Spitfire's?

Please focus on the fact that I questioned also the pilots' experience and the airplane's conditions during the RAF mockfight.

Very good! However, you should apply same standards to all the data, including the NACA tests, and particularly to anonymous internet sources who change their arguments all the time...

Glider

08-04-2012, 02:19 PM

"Some substance" is not a fact. "Researching for the detail and mandatory verification of the source are the primary rules of an historian", it's been said by one of my friends (historian).

I totally agree with your friend. Ask him what he thinks about theories that have no support, I am confident that he will consider it a theory no more and no less.

Until there're unanswered questions then there's no fact. If have the right to doubt of it if it's not clear and so I ask you for detail.
There is a difference between a question that can be dealt with and one that cannot. Going back to your starting point "Researching for the detail and mandatory verification of the source are the primary rules of an historian", it's been said by one of my friends (historian).
You have the question, you do the research, then and only then do you have a position until then its a question.
Lets use an example. You implied that accidents were being ignored, you said it without any supporting evidence and I consider it to be an insult to those involved and its something that I would never say without serious research. I suggest you ask your friend about my approach and see what he says.

You also implied that other organisations might have investigated accidents. Again its a theory one that has no evidence behind it. As far as I am aware there is no other organisation so its a theory no more and no less. If you think there was another organisation then I suggest you look for it.

On both of these points if there is some evidence behind your position then I will spend as long as it takes to find the true position.

Can I? Or I have been labled as naysayer? Or a Blue pilot who want to pork the Spitfire?
Don't worry... when we'll be talking about the 109 I'll post questions about that too if the "fact" are not detailed.

I look forward to that. Its also worth noting that on the Me109 vs Spitfire thread my choice for the BOB period was the Me109 so don't put me into the pro Spit camp either

Please focus on the fact that I questioned also the pilots' experience and the airplane's conditions during the RAF mockfight.

I don't know your opionion about that, but it state that some pilots were not using the plane at it's full performance because they were afraid.

Now why should them be afraid if the plane was easy to fly? Could it be that those planes where not good as the others, or maybe the plane has a characteristic that they wanted to avoid. The author seems to claim the latter, but he says "probably" (IIRC)...

Some pilots in the front line were probably afraid as they could well be inexperienced, flying a high performance aircraft they may have had as little as 10 hours in, against superior numbers, with in the opposing Me109 a fighter every bit as good as the plane they were flying in.
Those in the test are very interesting and expose the difference between being experienced and skilled. Those nervous were probably experienced those not were skilled. Taking the aircraft to the edge is difficult and demands confidence and skill, they lacked the confidence. All airforces had similar issues, in the Me109 the majority of pilots would not take the turn past the deployment of the leading edge flaps. This is a personal view but its in this area where I believe the RAF lost out by not having a two seat SPit for training. If you have someone in the cockpit who takes you to the edge and shows you that it is safe, what the warning signs are you can grasp it easily. Without it finding the edge is a nervous moment.
Gliders handle in many ways in a similar manner to ww2 fighter. We have buffet as the warning before the stall, the high speed stall and the spinning of different types. The first time you show someone how to spin or the high speed stall they are normally scared to death. Once they get used to the feeling some will do it frequently, its a buzz.

The skilled pilot will always get that extra 5/10% out of the aircraft. I used the example of the Zero and the Hellcat. Most would agree that overall the Hellcat is the better fighter but if S Sakai was in the Zero how would you rate your chances?

Of course the poster who want to picture they favourite plane as the better had claimed that the pilot's on the 109 was high skilled (and I can't doubt it, by logic) and the outturned ones were worser... Now please tell me why I'm the bad guy formaking questions while the "it's so because I tell it" guys are the good one?

TheGerman Test Establishent were very clear in their advice to German pilots. Do not enter a turning fight with the Spitfire or Hurricane. They would not have had a pro RAF stance.

Anyway you keep missing the point: it's not "how many times it happened", it's "if it can happen".

This is where we differ. There is an old saying, if it can happen it will. If its easy to reach the limit and crash then the limit will be reached and planes will crash. However the planes didn't crash in any numbers.

Now I ask to you: do you think they fought as the players are used to do in this sim?

Take the doc about the mock fight in which some RAF pilots could not outturn the 109 becouse of the fear to spin. Now reproduce the same mock fight in sim: experience makes me say that an average pilot (one who actually understood the limits of the plane) will always outturn the 109.

Agree

In this sim most pilots fly as there is no tomorrow (since they are allowed to do it, as to fly at 7km with the open cockpit): logically they do critical manouvres far more than the real pilots, so the issue of a plane has to be more evident...

Agree if applied to all aircraft types

So do you see why I claim that your document (Mr.Newton's interview) is not helpful here? First it's incomplete since it's the number of reported accidents, not all the accidents

It is as complete as it can be. No doubt the german authorities had a simiar accident investigation team and they would have similar limitations.

Its more than you have put forward. You have a theory but nothing behind it
[quote]
Ah! It's called intellectual honesty!

You posted that interview claiming this: "To get a feel for how fragile the SPitfire was the following is a posting I found which breaks the losses bytype. Remembering that 20,000+ Spts were built during WW2 the numbers are pretty low".

You were stating that only 46 spitifires were lost for structural failure on more than 22000!!!

Not knowing if the accidents over the sea were to be investigated by the AAIB (as I honestly and correctly asked), but it's easy to think they weren't (as other thinks it's a logic thing)... so 46 on 22000 is not an attendible number, while you stated it was the true one.

It is as good a number as it can be. I stand by the numbers as an indication that they are very low for this type of aircraft. I notice that no one has disagreed with this statement.
No one has any idea as to how many were lost away from the home areas due to structural issues but this is a statement of fact, not a conspiracy theory.

This is the reason I posted that it as small sample of the total Spitfire lost. And I remain with this convinction.

fine

[QUOTE=Glider;451098]
Possible but very unlikely. The reports are procduced during the war, the book many years later.
[quote]
And on what are based the books? Does the author invent the numbers or he did a research for documents like we do?

He was the investigating engineer at the time, his reports obviously would have been done as the incidents were reported. The M S book was produced years later on an aircraft by aircraft basis, I don't see how one could be based on the other.

If the source is about a small sample of accidents (as this one) or unattendible (and this's not the case) you can report it in 20 books... it remains about a small sample of accidents.

No this is all the accidents that were reported to the team. A small sample implies that others were ignored and there is no evidence to support that theory.

Can you answer? Do you still claim the 46/22000?

I hope you can anwser, or I start thinking that you can be one of those amatour historian (luckly) expert on spreading disinformation bacause of a personale agenda: I hope you are not, at first you impressed me as an nice honest guy.

There is no other basis for showing a ratio. We do not know how many were lost due to structural losses over the sea or enemy areas. Clearly some would have been but we will never know. Comparing what we know against production is an imperfect ratio. However it is one that we should be able to replicate on other aircraft types and is the only valid approach that I can think of. If you have a better idea then I will take it.

PS I am a nice honest guy

[Accusing what? I only asked if those accidents were ignored by the AAIB (not reported to them by the RAF).. some other posters honestly claimed that it's very probable that those accidents were not reported to AAIB since without wreckage were could not be an investigation.
I asked for it before and you, as the claimer of the AAIB's 46/22000 should have given an answer, researching instead of quoting a text without asking yourself the accuracy of the data (not on AAIB reported accidents, but on all the entire picture of the Spitfire lost in an accident).

Insulting? I'm starting to losing my patience with these accusations... please, Glider, remove them.

I apologise for any insult totally. I am touchy about people who imply that accidents are ignored by the investigating bodies. My son is a safety Inspector in nuclear establishments and I spent some time in the RN accident Investigation team (only basically as the coffee maker) but I saw how seriously these people take their tasks. There is no evidence that accidents were ignored that I am aware of.

Did the Typhoon's issue have been reported to the AAIB? Do you know it? Where's the evidence?
I honestly asked if the wreckages were necessary to the AAIB: nobody said "yes, look at this document". So, until then, it's really probably that Typhoon's issue oversea were not investigated by the AAIB.

I'm questioning your evidences, I've not to prove anything that I've not questioned before. I'm playing the devil's advocate.

Yes the Typhoon issues were reported and it took a lot of time to find a solution. Wreckage helps and its only fair to add that I was wrong, most happened over the UK.
There were cases where there was little wreckage but tests were still undertaken to try and repeat the situation to find a cause. Probably the best example I can think of was the Halifax. It took some time to identify and sort out its problems re spinning. Most happened on missions and obviously there was little to go on

Yours it's a nice way to support facts: "if I have a little evidence than it's as I say".

Nope I always have something to support a case and its not, because I say so.

It's so wrong to have also the elevator sensibility as an plane's issue as clearly warned in the pilot's note?

Pilots notes are there to warn the pilot and err on the side of caution. Good example is the spinning. Early Spit pilots notes banned spinning but did tell the pilot that the plane would recover normally. Later ones allowed spinning but with permission from a senior officer.
The Spit could spin and would recover but they didn't want to see pilots putting planes at risk.
The P47 pilots notes say that you cannot do more than 1/2 a turn when spinning (not my definition of a spin I admit) but again it could spin more than that and recover.
This carried on after the war and probably continues. The Hunter T8 pilots notes say that spinning is banned period, but I have recovered from a couple of spins in one. In reality the Hunter spins and recovers normally as long as you recover in the first two turns. After that is oscillates, you can get disorientated and its time to leave

And here we go with the accusation of be Pro-Blue and Anti-Red!!! Good job! Glider, I thought you were different... In this message board it's impossible to be objective.
Its quite possible to be objective and we covered the pro anti bit earlier.

Have I to put it under my sig?
nicely

6S.Manu

08-04-2012, 02:31 PM

Well, as you seem to be so productive text wise today, could you explain me why it's only the blue side who want's to model the longitudal stability and elevator control after the worst case scenario (Rotol propeller and the CoG beyond the limits) for all the early Spitfire's?

If you provide a method to identificate which poster are part of the "blue side" I could give a partial answer: but I don't think it's true that only the blue want this feature modelled. I think to some friends used to fly Spitfire who could actually welcome this feature in name of the realism.

Anyway it's not a smart question: "why only the blue side want the the feature modelled?" can easily become "why only the red side don't want the feature modelled?"

We should leave away this Red vs Blue thing...

Very good! However, you should apply same standards to all the data, including the NACA tests, and particularly to anonymous internet sources who change their arguments all the time...
Do you mean that the test in the first post is not real? I know there are some posters able to find the source in few time (NZthypoon is surprising ;-) ) so if it was a false document it could be easily unmasked.

:-)

bongodriver

08-04-2012, 02:41 PM

Do you mean that the test in the first post is not real? I know there are some posters able to find the source in few time (NZthypoon is surprising :wink: ) so if it was a false document it could be easily unmasked.

No, he is saying you should treat 'all' the evidence the same, are you saying everyone elses evidence is a lie?

NZtyphoon

08-04-2012, 03:07 PM

Do you mean that the test in the first post is not real? I know there are some posters able to find the source in few time (NZthypoon is surprising ;-) ) so if it was a false document it could be easily unmasked.

The reason I can find documentation so quickly is because I know how and where to look. I enjoy ferreting around in books, archives etc - unlike some of my contemporaries. :grin:

6S.Manu

08-04-2012, 03:23 PM

No, he is saying you should treat 'all' the evidence the same, are you saying everyone elses evidence is a lie?
No... There is a ton of documents in this thread... I don't think to have questioned them all. :-|

Unmask away - the reason I can find documentation so quickly is because I know how and where to look: if that's a problem with you I can't help that.
Mine was a compliment.
OT: BTW Can I ask if you know a source for the RR Merlin family? I'm trying to develop a framework about engines and I'm interested to have some data.

I'm not asking you to do my work: I need only a clue about a website or a book. Thanks!

Igo kyu

08-04-2012, 04:03 PM

I totally agree with your friend. Ask him what he thinks about theories that have no support, I am confident that he will consider it a theory no more and no less.
No it's not. It is a hypothesis, which is the early stage of a theory.

Glider

08-04-2012, 06:41 PM

No it's not. It is a hypothesis, which is the early stage of a theory.

point taken

MiG-3U

08-04-2012, 09:13 PM

If you provide a method to identificate which poster are part of the "blue side"...

Well, I see blue side planes on the signatures, is that a poor indicator? Sorry if you feel offended.

Anyway it's not a smart question: "why only the blue side want the the feature modelled?" can easily become "why only the red side don't want the feature modelled?"

Actually I'm asking why you, regardless your color, are demanding that the longitudal stability and elevator control of the early Spitfire's after the worst case scenario?

The worst case scenario means here a Rotol propeller and CoG behind the aft limit for that configuration, like in the NACA tested Spitfire.

Note that typical pre war or BoB service CoG for a Spitfire with DeHavilland propeller ok even for the Spitfires flying today. Actually even the CoG NACA used for a Rotol propelled variant is ok with the DeHavilland prop... but not with the Rotol prop.

And the manual containing control reversal warnings is for the Rotol propelled variant.

Do you mean that the test in the first post is not real?

Of course it's real but if you question pilots comments, you should also apply the same standard for all the data, including that report:

1. They did not know the CoG for military load.
2. They tested just one CoG position.
3. The CoG they used, 31.4" behind leading edge at the root is 7.8" aft datum. The rear limit for the same configuration is 7.5".

No... There is a ton of documents in this thread... I don't think to have questioned them all. :-|

Actually you should, and more precisely, put things on right contex. Yes, there is plenty of documentation posted, including critics on NACA test (even wartime critics by RAE).

Crumpp

08-04-2012, 09:42 PM

They did not know the CoG for military load.
2. They tested just one CoG position.
3. The CoG they used, 31.4" behind leading edge at the root is 7.8" aft datum. The rear limit for the same configuration is 7.5".

:rolleyes:

31.4%....MAC

ATAG_Dutch

08-04-2012, 11:25 PM

:rolleyes:

Crumpp

08-04-2012, 11:28 PM

The worst case scenario means here a Rotol propeller and CoG behind the aft limit for that configuration, like in the NACA tested Spitfire.

:rolleyes:

Fixed Pitch Wooden Airscrew

Longitudinally, the aircraft is stable with centre of gravity forward, but is unstable with centre of gravity normal and aft with engine 'OFF' and 'ON'. Longitudinal stability records are attached.

http://www.spitfireperformance.com/k9787-fuel.html

Crumpp

08-04-2012, 11:38 PM

Note that typical pre war or BoB service CoG for a Spitfire with DeHavilland propeller ok even for the Spitfires flying today.

Not with the longitudinal instability......

NZtyphoon

08-04-2012, 11:50 PM

Mine was a compliment.
OT: BTW Can I ask if you know a source for the RR Merlin family? I'm trying to develop a framework about engines and I'm interested to have some data.

I'm not asking you to do my work: I need only a clue about a website or a book. Thanks!

No problems: a reasonable starting point can be found on this site:
http://www.spitfireart.com/merlin_engines.html

Some valuable articles can be downloaded from Flight Global:
eg: http://www.flightglobal.com/pdfarchive/view/1942/1942 - 0449.html
http://www.flightglobal.com/pdfarchive/view/1942/1942 - 2609.html
or
http://www.flightglobal.com/pdfarchive/view/1946/1946%20-%200164.html

or for the Griffon (http://www.flightglobal.com/pdfarchive/view/1945/1945%20-%201852.html)

You can download a Merlin 61 Maintenance Manual Here (via DepositFiles) (http://avaxhome.ws/ebooks/history_military/Rolls_Royce_Merlin_Two_stage_Two_Speed_Engine_Main tenance_Manual.html)

One really good source for books is the Rolls-Royce Heritage Trust (http://www.rolls-royce.com/about/heritage/publications/)

Hope this helps.

NZtyphoon

08-05-2012, 12:15 AM

The worst case scenario means here a Rotol propeller and CoG behind the aft limit for that configuration, like in the NACA tested Spitfire.

:rolleyes:
Instead of just being smart and making rolleyes how about proving, with documentation, that this statement is incorrect. Prove that you are not making a worst-case scenario out of just two documents: Prove that the Spitfire had such bad longitudinal stability characteristics that it affected its abilities in general flight and in combat and, above all PROVE that this can be replicated in a flight sim made for PCs.

Crumpp

08-05-2012, 12:36 AM

Instead of just being smart and making rolleyes how about proving, with documentation,

This is the second or third time in this same thread the same argument has arisen.

The instability existed in all early mark Spitfires at normal and aft CG until it was fixed with the inertial weights.

It is a function of the tail design and elevator, static margin, and fuselage length.

The Operating Notes are full of warnings about it. It was not limited to one propeller or a specific load.

It was at NORMAL and AFT cg.

NORMAL....

Noun: The usual, average, or typical state or condition.

Your whole premise of the Constant Speed Propellers being the "most adverse condition" is just plain wrong.

Which do you think is heavier? A three bladed CSP or a two blade fixed pitch wooden propeller? The correct answer is the CSP.

What do you think happens to the CG when you add weight to the front of the aircraft? Do you think it shifts forward or back?

NZtyphoon

08-05-2012, 12:56 AM

This is the second or third time in this same thread the same argument has arisen.

The instability existed in all early mark Spitfires at normal and aft CG until it was fixed with the inertial weights.

It is a function of the tail design and elevator, static margin, and fuselage length.

The Operating Notes are full of warnings about it. It was not limited to one propeller or a specific load.

Prove that you are not making a worst-case scenario out of just two documents: Prove - with documentation - that the Spitfire had such bad longitudinal stability characteristics that it affected its abilities in general flight and in combat and, above all PROVE that this can be replicated in a flight sim made for PCs.

Crumpp

08-05-2012, 12:57 AM

Here is a little experiment you can do at home, NzTyphoon.

Make a paper airplane. Toss it.....

See how stable it flys.

Now add a paperclip to the nose and throw it again.

Which is more stable?

Crumpp

08-05-2012, 01:00 AM

Prove - with documentation

ok

The Stability and control characteristics of the Early Mark Spitfires:

Now let's look at the Spitfire in an abrupt pull out as measured by the NACA.

http://img98.imageshack.us/img98/3200/spitfireabruptpullup.jpg (http://imageshack.us/photo/my-images/98/spitfireabruptpullup.jpg/)

First thing to notice is the stick forces. There are light but acceptable in abrupt pull outs. While very steep, the slope of the curve matches our acceleration curve and the controls float without overcoming the inherent stability of the design. The steepness of the curve tells us the pilot is able to very rapidly load the airframe. In fact, the NACA had to make allowance in their stick fixed measurements to prevent damage to the aircraft from acceleration because of the rapid onset the controls allowed.

However, if we look at the acceleration curve we see an abrupt change and not the desirable smooth curve. This points to the stability characteristics contributing to the rapid fluctuations in acceleration that the aircraft exhibits under other conditions.

Next we will get into the unacceptable longitudinal stability characteristics of the design.

We will look at a condition of flight essential to a dogfighter. The ability to make abrupt turns.

The pilot must be able to precisely control the amount of acceleration he loads on the aircraft. All aircraft performance depends on velocity. In order to get maximum performance out of the aircraft above maneuvering speed, Va, he needs to be able to make a 6 G turn and not exceed that load factor to prevent damage to the airframe. Below Va, the pilot needs to control the acceleration so that he does not stall the aircraft making the abrupt maneuver as well being able to maintain a maximum performance turn.

Doing that in an early Mark Spitfire was difficult and something only a skillful pilot could perform.

First the NACA report. Abrupt 180 degree turns were conducted at various entry speeds to gauge the level of control the pilot had in maintaining steady accelerations. The turns were also done to the stall point in order to gauge the behavior and amount of control.

"In turns at speeds high enough to prevent reaching maximum lift co-efficient" means turns above Va.

http://img404.imageshack.us/img404/2525/rapidturns.jpg (http://imageshack.us/photo/my-images/404/rapidturns.jpg/)

http://img513.imageshack.us/img513/6480/rapidturns2.jpg (http://imageshack.us/photo/my-images/513/rapidturns2.jpg/)

"By careful flying" a pilot can hold a steady acceleration. That agrees with the Operating Notes warning for the pilot to brace himself against the cockpit to get better control when making turns.

Now let's look at the measured results.

http://img843.imageshack.us/img843/6408/rapidturnfig15.jpg (http://imageshack.us/photo/my-images/843/rapidturnfig15.jpg/)

Here we see in a rapid left turn performed at 223 mph the test pilot is unable to hold constant acceleration on the airframe. Very small variations in stick movement and stick force changes of 1-3lbs results in large fluctuations in acceleration.

Taking two point we can compare the slope of the curves of stick input to acceleration over time.

For the intital pull up:

Acceleration over time 3.5G-(-.5G) divided by 4.5s-3.5s = m
m = 4

Stick force over time: (19lbs - 0lbs) divided 5lbs/G all divide by 4.5s-3.5s = m
m = 3.8

*The slopes should match and they are close enough.* +However, our stick force grows at a slower rate than our acceleration.+ This is the initial input of the pilot.

Now let's see the instability.

Stick force over time 15lbs-15lbs divided by 5lbs/G all divided by 6.8s-5.5s = m
m = 0

Of course m = 0, our stick is held fixed by the force measurement equipment

Acceleration over time 4.2G-3.2G divided by 6.8s-5.5s = m
m = .76

So, while our stick remains fixed, the aircraft continues to accelerate on its own. As the nature of instability, there is no correlation stick force input and acceleration.

Now, our pilot in this case only input force to reach 3.5G. In a stable airplane, we should see the aircraft dampen all subsequent accelerations which means the aircraft would not exceed 3.5G without control input.

In this case, the instability or divergent oscillation a 4.2G acceleration with stick fixed slightly below the stick force required to produce a 3.5G acceleration.

Next let's look at the pilots ability to control the accelerations in the pre-stall buffet.

http://img600.imageshack.us/img600/4313/stallbuffet.jpg (http://imageshack.us/photo/my-images/600/stallbuffet.jpg/)

Here we see the pilot was able to load the airframe to 5G's in 1 second to reach the pre-stall buffet 3 times. The smooth positive sloped portion of the curve represents the aircraft flying while accelerations are increasing. The top of the acceleration curve represents the pre-stall buffet. The bottom of the curve represents the stall point.

The amount of stick travel as measured by the NACA was not acceptable.

http://img94.imageshack.us/img94/2621/sticktravel.jpg (http://imageshack.us/photo/my-images/94/sticktravel.jpg/)

Next let's look at the opinion of Stability and Control Engineers on the Early Mark Spitfires.

http://img832.imageshack.us/img832/3063/twofamousairplanes.jpg (http://imageshack.us/photo/my-images/832/twofamousairplanes.jpg/)

http://img855.imageshack.us/img855/7210/twofamousairplanes2.jpg (http://imageshack.us/photo/my-images/855/twofamousairplanes2.jpg/)

http://img825.imageshack.us/img825/4462/twofamousairplanes3.jpg (http://imageshack.us/photo/my-images/825/twofamousairplanes3.jpg/)

http://img404.imageshack.us/img404/6078/skittishspitfire.jpg (http://imageshack.us/photo/my-images/404/skittishspitfire.jpg/)

There is no doubt that the Air Ministry was aware of the longitudinal instability of the early mark Spitfires.

Just some of the many references to the Longitudinal instability found in all of the early Mark Spitfires.

Spitfire Mk I Operating Notes, July 1940:

http://img109.imageshack.us/img109/7976/page10jv.jpg (http://imageshack.us/photo/my-images/109/page10jv.jpg/)

http://img26.imageshack.us/img26/2599/page12dh.jpg (http://imageshack.us/photo/my-images/26/page12dh.jpg/)

http://img542.imageshack.us/img542/9202/page13o.jpg (http://imageshack.us/photo/my-images/542/page13o.jpg/)

http://img607.imageshack.us/img607/2471/page15j.jpg (http://imageshack.us/photo/my-images/607/page15j.jpg/)

http://img651.imageshack.us/img651/2456/page16lu.jpg (http://imageshack.us/photo/my-images/651/page16lu.jpg/)

NZtyphoon

08-05-2012, 01:02 AM

Here is a little experiment you can do at home, NzTyphoon.

Make a paper airplane. Toss it.....

See how stable it flys.

Now add a paperclip to the nose and throw it again.

Which is more stable?

Go make your own paper aeroplanes: The NACA report concentrates on one aircraft which, in spite of your claims, may not have been correctly loaded:

http://i91.photobucket.com/albums/k304/Major_Sharpe/Quill4a.jpg

Tony had been test flying correctly loaded Mk Vs with us at Supermarine and he knew very well the difference between a stable and unstable aeroplane.

http://i91.photobucket.com/albums/k304/Major_Sharpe/Quill2-001.jpg
http://i91.photobucket.com/albums/k304/Major_Sharpe/Quill3-001.jpg

Supermarine's Chief test pilot knew more about flying the Spitfire and its capabilities and characteristics than NACA and took he took urgent action when he realised that there was a problem with badly loaded Mk Vs.

http://i91.photobucket.com/albums/k304/Major_Sharpe/Quill4.jpg

You can interpret documents any way you like - fact is that there are other valid opinions which show that longitudinal stability only became a real issue when the loading instructions were ignored or misunderstood at an operational level. As for the excerpts from your book the [stable] Hurricane, Typhoon and Tempest were highly manoeuverable and were greatly superior gun platforms to the skittish Spitfire.

This also falls down as a source because quite clearly some basic research is missing because both the typhoon and Tempest PNs state they were slightly unstable longitudinally, and only the Hurricane could turn inside the Spitfire... as for gun platform:

http://i91.photobucket.com/albums/k304/Major_Sharpe/Henshaw12-page-003c.jpg

The pilot's notes were read in conjunction with the Pilot's Notes General: Note that the PNG carry similar warnings to those in the Spitfire PNs see (ii) which applied to all aircraft
http://i91.photobucket.com/albums/k304/Major_Sharpe/PNG3a.jpg
http://i91.photobucket.com/albums/k304/Major_Sharpe/PNG4a.jpg

You have not demonstrated that you are not applying a worst-case interpretation to both the NACA flight trials and PNs.

Nor have you explained how you propose to alter the flight characteristics of a computer based flight sim to accurately replicate this so-called instability considering the plethora of different set-ups used by players.

MiG-3U

08-05-2012, 03:23 AM

Well, here we go again, the same stuff with flawed interpretation posted again and again.

Over and Out :)

Al Schlageter

08-05-2012, 03:54 AM

Well, here we go again, the same stuff with flawed interpretation posted again and again.

Over and Out :)

Just like the 100 octane threads.:( Why does myopic tunnel vision come to mind?

NZtyphoon

08-05-2012, 04:04 AM

Well, here we go again, the same stuff with flawed interpretation posted again and again.

Over and Out :)

At the very least putting a worst-case scenario on two documents while claiming that these alone are definitive proof of the Spitfire's bad longitudinal stability - when another NACA document on the Spitfire's stall characteristics was presented it was dismissed as being irrelevant:
http://i91.photobucket.com/albums/k304/Major_Sharpe/SpitfireVAStallCharacteristics-page-003a.jpg
http://i91.photobucket.com/albums/k304/Major_Sharpe/SpitfireVAStallCharacteristics-page-004a.jpg

It will be truly interesting to see how the proposed bug-tracker will define the "problem" and how it proposes to alter the Spitfire's flight characteristics to cater for a flight sim in which different equipment is used and tuned by individual players...

IvanK

08-05-2012, 05:01 AM

Its been put in on bug tracker:

http://www.il2bugtracker.com/issues/415

Alas no proof or in game tests in the bug tracker entry to indicate CLOD Spit MKI is indeed flawed in the Sim.

Glider

08-05-2012, 05:56 AM

A lot of energy is being spent on the Mk V which most would agree had an issue that was resolved by bob weights.
There seems to be no real evidence that a problem existed in the Mk I or II which were the versions used in the BOB

Crumpp

08-05-2012, 11:11 AM

There seems to be no real evidence that a problem existed in the Mk I or II which were the versions used in the BOB

LOL...Really??

Spitfire Mk I Operating Notes, July 1940:

http://img109.imageshack.us/img109/7976/page10jv.jpg (http://imageshack.us/photo/my-images/109/page10jv.jpg/)

http://img26.imageshack.us/img26/2599/page12dh.jpg (http://imageshack.us/photo/my-images/26/page12dh.jpg/)

http://img542.imageshack.us/img542/9202/page13o.jpg (http://imageshack.us/photo/my-images/542/page13o.jpg/)

http://img607.imageshack.us/img607/2471/page15j.jpg (http://imageshack.us/photo/my-images/607/page15j.jpg/)

http://img651.imageshack.us/img651/2456/page16lu.jpg (http://imageshack.us/photo/my-images/651/page16lu.jpg/)

http://img716.imageshack.us/img716/1650/x4268.jpg (http://imageshack.us/photo/my-images/716/x4268.jpg/)

Longitudinally, the aircraft is stable with centre of gravity forward, but is unstable with centre of gravity normal and aft with engine 'OFF' and 'ON'.

http://img855.imageshack.us/img855/4388/k9788stabilityexplained.jpg (http://imageshack.us/photo/my-images/855/k9788stabilityexplained.jpg/)

http://www.spitfireperformance.com/k9787-fuel.html

Glider

08-05-2012, 11:53 AM

Unfortunately for you there is little if any evidence of any bad outcomes. The first set of well worn docs are warning that obviously worked as wing failures were rare.

In July 1941 well after the BOB investigations were started. Had it been a problem in the bob the investigations would have started a lot earlier

And you have still to supply any evidence re the piles of wings waiting repair

Crumpp

08-05-2012, 12:08 PM

Well,

I can't post any pictures on bugtracker to show the documentation even using the same account as NzTyphoon.

Very Strange....

Perhaps 41 Squadron Banks who is the manager of Il2bugtracker can look into my acount settings and see if there is some reason for this.

I have tried every method available at photobucket as well as other hosting sites.

Crumpp

08-05-2012, 12:11 PM

Unfortunately for you there is little if any evidence of any bad outcomes.

??????

http://i1256.photobucket.com/albums/ii499/Crumpp1/X4268.jpg

http://i1256.photobucket.com/albums/ii499/Crumpp1/Spitfireserials2.jpg

http://i1256.photobucket.com/albums/ii499/Crumpp1/Spitfireserials.jpg

IvanK

08-05-2012, 12:15 PM

Crumpp

08-05-2012, 12:28 PM

Have you demonstrated that the Spit in Ver 1.08.18956 is actually bugged

Dive to Vne and pull up. You can't break the airframe even with full rudder applied at pull up.

Make an abrupt pull up from level flight and release the stick. The airframe loads on a normal slope and gently settles.

At Vmax, make a steep bank and abrupt turn to 180 degrees from heading.

Release the stick and the turn stops. If above Va, it should increase to airframe damage and accelerated stall.

It is all measureable.

macro

08-05-2012, 12:39 PM

Bug tracker is for Bugs.

Have you demonstrated that the Spit in Ver 1.08.18956 is actually bugged ? You indicated in this thread when asked about in game testing that all would be in the bugtracker post. All that is there is a series of statements replicating your posts in this thread.

I dont see any Ver 1.08.18956 test data to support your case in your bugtracker entry.

thats why i voted against it, nothing in there about how the game spit fm is wrong compared to this data.

im surprised to see there isnt one for structural damage under high g's, or is it there and i just cant find it?

Glider

08-05-2012, 12:51 PM

J Quill in June 1941 they did tests re wing failures. So until then it wasn't a noticable issue or the tests would have started in say Oct 1939

X4381 lost a wing in a dive. Quite possible when exceeding the dive speed

X4421 lost its wings when in a high speed stall after a steep dive ignoring the pilots notes

X4354 lost its wing in Dec 1941 at an OTU when in a dive. An old aircraft in a training unit in a dive probably exceeding the dive limitations

X4381 lost its wing in an OTU in a high speed dive out of cloud. An old aircraft probably exceeding its dive limits after loss of control in a cloud

Is that the best you can do?

PS what about all those that broke up when spinning, another major weakness (according to you)

Crumpp

08-05-2012, 12:54 PM

Ivan,

This is all easily seen in the math. I would think the program accounts for a Center of Gravity.

Crumpp

08-05-2012, 01:05 PM

Is that the best you can do?

????

I never said it was complete. I counted 13 incidents only halfway thru the serial listings for the just the Mark I in Morgan and Shacklady.

There some 9 pages of this irritating tiny print. You can go through them.

Again,

The measured and defined stability and control of the early mark Spitfires is neutral to unstable at normal and aft CG.

That statement holds true for any measured results.

Unfortunately, there are only a few measured results from the United Kingdom because there was no standard in place. In otherwords, there was no ruler outside of pilot opinion.

Crumpp

08-05-2012, 01:13 PM

when another NACA document on the Spitfire's stall characteristics was presented it was dismissed as being irrelevant:

Where do you get this stuff?

Nobody dismissed it as irrelevent. In fact, it agrees with the first NACA report.

Do you think the NACA was contridicting itself?

Did you read the report and note the conditions??

It all agrees, bud. Stop with your pointy tin foil hat theories.

Glider

08-05-2012, 01:25 PM

????

I never said it was complete. I counted 13 incidents only halfway thru the serial listings for the just the Mark I in Morgan and Shacklady.

There some 9 pages of this irritating tiny print. You can go through them.

Again,

The measured and defined stability and control of the early mark Spitfires is neutral to unstable at normal and aft CG.

That statement holds true for any measured results.

Unfortunately, there are only a few measured results from the United Kingdom because there was no standard in place. In otherwords, there was no ruler outside of pilot opinion.

I know it isn't complete and I appreciate the effort but all the ones you mention are not relevent to the case, so as I said, is this the best you can do.

Have you found any at all so far re spins, you will recall that you were once very keen saying that spits broke up in a spin and so far nothing to support it. In a similar manner we have nothing to support the piles of bent wings, or an unusual number of accidents, nothing at all. No mention of this as an issue in any of the hundreds of books that have been written about this aircraft and the BOB.

All we have is your spin of a known factor which pilots were warned of.

All we have is you making a worst case scenario out of something everyone was aware of and wasn't a major problem.

Edit - I should add that also have yet to prove that the level of instability admitted by one and all, is an unsafe level or even that it is unsuitable for a fighter.

robtek

08-05-2012, 02:55 PM

.......

All we have is your spin of a known factor which pilots were warned of.

All we have is you making a worst case scenario out of something everyone was aware of and wasn't a major problem.

No, all we have is a few people belitteling documented quirks of the early marks Spitfire with a energy that borders on fanatism.

The same people will probably fight with the same energy, to have all others planes quirks included in game.

Crumpps only mistake was not to start with the 109, i believe, not that this would have changed the then future Spitfire discussions, imo.

Al Schlageter

08-05-2012, 03:32 PM

NZtyphoon

08-05-2012, 10:16 PM

No, all we have is a few people belitteling documented quirks of the early marks Spitfire with a energy that borders on fanatism.

The same people will probably fight with the same energy, to have all others planes quirks included in game.

Crumpps only mistake was not to start with the 109, i believe, not that this would have changed the then future Spitfire discussions, imo.

What we have is people putting forward alternative POVs, with documentation - democracy in action, yet this is belittled as "fanaticism". I see no rules stating that people cannot debate the merits or otherwise of a case put forward in a thread.

IvanK

08-05-2012, 10:54 PM

Ivan,

This is all easily seen in the math. I would think the program accounts for a Center of Gravity.

But where is your in game data ?

CaptainDoggles

08-05-2012, 10:55 PM

What we have is people putting forward alternative POVs, with documentation - democracy in action, yet this is belittled as "fanaticism".

:rolleyes: Spare us the rhetoric and emotional appeals. That's not what democracy is and you know it.

fruitbat

08-05-2012, 10:57 PM

ahh, the blue smileys are catching.

VO101_Tom

08-05-2012, 11:09 PM

NZtyphoon

08-06-2012, 04:38 AM

:rolleyes: Spare us the rhetoric and emotional appeals. That's not what democracy is and you know it.

Democracy (http://www.youtube.com/watch?v=efKy4J81PTg&feature=related)

CaptainDoggles

08-06-2012, 04:42 AM

Didn't watch the video, too busy watching the Mars landing. Democracy is a system of government. A bunch of people shouting at each other on a forum is not democracy.

You used that word because you thought it would be more persuasive.

Crumpp

08-06-2012, 12:58 PM

Crumpp. I do not understand actually what you want? I understand the Spit control and stability tests. I do not understand how to realize these characteristics in the game, where the players have completely different controller (stick length, stick dimensions, turning points of the aileron and elevator)? If the old, unique stick characteristics want to apply to the most common joy forms, the "historically correction" compromised in any case. Not to mention that you can change all handling characteristics with the joy softwares.

Therefore, I vote against it. Not against of historical authenticity, but the applicability in the game.

Tom,

It is not just stick settings.

1. The aircraft moves to trim speeds but overshoots. That means it is always in motion and must be controlled.

Can it be controlled? Yes of course.

Is it easy to accurately aim while doing that? Not at all.

So while a player might mitigate the sensitive elevator and heavy ailerons, they would still have to constantly control the aircraft motion. This is especially noticeable in accelerated flight or turn.

A reworking of the stick settings would eliminate this and allow the stability and control features of each aircraft to be more accurately modeled. Just go the a dead zone to 100% curve. That way, somebody could flatten out response around the dead zone but the slope of the curve increases as we get closer to full deflection. One could "pick their poison" so to speak but could not eliminate modeled behaviors.

The developers can also model the airframe limits. Currently, you cannot bend or break the airframe and the accelerated stall is non-existent.

The aircraft's reaction to gun recoil could also be modeled. As an unstable platform, the arm is shorter which means less resistance to motion.

The penalties on turn performance for riding the buffet or pulling into it. Completely independent of stick settings.

The idea is to get player in the mindset of a WWII pilot flying the modeled type of aircraft. That is IL2 Cliffs of Dover main strength IMHO and why I got the game.

We have all seen the RAE concerns about pilot's not pushing the aircraft to the limits because of their fear of the flying qualities. That is fear is justified by the measured results of the NACA. Yes, the airplane had great stall characteristics too. The caveat being what is emphasized in the Operating Notes, correct and immediate application of the controls. The right control movements at the right time. If the pilot did not immediately make the correct inputs, the aircraft would spin after flicking out of the turn on a reciprocal course.

If he made the correct inputs, the aircraft recovered and even maintained a relatively high degree of aileron control just above stall. The NACA mentions that because it is unusual. Touching the ailerons on a stalled wing in general is not a good idea. Cessna drivers do it all the time, though, LOL. In most aircraft the rudder is the only effective control immediately post stall.

It does leave the aircraft with its tail toward the enemy and the choice of continuing with a slight altitude loss in slow flight or diving for more airspeed.

So the penalties for the buffet and the accelerated stall characteristics can also easily be modeled.

To mitigate the fact players could dial out the most important characteristic that made an early mark Spitfire unique, the sensitive elevator and heavy ailerons. Since players are going to cheat, developers can too. I did this in Warbirds and it worked great when I did the Bf-109 and Spitfire models.
If an accelerated stall is reached, the aircraft spins. This keeps players in the mindset to stay off the stall point.

So it eliminates a nice feature of the Spitfires stall characteristic but realistically, Spitfire pilots did not seek the stall except as rare method to escape an unwanted combat. If the players are going to cheat, let the developers do so as well.

DC338

08-06-2012, 01:11 PM

ok

Now let's look at the measured results.

http://img843.imageshack.us/img843/6408/rapidturnfig15.jpg (http://imageshack.us/photo/my-images/843/rapidturnfig15.jpg/)

Here we see in a rapid left turn performed at 223 mph the test pilot is unable to hold constant acceleration on the airframe. Very small variations in stick movement and stick force changes of 1-3lbs results in large fluctuations in acceleration.

Taking two point we can compare the slope of the curves of stick input to acceleration over time.

For the intital pull up:

Acceleration over time 3.5G-(-.5G) divided by 4.5s-3.5s = m
m = 4

Stick force over time: (19lbs - 0lbs) divided 5lbs/G all divide by 4.5s-3.5s = m
m = 3.8

*The slopes should match and they are close enough.* +However, our stick force grows at a slower rate than our acceleration.+ This is the initial input of the pilot.

Now let's see the instability.

Stick force over time 15lbs-15lbs divided by 5lbs/G all divided by 6.8s-5.5s = m
m = 0

Of course m = 0, our stick is held fixed by the force measurement equipment

Acceleration over time 4.2G-3.2G divided by 6.8s-5.5s = m
m = .76

So, while our stick remains fixed, the aircraft continues to accelerate on its own. As the nature of instability, there is no correlation stick force input and acceleration.

Now, our pilot in this case only input force to reach 3.5G. In a stable airplane, we should see the aircraft dampen all subsequent accelerations which means the aircraft would not exceed 3.5G without control input.

In this case, the instability or divergent oscillation a 4.2G acceleration with stick fixed slightly below the stick force required to produce a 3.5G acceleration.

Now I understand that Figure 15 does hint at what you are getting at yet I see no such problem in figures 16, 17 & 18 of the same report and you don't seem to analyse them in your argument? Odd as they are essentially they are same test as figure 15 but in the opposite direction (16) and at higher speeds (17 & 18). Looks like a relatively constant G was held throughout by the pilot. Or am I missing something?

The report alludes to "careful" flying. Does that mean "not careful" flying in the other charts.

Next let's look at the pilots ability to control the accelerations in the pre-stall buffet.

http://img600.imageshack.us/img600/4313/stallbuffet.jpg (http://imageshack.us/photo/my-images/600/stallbuffet.jpg/)

Here we see the pilot was able to load the airframe to 5G's in 1 second to reach the pre-stall buffet 3 times. The smooth positive sloped portion of the curve represents the aircraft flying while accelerations are increasing. The top of the acceleration curve represents the pre-stall buffet. The bottom of the curve represents the stall point.

The amount of stick travel as measured by the NACA was not acceptable.

http://img94.imageshack.us/img94/2621/sticktravel.jpg (http://imageshack.us/photo/my-images/94/sticktravel.jpg/)

Yet it does not say that is was dangerous flying quality. It just did not meet the Requirements laid out in report 755. It was not built to that standard so should it surprise that it doesn't meet all of them?

Now on the Spit V they did use a inertia weight to combat over sensitive elevators on that Mark. Why did they not demand a retro fit of inertia weights to the MK I & II that would have been in the OTU squadrons at the time if it was such a problem?

robtek

08-06-2012, 01:26 PM

I think of the Spit like a Porsche 911, a great car which is a delight to drift around corners, but you really have to work to hold the thin line before it bites you in the a**.

With a regular driver it is still a great sportscar and outperforms many of its competitors, but to have the edge you have to be a pro.

The same will be with the 109, where the pilot has the opposite problem of too high stick forces at high speeds.

Each needs his own tactic to use the quirks of ones plane for optimum efficiency.

SlipBall

08-06-2012, 01:30 PM

NZtyphoon

08-06-2012, 01:53 PM

Now I understand that Figure 15 does hint at what you are getting at yet I see no such problem in figures 16, 17 & 18 of the same report and you don't seem to analyse them in your argument? Odd as they are essentially they are same test as figure 15 but in the opposite direction (16) and at higher speeds (17 & 18). Looks like a relatively constant G was held throughout by the pilot. Or am I missing something?

Yet it does not say that is was dangerous flying quality. It just did not meet the Requirements laid out in report 755. It was not built to that standard so should it surprise that it doesn't meet all of them?

Now on the Spit V they did use a inertia weight to combat over sensitive elevators on that Mark. Why did they not demand a retro fit of inertia weights to the MK I & II that would have been in the OTU squadrons at the time if it was such a problem?

Slight correction on the Mk V - the reason the inertia weights were added was to help overcome a problem with poor cg loading at a squadron level, plus the added weight of new equipment not used in Spitfire Is and IIs (see Quill http://forum.1cpublishing.eu/showpost.php?p=451315&postcount=781 )

Crumpp

08-06-2012, 02:01 PM

The report alludes to "careful" flying. Does that mean "not careful" flying in the other charts.

Good questions.

No, these where done with "careful flying". If you read the report, they were done with force measurement equipment hooked to the controls.

The pilot could move the stick but when he let go, the equipment held it fast so the forces could be measured.

He could move the stick if needed to keep the accelerations within safe limits.

So, the controls in the test are done with about as careful flying as you can get. Most Spitfire pilot did not have a force gauge holding their controls fixed.

Yet it does not say that is was dangerous flying quality

It is dangerous under conditions the pilot can overload the airframe. That is why you see the incidence of in-flight structural failure's and the warnings in the Operating Notes.

It is dangerous when you need to shoot accurately and it is dangerous when you need to make an abrupt maneuver to avoid and enemy attack.

Yes, it can be controlled by the pilot and mitigated by his skill level. It requires such input.

You have hit upon the entire reason the Air Ministry did not have stability and control standards outside of pilot opinion.

The British were major pioneers in stability and control in the beginning but kind of floundered after World War I.

Crumpp

08-06-2012, 02:03 PM

the reason the inertia weights were added was to help overcome a problem with poor cg loading at a squadron level

Again, the RAE may have blamed it on that but they were also behind in Stability and Control research. The NPL pretty much stagnated until the efforts of Gates and Lyons came to fruition post war moving AWAY from the conclusion stability and control could not be defined without pilot input.

http://img651.imageshack.us/img651/6878/nplstandards.jpg (http://imageshack.us/photo/my-images/651/nplstandards.jpg/)

The opinion of the NACA was much different and their test aircraft was NOT overloaded and at a normal CG.

http://img856.imageshack.us/img856/863/spitfirelongitudinalsta.jpg (http://imageshack.us/photo/my-images/856/spitfirelongitudinalsta.jpg/)

bongodriver

08-06-2012, 02:22 PM

Notice how the problem was 'tails' breaking and not 'wings' bending that were the main case for structural failure, of course Crumpps highlight there mentions nothing about early Spits and in fact probably is refering to the MkV.

Al Schlageter

08-06-2012, 02:26 PM

It is dangerous when you need to shoot accurately and it is dangerous when you need to make an abrupt maneuver to avoid and enemy attack.

Spitfire pilots didn't seem to have that much trouble shooting down German a/c during the BoB despite being out numbered in the air over south-east England.

That is why you see the incidence of in-flight structural failure's and the warnings in the Operating Notes.

There are such warnings for American a/c.

Crumpp

08-06-2012, 02:31 PM

Why did they not demand a retro fit of inertia weights to the MK I & II that would have been in the OTU squadrons at the time if it was such a problem?

I know it was later modified with an inertial elevator. They did something to correct it, you can bet.

The fact remains, the RAE skirted around the problem because they had no real estabilished foundation for what to do with longitudinal instability.

Especially when the pilot's opinion ran contrary.

It is really interesting if you like the history of technological development. There was a guy in England who laid down all the math just before World War I. It was in center of pressure and metacenter so his mechanics were not completely correct but all his principles were as well as the use of polynomial co-efficients to describe motion. Professor GH Bryan's really cracked the nut on stability and control.

Some of his conclusion's are used today. The problem was when he tried to explain it, it was so complicated that most engineer's eye glazed over, mouths came open, and the drooling begain. Then, some pilot would hop in the same plane his big complicated set of equations had predicted was unstable and fly off in it.

You can control an airplane that is unstable, especially the long period oscillation the NPL became focused on. The 1903 Wright Flyer was so unstable, the techique used to land it was to fly close to the ground at low velocity and let the skids touch on the downward oscillation.

You could not estabilish a stabilized approach that is common in todays airplanes.

They flew extremely unstable aircraft all the time in the early days of aviation. The velocity and forces were low enough that stability and control just was not that important.

the major flight characteristic ever present is the feeling that if you took your hands off the stick or your feet off of the rudders, the Eindecker would turn itself inside out or literally swap ends." He also indicates that the all-moving surfaces continually hunted back and forth with an attendant feedback into the pilot's hands and feet. These characteristics describe an aircraft that by modern standards would be considered unpleasant to fly, would be unlicensable, and certainly would inspire little confidence in the mind of the pilot.

http://www.hq.nasa.gov/pao/History/SP-468/ch2-2.htm

That all changed with the advent in the powerful monoplane fighters of World War II. The speed and forces involved pushed the science of stability and control to the forefront.

Crumpp

08-06-2012, 02:34 PM

There are such warnings for American a/c.

Really, by god....don't model it, we might see "porked" american fighters....

:rolleyes:

Quick, withdraw the facts about the Spitfire!!! Run!! There will be revolution!!

:eek:

NZtyphoon

08-06-2012, 03:40 PM

The aircraft's reaction to gun recoil could also be modeled. As an unstable platform, the arm is shorter which means less resistance to motion.

Documented evidence for this, please.

Alex Henshaw's comments make interesting reading on the Spitfire as a gun platform and on its elevators:

http://i91.photobucket.com/albums/k304/Major_Sharpe/Henshaw12-page-003a.jpg

Note Henshaw comments that the Spitfire's elevators were light cf those of the Tiger Moth or Magister on which pilots trained....

Now, a comment on the Pilot's Notes used by Crumpp which can be found here: http://www.scribd.com/doc/4598146/Pilots-Notes-Supermarine-Spitfire-Mk-IIA-IIB-Merlin-XII-Engine - this is a most unusual set of PNs, even for a reproduction. For one thing these have detailed information and comments on combat skills and aerobatics, which few pilot's notes normally had.

http://i91.photobucket.com/albums/k304/Major_Sharpe/SpitIIcover.jpg
http://i91.photobucket.com/albums/k304/Major_Sharpe/SpitIICombatnotes.jpg
http://i91.photobucket.com/albums/k304/Major_Sharpe/SpitIIcombat2.jpg
http://i91.photobucket.com/albums/k304/Major_Sharpe/SpitIIaerobatics1.jpg

These were not the standard PNs issued to pilots on frontline units - those ones invariably had blue covers: (http://www.barbarossabooks.eu/british-military-aviation-pilots-notes-c-14_919.html?page=1&sort=20a) the notes that were issued to trainee pilots at OTUs had orange covers and these notes were conservative in their approach to ensure hotdog young pilots, who had gotten used to heavier elevators on the Tiger Moths etc, were made fully aware of the lighter Spitfire controls.

Again, the RAE may have blamed it on that (overloading at a squadron level) but they were also behind in Stability and Control research.

Wrong, once again, as Jeffrey Quill made quite clear he witnessed what had happened - unless Crumpp can show that he knows better about what happened in 1942 than Quill...nothing but speculation.

As for Crumpp's continued assertions about how hapless the Brits were when it came to defining control and stability? The first page shown by Crumpp is talking about 1910-1912: it has no relationship to the 1930s and the Spitfire whatsoever!
This is page 5 from the Von Karman Lecture 1970:
http://i91.photobucket.com/albums/k304/Major_Sharpe/VonKarmanLecture-page-005.jpg

Page 6 - the one posted by Crumpp
http://i91.photobucket.com/albums/k304/Major_Sharpe/VonKarmanLecture-page-006.jpg

What has what happened in1910-1912 got to do with ANYTHING in this thread??? :confused:

CF: 1937 ARC report

http://i91.photobucket.com/albums/k304/Major_Sharpe/ARCAR1937-page-001.jpg
http://i91.photobucket.com/albums/k304/Major_Sharpe/ARCAR1937-page-011a.jpg

CF: the 1939-48 ARC report
http://i91.photobucket.com/albums/k304/Major_Sharpe/ARCReview1939-48-page-001.jpg
http://i91.photobucket.com/albums/k304/Major_Sharpe/ARCReview1939-48-page-005a.jpg
http://i91.photobucket.com/albums/k304/Major_Sharpe/ARCReview1939-48-page-006a.jpg

Crumpp

08-06-2012, 05:15 PM

Do you read what you are highlighting or posting?

The Operating Notes almost verbatium repeat the exact same warning for the Spitfire Mk II AS THE MK I.

In fact, you have saved me the trouble of posting them.

What has what happened in1910-1912

Bryan's theories were developed before WWI but the attitude that pilot's determine flying qualities over the engineer persisited until after World War II.

It was not until AFTER World War II that the ARC developed a standard that all designs had to meet.

That is a fact.

The article you posted points this out.

First it concludes that the Aeronautical Research Council made the mistake of regulating stability and control engineering to an academic exercise leaving the practical to the opinion of pilots. Exact same thing the AAIA article I posted relates.

Then, the ARC concludes that a foundation was laid during the war for estabilishing a defined set of standards for stability and control.

http://img88.imageshack.us/img88/1434/arcreview193948page001.jpg (http://imageshack.us/photo/my-images/88/arcreview193948page001.jpg/)

http://img189.imageshack.us/img189/8797/arcreview193948page005a.jpg (http://imageshack.us/photo/my-images/189/arcreview193948page005a.jpg/)

http://img440.imageshack.us/img440/8320/arcreview193948page006a.jpg (http://imageshack.us/photo/my-images/440/arcreview193948page006a.jpg/)

http://img217.imageshack.us/img217/8906/britishlackofastandard.jpg (http://imageshack.us/photo/my-images/217/britishlackofastandard.jpg/)

Crumpp

08-06-2012, 05:59 PM

Documented evidence for this, please.

MMM, It is in the thread already. Read the stability characteristics of the Spitfire. You seem to not understand it or ignore it. Instead, you place more value on anecdotes which are impossible to quantify.

You also quote the lone voice in the wilderness from Alex Henshaw who never fired a shot in anger.

Let's get some from guys who flew both in combat:

This is the reality. The Longitudinal stability is a defining characteristic of the early Mark Spitfires. It is part of what makes the airplane unique and gives it personality.

http://img521.imageshack.us/img521/3024/hurricanevsspitfire.jpg (http://imageshack.us/photo/my-images/521/hurricanevsspitfire.jpg/)

http://img607.imageshack.us/img607/4739/hurricanevsspitfire2.jpg (http://imageshack.us/photo/my-images/607/hurricanevsspitfire2.jpg/)

Wow, check that out. The first pilot could not make a kill because when he touched the firing button, the nose pitched down due to the longitudinal instability.

The second pilot disliked doing aerobatics. He felt the ailerons where too stiff, the elevator to sensative, nose too long, and the cockpit too cramped.

You can google "Hurricane vs Spitfire gun platform" yourself and not the results. A defining characteristic of the early mark Spitfire is it's twitchiness as a gun platform. Yes, it too, is a function of the longitudinal instability.

The Spitfire was not a an airplane for the inexperienced or average pilot. It was a pilot's aircraft and demanded skill. For that skill, it rewarded those who mastered it with exceptional performance. That breeds affection.

robtek says:

I think of the Spit like a Porsche 911, a great car which is a delight to drift around corners, but you really have to work to hold the thin line before it bites you in the a**.

With a regular driver it is still a great sportscar and outperforms many of its competitors, but to have the edge you have to be a pro.

The same will be with the 109, where the pilot has the opposite problem of too high stick forces at high speeds.

Each needs his own tactic to use the quirks of ones plane for optimum efficiency.

Good analogy.

IMHO, the generalize the three fighters of the BoB....

The Spitfire is sportscar. The Hurricane a workings man's tool.

The Bf-109 is a shooting platform for a machinegun with an airplane built around it.

Crumpp

08-06-2012, 06:29 PM

Crumpp can show that he knows better about what happened in 1942

It does not require my opinion.

This is all measured and defined by the NACA, the same characteristics appear as warning in the Operating Notes, and are repeated in a flight testing as well as anecdotal evidence.

My suggestion would be to go school and take some aerodynamics classes.

BTB

08-06-2012, 07:25 PM

Sorry but have u read these articles?? These are first impression of a Pilot flying a new and different type of Plane. Of course it reacts totally "unnormal" as what he imagines and knew from the Hurricane.

And just because the Spit reacts quickly on a pitch input doesnt mean that she is a unstable gun platform in my opinion.

Thats why u practise as a Pilot to understand the plane and get used to it.

And thats why u have planes for "rookies" and "experts". But u can't compare or mess this with data because every Pilot has his own flying Skill and learning curve.

wikipedia: "Longitudinal stability

The longitudinal stability of an aircraft refers to the aircraft's stability in the pitching plane - the plane which describes the position of the aircraft's nose in relation to its tail and the horizon.[1] (Other stability modes are directional stability and lateral stability.)

If an aircraft is longitudinally stable, a small increase in angle of attack will cause the pitching moment on the aircraft to change so that the angle of attack decreases. Similarly, a small decrease in angle of attack will cause the pitching moment to change so that the angle of attack increases.[1]"

NZtyphoon

08-06-2012, 09:31 PM

Again, the RAE may have blamed it on that but they were also behind in Stability and Control research. The NPL pretty much stagnated until the efforts of Gates and Lyons came to fruition post war moving AWAY from the conclusion stability and control could not be defined without pilot input.

Crumpp's story has now changed from a blanket statement that the British had no standards on control and stability to one saying that the British "moved away from the conclusion stability and control could not be defined without pilot input."

The Americans no longer needed pilots because their know-all engineers could design perfect aircraft without any input from pilots whatsoever. Just pop an engineer into the cockpit...leave the pilots twiddling thumbs on the ground.

You have hit upon the entire reason the Air Ministry did not have stability and control standards outside of pilot opinion.

So why, pray tell was lack of pilot input such a wonderful development? Because it was purely subjective! Ignorant pilots could not quantify that seat of the pants feeling, nor could they accurately report on what had happened because they were too busy flying and controlling the plane.

That all changed with the advent in the powerful monoplane fighters of World War II. The speed and forces involved pushed the science of stability and control to the forefront.

Which is exactly what the British were saying in 1937
http://i91.photobucket.com/albums/k304/Major_Sharpe/ARCAR1937-page-011a.jpg

and 1938
http://i91.photobucket.com/albums/k304/Major_Sharpe/009a.jpg

MMM, It is in the thread already. Read the stability characteristics of the Spitfire. You seem to not understand it or ignore it. Instead, you place more value on anecdotes which are impossible to quantify.

You also quote the lone voice in the wilderness from Alex Henshaw who never fired a shot in anger.

Meaning that Crumpp has flown a Spitfire and fired its guns in anger - albeit in a flight sim - and knows more on the subject than Henshaw, who had simply spoken to Spitfire pilots about its qualities as a gun-platform. Then he goes into anecdotes which cannot be quantified and happen to be from pilots who had gotten used to the Hurricane and showed a certain amount of prejudice

http://img521.imageshack.us/img521/3024/hurricanevsspitfire.jpg (http://imageshack.us/photo/my-images/521/hurricanevsspitfire.jpg/)

http://img607.imageshack.us/img607/4739/hurricanevsspitfire2.jpg (http://imageshack.us/photo/my-images/607/hurricanevsspitfire2.jpg/)

As well as this Crumpp also claims that he knows better than Jeffrey Quill why Spitfire Vs were fitted with inertia weights:

Slight correction on the Mk V - the reason the inertia weights were added was to help overcome a problem with poor cg loading at a squadron level, plus the added weight of new equipment not used in Spitfire Is and IIs.
and the reply...
Again, the RAE may have blamed it on that but they were also behind in Stability and Control research.

http://i91.photobucket.com/albums/k304/Major_Sharpe/Quill3.jpg
http://i91.photobucket.com/albums/k304/Major_Sharpe/Quill4.jpg
http://i91.photobucket.com/albums/k304/Major_Sharpe/Quill5.jpg

Glider

08-06-2012, 10:46 PM

I was struck by the observation the British made that in the past they had relied too much on a thoretical view, which is exactly what Crumpp has, a theoretical view.

Crumpp has been adivsed of the late 1980's approach to this topic ie that its a blend of theory, handling and an awareness of the mission being undertaken. These more modern standards he has ignored

He keeps saying that the Spitfore broke up easily in a spin which is why it was banned in the Pilots Notes. Unfortunately he has yet to produce one example of such a loss. I should add that I expect there to be a few but the fact that Crumpp has failed to produce one says a lot

Crumpp also says that the Spitfire was prone to structural failure due to stability issues, but so far he has yet to produce one example. Again I should add that I expect there to be a few but the fact that Crumpp has failed to produce one says a lot

He has also made reference to piles of bent wings awaiting repair in the BOB but has yet to find one example

Crumpp has failed to produce any evidence that the level of instability was dangerous. Much is made of the fact that the pilots notes warn of this, rightly, but no comment that the notes worked as proven by the lack of crashes.
No comment has been made has been made that Pilots notes err on the side of caution, we only have a catastrophic reading.

There clearly was a problem with the Mk Vb and bob weights were introduced on operational aircraft until a better solution was found. The evidence is that this was caused by poor loading in the squadrons but it didn't matter the problem had to be solved and it was. Even her Crumpp insists that this was a problem from the start and bob weights were introduced into all early versions of the spitfire. UNfortunately no evidence has been put forward to support this view. INdeed what has been posted is clear that the Mk I and II were not impacted by the problem.

Much is made of the fact that the Spit wasn't a good gun platform, something that is hardly new and that some pilots were afraid to fly it. A contridiction if ever there was one. If the plane was so unstable why did the pilots love it? However he doesn't mentin that in the same document that the pilots loved the aircraft.
The British were so far behind the times apparently re stability and to prove this he uses a pre WW1 document, a time when they didn't know how to deal with a spin?

Crumpp makes much use of this type of statement

It does not require my opinion.
This is all measured and defined by the NACA, the same characteristics appear as warning in the Operating Notes, and are repeated in a flight testing as well as anecdotal evidence.
My suggestion would be to go school and take some aerodynamics classes.

A few observations on this
a)NACA were using a Mk Va, an old aircraft, known to be the one most suseptable to stability problems, one without a crew up to date with the latest rules and regs in the UK. They did their mesurements but even here, they never said that it was a danger, they did say it didn't meet their normal standards but they didn't say it was a danger. If they had thought it was that bad I am confident they would have said so as Americans are not known for holding back unpleasent truths.
b) No one denies that the Spit wasn't perfect which is why the Pilots notes say what they say, but I repeat they always are cautious.
c) Comments about flght testing. I have asked Crumpp often to supply any flight test from any nation (including Germany) who found this aircraft dangerous this question is still outstanding.. I can only conclude that he has no evidence and by saying this he is exagerating his case
d) Going to classes on aerodynamics. Crumpp may or may not have had some training in aerodynamcis, I don't know.
I do know he offerred to debate longitudinal instability by a number of standards. Unfortunately one of these was to do with roll rates for differing types of aircraft and one was to do with the Rules and regulations about ordering spare parts to stop counterfit parts entering aircraft. Again I believe he was trying to exagerate the strength of his position

Above all of this is the lack of accidents. All the issues he talks about are serious safety issues but we have a serious lack of any incidents.

I bring you back to the first point in this posting.
I was struck by the observation the British made that in the past they had relied too much on a thoretical view, which is exactly what Crumpp has, a theoretical view.
Crumpp by not considering the views and experiences of those who flew the aircraft is relying almost totally on a theoretical approach. The standards of the late 1980's emphasise the importance of mixing theory, hands on experience and the task the plane was designed for, by ignoring this he is making the same mistake the British made in the 1920's. The last ones that I used are MIL-STD-1797a but these may have been modified

robtek

08-06-2012, 11:05 PM

.....
Above all of this is the lack of accidents. All the issues he talks about are serious safety issues but we have a serious lack of any incidents.......

There might be hundreds of Spitfires being lost over sea or behind enemy lines because of mishandling in stress situations, all disregarded because being accorded to enemy action.
Nobody knows that for sure.
The only data we have is a per se incomplete list of researched accidents.

bongodriver

08-06-2012, 11:07 PM

I heard that some Spitfires were pink, maybe they should all be pink?

IvanK

08-06-2012, 11:10 PM

I have a set of Orange covered Spitfire MKIIA notes (Paper reprint) that bear little resemblance to the ones in SCRIBD.

As was discussed in this "Thread that never ends" in the set I have Spinning was permitted if pilots were authorised by the CO or CFI at the OTU level. The Scribd ones say deliberate spinning was prohibited.

So two references with opposed statements.

IvanK

08-06-2012, 11:13 PM

Originally Posted by Crumpp http://forum.1cpublishing.eu/images/styles/blackyellow/buttons/viewpost.gif (http://forum.1cpublishing.eu/showthread.php?p=452052#post452052)
The aircraft's reaction to gun recoil could also be modeled. As an unstable platform, the arm is shorter which means less resistance to motion.

Cough If you actually flew the sim you would see it is modelled !

ATAG_Dutch

08-06-2012, 11:30 PM

Cough If you actually flew the sim you would see it is modelled !

And there's the rub. ;)

NZtyphoon

08-07-2012, 12:04 AM

Reading the bibliography to the text of a lecture delivered in 1970 and referred to by Crumpp as definitive proof of Britain's lack of control and stability standards: Development of Airplane Safety and Control Courtland D. Perkins
(http://forum.1cpublishing.eu/showpost.php?p=452071&postcount=837)

http://i91.photobucket.com/albums/k304/Major_Sharpe/Developmentofairplanestabilityandcontroltechnology 1970VonKarmanLecture-page-012.jpg

http://i91.photobucket.com/albums/k304/Major_Sharpe/Developmentofairplanestabilityandcontroltechnology 1970VonKarmanLecture-page-001.jpg

The references stop at an ARC paper PUBLISHED IN 1913 - NOT ONCE does the author refer to the ARC papers from 1937 through to 1939-48, nor does he have any references concerning British research during the war years, instead concentrating almost exclusively on American aeronautical research - he had no idea of what sort of development the British had put in after 1913: this one is busted.

I wonder what we would see if we looked at the bibliograpies of most of the books referenced by Crumpp - how many of them concentrate on American research, ignoring Britain?

Crumpp

08-07-2012, 01:58 AM

Reading the bibliography
NzTyphoon,
Why do you keep confusing individual research with an established standard for all????

You obviously cannot differentiate between the two.

It is a fact, there was not an established standard for stability and control in the United Kingdom during WWII.

Glider,

You have constructed so many fantasies and misconception about this I don't even know where to begin.

Read the report. It is measured and defined.

What do you have an issue with?

You really don't need much to understand it. You can read the plain English text for the warnings in the Operating Notes, right??

You seem to deny they exist and keep accusing me of making something up?

As for spin recovery, is it so difficult to understand recovery ends in a dive?

Read the Operating Note warnings!!!

Although the POH is the primary reference for recovery from a spin, the following can be used as a general procedure:

P - Retard the throttle to idle. In most aircraft, power hampers the recovery.

A - Ailerons neutral. Many pilots will attempt to recover from the spin using the ailerons. This may actually make the problem worse.

R - Apply full opposite rudder. Apply rudder opposite the rotation of the spin. If you have trouble determining which way the airplane is spinning, look at your turn coordinator or turn needle. It will indicate the direction of rotation.

E - Apply forward elevator. Immediately after applying opposite rudder, apply a quick forward motion on the control yoke and hold anti-spin controls until the aircraft starts to recover.

D - Recover from the dive. Once you have completed the four previous steps, and the rotation stops, recover from the dive. The descent rate may be over 5000 feet per minute and the airspeed will rapidly exceed redline. Remember to neutralize the rudder after the rotation stops.

http://www.aopa.org/asf/publications/topics/stall_spin.html

Go out and do some spins in the an airplane, please!!

Make sure it is not approved to spin and leave the chutes on the ground. <joking>

:grin:

Crumpp

08-07-2012, 02:29 AM

NOT ONCE does the author refer to the ARC papers from 1937 through to 1939-48, nor does he have any references concerning British research during the war years, instead concentrating almost exclusively on American aeronautical research - he had no idea of what sort of development the British had put in after 1913: this one is busted.

Why don't you post the ARC standards.

Here is the NACA standards adopted during WWII. The USAAF and USN used these as the basis to define their own standards by 1944.

Until those individual service standards were adopted, they used the NACA's.

One impor-tant contribution made by the NACA in this area was its famous technical report, No. 755, "Requirements for Satisfactory Flying Qualities of Airplanes." Representing a decade of work, the NACA introduced to the industry a new set of quantitative measures to characterize the stability, control and handling qualities of an airplane. The military readily adopted the NACA findings and for the first time issued specific design standards to its aircraft manufacturers. It is a classic example of the partnership between the military, air-craft industry and the NACA.

http://www.nasa.gov/centers/langley/news/factsheets/WWII_prt.htm

End the speculation and just post the standards during the war for the ARC.

Thanks!!

:grin:

Crumpp

08-07-2012, 02:36 AM

Here is the USAAF and USN standards adopted in 1944.

During October 1944, the National Advisory Committee conducted a series of conferences with the”Army, Navy, and representatives of the aircraft industry for the purpose of discussing the flight-test procedures used in measuring the stability and control characteristics of airplanes. The conferences were initiated by the Army Air Forces, Air Technical Service Command, to acquaint the flight organizations of the industry with the flight
test methods employed by the NACA and to standardize the techniques insofar as possible as they are employed by the various manufacturers and agencies engaged in determining the flying qualities of airplanes

NzTyphoon will share the ARC standards with us shortly! :cool:

Crumpp

08-07-2012, 02:47 AM

I have Spinning was permitted if pilots were authorised by the CO or CFI at the OTU level.

What is the date on your Operating Notes that reference the spinning permission thru special training?

IvanK

08-07-2012, 03:32 AM

Not special training just authorisation.

Issue Date July 1940 Revised Dec 1941 and Amended up to Al No 25K which was added according to the AL sign off sheet as Aug 1942.

Crumpp

08-07-2012, 03:42 AM

Aug 1942

Ok, that is after the inertial elevator was added to the design.

IvanK

08-07-2012, 03:52 AM

Inertial elevator ??

Are you referring to the bob weight in the pitch circuit or increased balance area on the elevator as fitted to MKV's ???

DC338

08-07-2012, 04:15 AM

Can I ask for your analysis of figure 16 17 & 18 of the NACA report? It seems figure 15 was an anomaly when compared to the next 3 which where doing similar test?

Someone (whiny?) earlier quoted a report from the morgan book on the Spitfire about inertia weights being not required for the MK I & II as long as the rear oxygen bottle was removed. Would be interesting to see the full report.

MiG-3U

08-07-2012, 05:06 AM

IvanK,
The early version of the Mk II manual, which Crumpp is quoting, is for the planes with Rotol props only before the CoG limits were revised. Later the planes (any early Spitfire) with the Rotol props got tighter aft limits, 7.5" aft datum with atandard elevator and without bob weight, while the planes with the DeHavilland prop only got limitations for extended CoG limits, bob weigh required if CoG 7.9" aft datum. In other words bob weigh was not required for the planes with DeHavilland propeller.

The later manual you are quoting is for the Mk IIs with both propellers, Rotol and DeHavilland, after the CoG limits were revised, hence no warnings about the elevator control reversal. Note that longitudal instability and elevator control reversal are related to each other and CoG but not the same thing.

As pointed out earlier with documentation and calculations, the NACA tested Spitfire had the CoG at 7.8" aft CoG and Rotol prop, in other words the CoG was behind the limits and the results are not representative for all the early Spitfires nor all CoG positions.

IvanK

08-07-2012, 05:10 AM

I think the Oxy bottle statement is discussed on P143 of the Morgan Shacklady book.

Here is the bit.

http://i40.photobucket.com/albums/e215/zulu64/Spitbobwt.jpg

The 30 June meeting discussing the general fitting of bob weights refers only to the MKV.

The Bob weight was initially trailed on the one off Spit MKIII. It was tested also on a single MKII airframe P7280 that features in a lot of the RAE tests.
So unless more evidence is provided there is nothing to confirm that bob weights were actually fitted to operational MKII's

Spin trials by RAE on the MKII and MKI (as posted earlier in this thread) generally considered spin characteristics as normal ... no real drama.

Here they are again !
http://i40.photobucket.com/albums/e215/zulu64/X1.jpg

http://i40.photobucket.com/albums/e215/zulu64/recovery.jpg
http://i40.photobucket.com/albums/e215/zulu64/X2.jpg

http://i40.photobucket.com/albums/e215/zulu64/SpitII_Spinning.jpg

Thanks Mig-3U more evidence that operational Spit II's wernt fitted with Bob weights.

NZtyphoon

08-07-2012, 05:16 AM

Thanks Ivan.
NzTyphoon,
Why do you keep confusing individual research with an established standard for all????

This mumbo-jumbo is an example of Crumpp's intellectual dishonesty coming to the fore - the document he has cited in an attempt to bolster his "case" has nothing to do with the point he is trying to prove. "The Development of Airplane Stability and Control Technology" has done no research into British aeronautical development after 1913 and, as such, it has nothing whatsoever to do with the Spitfire's longitudinal stability. Crumpp has not bothered evaluating the sources used by a publication before citing it as "evidence" - this is one of the basics of historical research.

http://i91.photobucket.com/albums/k304/Major_Sharpe/Developmentofairplanestabilityandcontroltechnology 1970VonKarmanLecture-page-012.jpg

During October 1944, the National Advisory Committee conducted a series of conferences with the”Army, Navy, and representatives of the aircraft industry for the purpose of discussing the flight-test procedures used in measuring the stability and control characteristics of airplanes. The conferences were initiated by the Army Air Forces, Air Technical Service Command, to acquaint the flight organizations of the industry with the flight test methods employed by the NACA and to standardize the techniques insofar as possible as they are employed by the various manufacturers and agencies engaged in determining the flying qualities of airplanes.

So, while NACA had formulated a set of specifications they had yet to be properly standardised because as late as October 1944 NACA was still discussing how to implement the specifications with representatives of the Army, Navy and aircraft manufacturers. This does not say anything about the specifications being adopted in 1944 - just being discussed pending adoption.

Now, Crumpp insists on an Aeronautical Research Committee report confirming British standards in control and stability; what Crumpp doesn't seem to realise is that the ARC is an advisory body which works to distribute information and reports to the likes of the National Physical Laboratories, RAE and manufacturers (para 2 Policy of the Committee). Unlike NACA it does not do its own research: unlike NACA papers on stability and control can only be accessed via archives such as this entry, NA Kew (http://www.nationalarchives.gov.uk/catalogue/displaycataloguedetails.asp?CATLN=6&CATID=3121793).

http://i91.photobucket.com/albums/k304/Major_Sharpe/ARCReview1939-48-page-003.jpg

Reports tabled in ARC report 1939:
http://i91.photobucket.com/albums/k304/Major_Sharpe/ARCAR1939-page-004-1.jpg

As it is bug tracker #415 won't be gaining any traction at any time soon, so there isn't much future in pursuing this thread any further.

bongodriver

08-07-2012, 07:30 AM

So.....can we have that 109 thread now?

Crumpp

08-07-2012, 11:02 AM

It is very simple NzTyphoon.

Post the standards developed by the ARC.
Thanks!!

"The Development of Airplane Stability and Control Technology" has done no research into British aeronautical development after 1913

Wow,

Let's not be obtuse. I never said there was no research in stability and control.

I said they stagnated into an attitude that flying qualities was an academic exercise and that the pilot's opinion was what was practical.

Big difference from what you are claiming.

The NACA took a different route. They developed techniques as well as equipment to measure and quantify behaviors. Part of that system was training test pilots and developing manuevers to define behaviors within flying qualities. In fact, it was Cooper's experience as a test pilot at the NACA that led to the development of the Cooper-Harper Rating scale.

http://www.google.com/url?sa=t&rct=j&q=cooper%20rating%20aircraft%20handling%20naca&source=web&cd=4&sqi=2&ved=0CFQQFjAD&url=http%3A%2F%2Fhistory.arc.nasa.gov%2Fhist_pdfs% 2Fbio_cooper.pdf&ei=yvYgUMzyGon06AGpkYCwCw&usg=AFQjCNHJ2ORdKQ0QHE5XzIxnwH4SfCszng

Are you referring to the bob weight in the pitch circuit or increased balance area on the elevator as fitted to MKV's ???

No, I are referring to the one fitted to Spitfire Mk I's to correct the longitudinal instability.

bongodriver

08-07-2012, 11:12 AM

No, I are referring to the one fitted to Spitfire Mk I's to correct the longitudinal instability.

Never happened, only the MkV was 'ever' fitted with a bob weight.

I said they stagnated into an attitude that flying qualities was an academic exercise and that the pilot's opinion was what was practical.

God forbid that when designing something to be operated by a human you would ever actually ask those humans for any advice.

I wonder why on some adverts the slogan 'designed by XXX for XXX' is used, it's almost like the oppinion of the end user counts for something.

NZtyphoon

08-07-2012, 11:21 AM

It is very simple NzTyphoon.

Post the standards developed by the ARC.
Thanks!!

Having wasted hours trying to get Crumpp to provide some documentary evidence to prove his cock-eyed theories on 100 octane I am not interested in complying with these demands.
"The Development of Airplane Stability and Control Technology" has done no research into British aeronautical development after 1913.

Wow,

Let's not be obtuse. I never said there was no research in stability and control.

I said they stagnated into an attitude that flying qualities was an academic exercise and that the pilot's opinion was what was practical.

Big difference from what you are claiming.

Let me complete that for Crumpp:

"The Development of Airplane Stability and Control Technology" has done no research into British aeronautical development after 1913 and, as such, it has nothing whatsoever to do with the Spitfire's longitudinal stability

The only one being obtuse is Crumpp, who tried to use an irrelevant paper to bolster his "case". Anyway I'm done wasting time on Crumpp flogging his dead horse and pointless bug tracker - he can waste as much time as he likes here.

Crumpp

08-07-2012, 11:55 AM

Spin trials by RAE on the MKII and MKI (as posted earlier in this thread) generally considered spin characteristics as normal ... no real drama.

Except that spins are prohibited.

They never changed the Operating Notes. It is not because they are lazy. Nor is it because they want to "reduce risk" by not training their fighter pilots in spin/upset/unusual attitudes.

Spin training, upset, and unusual attitude training is essential to a fighter pilots core mission.

I said from the begining, any engineer can look at a design sitting on the tarmac and know if the airplane has a high chance of normal spin recovery assuming the CG is normal or forward. The Spitfire has all the characteristics required to spin normally.

Therefore, the only real issue is the longitudinal instability.

The never changed it because a high speed dive is generally the result of spin recovery and a Spitfire pilot could break the airplane rather easily.

http://img842.imageshack.us/img842/3954/spunandwingsfail.jpg (http://imageshack.us/photo/my-images/842/spunandwingsfail.jpg/)

I was just curious if spin trials were done after the longitudinal instability was fixed in the Spitfire Mk I's.

The approval to train after being checked out by a Squadron Commander or CFI at an OTU certainly did not appear until the airworthiness directive fixed the instability.

http://img513.imageshack.us/img513/6268/inertialweightelevator.jpg (http://imageshack.us/photo/my-images/513/inertialweightelevator.jpg/)

Crumpp

08-07-2012, 12:09 PM

documentary evidence to prove his cock-eyed theories on 100 octane I

You mean like the fact it is not the specified fuel in the portion of the Operating Notes entitled "Notes on a Merlin Engine" is a strong indicator the fuel is still undergoing service testing?

I never disputed the fuels use, just the silly notion it was the only fuel available and the adopted service fuel.

Who would ever suggest they were still undergoing 100 Octane fuel testing in August of 1940 simply on the basis the facts do not align?

http://img20.imageshack.us/img20/6282/83062903.jpg (http://imageshack.us/photo/my-images/20/83062903.jpg/)

100 Octane is completely off topic. Start your own thread if you want to debate it.

41Sqn_Banks

08-07-2012, 12:12 PM

The never changed it because a high speed dive is generally the result of spin recovery and a Spitfire pilot could break the airplane rather easily.

Honestly I always thought a high speed dive is the typically the result of a prolonged dive. Is diving also prohibited?

Crumpp

08-07-2012, 12:14 PM

NzTyphoon,

It is not my theory nor is that one report the basis of the conclusion the United Kingdom aviation authority did not have stabilit and control standards.

Simply post the ARC standards used during the war. They will be written in a simliar fashion to EVERY other stability and control standard in the world.

They will define the acceptable qualities in an airplane.

Just like the NACA did!!

Here is the link to the UK ARC reports:

http://aerade.cranfield.ac.uk/listarcrm.php

Crumpp

08-07-2012, 12:26 PM

Honestly I always thought a high speed dive is the typically the result of a prolonged dive. Is diving also prohibited?

What does a deliberate dive have to do with a spin?

In spin recovery with longitudinal instability, if the airplane is below Va, the risk of secondary stall is greatly increased.

Above Va, the risk of airframe destruction is greatly increased.

Understand?

41Sqn_Banks

08-07-2012, 12:56 PM

What does a deliberate dive have to do with a spin?

In spin recovery with longitudinal instability, if the airplane is below Va, the risk of secondary stall is greatly increased.

Above Va, the risk of airframe destruction is greatly increased.

Understand?

The pull up during spin recovery above Va has increased risk of airframe destruction.
The pull up during dive recovery above Va has increased risk of airframe destruction as well.

Why is one prohibited and the other not?

BTB

08-07-2012, 01:13 PM

http://it.scribd.com/doc/4598146/Pilots-Notes-Supermarine-Spitfire-Mk-IIA-IIB-Merlin-XII-Engine

robtek

08-07-2012, 01:14 PM

Crumpp

08-07-2012, 01:44 PM

Why is one prohibited and the other not?

See robtek's post, 41 Banks.

Exactly, in a normal dive, it would be very unusual for the pilot to be "behind the airplane". In an accidental spin, it is very likely the pilot will be "behind the airplane".

Goes back to aviation axiom, "Never Let an Airplane take you someplace your brain did not get to at least 5 minutes before."

Right BTB,

If you read the spin recovery procedures in the Operating Notes, it instructs the pilot to make a prolonged dive.

With the longitudinal instability, the aircraft would require more more velocity to buffer against over controlling the recovery and inducing a secondary stall.

In otherwords, the low stick forces and large elevator changes for very small stick inputs make the aircraft vulnerable to secondary stalling in a normal spin recovery sequence.

The high dive speed required to recover from a spin also make the aircraft vulnerable to exceeding the airframe limits by overcontrolling.

I would not be surprised to discover the Spitfire Mk I was cleared to spin after being fitted with an inertial elevator to correct the longitudinal instability.

41Sqn_Banks

08-07-2012, 01:46 PM

Probably because a controled dive with a defined level out altitude is different from a spin with a uncontroled loss of altitude and therefore the possible increased urgency to level out before hitting the ground.

Indeed, spinning is one of the most dangerous man oeuvres. Combined with the fact that there is little to no benefit from a deliberate spin it's the simplest solution to prohibit it.

Btw I don't get why topic has so many pages. Just read the Pilot's Notes, it's all there:

- exceptional/remarkable light elevator response even at high speed, which is a good thing and a bad thing (risk of high speed stall and blackout/break up the aircraft if pilot is not carefully)
- instability in turns (elevator becomes lighter in turn)
- stall warning/buffeting/buzz (best turn rate is achieved slightly before buffeting)

Now let's look at the current FM and find out if this is represented.

winny

08-07-2012, 01:53 PM

I see you're still using the MK V as your data source for a Mk I/II.

Lmao.

Anyway, this thread is supposed to be about early mark spitfires.
Can I please see some data for a MK I or II?

I'm bored by all this Mk V stuff. It's irrelevant to CLoD.

It doesn't matter what was prohibited and what wasn't. For every single time Crumpp has said that the pilot's notes forbid something I have been able to find a combat report or pilot account where the same manouvers were done deliberately by a pilot. Brian lane deliberately entered spins, deliberately stalled etc etc.

Here we go again with the pilots notes red herring..

Pilots notes are just someone's opinion. They are not proof that prohibited manouvers were never performed. They are just a set of reccomendations. Good pilot's overcame their machines limitations on both sides.

Crumpp

08-07-2012, 01:54 PM

Being behind the airplane is a requirement to get in an accidental spin in the first place.

Just read the Pilot's Notes, it's all there

FACEPALM!!!!

From the first post in this thread AND the bugtracker....

Just some of the many references to the Longitudinal instability found in all of the early Mark Spitfires.

Spitfire Mk I Operating Notes, July 1940:

Crumpp

08-07-2012, 01:58 PM

Pilots notes are just someone's opinion. They are not proof that prohibited manouvers were never performed. They are just a set of reccomendations. Good pilot's overcame their machines limitations on both sides.

Noted Winny...

In your opinion the Operating Notes are just for sissy's.

If you ever fly an airplane, be sure to tell that to the Aviation Authority, your instructor, and your insurance company.

Put it on your resume too. Maybe NASA or ESA will hire you as a test pilot.

Probably not, but you can dream.

winny

08-07-2012, 01:59 PM

See robtek's post, 41 Banks.

Exactly, in a normal dive, it would be very unusual for the pilot to be "behind the airplane". In an accidental spin, it is very likely the pilot will be "behind the airplane".

Goes back to aviation axiom, "Never Let an Airplane take you someplace your brain did not get to at least 5 minutes before."

Right BTB,

If you read the spin recovery procedures in the Operating Notes, it instructs the pilot to make a prolonged dive.

With the longitudinal instability, the aircraft would require more more velocity to buffer against over controlling the recovery and inducing a secondary stall.

In otherwords, the low stick forces and large elevator changes for very small stick inputs make the aircraft vulnerable to secondary stalling in a normal spin recovery sequence.

The high dive speed required to recover from a spin also make the aircraft vulnerable to exceeding the airframe limits by overcontrolling.

I would not be surprised to discover the Spitfire Mk I was cleared to spin after being fitted with an inertial elevator to correct the longitudinal instability.

Yawn, how's this relevant to CLoD?

You've made your point, the elevators on the spits should be sensitive.... News flash.. In CLoD they already are.

So what would you do to the Spit in game? What would you change? Bearing in mind that stick forces are irrelevant? After god knows how many posts I've yet to hear anything from you about how the MK I or II in game is behaving incorrectly.

So, what is wrong with the current FM in CLoD?

winny

08-07-2012, 02:04 PM

Noted Winny...

In your opinion the Operating Notes are just for sissy's.

If you ever fly an airplane, be sure to tell that to the Aviation Authority, your instructor, and your insurance company.

Put it on your resume too. Maybe NASA or ESA will hire you as a test pilot.

Probably not, but you can dream.

Nice reply, attack the poster not the point... And don't put words into my mouth. Where did I say the notes were for cissys?

I didn't. I pointed out that I have pilots accounts of all of the prohibited moves you have mentioned being performed. So the pilot's notes bear no relation to what sometimes happened. Or are you going to tell me that these people who were there were lying?

Again. What changes need to be made to the MK I or II in the game?

robtek

08-07-2012, 02:06 PM

Indeed, spinning is one of the most dangerous man oeuvres. Combined with the fact that there is little to no benefit from a deliberate spin it's the simplest solution to prohibit it.

Btw I don't get why topic has so many pages. Just read the Pilot's Notes, it's all there:

- exceptional/remarkable light elevator response even at high speed, which is a good thing and a bad thing (risk of high speed stall and blackout/break up the aircraft if pilot is not carefully)
- instability in turns (elevator becomes lighter in turn)
- stall warning/buffeting/buzz (best turn rate is achieved slightly before buffeting)

Now let's look at the current FM and find out if this is represented.

Nice summarisation, that of course will be ignored by all who are looking for a dispute instead a solution.

BTB

08-07-2012, 02:44 PM

See robtek's post, 41 Banks.

Exactly, in a normal dive, it would be very unusual for the pilot to be "behind the airplane". In an accidental spin, it is very likely the pilot will be "behind the airplane".

Goes back to aviation axiom, "Never Let an Airplane take you someplace your brain did not get to at least 5 minutes before."

Right BTB,

If you read the spin recovery procedures in the Operating Notes, it instructs the pilot to make a prolonged dive.

With the longitudinal instability, the aircraft would require more more velocity to buffer against over controlling the recovery and inducing a secondary stall.

In otherwords, the low stick forces and large elevator changes for very small stick inputs make the aircraft vulnerable to secondary stalling in a normal spin recovery sequence.

The high dive speed required to recover from a spin also make the aircraft vulnerable to exceeding the airframe limits by overcontrolling.

I would not be surprised to discover the Spitfire Mk I was cleared to spin after being fitted with an inertial elevator to correct the longitudinal instability.

Look Crumpp, they said: " Allow the airplane to gather a speed of well over 150 mph, (thats not a high speed dive), before gradually easing out... " to reach this spead, thats your prolonged dive.
Recover the spinning, " there is no difficulty in recovering, provided the standard method is correclty used, i.e , full opposite rudder (maintained unter the spin stops) and stick slowly forward when recovery begins.... . " Thats what they (the Pilots) have learned since Flight school.

For all that you are trying to prove there exist advises.

Please do me a favour and make some guestflights in a Glider to understand this practically or in an aerobatic plane. Or look into some youtube videos to get an imagine how this looks like.
;D

EDit: just a few links
http://www.youtube.com/watch?v=Rne-kJgVIKY&feature=related

http://www.youtube.com/watch?v=ZU14FfPbQRo&feature=autoplay&list=ULGM9b3bbqVdk&playnext=1

http://www.youtube.com/watch?v=-8IlpENTJP4&feature=related

robtek

08-07-2012, 03:16 PM

Look Crumpp, they said: " Allow the airplane to gather a speed of well over 150 mph, (thats not a high speed dive), before gradually easing out... " to reach this spead, thats your prolonged dive.
Recover the spinning, " there is no difficulty in recovering, provided the standard method is correclty used, i.e , full opposite rudder (maintained unter the spin stops) and stick slowly forward when recovery begins.... . " Thats what they (the Pilots) have learned since Flight school.

For all that you are trying to prove there exist advises.

Please do me a favour and make some guestflights in a Glider to understand this practically or in an aerobatic plane. Or look into some youtube videos to get an imagine how this looks like.
;D

BTB, to be so condescending on such thin ice, ts ts ts.

150 mph, in a vertikal dive, with a GRADUALLY recovery, surely you'll reach a pretty high velocity before leveling out, accelerating all the time.

That is not a > 500 kg glider but a 3 ton machine with a not that much larger front surface.

BTB

08-07-2012, 03:33 PM

http://www.youtube.com/watch?v=PBes98c8RSA

http://www.youtube.com/watch?v=c4XbkwMdZvY&feature=related

http://www.youtube.com/watch?v=Kn3RfeyhGWQ&feature=relmfu

http://www.youtube.com/watch?v=_J9N8nQV6Hk&feature=related

41Sqn_Banks

08-07-2012, 04:26 PM

BTB, to be so condescending on such thin ice, ts ts ts.

150 mph, in a vertikal dive, with a GRADUALLY recovery, surely you'll reach a pretty high velocity before leveling out, accelerating all the time.

That is not a > 500 kg glider but a 3 ton machine with a not that much larger front surface.

Mass doesn't matter in vertical acceleration*. The speed doesn't instantly increase from below 150mph (second stall) to above x mph (aircraft breakup).

41Sqn_Banks

08-07-2012, 04:41 PM

CaptainDoggles

08-07-2012, 04:49 PM

Mass doesn't matter in vertical acceleration*

That's only true in a vacuum. You have to account for density (among other things) when in the atmosphere.

robtek

08-07-2012, 05:06 PM

Again I don't get the discussion. All source state that spin recovery is pretty standard for Spitfire. The only "problem" is the light elevator/relative instability, which makes precise control more difficult than in other aircraft, but this is only a issue if the pilot is not used to the aircraft.
It's like driving a car with a sensitive clutch. You must be careful on the first day, but after a week it won't make a difference and you make use of the benefits.

The thing is that if a pilot has a stall a bit closer to the ground and has to recover under stress, as the ground is rising to meet him, it takes nerves of steel to first let the speed build up to 150 mph in a vertical dive and then to gradually recover from the dive.

In the Spitfire it should be possible to overstress the plane if not done correctly as there is only about 2lbs per g stick force needed, where in other planes the pilot may not have the power to recover soon enough or to overstress the airframe.

Glider

08-07-2012, 06:03 PM

You mean like the fact it is not the specified fuel in the portion of the Operating Notes entitled "Notes on a Merlin Engine" is a strong indicator the fuel is still undergoing service testing?

I never disputed the fuels use, just the silly notion it was the only fuel available and the adopted service fuel.

Who would ever suggest they were still undergoing 100 Octane fuel testing in August of 1940 simply on the basis the facts do not align?

http://img20.imageshack.us/img20/6282/83062903.jpg (http://imageshack.us/photo/my-images/20/83062903.jpg/)

100 Octane is completely off topic. Start your own thread if you want to debate it.

These tests were on the 100 octane fuel produced in the UK as a back up in case the supplies from the USA were insufficient

Glider

08-07-2012, 06:07 PM

There might be hundreds of Spitfires being lost over sea or behind enemy lines because of mishandling in stress situations, all disregarded because being accorded to enemy action.
Nobody knows that for sure.
The only data we have is a per se incomplete list of researched accidents.

As probably 90% of Mk I and Mk II combats were over the UK I doubt that hundreds were lost behind enemy lines or over the sea. So the comment about a lack of examples is a valid one.

One has been identified in volved in a spin. Crumpps comment was typical The never changed it because a high speed dive is generally the result of spin recovery and a Spitfire pilot could break the airplane rather easilyThe fact that this example was in a high speed dive from low cloud, then did a violent pull up presumably to avoid hitting the ground, suffered a high speed stall, then spun and then had a wing failure tells me that it was far from easy to break a Spitfire wing. It was very difficult.

Edit - I should add that to say that a high speed dive is generally the result of a spin recovery is rubbish, any pilot with spin experience would know that. In combat a high speed dive is normally the result of combat, trying to evade or bounce an enemy aircraft. Spinning is slow speed activity and recovering doesn't take long you have to wait until you have sufficient speed. Its the wait that is often the more dangerous time as if you try to pull out with insufficient speed the plane tends to sink (often called mush)and can still hit the ground. Holding your nerve until speed has been reached with the ground coming up can be difficult for some pilots to learn.
If you are in a high speed spin you are normally dead whatever happens to the plane as you will be trapped by the G forces, unable to open the cockpit or get out

Crumpp

08-07-2012, 10:24 PM

150 mph, in a vertikal dive, with a GRADUALLY recovery, surely you'll reach a pretty high velocity before leveling out, accelerating all the time.

Exactly.

Your thrust vector adds to gravity, lift opposes drag <unless you dive a zero lift angle>

In short, away you go...

in an aerobatic plane.

Like the one in my hanger???

That passenger is Col. Phil Lacey.

The Fitzpatrick Custom was just a dream in 1947 when a former World War II fighter pilot, Phil Lacey, showed his friend Al Fitzpatrick some of his car sketches.

Read more: http://www.autoweek.com/article/20060911/free/60830003#ixzz22txOQq1j

Col. Lacey flew P-40's, P-39's, and P51's with the 8th USAAF in World War II. In Korea he flew F-86's and Vietnam, Canberra bombers.

You don't what aerobatics is until you seen Phil take the stick, LOL. That old man can fly the paint off an airplane.

And yes, he reads and abides by the Operating Notes.....

Crumpp

08-07-2012, 10:31 PM

I should add that to say that a high speed dive is generally the result of a spin recovery is rubbish

Read the Operating Notes.....

150 mph, in a vertikal dive

BTW, you are not necessarily going to be vertical nor is certain you will enter a high speed dive.

There is a good possibility of that happening.

Sandstone

08-07-2012, 11:04 PM

Wow, Lacey must be one of the oldest aerobatic pilots flying. At least 92, I'd guess, if he flew in WWII. Good for him!

bongodriver

08-07-2012, 11:23 PM

Exactly.

Your thrust vector adds to gravity, lift opposes drag <unless you dive a zero lift angle>

In short, away you go...

Negative....if you are throttle closed then there is no thrust vector to add and a disking prop adds to drag, acceleration is 'not' infinite (see Captaindoggles post for a reason), in some aircraft a vertical dive will not even reach Vne.

since when did lift oppose drag?, lift opposes weight and thrust opposes drag, lift actually adds to drag because lift generates induced drag, if you fly at 'zero lift' then there is no induced drag.

Like the one in my hanger???

Ohh!....a thorp t18....that's gotta be one of the ugliest mothers I've ever seen.

That passenger is Col. Phil Lacey.

Col. Lacey flew P-40's, P-39's, and P51's with the 8th USAAF in World War II. In Korea he flew F-86's and Vietnam, Canberra bombers.

You don't what aerobatics is until you seen Phil take the stick, LOL. That old man can fly the paint off an airplane.

And yes, he reads and abides by the Operating Notes.....

Is this supposed to convince us you know what you are talking about? because I'm even less convinced of that now.

Glider

08-07-2012, 11:25 PM

A couple of obvious points,
1) if you are in a verticle dive then you are already going 150 + or will be in seconds so there is no delay
2) gradual will be smoothly for obvious reasons you dont want to exceed VNE or hit the ground, its a balance.

And we still don't have any accidents the acid test of fragility

PS please show me where is says that a high speed dive is generally the result of a spin recovery

IvanK

08-07-2012, 11:29 PM

"Spin training, upset, and unusual attitude training is essential to a fighter pilots core mission."

Actually Crumpp I think you might find that in EVERY current front line fighter deliberate spinning is prohibited !

Upset and unusual attitude training is in fact an essential requirement for every pilot, its mandated for Instrument ratings (in most countries). These terms were not used in WWII and are relatively recent terms.

As for spin training that should imo be mandatory as well ... sadly however it has been removed from the basic syllabus in a lot of countries.

As to this importance being placed on 150MPH before attempting recovery ... baloney !! that is a typical academic approach (as is this entire thread !) to the written word. Its in there to provide guidance to the lowest common denominator. As we all know after recovering from an unintentional spin, its simply a matter of getting your s... in one pile then smoothly recovering from the dive ... no magic just normal piloting to not depart the thing again. Its just like the 90degree nose down at low level scenario (you know the one you didn't want to be in in an aeroplane with stability issues) I suggested earlier .. you going to wait for 150 and risk hitting the ground or get on with your pilot stuff and "Fly the aeroplane" !

We should be able to crack the 1000post mark on this "never ending story" soon... just 100 posts to go.

By the way where is the in game test data in in Ver 1.08.18956 to support your bugtracker entry ?

Glider

08-07-2012, 11:37 PM

As for spin training that should imo be mandatory as well ... sadly however it has been removed from the basic syllabus in a lot of countries.

Its mandatory in the UK for Glider Pilots before they go solo. The test is to enter a full spin at 1,000ft (yes one thousand) from a variety of different scenarios and recover. Trust me at that height you dont see the world go around, just the tree that is in front of you. Its always a B_____ C_____ moment the first time you let a student do it

NZtyphoon

08-08-2012, 12:04 AM

Getting back to Crumpp's very first posting to start this thread

Amoung the Western Front warring powers during World War II, only two nations had measurable and definable stability and control standards. The two nation were the United States and Germany.

We also have Crumpp stating:

Here is the USAAF and USN standards adopted in 1944.

During October 1944, the National Advisory Committee conducted a series of conferences with the”Army, Navy, and representatives of the aircraft industry for the purpose of discussing the flight-test procedures used in measuring the stability and control characteristics of airplanes. The conferences were initiated by the Army Air Forces, Air Technical Service Command, to acquaint the flight organizations of the industry with the flight
test methods employed by the NACA and to standardize the techniques insofar as possible as they are employed by the various manufacturers and agencies engaged in determining the flying qualities of airplanes

Ergo: Not one of the aircraft fielded by the Americans during WW2 was designed to Crumpp's set of "standards" - until things were standardised some time after a series of conferences held in October 1944 the American aviation industry was operating to a similar system to that of the British. This whole waste of time argument has been a huge red herring by Crumpp because it is completely irrelevant to anything to do with the design of the Spitfire. :!:

Let's not be obtuse. I never said there was no research in stability and control.

I said they stagnated into an attitude that flying qualities was an academic exercise and that the pilot's opinion was what was practical.

Big difference from what you are claiming.

The NACA took a different route. They developed techniques as well as equipment to measure and quantify behaviors. Part of that system was training test pilots and developing manuevers to define behaviors within flying qualities. In fact, it was Cooper's experience as a test pilot at the NACA that led to the development of the Cooper-Harper Rating scale.

http://www.google.com/url?sa=t&rct=j&q=cooper%20rating%20aircraft%20handling%20naca&source=web&cd=4&sqi=2&ved=0CFQQFjAD&url=http%3A%2F%2Fhistory.arc.nasa.gov%2Fhist_pdfs% 2Fbio_cooper.pdf&ei=yvYgUMzyGon06AGpkYCwCw&usg=AFQjCNHJ2ORdKQ0QHE5XzIxnwH4SfCszng

And When did Cooper become a Test Pilot for NACA? 1945! NACA was as dependent on test pilot's opinions as any other nation throughout most of WW2 and probably beyond.

The fact that the Spitfire did not meet some of NACA's criteria, formalised in 1941, should be of no surprise to anyone - I would suggest very few aircraft designed during the late 30s would have met NACA's criteria in full. This thread has been a complete waste of time. :evil:

Crumpp

08-08-2012, 12:34 AM

Who said anything about infinite acceleration?

....if you are throttle closed then there is no thrust vector

Did they teach you this in your flight training? I highly doubt it.

Wow, guy....

lift opposes weight and thrust opposes drag,

Only in level flight...

Check out a climb triangle, pilot. A dive is the same as a climb, only difference is how we sum the force vectors.

Weight changes at the sine of the angle.

Sine 90 = 1

When you point the nose straight down (90 degrees), all the weight becomes thrust.

So even though you pull back the throttles on your 2000 hp WWII fighter that weighs 7000 lbs....

Let's see...

Sine 90 * 7000lbs = 7000 lbs of thrust going straight down!

Compare that too:

2000hp*.8np = 1600thp

Thrust @ 150 mph = (1600thp*325)/130.35Kts = 3989.26lbs of thrust.

So you instead of the 4000lbs of thrust available from your engine at full throttle, you have only added almost twice as much at 7000lbs!!

lift actually adds to drag because lift generates induced drag, if you fly at 'zero lift' then there is no induced drag.

The lift vector is now shifted 90 degrees. The wing still generates lift but it is only opposed by drag. (Weight cosine 90 = ZERO)

The plane will not fly straight down unless held at the zero lift angle of attack. Instead, lift will accelerate it on x-axis or what you know as the Thrust and Drag axis from level flight.

Yes there is induced drag too.

since when did lift oppose drag?,

In a verticle dive.

All this is off topic, take it somewhere else.

Start a new thread if you want to understand the forces of flight.

Actually Crumpp I think you might find that in EVERY current front line fighter deliberate spinning is prohibited !

Most fly by wire systems are set up to act as antispin devices. It does happen on accident though. It is generally not recommended for training because of the relaxed stability of most Fly by Wire fighters.

Sort of like the longitudinal instability of the Spitfire...only much more extreme.

As for spin training that should imo be mandatory as well ... sadly however it has been removed from the basic syllabus in a lot of countries.

Absolutely. It was a requirement for my CFI. Accelerated stalls are back too for Commercial certs. I was glad to see that.

Crumpp

08-08-2012, 12:37 AM

NACA was as dependent on test pilot's opinions as any other nation throughout most of WW2 and probably beyond.

No, it was dependant upon a set of defined standards and measured results.

Pilot opinion was a factor of secondary importance. He was a monkey in the cockpit that operated the measuring equipment and flew the specific profiles.

He did not fly around on a sunny day to report back how wonderful the airplane felt.

Crumpp

08-08-2012, 12:48 AM

Ergo: Not one of the aircraft fielded by the Americans during WW2 was designed to Crumpp's set of "standards" - until things were standardised some time after a series of conferences held in October 1944 the American aviation industry was operating to a similar system to that of the British. This whole waste of time argument has been a huge red herring by Crumpp because it is completely irrelevant to anything to do with the design of the Spitfire.

:rolleyes:

Only a few narrow minded individuals see this as some attack on their favorite gameshape.

It is the measured and defined flying qualities that make up the "personality" of the airplane.

These characteristics are what make an early Mark Spitfire a unique airplane with its own individual behaviors.

Of course, not all of the airplanes, like the Spitfire, met every requirement. Nobody has claimed anything different. Most were designed before there were any defined standards.

The NACA standards provide a good frame of reference to model these behavior because they measured and defined so many of the WWII aircraft. Most of these airplanes were fixed as a result but many served for long periods of time before their flying qualities were evaluated under a measured and defined system.

That gives us some great information to see those flying qualities added to the game.

Otherwise, it is not much of simulation of a specific airplane if the gameshape does not have the same flying qualities as the airplane it supposed to represent.

This has nothing to do with how well an airplane turns, how fast it goes, climb, or any specific performance. This has to do with how the airplane behaves in achieving that performance.

IvanK

08-08-2012, 01:11 AM

"Otherwise, it is not much of simulation of a specific airplane if the gameshape does not have the same flying qualities as the airplane it supposed to represent."

Other than quoting reams of academic data this is the very thing you are yet to prove.

You have raised a Bugtracker tracker entry on a subject but have yet to provide any proof to support it that in fact it is a bug in game. You have by your own admission not flown the Sim that much or for example kept up to date with the numerous Beta patches. You opined that gun recoil should be modelled, If you flew the sim you would know that in fact it is.

When you started this thread its purpose was to discuss this issue as it pertained to early mark spitfires IRL, not for a bug tracker entry. It then morphed into this academic treatise that spawned your bug tracker entry. When are you going to actually do some some in game flight testing to actually substantiate your claim that the FM is porked in the Sim ?

NZtyphoon

08-08-2012, 01:16 AM

No, it was dependant upon a set of defined standards and measured results.

Pilot opinion was a factor of secondary importance. He was a monkey in the cockpit that operated the measuring equipment and flew the specific profiles.

He did not fly around on a sunny day to report back how wonderful the airplane felt.

What a sad, sad commentary on Crumpp's attitude towards test pilots who often put their lives on the line in all countries. I wonder what Chuck Yeager, Richard Bong or Bill Bridgeman and others would say and do to Crumpp were he to tell them that they were nothing but monkeys in a cockpit operating measuring equipment and flying set profiles...one can only dream! :grin::grin::grin:

Crumpp

08-08-2012, 01:37 AM

You have raised a Bugtracker tracker entry on a subject but have yet to provide any proof to support it that in fact it is a bug in game.

Dive to Vne, stomp on the rudder, and pull back as hard as you can.

Fly the airplane in the buffet and time your turn.

Pull back on the stick, release, and note the behavior of the airplane.

Fly at Vmax, pull hard back, hold it at full deflection, and note the behavior.

Fly the airplane trimmed for slow flight, let go of the stick, fire the guns, and note the behavior.

I have played the game and note the behaviors as I play. Just because I don't spend my time making excel spreadsheets does not mean the points are invalid.

NZtyphoon

:rolleyes:

Crumpp

08-08-2012, 01:45 AM

The job of a Test Pilot as per MIL-Spec Standards...

http://img838.imageshack.us/img838/605/testpilot.jpg (http://imageshack.us/photo/my-images/838/testpilot.jpg/)

Same as it was under the NACA.

DC338

08-08-2012, 02:39 AM

Why don't you read the rest of the statement. The must be some pretty smart monkeys.
Still waiting for analysis of figures 16 17 18 and why 15 isn't an anomaly.

IvanK

08-08-2012, 02:43 AM

"I have played the game and note the behaviors as I play. Just because I don't spend my time making excel spreadsheets does not mean the points are invalid."

No just your gut feeling not actually measured and or recorded. You post so many charts to support your statements in this thread then jump in the sim and just wing it !

NZtyphoon

08-08-2012, 02:44 AM

Pilot opinion was a factor of secondary importance. He was a monkey in the cockpit that operated the measuring equipment and flew the specific profiles.

Contrast this with Crumpp's own posting on what was required by his "monkey(s)"...

http://i91.photobucket.com/albums/k304/Major_Sharpe/testpilot.jpg

Which is also a good description of the test pilot responsible for developing the Spitfire.

Alex Henshaw, chief test pilot at the Castle Bromwich factory, wrote, “Jeffrey’s greatest gift to those technicians with whom he worked was his concise analysis of technical problems and his ability to articulate them in a language they clearly understood. Last but not least was the complete integrity of his test reports.”

Fly the airplane trimmed for slow flight, let go of the stick, fire the guns, and note the behavior.

I have played the game and note the behaviors as I play. Just because I don't spend my time making excel spreadsheets does not mean the points are invalid.

Yep, let go of the stick and fire those guns just like real pilots! :grin::grin::grin:

IvanK

08-08-2012, 03:32 AM

In the end it comes down to the last sentence as underlined here, Mr Mel Gough NACA :

http://i40.photobucket.com/albums/e215/zulu64/Jointftrconf1.jpg
Report of joint Fighter Conference NAS Patuxent River, MD 16-23 Oct 1944.

And the end user of the Spitfire the combat fighter pilot was very happy !

CaptainDoggles

08-08-2012, 03:44 AM

In the end it comes down to the last sentence as underlined here, Mr Mel Gough NACA :

...

And the end user of the Spitfire the combat fighter pilot was very happy !Nobody's saying the pilots weren't happy. Why is this relevant?

Glider

08-08-2012, 09:05 AM

Nobody's saying the pilots weren't happy. Why is this relevant?

Because it shows how important the test pilots views are

NZtyphoon

08-08-2012, 09:40 AM

It is the measured and defined flying qualities that make up the "personality" of the airplane.

These characteristics are what make an early Mark Spitfire a unique airplane with its own individual behaviors.

Otherwise, it is not much of simulation of a specific airplane if the gameshape does not have the same flying qualities as the airplane it supposed to represent.

This has nothing to do with how well an airplane turns, how fast it goes, climb, or any specific performance. This has to do with how the airplane behaves in achieving that performance.

To mitigate the fact players could dial out the most important characteristic that made an early mark Spitfire unique, the sensitive elevator and heavy ailerons. Since players are going to cheat, developers can too. I did this in Warbirds and it worked great when I did the Bf-109 and Spitfire models.
If an accelerated stall is reached, the aircraft spins. This keeps players in the mindset to stay off the stall point.

So it eliminates a nice feature of the Spitfires stall characteristic but realistically, Spitfire pilots did not seek the stall except as rare method to escape an unwanted combat. If the players are going to cheat, let the developers do so as well.

Not only has Crumpp failed to realise that this is a flight sim, with all the variables of hardware and software adopted by players, he is also proposing to make the Spitfire so hard to fly by inexperienced gamers that many will just give up after constantly crashing and burning, or having the plane fly apart, as soon as they make a small mistake. He also wants to deny players even the option of using the Spitfire's good stall characteristics.

klem

08-08-2012, 09:49 AM

Dive to Vne, stomp on the rudder, and pull back as hard as you can.

Fly the airplane in the buffet and time your turn.

Pull back on the stick, release, and note the behavior of the airplane.

Fly at Vmax, pull hard back, hold it at full deflection, and note the behavior.

Fly the airplane trimmed for slow flight, let go of the stick, fire the guns, and note the behavior.

I have played the game and note the behaviors as I play. Just because I don't spend my time making excel spreadsheets does not mean the points are invalid.

What were your five results, what were your expectations and how did you come by them?

Crumpp

08-08-2012, 10:27 AM

The must be some pretty smart monkeys.

Yes they are very intelligent, disciplined, and highly educated. It is one of the toughest jobs in existence.

Damn now he has a CFI I say this as before Crump only claimed a PPI.

I am sorry. Do I need your permission to get ratings, train, and get a job flying? You are not hireable as a PPI.

Who do you people think you are????

Crumpp

08-08-2012, 10:59 AM

No just your gut feeling not actually measured and or recorded. You post so many charts to support your statements in this thread then jump in the sim and just wing it !

If I had the time I would. Why do you think it has taken so long for me to get the post's out in this thread.

I don't put food on my table by helping to develop realistic flight simulators.

However, I have another source of income, a family to support, and all the things that come with that.

Crumpp

08-08-2012, 11:57 AM

In the end it comes down to the last sentence as underlined here, Mr Mel Gough NACA :

Mel Gough was a test pilot for the NACA.
The quote is in the context of the meeting to determine stability and control standards for the individual services, the US Navy and Army Air Corps.

The NACA already had developed stability and control standards and Mel Gough was a co-developer of those standards.

The end result is the document posted below. It did not result in things being left up to "how much instability one can stand".

In fact, Mel Gough was one of the pioneers in eliminating the "pilot opinion" standard.

The handling qualities of all future airplanes would be based on the parameters they outlined. Up to that time a pilot would fly an airplane, and the attitude was, “Well, if you go back and fly it the second time, it must be a good airplane.” Or the pilot would be asked, “What is it that you like about the plane?” And those early-time pioneer pilots would try to describe what it was they liked about the airplane. Whether the stick forces seemed too heavy or if the plane didn’t roll fast enough, etc. It was all kind of subjective stuff based on pilots’ opinions.

Then Mel and Bob decided, “Let’s quantify this. Let’s put some numbers to these opinions.” What is it that a pilot likes in a fighter as well as in all other categories of planes? What does the pilot want to feel? What response is he looking for? How much G [gravitational] force does he want to pull? How much can he handle in a roll? When does he get uncomfortable or reach his limit of physical response. Is any of this different in a fighter or a bomber? Does he expect the same stick forces and rudder forces in a fighter as he does in a bomber?
So all of that became a matter of negotiation, and between the two of them, the pilot and the engineer, they quantified the parameters. They wrote what I call a bible of stability and control and described what ideal handling qualities are in any type of aircraft. It was no longer up to the designer and manufacturer to produce and present a product that was satisfactory to their designers and test pilots. It was a mandate to meet the requirements outlined by NACA.

http://www.google.com/url?sa=t&rct=j&q=mr%20mel%20gough%20naca&source=web&cd=4&sqi=2&ved=0CFQQFjAD&url=http%3A%2F%2Fwww.jsc.nasa.gov%2Fhistory%2Foral _histories%2FNACA%2FCavalloSA_9-30-05.pdf&ei=-kciUMPqEIXF6wG-_IGIDw&usg=AFQjCNGWy3TZRl0zWlrYI69j8yvj-7PvKg

The result is attached. It is the quantified answer to the question, "How much instability can one stand?"

In England, Jeffery Quill was the Chief Test Pilot for the development of the Spitfire. If it met his standards in his opinion, without quantification, it went forth despite the some early testing investigating the longitudinal instability, his acknowledgement, and all the warnings found in the Operating Notes that are the result of longitudinal instability.

It was not until the design was evaluated under a set of measured and defined standards that the longitudinal instability was quantified and fixed in the Spitfire.

IvanK

08-08-2012, 12:16 PM

And supposedly the clod spitfire doesn't in YOUR opinion meet some standards in your mind that you refer to without quantification.

All this stuff about things being measurable and to defined standards then when asked how you find them in the Sim all we get is:

"Fly the airplane in the buffet and time your turn.

Pull back on the stick, release, and note the behavior of the airplane.

Fly at Vmax, pull hard back, hold it at full deflection, and note the behavior.

Fly the airplane trimmed for slow flight, let go of the stick, fire the guns, and note the behavior.

I have played the game and note the behaviors as I play. Just because I don't spend my time making excel spreadsheets does not mean the points are invalid."

When others actually go out there test and document and show their results you jump on them questioning every detail of their efforts. ... what were the conditions etc etc.

Please give us a break and at least practice what you preach !

DC338

08-08-2012, 12:27 PM

It was not until the design was evaluated under a set of measured and defined standards that the longitudinal instability was quantified and fixed in the Spitfire.

Can you explain this further. Fixed As a result of NACA? How? Surely not.

Can we have a analysis of figures 16 17 & 18 pointing to the instability in these test? It would appear tha 15 is an anomaly when compared to the later test.

Crumpp

08-08-2012, 01:44 PM

Can we have a analysis of figures 16 17 & 18 pointing to the instability in these test? It would appear tha 15 is an anomaly when compared to the later test.

It is different conditions.

In Figure 15 we see the result of the pilot just pulling the stick back and entering a turn. That is the inherent stability of the aircraft without pilot input. It tells us the workload the pilot needs to exert.

In figure 16, he pushes the stick forward in the measuring equipment.

In figure 17 and 18, he demonstrates the stability thru careful flying.

Figure 15, In other words it is the measured results of what happens if you are new player and you turn the Spitfire and keep the stick pulled back like a stable aircraft to maintain the turn.

In figure 16 we see the proficient but not the expert at controlling the aircraft. He pushes forward and his ability to control the aircraft improves. He still is not getting that steady level of acceleration.

In figure 17 and 18, we see the pilot carefully matches the unstable accelerations to produce a steady level of acceleration.

Klem,

The aircraft in the game acts stable both static and dynamic. It returns to trim and dampens the oscillation. Only in a steady state climb does it begin to act neutral.

I don't know the games code, but it seems like they made it "just statically stable" in level flight without the dynamic instability. When an aircraft enters a climb, the stability margin is reduced so we see the neutral static stability.

The spin modeling is excellent for a game. It took an average of at least two turns to recover when correct input was held. I liked it.

The stall behavior when reached is good too.

The issue is the amount of control required to maintain a turn is not representative of the longitudinal instability.

The inability to exceed the airframe limits. You can pull as hard as you want on the stick without fear of breaking the airplane.

The buffet effects are under modeled. In the game, The turn rate improves IN the buffet without any advantage for correctly flying a maximum turn rate performance turn. The turn performance does not begin to taper off until just before the stall when the slope becomes rather steep. That is not correct. Turn rate should decay in the buffet as a function of the strength of the buffet.

The buffet itself is under modeled. It is like a nibble when we see from the NACA report it imparted noticeable accelerations on the aircraft. Those accelerations are quantified in figures 13 and 14 of the NACA report.

In other words, your turn rate in the game improves in the buffet until just before the stall point and the airplane does not shake as the real thing.

That is part of the stall warning. The idea is to have it so you know to back off and not stall. It is essential to the control of an longitudinally unstable aircraft to have that large and distinct stall warning as well as the ability to maintain control in it. The large accelerations warn of the impending stall and increase the power required to make the turn. This also encourages realism. He rewards the players that fly on the edge to the nibble and back off to smooth air. It has the added benefit of precisely defining that point to an experience player.

Crumpp

08-08-2012, 02:16 PM

you jump on them questioning every detail of their efforts.

I am sorry if that is your perception. It is not the case or my intention.

I only post to try and help the testor's efforts.

For example, posting aircraft performance test's without the conditions for both aircraft and atmosphere does not tell one if the airplane is performing at it should under other conditions.

It should not be surprising that those questions come up when the information is not presented only the results.

NZtyphoon

08-08-2012, 10:29 PM

In England, Jeffery Quill was the Chief Test Pilot for the development of the Spitfire. If it met his standards in his opinion, without quantification, it went forth despite the some early testing investigating the longitudinal instability, his acknowledgement, and all the warnings found in the Operating Notes that are the result of longitudinal instability.

It was not until the design was evaluated under a set of measured and defined standards that the longitudinal instability was quantified and fixed in the Spitfire.

Alas Jeffrey Quill - he spent thousands of hours in flight, testing and developing real Spitfires in real conditions, and thus we find out that he had no idea of what he was doing by an American sitting in front of a computer who had "tested" the Spitfire a couple of times on a flight sim and he did find it wanting. And because of Quill Spitfires went forth unstable and drunken in their flight.

Thus it was the Yanks who came to the rescue and fixed the hitherto unstable machine by waving their magic flight reports and inertia weights and speaking in unison "Fix this Spitfire it does not meet our standards!" The British quavered and lo! they fixed the Spitfire forever. And the tale told by Quill, that the inertia weights were fitted after the discovery of badly loaded Spitfire Vs in Fighter Command service was horse pucky.

Crumpp

08-08-2012, 11:20 PM

Thus it was the Yanks who came to the rescue and fixed the hitherto unstable machine by waving their magic flight reports and inertia weights

1. Did inertial weights get added to the design to fix the Longitudinal instability....YES.

2. Did this occur during the Battle of Britain.......NO, the longitudinal instability was not fixed during the Battle of Britain.

3. Should the Spitfires modeled in the game exhibit the longitudinal instability.....YES.

4. Do they now exhibit the longitudinal instability in the game....NO.

As "yanks coming to the rescue"....that is a very myopic view and far from the truth.

It was Gates and Lyon's efforts that brought a measureable standard to the UK aviation authority. Yes he based those standards on the NACA's efforts just as the NACA based part of their standards on his work.

And the tale told by Quill, that the inertia weights were fitted after the discovery of badly loaded Spitfire Vs in Fighter Command service was horse pucky.

And I suppose they added the inertial elevators to the Spitfire Mk I because nobody in the RAF could read a load plan or do a weight and balance?

I am sure there was an issue in the Mk V when it first came out with the operators incorrectly loading the aircraft. That certainly did not help the longitudinal instability of the design making a bad situation much worse, but it was not the reason for the longitudinal instability.

Crumpp

08-08-2012, 11:27 PM

Can you explain this further. Fixed As a result of NACA? How? Surely not.

The inertial devices added to the elevator control is the fix for the longitudinal instability.

You add weights to the control and those weights act to artificially increase the amount of control force required.

NZtyphoon

08-08-2012, 11:58 PM

Bug #415 and this thread (http://www.youtube.com/watch?v=S-Xrlf3taEo)

Crumpp

08-09-2012, 12:59 AM

Bug #415 and this thread

Maybe, but it is not because the stability and control characteristics are modeled in the game or that they cannot be modeled.

More to do with community politics than aircraft behaviors.

Crumpp

08-09-2012, 02:49 AM

IvanK says:
When you started this thread its purpose was to discuss this issue as it pertained to early mark spitfires IRL, not for a bug tracker entry

I thought you all wanted realism in your game. I see that is not the case.

IvanK

08-09-2012, 03:25 AM

I thought you all wanted realism in your game. I see that is not the case.

LOL When you have spent 1/10th of the time that many of us have supporting realism, providing original source documentation,testing utilities, face to face meetings overseas with the devs and testing in the IL2 classic and IL2 CLOD come and talk about not wanting realism.

bongodriver

08-09-2012, 07:40 AM

So....can we have a 109 thread now?

klem

08-09-2012, 09:25 AM

It is different conditions.

In Figure 15 we see the result of the pilot just pulling the stick back and entering a turn. That is the inherent stability of the aircraft without pilot input. It tells us the workload the pilot needs to exert.

In figure 16, he pushes the stick forward in the measuring equipment.

In figure 17 and 18, he demonstrates the stability thru careful flying.

Figure 15, In other words it is the measured results of what happens if you are new player and you turn the Spitfire and keep the stick pulled back like a stable aircraft to maintain the turn.

In figure 16 we see the proficient but not the expert at controlling the aircraft. He pushes forward and his ability to control the aircraft improves. He still is not getting that steady level of acceleration.

In figure 17 and 18, we see the pilot carefully matches the unstable accelerations to produce a steady level of acceleration.

Klem,

The aircraft in the game acts stable both static and dynamic. It returns to trim and dampens the oscillation. Only in a steady state climb does it begin to act neutral.

I don't know the games code, but it seems like they made it "just statically stable" in level flight without the dynamic instability. When an aircraft enters a climb, the stability margin is reduced so we see the neutral static stability.

The spin modeling is excellent for a game. It took an average of at least two turns to recover when correct input was held. I liked it.

The stall behavior when reached is good too.

The issue is the amount of control required to maintain a turn is not representative of the longitudinal instability.

The inability to exceed the airframe limits. You can pull as hard as you want on the stick without fear of breaking the airplane.

The buffet effects are under modeled. In the game, The turn rate improves IN the buffet without any advantage for correctly flying a maximum turn rate performance turn. The turn performance does not begin to taper off until just before the stall when the slope becomes rather steep. That is not correct. Turn rate should decay in the buffet as a function of the strength of the buffet.

The buffet itself is under modeled. It is like a nibble when we see from the NACA report it imparted noticeable accelerations on the aircraft. Those accelerations are quantified in figures 13 and 14 of the NACA report.

In other words, your turn rate in the game improves in the buffet until just before the stall point and the airplane does not shake as the real thing.

That is part of the stall warning. The idea is to have it so you know to back off and not stall. It is essential to the control of an longitudinally unstable aircraft to have that large and distinct stall warning as well as the ability to maintain control in it. The large accelerations warn of the impending stall and increase the power required to make the turn. This also encourages realism. He rewards the players that fly on the edge to the nibble and back off to smooth air. It has the added benefit of precisely defining that point to an experience player.

OK, let me stick my neck out a mile and try to find some common ground.

I'm no aerodynamicist but all Crump is saying is that the low level of longitudinal stability of the Spitfire is not properly represented in the game and the buffet/stall characteristics are not right. I haven't tried it or flown it on the edge (I've only flown it once since the patch) so I don't know but it would be nice to have the characteristic and helpful pre-stall buffet and I think what Crump is saying is that the FM doesn't provide it.

However I think most of us are currently concerned with more significant issues like it is (was?) too damn slow and perhaps that has led to a low tolerance level for this particular issue. Again, I haven't tried the Spit more than one sortie because I've been concentrating on the Hurricane which is also too slow. Whether it is the power modelling of the Merlin III, prop modelling, drag modelling or some other aspect we don't know either but that's another thread.

I think the basic argument may have value but what does come across is entrenched attitudes on a personal level and arguments about whether NACA findings should or should not be used. Apparently these came much later but should they be used as a reference if they are correct for the Spit MkI/II? Their validity has been challenged because of NACA's own admissions about possible errors. OK, forgive me for not trawling through all 94 pages of the thread but where are the relevant RAE or A&AEE or other British data for the same problem? If longitudinal instability was a fact the data should show that and the thread could come back on track.

Perhaps instead of binding himself to NACA Crump would accept historical data other than NACA's and use that in his explanation of "Stability and Control characteristics of the Early Mark Spitfires". His point should hold good if the basic premise is correct, i.e. longitudinal stability is not modelled properly.

The real shame of the thread, whether you agree with NACA or not, is that Crump set out to explain something and it has been shoved off track by arguments of various kinds including red herrings like differences in players joysticks. As several early posts said, its something worth pursuing in the battle to get the FM as near correct as possible. Just need to agree the data.