Spitfire & Hurricane flight model & engine performance thread. (1.09 patch)
 

I thought we could do with a thread to discuss the changes & way things work now with the 1.09 patch. I've copied some peoples observations for other threads.

PLEASE POST YOUR OBSERVATIONS

I'll start with the pilot notes for Merlin XII engine as a reference. (thanks to ATAG_Snapper)
http://www.djow.co.uk/il2/MerlinXIIchart.jpg

I tried a climb in the Spit2a and had these results:

Climbing at 7lb boost, 2,850rpm, IAS ~155, rad half open.
Temp gauges all within limits when at 17,000ft my rpm started fluctuating wildly, causing cockpit shake. I was unable to control my rpm.
Oil = 85, Water = 100.

Only way i could stop the shaking was sub 2,100 rpm & sub 4 lb boost.. managed to get to 19,000ft but could not maintain a climb..

These observations and been confirmed by others.




I've noticed the Merlin likes to 'conk out' if you reduce throttle & therefore rpm too much. I had this happen couple times while taxing & coming into approach finals.

Lets build up a good picture how how to get the best out of the British fighters and feedback to the Dev team as what needs addressing before the patch goes to Steam.

I took the Spit 100 to a ride.

- it seemed to me that it still not hitting 100 octane performance, still 280 mphish, even with boost and +12
- breaking the aircraft in dive is not possible with elevator only, only if trim is used to assist
-roll rate at high speed seems to have been reduced (which is correct no measurements yet)

it's unbelievable, they are actually very slightly slower now would you believe!

100 octane at sea level:

hurri 255/275mph

spit 260/280mph

still hand grenades too.

I'm finding it difficult to adequately phrase a response to all of the threads relating to this latest patch without incurring a further infraction of forum rules.

When the Blenheim was deemed 'unflyable', I listened, studied, flew to destruction, then made tutorial videos. I hope I got people flying, and restored some faith.

When people were having problems navigating and understanding the course setter and gyro in the RAF planes, I listened, studied, flew in the wrong direction, flew in the right direction, then made tutorial videos. I hope I got people steering straight, and restored some faith.

When the 100oct Spit was deemed 'unflyable', I listened, studied, flew to destruction, and made more tutorial videos. I hope I got people flying, and restored some faith.

Now I have little faith left myself.

I dont belive that they are not able to make accurate performacne and FM of these planes.

It was even possiblie to do in old IL2 - i mean maxiumum speed, climb rate, roll rate and turn rate with not such problem. I know beacuse i for some time i was making FM tunings and mods for IL2.

I just dont belive they cant do it for CLoD.

Give me paramaters and FM code and i would do it for 2-3 weeks.

+ 1000
I'm getting the same results as MadTommy and trademe900 - absolutely ridiculous that this has not been sorted. My thanks to Kwiatek and ATAG_Dutch for their hard work, but I too have lost faith in whatever process have led to this cock-up.

Actual Flight test results with Spitfire II with 100 octane fuel:

547 km/h at 5000 m altitude (339 mph at 16 400 feet)
460 kmh/ at 0 m altitude (285 mph at 0 feet)

Strange shaking at 11,000 ft at mid-boost in Spit 1a 100 oct
 

I now get strange engine shaking at power settings between 2-4 lbs boost at 11,000 ft in a Spit 1a 100 octane.

It's almost as if the initial release mixture mess is back again. Sean (IvanK) has recently made it abundantly clear to them that mixture was auto-rich with altitude.

Maybe they just can't believe all WW2 fighters were not like Soviet ones!

56RAF_phoenix

So we're gonna believe a German flight test cause 'cause Kurfurst likes it...that's funny. What's even funnier is it describes the Spitfire II as using a Merlin III :grin::grin:

Actual results in attached file with jpg of results for max speeds and climb for Spitfire MkIa/100oct.

This Spitfire seems to have closed about 50% of the gap to historical data, a similar upward tweak on top might do the trick. Generally speaking it is around 93%-95% of the A&AEE level speed results but only achieving about 65%-70% of the A&AEE climb results. NOTE these climb tests, including A&AEE, are with BCO off.

Template is attached and up to date for anyone wanting to test other aircraft. It would be good to see the 109s done this way for comparison by someone who knows how to fly them. Its easy, just fly accurately and the data is collected and also calculated to Standard Day performance. Instructions are included in zip file.

You can do Speed, Climb and Turn tests and as the ouput data is wide-ranging perhaps many other tests too. You can test many aircraft by just copying over the .bak mission file as Performance.mis. There is an aircraft at every 1000 feet (30 of them) for level speed at altitudes. You can create more missions for other aircraft. All aircraft are available at various bases. Be sure to edit the output file path to suit your PC (see instructions).

EDIT1: More data obtained. Drops off (dies) above 20,000 ft and it only flew up there because I set it there in the FMB. See thumbnail. It is impossible to maintain any kind of speed at 24,000 ft, the plot at 24k is just a representation as it was still slowly falling as was altitude. My climb test, see Edit2, began to fall apart above 18,000 feet.

EEEEK!! PLease ignore the label "CoD TAS at 2650 rpm", its a mistake, there is no curve for it.

EDIT2: Climb test jpg added. Time to 18,000 ft 10 mins instead of 6.7mins. R.O.C and therefore Time to Height fall away above 5,000 feet when tracking the A&AEE RPM/Airspeed test.

EDIT3: Aircraft fuelled to A&AEE test weight 6050lbs (98% CoD fuel).

EDIT4: Sorry I forgot my sources.
Climb:
http://www.spitfireperformance.com/n3171.html
"CLIMBING TRIALS"
Speed:
http://www.spitfireperformance.com/spit1vrs109e.html
"Spitfire MkI vs Me109E Level Speed Performance"
EDIT5: Added Turning tests and up to date zip file
Turning Test sources:
http://www.spitfireperformance.com/spit109turn.gif
Turn rate well below historical data and Radius of Turn too high.
Possibly related to the climb test problems.

Nice one lads.. lets keep the data & tests coming. :)

Spitfire MkIa 100 octane data updated
 

Just finished it.

http://forum.1cpublishing.eu/showpos...6&postcount=10

Is anyone at 1C reading this? I'll link to it in the bug thread.

Turn tests added. See above link. Performance is down.

Nice work, thanks for posting!

Excellent work indeed, but could you use perhaps more distinct colour and labels etc.?

Its very hard to tell what is what...

Well I paired off the same test curves in the same colour and used different chart point markers for the sources, e.g. Red for BCO Speeds with a square data marker for A&AEE, a Triangle for CoD and so on.

I also tried to list the curve titles so that they read downwards following the uppermost curve down to the bottom most.

Hope that helps.

I expect I've flouted some convention or other but you are intelligent guys :)

OK well, at step forward at last as of the patch on the 12th!

Historical I am afraid...

Depends what you are talking about Kurfurst. In top speed at particular altitudes then yes, but in climb absolutely not.

I mean speed. The Mk II was cleared for +9, the Mk I for +12 in emergency during BoB, so at low levels the Mk I is of course a bit faster.. but I did not test the new patch yet, though I heard that the 100 octane RAf planes are finally fixed speed wise, yes? :)

The Merlin XII was also cleared for +12. Not that I disagree with you regarding top speed at S/L at +12 vs +9lbs. boost.

I wonder what klem will say after he will test the new FMs. Sounds like good news though so far.

I think it was discussed and shown that +12 combat rating was cleared for the Merlin XII only well after BoB, though there was some sort of take off rating that was pretty much useless for anything else but to shorten takeoff.

The BoB was just starting in July 1940.

The Spitfire II Pilot Notes, dated July 1940, say 12lb boost can be used to 10,500ft. A boost of 12.5lb can be used for take off to 1,000ft.

http://www.zenoswarbirdvideos.com/Im...pit2Manual.pdf

I'm afraid zeno is inaccurate here. I think I have the Spitfire II pilot notes without any amendments, at least the amendment list is there and empty. This should be the original version dated July 1940. In there, the engine limitation for all out level is 9lb boost.

It appears that the all out level increase was at latest added with amendment list 31 / L, at a date that is not known to me.

The zeno version is missing the amendment list and does not shed any light on the "when".

It doesn't matter. If you had a 109 on your backside or gave chase then you'd hammer the thing. I'm pretty sure that most 19 year olds don't drive 'according to approved ratings' but it doesn't mean it can't do it

It does matter, because it was necessary to modify the automatic boost control in order to have it deliver 12lb when in override. It would always have been possible to override it, but in the worst case you could end up with boost exceeded 30lb and destroy the engine instantly.

Indeed JtD.

And there you have it....12lbs boost up to 1000' for take off or for a maximum of 3 minutes otherwise.

I'm sure nobody is suggesting 3 minutes was used to get to 1000'

A different system, bongodriver. It was limited to low altitude and could not provide boost at higher altitudes. Simply put, it had a full throttle altitude of 1000 feet, which would give you less than 9lb at altitudes exceeding 4000 feet. It's really just a take off setting.

Not really.

Spitfire is only the same speed as the Hurricane at altitude now (320mph at 18,000 feet), it is still very slow.

At sea level they are all good though.

No it wasn't.

No one knows what date the amendment was from the discussions here, and you can't say with any certainty when it was cleared without the date of the amendment, all we know is it was after july'40 sometime.

It could of been in September for all we know or well after BoB, without the date, its just speculation, so don't spread you want to believe as fact.

First documented use of emergency boost with a Spitfire II is 21 August: http://www.wwiiaircraftperformance.o...-21aug40-1.jpg

Double standard view on the subject:

The use of +12 in Spifire II is
a) documented in combat reports as "emergency boost" 8 days after the first operational use
b) authorized in a later edition of the manual
c) the cut-out is mentioned in the earliest edition of the manual for emergency use. Without a specific modification to +12 boost the cut-out would enable the pilot to obtain any boost up to +17
Invalid. Not enough proof, even if there is nothing that prevents the pilot from using it. The combat report doesn't mention +12 boost, maybe the pilot used the cut-out to obtain the regular boost +9 manually instead of simply moving the throttle full forward.

On the other hand there is 1.4/1.45 ata for DB601A which
a) is restricted to take-off in any edition of the manual
b) is not mentioned by any pilot report for anything else than take-off
Valid. There is nothing that prevents the pilot from using it in combat.

Wishful thinking. It doesn't say +12 lbs boost, it says 'emergency boost', which we all know was +9, as per the manual. Selective and wishful use of evidence...

And as such irrelevant for BoB period. Same site you use as a source claims that the 1-min boost for the DB engine was not cleared until 1942, by when the Emil was withdrawn from service. :D It also claims a gazillion other BS for LW planes and has achieved an unenviable reputation for bias and manipulation as a result.

So by all means model the boost cutout and enable pilots to obtain +17 lbs boost and blow their engines at free will...

In contrast of +12 boost being physically restricted (impossible) on the Spitfire II. Nothing restricts the use of 1.4/1.45ata in the 109/110/111, expect for the 1-min clockword which is already present and modelled.

Show me say 10 German pilot reports then which 'does not mention it'. No, you have not seen ANY, you just make up an arguement, neglecting the fact that German pilot reports never seem to mention any boost levels during the whole war, and here's why - unlike the British, they had automated systems since the start of the war, so boost levels were meaningless to their pilots - they did not have to set it separately. Neither they needed to overboost woefully undersized engines to compete and thus it was utterly irrelevant to pilots.

Let me show you a real example of double standard.

RAF fans like yourself wish to have a plane modelled in the sim after a crayon graph they drew up themselves in desperation as there is curiously not a single +12 lbs boost report being made, so they had to make up one and wave it around. Ring a bell?

RAF fans like yourself wish NOT to have a plane modelled in the sim after a doucmented and guaranteed tests just because it shows that their cherished RAF plane with much larger drag and 25% greater wing area is, horriblle say, was slower than the blue plane with more power and less drag at sea level.

Said RAF fans then come to the forums and complain about a German rating that was there, and ask for a RAF boost that wasn't there, and wish to model that boost based on no performance test at all.

Oh dear, Kurfurst has gone on another one of his rants.:(

The Merlin in Perspective, no.2 in the R-R Heritage Trust's Historical Series

"Before the end of the Battle Spitfire IIs with Merlin XIIs were in service, with the supercharger gear ratio increased from 8.58 to 9.09:1 giving a better full throttle height at 12lb boost......"

You make it sound as if it was a useless option or a bad idea, but it is not. If it is combined with a decent overheat / engine damage model, it would imho be the best and most useful way of implementation in game. The engine could take 12lbs of boost, as we know from the take off setting, and disabling the automatic boost control would give the player a chance to manually set and maintain it. What it is not is a simple press a button solution. It is the minimum that was available historically, it's useful and interesting.

Thanks 41Sqn_Banks for the 17lb figure, I wasn't sure if other restrictions were in place before the 12lb modification was carried out. So I went with worst case.

About +17 is the amount of boost that the supercharger can produce at sea level, it's not restricted.

That I find highly unlikely, if it can produce +9 lb at 17000 feet, it should be able to produce about ((9+14)/527*1013)-14 lb at sea level, which is about +30 lb. The compression ratio should not change much. If it does happen, though, there's some sort of throttle in the way, and be it just too small cross sections somewhere between the intake and the supercharger.

(Note about the calculation: (9+14) - total pressure in the supercharger at full throttle altitude; 527 - outside pressure at full throttle altitude; 1013 - outside pressure at sea level; - 14 - to get from total pressure in the supercharger to overboost as used by the British)

Not with the Spitfire II which is what Kurfurst is talking about. This has a Merlin XII engine designed for 100 only.

I am not sure why Kurfurst agreed with you in the subsequent post unless he forgot which aircraft he was talking about ;)

I agree, I don't have a problem with that, but it's the clearance to use it I'm talking about.

When I was 18 I didn't have clearance to take my engine in my Ford Fiesta 1300S into the red all of the time but when my six was occupied by another kid in an Escort or Golf I pulled the tit and away we went down those country roads like dickheads. After a while I blew the camshaft out of the side of the block, I'm pretty sure Ford didn't recommend this.

http://www.carfolio.com/images/dbima...fiesta_xr2.jpg

I should scan a photo of my heap of crap, I would've killed for one of these. :lol:

A fellow country road boy racer........My 2.0L Mk4 cortina was a beast.

I read the rest. Firstly, Kurfurst, would you mind not ranting please, your post looks like it comes from a luftwhiner and you've lately managed to curtail that. As such people began to take you more seriously. Your comments about RAF fliers are offensive, when have you ever heard me rant about 109 boost use? My only complaint with your figures is that your graph is 30 kmph faster than any actual test and nobody can account for it - that's why you are in a constant argument and the only people who agree with you are the 109 fliers with an agenda for Spit bashing.

It should ALL be modelled for ALL types, then it's up to the pilot if he breaks it. In the future with scripting (and even now with Banks co-op) you will only get one flight, one life and one engine so fine - break it and die in the channel. Let's concentrate on getting 1C to model this as close to the evidence we have at our disposal as possible and use some damn common sense!

Dang! I edited my post from 'Cortina' to 'Escort' because I figured nobody would remember the old monster. Oh yes, I loved the Cortina, my mate had one and Christ - how am I alive today!?! Then there was the Capri 2.8i - that was for the big league ;)

I hope I got people flying, and restored some faith.
http://www.rdox.info/01.jpghttp://www.rdox.info/02.jpghttp://www.rdox.info/8.jpghttp://www.rdox.info/9.jpg
http://www.rdox.info/0.jpg

Hi Dan, how would you have done that? Are you a dev or something?

+9 was also climb boost (at 2850 rpm) and there was also all out setting which was +9. All out suggets just full throttle and full rpm, it is not emergency boost and pilots would not refer to it as emergency boost.

With BCC-O, Merlin XII was technically capable of pressures higher than +9lbs., it was certainly safe to operate it at +12lbs. (for that was the take-off power with the throttle gate system and also supported by simple fact that XII was improved III and III was approved for that MAP). +17lbs. is consistent with R-R raw tests but perhaps JtD is right, I don't know. I agree that as for Pilot's Notes the Merlin XII are set correctly for the sim (at +9lbs max), there is not enought direct evidence and the date of amendment is not clear, unofrtunately. The best authority at early Merlins is the Merlin in perspective publication quoted by Al Schlageter in here but it does not clarify the date of emergency boost amendment. There was no modification necessary to achieve that fore sure, it was physically possible to have boosts higher than +9lbs from day one on Merlins XII.

I agree with you that it would be great and interesting to have the BCC-O (ABC) modelled, I would not mind. It is logical and almost certain that it has been used in combat.

For the operation and technical details of both Take Off power and ABC, there were some interesting scans and description by Banks in some other thread.

Well to be fair, the automatic boost control was also automated as the name suggests and yet pilots verbally referred to its use in many instances when they decided to override it. :o

There was actually very specific vocabulary to describe the use of emergency combat boost. The same went for any other conflict where they could use some extra power available (e.g. afterburners in Vietnam war) and often described it in their narrations, written or spoken. I am sure German pilots would be doing the same if that was the case. The only thing that could explain that lack of specific references to Erhoehte Notleistung (and mind you it referred to by the pilots in some late war combat literature as they were flying German aircraft with extra combat power designed by one mean or another) is that in the Emil, for emergency MAP one had to slam the throttle fully forward, there was no switch or knob or any gate to go through to prevent the use of 1,45 ata. So perhaps that is why.

I'm struggling with some of the logic behind the use of 12lbs here.......for the life of me I can't think of a single circumstance where a pilot would need to break a sealed lever to get an emergency take off boost in a single engine aircraft, take off performance should be accounted for using max available non emergency power...........OR have I got the wrong idea and 12lbs boost was available without breaking the seal but was instead achieved by use of a throttle gate and was automatically reduced above 1000' and if you hadn't climbed above 1000' on departure you were expected to reduce after a max of 3 minutes? thereafter the max boost was 9lbs?........which means that the sealed boost lever has not yet been used.......I wonder what would happen if I used it?

Nah! the cortina would eat Crapi's for breakfast........The Crapi handled like a boat.

You are of course correct. +17 boost is for Merlin III, but Merlin XII runs at much higher boost.

However I doubt that any Merlin XII had a unrestricted boost cut-out.

Also with the Merlin XII. You would need to modify the automatic boost control so that it would be limited to 12 lb boost when disengaged. IIrc, this was done with reducing the cross section of the bypass.I agree, but I'd look at it the other way round - I can't be sure it always had. Do you have the Merlin XII handbook?

There appears to have been two methods of bypassing the boost control.

The throttle had a gate, at which the normal max 9lbs boost was produced. At the gate you could shift the throttle to the left then forward to achieve +12.25lbs for takeoff.

Emergency combat boost of +12lbs was also available with the throttle at the normal max position (+9lbs) by pushing forward the red tab we are familiar with froim the Spitfire MkIa/100 octane.

Why there should have been two methods I don't know. I have the attached on my hard drive for the Spitfire MkII, I'll try to find out more if we have a copy of an original Manual at the museum.

What klem is referring to is what I mean JtD. IIRC the Merlin XII did not require field modification, this was already done at the factory, and the throttle was different and designed with a dog leg 'gate' in order to move from max 9lbs to emergency 12lbs. It's a slightly different system to the Spitfire I. I have "Merlin In Perspective" - it's Robo's copy and I'm getting through it slowly!

the 2 methods make some sense taking into account JTD's mention of the automatic cutting out of 12lbs take off boost above 1000', the use of the famous red lever should give the emergency 12lbs instead of an instant engine death boost and is available for use when above 1000', it simply stands to logic that the fabled combat boost was 12lbs, as 9lbs was achieved by default at full throttle and we know the engine could handle 12lbs for at least 3 minutes.....more than enough time for a 'tight spot' in combat.

I always thought the instant engine death boost levels were only achieved when people went and started putting matchsticks in holes they shouldn't have.

As interesting as this might be for some of you, this thread was meant to be for posting observations about the performance of the Spit & Hurri as it is in game, not another discussion about historic records relating to flight models.

But hell at least people aren't slagging each other off. :)

;)

...and your first post starts with an out of game document... :confused:

Attached a description of the automatic boost control unit as in the Merlin II. You can see how the cut out would work. You can see that it would give full boost, only depending on throttle setting, when the cut off was engaged.

Guess this has been posted before, but so what.

On the Merlin 20 series, the maximum boost available in case of the cut off engaged was regulated through bleed holes of a particular size - which at least required different cut out valves. This way the cut off no longer disabled the abc completely, it just reset it to a higher boost level.

The take off setting did not use the mechanism of the cut out valve, but went a different way, the particulars of which I don't remember right now. It essentially is a fixed throttle setting around the abc as opposed to an abc controlled boost, managed through varying throttle settings depending on a pressure balance. The boost limit with engaged abc cut off and the boost limit with the take off setting are not related.

The necessary modification for the Merlin XII when using all out level with 12lb boost would be a modification of the cut out valve.