A newbies impression of the 109 and spit

[Kurfürst]

[QUOTE=BlackbusheFlyer;419116]Sorry Kurfurst but you are wrong about the spit elevators, they were sensitive yes but can in no way way be classed as ultra sensitive. I am a real world aerobatic pilot generally flying a Pitts special, and have flown many aerobatic types. The elevator on these aircraft IS sensitive, much much more so than the Spit. The Spitfire that went into service was and always has, been described as having well balanced controls (a twitch elevator would not accord this distinction!).

I would have respectfully disagree with you assessment, particularly about control harmony. It was a weak part of Spitfire control, as the elevator indeed touchy, while. One Spitfire pilot described the phenomenon as 'touching the elevator with a light fingertip, while arm-wrestling the ailerons'. I would suggest you to study the Spitfire II pilot notes on control aspects, basically they all about instability in pitch and poor control harmony, here: http://forum.1cpublishing.eu/showpos...17&postcount=4

It particularly challenging thing to do when flying near the stall, NACA for example found that the stall boundary on the controls was very small, just 3/4 inch of stick movement having been found between the first sign of stall and actual stall. This was offset party of course by ample stall warnings and otherwise good stall characteristics, but it took an experienced pilot to fly the aircraft to its limits.

It is a well known fact that the British aircraft types were much more forgiving than the German equivalents, a factor in itself in the supremacy of the Spitfire over the ME109 during the Battle of Britain. You had 'green' pilots on both sides, but the Spitfire was markedly easier to fly for those pilots allowing inexperienced pilots to get more out of the machine than was typical of the Germans.

Again, an urban myth. British reports from the time readily admit the opposite. See:
http://kurfurst.org/Tactical_trials/...ls/Morgan.html

5. Fighting Qualities of the Me. 109. – 5.1. Dog-fights with Spitfire and Hurricane.

Mock fights were staged between the Me. 109 and a Spitfire, both flown by pilots of the R.A.E. In addition a number of fighter pilots, all of whom had recent experience of operational flying, visited the R.A.E. with their Spitfires and Hurricanes in order to practice combat with the Me.109 ; during these fights the Me.109 was flown by an R.A.E. pilot who had completed the handling tests described earlier in this report, and was thus thoroughly familiar with the aircraft and could be expected to get the best out of it. A brief account of the information provided by these fights has already been publishedlO. The following notes summarise the results obtained.

The arrangements were for the aircraft to take off singly and meet at about 6,000 ft. The Me.109 then went ahead and commenced to turn as tightly as possible to see if it would out-turn our own aircraft. After doing three or four tight turns in both directions the Me.109 was put into a dive, followed by a steep climb. The aircraft then changed position and repeated the above programme, after which the pilots engaged in a short general fight.

When doing tight turns with the Me.109 leading at speeds between 90 m.p.h. and 220 m.p.h. the Spitfires and Hurricanes had little difficult in keeping on the tail of the Me. 109. During these turns the amount of normal g recorded on the Me. 109 was between 2½ and 4 g. The aircraft stalled if the turn was tightened to give more than 4 g at speeds below about 200 m.p.h. The slots opened at about ½ g before the stall, and whilst opening caused the ailerons to snatch ; this upset the pilot's sighting immediately and caused him to lose ground. When the slots were fully open the aircraft could be turned quite steadily until very near the stall. If the stick was then pulled back a little more the aircraft suddenly shuddered, and either tended to come out of the turn or dropped its wing further, oscillating meanwhile in pitch and roll and rapidly losing height ; the aircraft immediately unstalled if the stick was eased forward. Even in a very tight turn the stall was quite gentle, with no tendency for the aircraft to suddenly flick over on to its back and spin. The Spitfires and Hurricanes could follow the Me.109 round during the stalled turns without themselves showing any signs of stalling.

The good control near the stall during these turns at full throttle contrasts with the results obtained from the ADM. 293 tests (section 4.42)) for when gliding the aircraft becomes unsteady at 10 m.p.h. above the stall. Slipstream thus appears to have a steadying influence on the behaviour of the Me.109 near the stall.

After these turns the Me.109 was put into a steep dive at full throttle with the airscrew pitch coarsened to keep the r.p.m. down. It was found that both the Hurricanes and the Spitfires could keep up with the Me.109 in the dive; the aircraft with constant speed airscrews could do this more readily than those with two-pitch airscrews. The ailerons and elevator of the Me.109 became so heavy in the dive that rapid manceuvring was impossible, while, as explained in section 4.22, banked turns could be done more readily to the right than to the left because of the absence of rudder bias.

The Me.109 was then pulled out of the dive and climbed at a very low airspeed at an unusually steep attitude. The aircraft was under perfect control during the climb, and could be turned with equal facility in either direction. Under these conditions it outclimbed our aircraft in most cases, since most of our pilots climbed at a higher airspeed and a flatter angle, keeping below the Me.109 and waiting for it to come out of the climb.

However, other pilots who chose to climb at very low airspeeds, mainly those with constant-speed airscrews, succeeded in keeping on the tail of the Me.109, although the Me.109 pilot thought they would have difficulty in keeping their sights on him steadily, as he was at a steeper attitude than their sights could " line ".

In most cases this steep climb at low airspeed was the only manceuvre whereby the Me.109 pilot could keep away from the Hurricane or Spitfire. During the general fighting which folIowed the set programme, one other feature of advantage to the Me.109 emerged. If a negative g is put on the aircraft for a short time, the engine does not cut as it is of the direct injection type; whereas on the Spitfire or Hurricane the engine immediately splutters and stops when negative g is applied, because the carburettor quickly ceases to deliver petrol under these conditions. Hence the Me. 109 pilot found that a useful manceuvre when being chased was to push the stick forward suddenly and do a semi-bunt, if our fighters followed him their engines cut giving the Me.109 a chance to get away ; this was particularly useful against the Hurricane, as its top level speed is less than that of the Me. 109 so that once the Me. 109 had escaped in this way it could avoid combat. The Spitfire, on the other hand, soon caught the Me.109 after this manceuvre.

When the Me.109 was following the Hurricane or Spitfire, it was found that our aircraft turned inside the Me.109 without difficulty when flown by determined pilots who were not afraid to pull their aircraft round hard in a tight turn. In a surprisingly large number of cases, however, the Me. 109 succeeded in keeping on the tail of the Spitfire or Hurricane during these turning tests, merely because our Pilots would not tighten up the turn suficiently from fear of stalling and spinning.

The oversensitiveness of the Spitfire I elevator and its tendency to flick over fall entering a spin was also noted by earlier British trials (April 1940) involving a Curtiss Hawk and by German trials in the summer of 1940, and by NACA in 1941 on Spit VA (metal ailerons):

I don't understand your point, Kur.

Yes, the Spit may have had a sensitive elevator. Yes, in case it went into a spin it may have done so in a violent manner.

But again, there is abundant indications by pilots that flew the spit that the airframe provided pilots with sufficient warning before this dangerous behaviour occured. This is, as I explained above, due to the fact that the spit had cranked wings with the inner sections of the wing stalling before the outer sections. The resulting buffeting provided a warning to the pilot.

Stalling on the inner section is in no way dangerous as long as it is approximately symmetrical. I've seen with my own eyes during an experimental flight on a piper that also had cranked wings that basically this plane needs only 1/3 of its wing unstalled to provide sufficient lift. It will have been similar for the spit.

Now what you do is to confuse inexperienced pilots with seasoned ones. Inexperienced pilots of course will have the natural reflex to avoid any situation that puts them at discomfort as they still lack the confidence that comes with routine. They were absorbed by too many things to do at the same time that they had simply no mental resources to make the intelectual reflexion about buffeting as a safety warning even though they might have been told so in theory. They heard that being taught to them but only retained that buffeting means that stall is imminent and therefore has to be avoided. BTW on the German side inexperienced pilots also usually avoided to fly in that way that opened the slats. My guess is for the same reason as their British counterparts. Just try to put yourself in their shoes or remember you after having won your driving license. My guess is that anybody who loves his life will be prudent when trying to familiarize with a new way of motion (driving, flying) or a new type. The procedure most will adopt is to slowly increase the envelop of one's action with growing confidence. Well, that's how I feel when I have a new car with which I am not familiar with. It takes me a while to become more bold with it. I am surely not starting to race like Schumacher on the German Autobahn with a newly bought car.

[Kurfürst]

Originally Posted by 41Sqn_Stormcrow

I don't understand your point, Kur.

Yes, the Spit may have had a sensitive elevator. Yes, in case it went into a spin it may have done so in a violent manner.

But again, there is abundant indications by pilots that flew the spit that the airframe provided pilots with sufficient warning before this dangerous behaviour occured. This is, as I explained above, due to the fact that the spit had cranked wings with the inner sections of the wing stalling before the outer sections. The resulting buffeting provided a warning to the pilot.

My point is basically the difference how the Spitfire and 109 behaved when getting near the stall. Both gave plenty of warnings, but the difference was as I see it is that once riding the stall, the Spitfire gave very little margin before you actually stalled, and once stalled it went medieval on you. The 109 otoh could be still pulled with confidence, with plenty of margin for pilot error, as the pitch control was not so sensitive at all, and stall itself was benign and recovery by easing back on the stick instant once it occured. In short I believe the stall and flying the aircraft to its limits was much easier on the 109 - which I as not such a good pilot admire the most when I fly it, and which is why I never liked to fly the 190, Spit or Yak 3. All the latter require much more finesse to fly.

That is said, the 109 due to its higher stalling speed had lower absolute limits when it came to manouvering, so it could not pull such a tight/fast turn, but this is not so important to me as I can reliably push the 109 to its limits all the time.

The 'handling' issue is complex.

Stalling on the inner section is in no way dangerous as long as it is approximately symmetrical. I've seen with my own eyes during an experimental flight on a piper that also had cranked wings that basically this plane needs only 1/3 of its wing unstalled to provide sufficient lift. It will have been similar for the spit.

Absolutely true, but IMHO there is some misunderstanding about the stalling of the wing roots. All fighters and aircraft are designed as such, its hardly unique to the Spitfire at all. They make planes to stall in the root first because the pilot needs to retain aileron control. On the Spit, Fw 190 etc., pretty much every plane w/o slats its achieved by using washing, or cranking the wings so that the outer section has lower AoA than the inner and would thus reach stalling incidence later. On slatted aircraft like the 109, Lavochkins etc. the same is achieved by leading edge slats - its no coincidence that these cover the wing area ahead of the ailerons!

Now what you do is to confuse inexperienced pilots with seasoned ones. Inexperienced pilots of course will have the natural reflex to avoid any situation that puts them at discomfort as they still lack the confidence that comes with routine. They were absorbed by too many things to do at the same time that they had simply no mental resources to make the intelectual reflexion about buffeting as a safety warning even though they might have been told so in theory. They heard that being taught to them but only retained that buffeting means that stall is imminent and therefore has to be avoided. BTW on the German side inexperienced pilots also usually avoided to fly in that way that opened the slats. My guess is for the same reason as their British counterparts. Just try to put yourself in their shoes or remember you after having won your driving license. My guess is that anybody who loves his life will be prudent when trying to familiarize with a new way of motion (driving, flying) or a new type. The procedure most will adopt is to slowly increase the envelop of one's action with growing confidence. Well, that's how I feel when I have a new car with which I am not familiar with. It takes me a while to become more bold with it. I am surely not starting to race like Schumacher on the German Autobahn with a newly bought car.

Absolutely agree, when I was doing my licence I had three cars to learn on (one of them being an absolutely horrid old Ford Escort, which I absolutely hated) and I always needed about 5 hours in the new ones to get familiar and instinctly 'feel' their behaviour. OTOH I am very familiar with my own car, which has superb and delightful response (which is why I am so reluctant to give it up) and can really get the maximum out of it now, and with growing experience, I need a lot less time to adjust to a new car.

Back to the planes, as a rookie I would be more confident to experiment and push things a bit more in a plane that tolerates my mistakes more. Straightforward handling and not having to bother with a million others things like engine controls helps a confused rookie a lot. The car example is pretty good actually, because while learning to drive the most difficult thing was to absorb all the things and information that were happening around me, giving me very little capacity to actually drive the car. With time and experience, much of that absorbing becomes a second nature, and automatic, instinctual.

ps. as for the Autobahn, its a dreadful experience at first if you are not got used to cars flashing by constantly at 200 + km/h..

[NZtyphoon]

Originally Posted by 41Sqn_Stormcrow

I don't understand your point, Kur.

Yes, the Spit may have had a sensitive elevator. Yes, in case it went into a spin it may have done so in a violent manner.

But again, there is abundant indications by pilots that flew the spit that the airframe provided pilots with sufficient warning before this dangerous behaviour occured. This is, as I explained above, due to the fact that the spit had cranked wings with the inner sections of the wing stalling before the outer sections. The resulting buffeting provided a warning to the pilot.

Stalling on the inner section is in no way dangerous as long as it is approximately symmetrical. I've seen with my own eyes during an experimental flight on a piper that also had cranked wings that basically this plane needs only 1/3 of its wing unstalled to provide sufficient lift. It will have been similar for the spit.

Stormcrow's comments are borne out by
NACA report Spitfire Va stalling Characteristics

I also note the following conditions in the Wright Field report quoted by Kurfurst:
NACA report Measurements of the Flying Characteristics of the Spitfire Va

(Tests, Results and Discussion, page 5) All of the flying qualities tests were made with the
center of gravity at a distance of 31.4 inches behind the
leading edge of the wing at the root. The mean aerodynamic
chord of 85 inches was computed to be 4.80 inches
back of the leading edge of the wing at the root. The
center of gravity was therefore at 31.4 percent of the
mean aerodynamic chord. Because no accurate drawings of
the Spitfire were available, the calculated location of
the mean aerodynamic chord may be somewhat in error.


The center-of-gravity location with full military
load is not known.

According to the cg diagram of an earlier Spitfire I (attached) the cg was a maximum of 7.6" aft of the datum point, which is 19.5" aft of the wing leading edge, a total of 27.1" aft of the wing leading edge, or 4.3" forward of NACA's calculated cg.

while here the cg for a Spitfire Va tested at a loaded weight of 6,450 lbs by the A&AEE was 6.2" aft of the datum point, or 25.7" aft of the wing trailing edge, almost 6" forward of NACA's calculations, making their Va tail heavy, albeit their Spitfire weighed 6,184 lbs, which should not be enough of a difference to affect the cg that much.

How is it possible for a report to determine elevator characteristics when the cg of the test aircraft may not be set up properly? Nor do we know how the Spitfire in the RAE tests was set up.

[NZtyphoon]

Originally Posted by Kurfürst

My point is basically the difference how the Spitfire and 109 behaved when getting near the stall. Both gave plenty of warnings, but the difference was as I see it is that once riding the stall, the Spitfire gave very little margin before you actually stalled, and once stalled it went medieval on you.

NACA report Spitfire Va stalling Characteristics with reference to the concluding remarks on page 9...

The airplane possessed some unusual characteristics in stalls that are not required in reference 1. The motion beyond the stall was not violent and an unusual
amount of lateral control was available in many flight conditions, even when full up elevator was applied. The good stalling characteristics allowed the airplane to be
pulled rapidly to maximum lift coefficient in accelerated maneuvers in spite of its neutral static longitudinal stability.

From Spitfire Va Flight Characteristics

Characteristics of the elevator control in accelerated Flight: (pages 8 & 9)

The elevator control was found to be powerful enough to develop either the maximum lift coefficient or the allowable load factor at any speed....(page 8 )

The Spitfire airplane had the unusual quality that allowed it to be flown in a partly stalled condition in accelerated flight without becoming laterally unstable. Violent buffeting occurred, but the control stick could be pulled relatively far back after the initial stall flow breakdown without causing loss of control. With the gun ports open, lateral instability in the form of a right rolll occurred, but not until an up-elevator deflection of 10° had been reached and unmistakeable warning in the form of buffeting had occurred. This subject is discussed more fully in reference 2.

The excellent stall warning made it easy for the pilots to rapidly approach maximum lift coefficient in a turn so long as the speed was low enough to avoid undesirably large accelerations at maximum lift coefficient.
The excellent stall warning possessed by the Spitfire was obtained at the expense of a high maximum lift coefficient. The maximum lift coefficient in accelerated flight was 1.21, while the average lift coefficient throughout a stalled turn was usually about 1.01 (9)

The report goes on to state:

In turns at speeds high enough to prevent reaching maximum lift coefficient because of the excessive accelerations involved, the small static longitudinal stability of the Spitfire caused undue sensitivity of the normal acceleration to small movements of the stick. As shown by the time histories of high-speed turns (figs. 15 to 18 ), it was necessary for the pilot to pull back the stick and then ease it forward almost to its original position in order to enter a turn rapidly without overshooting the desired normal acceleration. Although this procedure appears to come naturally to a skillful pilot, flight records from other airplanes show that a turn may be entered rapidly and the desired normal acceleration may be held constant by a single rearward motion of the stick provided the static stability of an airplane is sufficiently large. By careful flying, the pilot was able to make smooth turns at high speed, as shown by figures 17 and 18. Ordinarily, however, small movements of the stick caused appreciable variations in the normal acceleration, as shown in figures 15 and 20.

This hardly speaks about a deadly stall and it certainly doesn't mean the Spitfire was inherently dangerously unstable as claimed by Crumpp. It would be interesting to know whether this Spitfire, as tested, might have been marginally unstable, because, as noted, the cg position was not accurately known. It would also be interesting to know how the elevator control was affected by the extended mass balances described by Jeffrey Quill.

Getting back to flight qualities in CloD, how would it be possible to replicate these qualities?

[Crumpp]

As this phrase, as it stands here, is to my knowledge right, it does not apply to the spitfire.

Yes and that is why I specifically did not address the Spitfire. In the Spitfire, the benefit of having an elliptical wing efficiency was all but eliminated in compensating for the stall characteristics of an elliptical wing.

[Crumpp]

Stormcrow's comments are borne out by
NACA report Spitfire Va stalling Characteristics

It would help if you understood everything that report says instead of select phrases out of context. If you can't do that , it is practically impossible to hold a discussion.


If you read the report, it states the conditions the aircraft exhibited a very harsh stall. One of those conditions would be in a steep bank with gun ports open. Under those conditions, the aircraft would develop a roll instability and resulting spin.

The conditions matter in aerodynamics.

Yes the Spitfire gave very good stall warning. That large buffet zone comes at a price in diminishing turn performance.

Longitudinal Stability has nothing to do with stall characteristics except to determine how fast the pilot can move the wing through its useable angle of attack range.

The NACA rated the Spitfire as having unacceptable longitudinal stability and control in all conditions of flight. It is either neutral or unstable and this was corrected with bob weights in later marks.

That is not a bias, it is just a fact. None of these aircraft were perfect regarding stability and control. Some were worse than others and it is a fact the early mark Spitfires exhibited a dangerous longitudinal instability. It was an infant science when they were developed.

[NZtyphoon]

Originally Posted by Crumpp

It would help if you understood everything that report says instead of select phrases out of context. If you can't do that , it is practically impossible to hold a discussion.

Some were worse than others and it is a fact the early mark Spitfires exhibited a dangerous longitudinal instability. It was an infant science when they were developed.

Nonsense Crumpp - you are the one who is taking things out of context - note what the report said about the cg calculations cf the A&AEE report on the same aircraft type - the possibility was that the Spitfire flown by NACA was slightly tail heavy.

Not forgetting also what Quill had to say about the early Spitfires - "In general configuration the Mk I and Mk II production aeroplanes were almost identical to the prototype and so there was no problem with their stability. (231-232)" I'll take his word over yours any day.

As for having a "discussion" with you Crumpp - not interested because I know you'll turn it into a loooong, tedious thread, arguing over minute detail, while sticking to your opinion that the Spitfire was "dangerously unstable" no matter what. I don't care what you think because I know you're not interested in any one else's opinion, except when they agree with you.

[Kurfürst]

Originally Posted by NZtyphoon

Nonsense Crumpp - you are the one who is taking things out of context - note what the report said about the cg calculations cf the A&AEE report on the same aircraft type - the possibility was that the Spitfire flown by NACA was slightly tail heavy.

Every report ever written on the Spitfire has apparently flawed because they were always have been made on a 'rogue' plane or a single example that proves nothing etc.

How boring.

Not forgetting also what Quill had to say about the early Spitfires - "In general configuration the Mk I and Mk II production aeroplanes were almost identical to the prototype and so there was no problem with their stability. (231-232)" I'll take his word over yours any day.

Except that everyone knows that Quill is khmm... the most outspoken priest of the Spitfire ever. If you ask Quill, the thing had no faults, and they were also immediately and complete fixed. Over and over again. Which is why he is liked to be quoted so much, as if his word was some kind of ultimate judgement which overwrites detailed reports. Quill may have an opinion, but these reports have the hard facts.

Personally I find Henshaw far, far more objective. At least he doesn't try to make it like how everything was made just perfect, despite some very obscene hiccups in the development (fabric ailerons being one of them)

As for having a "discussion" with you Crumpp - not interested because I know you'll turn it into a loooong, tedious thread, arguing over minute detail, while sticking to your opinion that the Spitfire was "dangerously unstable" no matter what. I don't care what you think because I know you're not interested in any one else's opinion, except when they agree with you.

That's pretty much the very best self-description I have ever read. I mean you keep playing the know-it-better smartass everytime, and then make it like as if the 'a loooong, tedious thread' its someone else fault, and then comes the usual yada-yada about your precious time and how you will put everyone on ignore.

Problem is, you've only registered here to carry over some feuds from other places, and you have made almost as many posts in 2 months as Crumpp or I did in 4 years.

Nope, arguing over minute details is exactly what you like to do. At least don't blame it on others.

[6S.Manu]

The motion beyond the stall was not violent and an unusual
amount of lateral control was available in many flight conditions

The Spitfire airplane had the unusual quality that allowed it to be flown in a partly stalled condition in accelerated flight without becoming laterally unstable

You know that this matter can't be resolved right, do you?

not violent: there is no meter for the stall to be "violent/not violent".
unusual amount: is it possible to quantify the usual one? And usual compared to?
many flight conditions: which ones?
party stlled: again... no numbers.

If we want the real numbers we have to rent a spitfire, install on it all the modern testing stuff and run it.

I've never loved much the 109 while I've always hated the Oleg's Spitfire (but I love the real one since I was a kid): anyway I've never trusted the myth of the elliptical wings because of these planes fly against the physic laws compared to all the other ww2 planes.