BoS fighters roll comparison

[Brano]

Try to contact user bivalov,he can do both languages and could forward your questions to Russian part of the forum. I'm not that good at writing in russian,they would laugh at my puny attempts

[Holtzauge]

Try to contact user bivalov,he can do both languages and could forward your questions to Russian part of the forum. I'm not that good at writing in russian,they would laugh at my puny attempts

Well in the country of the blind the one-eyed man is king! Personally I'm on the level of consulting a Cyrillic/Latin table whenever I run into something Russian I can't run through Google translate.

 

Thanks for the tip. Maybe I will contact bivalov then......

[Crump]

[Edited]

 

[Edited]

Edited January 22, 2016 by Bearcat

[MiloMorai]

   Too bad your so stubborn.

Kettle calling the pot black, be sure.

:biggrin: :biggrin:

[Holtzauge]

Really, because I would thinking that Sweden being so close to Russia that anyone involved in the Swedish aerospace defense sector would be more familiar.  Shouldn't they be more familiar?

 

 And nobody is "trolling".....the question is serious.  Nobody begged you to make the claim you are an aeronautical engineer involved in Swedish defense aerospace.  You made that claim.

 

Then you make silly declarations like your C+++ calculation is absolute without margin of error.  In fact, that has been most the friction between us is your insistence that your estimates are 1000% correct when they do not agree with measured data.

 

If you were an engineer, then you would know things like margin of error, significant digits, and what a performance estimate actually tells you instead of bogging down discussion over minutia because you do not understand your estimates are not absolutes. 

 

It is only been lately after Yo-Yo set you straight on that point that you have produced some worthy of discussion results.  Too bad your so stubborn.

 

Well Crump, if you insist:

 

I have a Master of Science degree from the Royal Institute of Technology, Stockholm, Sweden. Graduated in 1986 specializing in aerodynamics and structural engineering. My master’s thesis covered the influence of external stores such as missiles, drop tanks etc. on the performance of jet aircraft. It is a derivate of this program I use to make the C++ simulations I sometimes post in this and other forums by the way.

 

I have worked from 1987 to 2000 at various Ericsson and SAAB owned defence companies, During my time there I have worked with structural engineering, systems engineering and as project leader and in marketing. I have represented the companies I worked for at both Farnborough and Le Bourget.  I have during my time with these companies dealt with Boeing, Lockheed, Dassualt, BaE, DASA etc.

 

I have mainly worked on the ECM systems for the AJ-37 Viggen, JA-37 Viggen and the JAS-39 Gripen aircraft and on ECM training systems. This work spanned everything from mechanical engineering, i.e. structures, microelectronics, microwave electronics and systems engineering for both internal ECM systems and external pod mounted systems. As a point of curiosity, I have also worked on the cooling systems for pod mounted ECM systems which has turned out handy lately with you and Kurfurst sharing your deep insights on the subject of radiators.

 

Now, seeing you are such an expert in aeronautics Crump and continue sniping about my competence you must have a really massive and impressive resume. How does it read again? I’m sure I’m not the only one wondering.

 

So let’s hear it Crump, it’s showtime. It’s time to put up or shut up.

Edited January 21, 2016 by Holtzauge

[Crump]

[Edited]

 

 

on the performance of jet aircraft.

 

 

[Edited]

Edited January 22, 2016 by Bearcat

[NZTyphoon]

OT

Main wing on Yak was not made from just "wood".Maybe someone thinks of it like you chop a tree and then you shape it with axe into main wing spar   

Its a bit more complicated.It was in fact composite construction.Main spar was made from 4 pieces of pinewood+intersecting rectangle-like ribs joining upper 2plyed glued pinewood part with lower 2plyed pinewood part+front and rear plywood layer to give it final "box-like" look.All glued together.It created a rigid yet reasonably lightened construction.

The aim of this construction was to get equal properties comparing to metal design.The dawnfall was the increased weight of such construction,of course.

 Flaps were "Frise" type,made of duraluminium covered with linen.

end of OT

 

According to Gordon & Khazanov*, Lavochkin used wood that was impregnated with phenol for key structural elements, such as the spars and fuselage longerons; this was a form of composite that was stronger and more fire-resistant than conventional woods, albeit it was heavier. Another source# says that this delta-drevsina could be moulded into shape.

 

*Yefim Gordon and Dimitri Khazanov: Soviet Combat Aircraft of the Second World War - Volume One: Single-Engined Fighters

# George Mellinger: LaGG & Lavochkin Aces of World War 2

Edited January 21, 2016 by NZTyphoon

[303_Kwiatek]

Wood is not bad material at all. There are CAP aerobatic planes made from wood and got high ultimate load factor. . More problem for Soviets planes was manufacture issues and bad quality glue. There were very frequental cases with riped wings skins. Even Yak-3 got such problems with speeds above 700 km/h. Probalby there were other issues too ( not adequate controls balance  fluttter etc).

 

I no wonder that all Soviets planes from these era got very restricted maximum dive speeds. How it is in BOS all we know - all Russian fighters could dive up to 750 kph IAS where in manulas from 1942-1943 was maximum dive speeds 620-650 kph IAS.

Edited January 21, 2016 by 303_Kwiatek

[Holtzauge]

[Edited]

 

 

 

 

[Edited]

Excellent. Can you post a link to your profile?

 

BTW, why can't you post a short resume here? Just a few paragraphs like me or are you too modest?

 

Also, I'm not surprised that you are stunned by what I write since it's obvious you have no idea about security classifications. What I wrote comes straight out of my CV. But you are right, where I worked I needed security classification. This is also why I know what I can write and what I can't. Your comment just highlights you understand nada which was what I expected.

 

And yes, my C++ predictions only work in Newtonian Physics. [Edited]

Edited January 22, 2016 by Bearcat

[Holtzauge]

According to Gordon & Khazanov*, Lavochkin used wood that was impregnated with phenol for key structural elements, such as the spars and fuselage longerons; this was a form of composite that was stronger and more fire-resistant than conventional woods, albeit it was heavier. Another source# says that this delta-drevsina could be moulded into shape.

 

*Yefim Gordon and Dimitri Khazanov: Soviet Combat Aircraft of the Second World War - Volume One: Single-Engined Fighters

# George Mellinger: LaGG & Lavochkin Aces of World War 2

Yes, and as I said earlier on in this thread, the way the La-5 is built up is really impressive and a really good example of what the Germans call "Leichtbau". I have the La-5 "Samolet" and it's full of beautiful drawings showing the inner structure and how they used wood to their advantage.However, If those guys back then had had carbon fibre and epoxi you can be sure they would have come up with a revised design that was both much lighter and stiffer and which would most likely have raised the Vne considerably.

Edited January 21, 2016 by Holtzauge

[Crump]

This is all you need to know:

 

http://forum.il2sturmovik.com/user/1354-crump/

 

 

 

Also, I'm not surprised that you are stunned by what I write since it's obvious you have no idea about security classifications. What I wrote comes straight out of my CV. But you are right, where I worked I needed security classification. This is also why I know what I can write and what I can't. Your comment just highlights you understand nada which was what I expected.  

 

That is the first thing you learn....let everyone know you know secrets......brag about it on an internet gaming site....

 

No, Holtzauge....I do not believe you.  I think your Dad might have worked in the industry and he would be pretty pissed off if he saw your childish display.   

 

Please check your PMs.

Edited January 22, 2016 by Bearcat

[Holtzauge]

Well, it's getting late here and I have work tomorrow so this will just have to wait until tomorrow evening CET.

 

From what you are posting it looks like you are now attempting to get the thread locked and pruned. Well I hope you don't succeed and the moderators leave all that you and Kurfurst have written above because IMHO it would be better to leave it as it is because it's truly revealing.......

Edited January 21, 2016 by Holtzauge

[NZTyphoon]

Yes, and as I said earlier on in this thread, the way the La-5 is built up is really impressive and a really good example of what the Germans call "Leichtbau". I have the La-5 "Samolet" and it's full of beautiful drawings showing the inner structure and how they used wood to their advantage.However, If those guys back then had had carbon fibre and epoxi you can be sure they would have come up with a revised design that was both much lighter and stiffer and which would most likely have raised the Vne considerably.

 

Again, if the lower Vne of the Russian fighters was due to aeroelastic effects like aileron reversal or flutter, then a carbon composite Yak built on the same principles would be

 

Just imagining a Yak-3 made out of carbon composites...   More seriously, the Russians were able to adapt their designs (eg; Yak-9) to use duralumin and other lightweight alloys as production and imports improved; any thoughts from you or Ze-Hairy as to how or whether this would have affected the Vne and roll rates?

Edited January 21, 2016 by NZTyphoon

[Brano]

LaGG-3 and its derivate La-5 was developed from the beginning as aircraft using as much non deficit materials as possible.Such was the specification. Not because Soviets didn't know how to manufacture all-metal airplanes.In fact Soviets were pioneers of all-metal designs,Tupolev OKB being the world leading design bureau releasing mass produced models since 1920s.Most mass peoduced SB family of bombers as example.Followed by Ilyushin OKB (Db-3/Il-4) and Petlyakow Pe-2 and Pe-8 heavy bomber.

Interesting side note about La-5.Problem of separated wing upper layer of linen during flight was caused not by wrong design,but by not following technological process.Factories exchanged important component of Ash-22 filler (lead yellow pigment),used to treat surface prior to applying the paint,with less deficit iron minimum pigment.Without authorisation.Leading to high stress of the upper layer during hot summer days,cracking the surface and letting water and humidity to do their job.This eventually went into change of camouflage schemes,as deficit lead yellow pigment was also used to produced well known dark/ light green camouflage, to usage of largely available grey pigments.From mid 1943 till 45 it was well known new light/dark grey camouflage of soviet airplanes.

Last side note in my off- topic is related to postwar Czechoslovak air force.La-5 and La-7 composed 40% of our fighters in 1945.Lifetime of lawotschkins was set by manufacturer for 2 years (like warranty we have nowdays for common house appliances) So in 1946,this warranty has expired.Of course our military leadership wanted to use those fighters further,as there was no other better substitute for them.They decided to stress- test them in our VLU (aviation research institute).To everyone's surprise, even after 2 years of manufacturer's warranty,lawotschkas retained 10x structurals toughness limit comparing to 6x required by manufacturer for safe exploitation. They served well untill 1950,to be replaced by jet engine propelled MiG-15s.Real testimony to the original design.

[LukeFF]

Can you name any other fighters made of wood that saw front line service?

 

He 162

[LukeFF]

 

 

How it is in BOS all we know - all Russian fighters could dive up to 750 kph IAS where in manulas from 1942-1943 was maximum dive speeds 620-650 kph IAS.

 

...and Han has explained why they use the numbers they use. 

[Dr_Molenbeek]

...and Han has explained why they use the numbers they use. 

 

Yes and he always use the same anecdote of a LaGG-3 pilot who passed 700km/h IAS "without problem", yet in BoS Vne of LaGG-3 and La-5 is around 800km/h.

 

Now go back to topic.

[Dakpilot]

Yes and he always use the same anecdote of a LaGG-3 pilot who passed 700km/h IAS "without problem", yet in BoS Vne of LaGG-3 and La-5 is around 800km/h.

 

Now go back to topic.

 

Han : Actually, we have flight test report on LaGG-3 which shows that it's diving a little more than 700 km/h IAS without problems. So, we have set Flutter start at 750km/h IAS, +50 km/h to fastest known limit

 

Cheers Dakpilot

[Bearcat]

This thread is moving very close to being locked... All those whose posts have been edited.. please consider what you posted and try to keep things from getting personal.

[JtD]

Thanks for taking the time, Bearcat.

[=362nd_FS=Hiromachi]

Huh, finally, topic may go back to the point.

 

So now is the question, did you Hairy try to ask bivalov or sokol about that Russian evaluation of 109 G-2 model ? I see a lot of potential in those graphs, that could help to understand some problems at  least. 

Edited January 22, 2016 by =LD=Hiromachi

[Holtzauge]

This thread is moving very close to being locked... All those whose posts have been edited.. please consider what you posted and try to keep things from getting personal.

Roger that and wilco.

[Holtzauge]

Now let's talk seriously... Does anyone here has data to share about Bf 109F/G roll rate ?

 

I only know this (DVL evaluation): http://bbs.hitechcreations.com/smf/index.php?topic=160997.0 (the image is gone, sadly)

 

Max roll rate of Bf 109F-2, at 30kg/66lbs stickforce :

200 kph = 45 deg/sec (0.8rad)

300 kph = 68 deg/sec (1.2rad)

400 kph = 83 deg/sec (1.45rad)

480 kph = 20kg/44lbs limit

500 kph = 88 deg/sec (1.55rad)

600 kph = 91 deg/sec (1.6rad) - peak value

700 kph = 56 deg/sec (0.98rad)

800 kph = 23 deg/sec (0.4rad)

 

(speed is TAS, and altitude is 3000m)

Here is the missing picture. It requires a bit of interpretation because it only shows data for 20 and 30 Kg stick force but I scribbled in the data point for 50 lb (22.7 Kg) in there. IIRC then the test was done with max 11.8 deg deflection but it’s the extrapolated value at 15 deg that should be read off because AFAIK this was the max deflection possible according to the report.

 

In addition, the x-axes is in TAS so this needs to be converted to EAS to be comparable to BoS values which if we look at the data point I marked, around 490 km/h TAS corresponds to around 420 Km/h EAS at 3 Km altitude.

 

Reading off around 1.55 rad/s in the diagram this gives around 89 deg/s at 420 Km/h EAS at 3 Km altitude. Note that this value is actually only valid at this particular altitude because you will get different roll results at different altitudes with the same EAS but since the NACA diagram is for 10,000 ft they are close enough to be comparable.

 

Finally, since this figure was originally posted by Gripen and there have been claims in this forum that that’s me, let me make it very clear: I am not Gripen and since I acquired a copy from what  I believe is a mutual friend I know there is no conspiracy.

 

Edit: It's been some time since I last read the report and I see now that it is actually the thicker dash dot dash line you should use after all: Apparently the maximum aileron deflection possible decreased with increasing speed (dynamic pressure) due to give in the linkage and rods controlling the ailerons so that while the pilot moved the control column to the max, the ailerons moved less and less as speed increased. So reading off a new value for 50 lb stick force, the corner point now looks like it is located at 440 km/h EAS (510 Km/h TAS) with a max roll rate of around 1.41 rad/s, i.e. circa 81 deg/s.

Edited January 23, 2016 by Holtzauge

[Dr_Molenbeek]

Huh, finally, topic may go back to the point.

 

So now is the question, did you Hairy try to ask bivalov or sokol about that Russian evaluation of 109 G-2 model ? I see a lot of potential in those graphs, that could help to understand some problems at  least. 

 

I asked Bivalov and waiting for an answer.

 

EDIT: Holtzauge, thank you very much for the chart.

Edited January 28, 2016 by Ze_Hairy

[Dr_Molenbeek]

[Holtzauge]

 

Ok, interesting to see the DVL data in a chart together with the BoS values. Why not add the numbers for the Russian fighters from your first post? Would be good for comparison.

 

So the conclusion is that the Me-109F4 roll rate in BoS is optimistic: OTOH we don't have any IRL data on the Russian fighters AFAIK? ( I have not received any reply to my query to bivalov anyway)......

 

So IMHO it makes no sense to ask for any adjustment of the F4 roll rate unless we have some input on the IRL roll rate of the Russian fighters because it may well be so that all aircraft roll better in BoS compared to IRL, Russian fighters included.......

[unreasonable]

Very nice chart Ze_Hairy.

 

I do not know if 109's roll rate should be adjusted - as Holtzauge says comparison with Soviet fighters also relevant. I cannot help feeling, however, that some of the complaints about the 190's performance in BoS would be have been less if the 109 roll had been closer to your figures from the start.  Pilots used to the 109 would then be getting into the Fw and experiencing a much better roll rate especially at high speeds.

 

So much of the "feel" assessment is compared to what you are used to. If the 109's roll is reduced now though, imagine the howling... 

[Holtzauge]

Very nice chart Ze_Hairy.

 

I do not know if 109's roll rate should be adjusted - as Holtzauge says comparison with Soviet fighters also relevant. I cannot help feeling, however, that some of the complaints about the 190's performance in BoS would be have been less if the 109 roll had been closer to your figures from the start.  Pilots used to the 109 would then be getting into the Fw and experiencing a much better roll rate especially at high speeds.

 

So much of the "feel" assessment is compared to what you are used to. If the 109's roll is reduced now though, imagine the howling... 

Yes, since we have IRL numbers for the 109 and 190 at least those can be compared and from the way it is modeled now it looks like one of the main advantages the 190 had over the others is somewhat neutered since the roll rate of the others seem to be on the high side. Unfortunately, without any data on the Russian fighters we are reduced to guessing....

 

Edit: Well since there is no comparative data AFAIK, I hope there will no 109 change and consequently no howling!

Edited February 20, 2016 by Holtzauge

[unreasonable]

 

Edit: Well since there is no comparative data AFAIK, I hope there will no 109 change and consequently no howling!

 

But there is comparative data between the 190 and the 109. I am not in a position to judge it, but if the chart is right then the 109 needs a nerfing if the FM is to be a good simulation of the plane.

 

Also I quite enjoy reading the howling - it is sometimes very funny. 

[Dr_Molenbeek]

Why not add the numbers for the Russian fighters from your first post? Would be good for comparison.

 

 

First post edited.

Edited February 20, 2016 by Ze_Hairy

[JtD]

Thanks again for your efforts.

 

Do you have a special trick for testing the roll rate or do you just fly straight and level, hit the stick and use the stopwatch? I find it difficult keeping speed constant during rolls, though the changes might not be significant.

[Dr_Molenbeek]

I use the stopwatch only after that i've recorded the rolling test with Fraps, and immediately when the plane starts to roll, as you said from level flight.

 

And to keep speed during rolls i gain/lose a bit of altitude, which is also why i don't go above 650km/h in my test, i would lose too much altitude.

[Wulf]

Can anyone explain to me (and this has possibly been explained many times previously) why the Bf 109 F2 and F4 should have appreciably different roll rates?   I'd have thought they'd be very much the same.  Wasn't the only significant difference between the two horsepower and the size of the cannon?  How would that change the rolling characteristics?

[Dr_Molenbeek]

Can anyone explain to me (and this has possibly been explained many times previously) why the Bf 109 F2 and F4 should have appreciably different roll rates?   I'd have thought they'd be very much the same.  Wasn't the only significant difference between the two horsepower and the size of the cannon?  How would that change the rolling characteristics?

 

Are you saying that the Bf 109F-2 in BoM rolls slower than the F-4 ?

 

I don't have BoM so i can't try it.

[unreasonable]

Can anyone explain to me (and this has possibly been explained many times previously) why the Bf 109 F2 and F4 should have appreciably different roll rates?   I'd have thought they'd be very much the same.  Wasn't the only significant difference between the two horsepower and the size of the cannon?  How would that change the rolling characteristics?

 

F2's engine is lighter than F4's - the wing and almost everything else is the same. So I would expect the F2 to be slightly faster to reach continuous roll at a given speed - although I do  not know by how much - but continuous roll to be the same.

 

I would guess that the difference is measurable but fairly insignificant from a piloting POV. But I do not have test pilot skills to prove it. 

Edited February 25, 2016 by unreasonable

[Wulf]

Are you saying that the Bf 109F-2 in BoM rolls slower than the F-4 ?

 

I don't have BoM so i can't try it.

 

Oh,um.... I was just going off the chart above which features both the F2 and F4.  Maybe I'm reading it wrong but doesn't it indicate that the F4 is somewhat quicker in the 'rolling plane' than the F2?

 

 

 

 

F2's engine is lighter than F4's - the wing and almost everything else is the same. So I would expect the F2 to be slightly faster to reach continuous roll at a given speed - although I do  not know by how much - but continuous roll to be the same.

 

I would guess that the difference is measurable but fairly insignificant from a piloting POV. But I do not have test pilot skills to prove it. 

 

 

Okay, I see what you're saying but would the extra weight, evenly distributed as it would be, right around the center line, really result in an appreciable/measurable difference in roll? 

Edited February 25, 2016 by Wulf

[6./ZG26_5tuka]

The DB601 E is only 10kg heavier than the Db-601 N (620 vs 610 kg) so the difference is be negligible. There also wasn't much of additional equipment on the F-4 that could result in a significantly higher roll rate.

 

Maybe it would be better to reproduce the test to confirm Hairys numbers on the F-2 especially considering he doesn't even own it himself.

Edited February 25, 2016 by Stab/JG26_5tuka

[unreasonable]

The DB601 E is only 10kg heavier than the Db-601 N (620 vs 610 kg) so the difference is be negligible. There also wasn't much of additional equipment on the F-4 that could result in a significantly higher roll rate.

 

Maybe it would be better to reproduce the test to confirm Hairys numbers on the F-2 especially considering he doesn't even own it himself.

 

But the F4's take off weight was over 200kg altogether heavier than the F2: about 10%  - heavier cannon, armoured glass as standard, (also, I think a different propellor?). 

 

I have no idea if the result is negligible or not - sadly I do not have test pilot skills so I will have to wait and see....

[Dakpilot]

Oh,um.... I was just going off the chart above which features both the F2 and F4.  Maybe I'm reading it wrong but doesn't it indicate that the F4 is somewhat quicker in the 'rolling plane' than the F2?

 

 

 

The chart is not showing comparable data between F2 and F4 (in the sense you are thinking)

 

F4 was measured in game F2 (DVL evaluation) was not

 

Cheers Dakpilot

[unreasonable]

The chart is not showing comparable data between F2 and F4 (in the sense you are thinking)

 

F4 was measured in game F2 (DVL evaluation) was not

 

Cheers Dakpilot

 

That is how I read it as well - ie that the F4 in game perhaps should be - at best -  as fast to roll as the F2 DVL evaluation as per the chart, and possibly fractionally slower, while the BoM F2 should match the chart.