Wrong Russian fighters performance at high alts again

[=362nd_FS=Hiromachi]

These clearly show performacne of Yak-1 from 1943 after aerodynamic improvements.  Russian achived about 20 kph max after these fixes.  So Yak-1 from 1943 reached 531 kph at deck and 592 kph at  2 gear of supercharger ( around 4 km).

This improvements were introduced in December 1942, while Battle of Stalingrad lasted the whole time.

[303_Kwiatek]

Not before series 99.  As you know in game we got series 66.

 

Beside Yaks after these changes got only 1 mg  - 7.62 which mean also less take off weight  ( below 2900 kg)

 

In game we got Yak-1 with 2 mgs.

Edited February 21, 2015 by 303_Kwiatek

[=362nd_FS=Hiromachi]

Not before series 99.  As you know in game we got series 66.

That is correct, I absolutely agree. However some of the improvements were already incorporated in September 1942 as the production of the Yak-1s with M 105-PF started.

This simply requires dedication to find out in what exactly all the series varied. 

[II./JG77_Manu*]

 

That is correct, I absolutely agree. However some of the improvements were already incorporated in September 1942 as the production of the Yak-1s with M 105-PF started.

This simply requires dedication to find out in what exactly all the series varied. 

 

Hey Hiromachi, cheers for your involvement here. But one thing, the data you presented is from the Yak-1b. It has nothing to do with the Series 67 we have right now in game. We have presented enough data so far, about the "normal" PF version, which gets it's full throttle altitude at 3650m with a speed of 571. The Yak1b with PF engine (i don't know the first serial number of the inofficial "b" designation, i guess it was the 99) had another performance increase. It was already involved in the last stages of the Stalingrad campaign, but the Devs choose not to place it into the game, but the Series 67 which didn't have all those aerodynamical improvements, nor bubble canopy. So i guess, we should really take the normal PF data, and not the one about the Yak 1b the 67 was one of the very first Yaks with PF engine

[JtD]

...As you know in game we got series 66...

... Series 67 we have right now in game...

...This simply requires dedication to find out in what exactly all the series varied...

We have a series 69 in game. And we don't need to know in what all the series varied, because aircraft 15 of series 69 was tested at NII VVS. Performance already stated here many times, 510km/h@sea level, 571km/h@3850m @ 2917kg take off weight. So what you need to do is go and get that test report.

[Crump]

To not make it ride off topic for too long I didn't mean to say 600 km/h should be a "dead number" you'll crash and burn once reaching but a value to consider for pilot safety. If the structure has the strengh to exeed this value by a great ammount (as Crump claimed) there must be a different reason for the manual stated Vne making diving at high speed risky with the lagg-3.

 

I was just pointing out for you guys to remember the PEC curves for some the VVS designs are unusual.

 

The airspeed measurement instrumentation error curve (Position Error Curve) has a different slope as compared to other airspeed indicator installations.  That means the indicated airspeed error has a direct relationship with velocity instead of a inverse relationship.

 

http://forum.il2sturmovik.com/topic/3883-lagg-3-series-35/?p=115737

 

I highly recommend reading this thread to help with ideas to prove your point.   In it, the operational limits are linked to design changes in an appropriate timeline laid out by the documentation.

 

http://forum.il2sturmovik.com/topic/3883-lagg-3-series-35/

Edited February 22, 2015 by Crump

[JtD]

I was just pointing out for you guys to remember the PEC curves for some the VVS designs are unusual.

 

The airspeed measurement instrumentation error curve (Position Error Curve) has a different slope as compared to other airspeed indicator installations.  That means the indicated airspeed error has a direct relationship with velocity instead of a inverse relationship.

That's because you misread the table. In the La-7 566 indicated will get you 550 corrected, same way 270 indicated in the Typhoon will give you 260 corrected.

[Crump]

 

 

That's because you misread the table. In the La-7 566 indicated will get you 550 corrected, same way 270 indicated in the Typhoon will give you 260 corrected.

 

 

 

Of course....I misread the table... 

 

 

 

 

[JtD]

That's a LaGG-3, not a La-7. Assuming that the Finns use the same conventions like most other nations do for this chart, it is still interesting.

[JtD]

Btw, this is from the BoS "how we do it" section:

 

http://il2sturmovik.com/s/img/about/doc2.jpg

 

I hope that's not the Fw190 we've got.

[Reflected]

1) Thank you Kwiatek for taking the time for testing, and for pointing out your observations. No problem there.

2) The devs are making a great sim, that still has flaws to fix. No problem there

3) we all know fixing speeds is not a matter of changing a txt file. (although it was quite abruptly done in RoF recently) no problem there.

4) Kwiatek achieved speeds that are way off even compared to the best soviet propaganda. Same for the F-4. No "feelings", but black and white numbers, and screenshots. No problem there, these community members help the game evolve.

5) The Devs' only response is "No, it's correct, we've tested it, not gonna change" BIG PROBLEM THERE. It's numbers vs numbers, and clear as daylight. If it's too slow you can blame it on piloting skills but too fast is too fast.

6) Some community members go on protecting the devs, accusing Kwiatek of lack of hard data, "we don't care about your feeling of wrong", some go as far as "let's keep balance". THIS IS THE WORST PART. You guys are why the attitude mentioned in point 5 can work.

 

Then again, in RoF things got fixed (eventually) so I trust the devs will have a look at it. I hope it's just a few people with no idea about PR, and not the general attitude of all developers.

Edited February 23, 2015 by Reflected

[Crump]

 

 

That's a LaGG-3, not a La-7. Assuming that the Finns use the same conventions like most other nations do for this chart, it is still interesting.

 

 

Right.......

[=362nd_FS=Hiromachi]

Btw, this is from the BoS "how we do it" section:

 

http://il2sturmovik.com/s/img/about/doc2.jpg

 

I hope that's not the Fw190 we've got.

That starts to be ridiculous. One conspiracy after another...

 

FW-190 in this document makes slightly over 600 km/h at 6000 meters.

 

Kwiatek already tested FW-190 -> http://forum.il2sturmovik.com/topic/14625-wrong-russian-fighters-performance-high-alts-again/?p=233301

 

Condtion the same like before,  i decided to make test with 25 % radiators open  (  German RL speed test were made with 1/4 radiator open)

 

------------------Fw 190 A-3  ( 2 cannons)-------------------RL data ( ISA)

 

6 km------------1.32 Ata -  470 IAS ---- 628 TAS ---------- 630 TAS kph

------------------1.42 Ata -  486 IAS ---- 648 TAS-------- ---650 TAS kph

 

 

 

 

Rest planes   Fw 190 A-3,  109 G-2 and La5 got very accurate results comparing to RL data.

[JtD]

However, atmospheric conditions are not standard on the BoS maps. Kwiateks figures are not comparable to standard atmosphere conditions, as his conversion is not complete, for instance it does not take changes to engine power into account. Maybe you should starting thinking about the important bits and stop focussing on imagined slights.

[=362nd_FS=Hiromachi]

However, atmospheric conditions are not standard on the BoS maps. Kwiateks figures are not comparable to standard atmosphere conditions, as his conversion is not complete, for instance it does not take changes to engine power into account. Maybe you should starting thinking about the important bits and stop focussing on imagined slights.

There are no imagined slights.

If you are concerned with FW-190 performance than simply seek for in-corrections and prove them. 

 

http://il2sturmovik.com/s/img/about/doc2.jpg

I hope that's not the Fw190 we've got.

Because this cant even be called a "reasonable doubts". 

[JtD]

So I take it, you know for certain that this is not the Fw190 we've got? Have you got a source? And where's the memo that acknowledging that possibility is an insult?

 

And, besides this personal BS, can you manage to make a constructive on topic statement that isn't wrong?

[Brano]

However, atmospheric conditions are not standard on the BoS maps. Kwiateks figures are not comparable to standard atmosphere conditions, as his conversion is not complete, for instance it does not take changes to engine power into account. Maybe you should starting thinking about the important bits and stop focussing on imagined slights.

Can someone finish the conversion?So it becomes completed.

[Rama]

and if the conversation would turn less personal and less agressive, it would be nicer for the eventual readers.

[II./JG77_Manu*]

for a 100th time (not literally, but it feels like)

 

I/we/probably the Devs don't know the exact conditions back ~Dezember 1943. Of course the temperature on the ground is known, but at altitude it is not. I don't have to much clue in meteorology, but i know so far, that when you got 2 different places on the earth both at -10°, they can still have a very different temperature at 4k or 6k. It's dependent from the humidity in the air, which plays it's part in the density of the air. It's also dependent whether it is in a low pressure or in a high pressure area (low pressure-->cold air goes from higher altitude to lower altitude; high pressure-->warm air goes from the ground to mid to high altitude). 

 

So all the Devs can make is an estimation as soon as the planes are climbing away from the deck. Because of this point, i think it's just nonsense to look at the absolute numbers of every plane, like the same people are demanding again and again and again. No one knows how the planes should perform exactly. But everyone knows the relative performance between the planes in "normal" conditions. So the only thing which really makes sense is to compare the speeds of the planes in different altitudes, and the difference should be the same percental difference, like the test in normal conditions. (Unless there is some magic in the Stalingrad air, which let's only certain planes perform better, and others not).

And if you do that comparisons at different altitudes, you realize pretty fast, that they got them mostly wrong. So far i tested every fighter at 3 different altitudes.  (Btw the absolute numbers both real life and in game numbers are all spread over this and other topics, so i won't present them again.)

:

 

At 0 when you suppose that the Fw190-A3 is the worst model without adjustable grills,and you take the fastest Yak sources the speeds of all aircraft are pretty accurate. 109 F4 and Yak1 overspeed the other's are little bit in relative performance  OK

 

3650: If you suppose that the 190, the G2, and the La5 are right, the Lagg and the F4 overspeed a little, and the Yak overspeeds a lot. Of course you could see it the other way round, and say the Yak is right - then all other fighters are to slow.  fix the Yak, and i am ok

 

6000: Here it get's ridiculous. La5, 190 and G2 seem right. F4 overspeeds a little. PF engined Yak and Lagg are way way way to good. Clearly an error with high altitude performance of the PF engine. PF engine in game definitely does need rework, there is no data in the world, which shows that the Yak and the Lagg are coming anywhere near the performance in game, no matter how extreme you calculate the air conditions.

 

 

My conclusion is..fix the PF engine, fix the general overperformance of the F4 and the Yak, and we got very good flight models in the game.

 

Of course you could say after all that the Yak is right, but then you have a whole lot more work to do, to get the relative performances right. If this doesn't get fixed, and the relative Yak overperformance will carry on over the Yak 9 models, and the Yak 3, the Yak 3 will be the Eurofighter Typhoon performancewise (again, don't take it literal, guess i have to add this for a few guys in here). If they doesn't carry on the overperformance, they will have some awkard explanations to do, why "this successor isn't performing better then the last plane".....

 

so i really hope this gets adressed in time... and if i got the time in ~10 days, i will compile a whole report, and send it to the Devs. Because at least that huge high altitude discrepancy just can't be ignored..

 

I honestly also don't think that it's Russian bias in this case - this would make no sense, because the F4 is also overperforming. I just think, they got some variables in the PF engine wrong. (and something with the 1.42 ata setting in the F4)

Edited February 23, 2015 by Celestiale

[Uufflakke]

Can someone finish the conversion?So it becomes completed.

 

and if the conversation would turn less personal and less agressive, it would be nicer for the eventual readers.

 

Brano was replying to JtD about finishing the incomplete conversion not finishing conversation.

[JtD]

Can someone finish the conversion?So it becomes completed.

First we'd need to know the exact atmospheric details and for an accurate estimate we'd also need a good idea about the individual engines and their supercharging system. My personal rough estimates in the known sea level conditions give considerably lower speeds than present in game, so either there's a huge bug with the global FM or my rough estimate is too rough. I'm assuming the latter, but I don't think I'll be doing a more sophisticated estimate*. It would be most helpful if the developers took a minute and explained their modelled effects of cold/high density air in a couple of words, but I don't expect them to ever do that. I guess all we can do is wait for a map with standard conditions to check things more accurately. In the meantime, relative performance is the only way to go.

 

*Regarding the estimate - example Fw190: Expected sea level speed at combat/climb power under standard conditions is 520km/h. In game I'm getting around 535km/h true air speed, which is roughly 565km/h indicated in the conditions present. For this I'd need about 19% more power, and I don't see how the 10% cooler temperature will do that, it should be around 10%, for all I know.

[II./JG77_Manu*]

 

 

Regarding the estimate - example Fw190: Expected sea level speed at combat/climb power under standard conditions is 520km/h. In game I'm getting around 535km/h true air speed, which is roughly 565km/h indicated in the conditions present. For this I'd need about 19% more power, and I don't see how the 10% cooler temperature will do that, it should be around 10%, for all I know.

 

 

523 for the draggy 190, but that surely doesn't make a big difference. But now look at the other planes, like the F4 or the Yak, they are overspeeding even more (saw 4 sources so far claiming the ground speed of the Yak 500, and one saying 510, i don't get why we take this for granted anyway)

[JtD]

510 is the figure from the 15-69 test report. Not being taken for granted, in fact it appears that the aircraft was tested without radio, but in absence of evidence there's little point in making an argument against that result.

 

And yes, other aircraft achieve similarly high speed increases over standard conditions at sea level, and therefore give the same oddity with the required power.

[Rama]

Brano was replying to JtD about finishing the incomplete conversion not finishing conversation.

I wasn't replying to Brano. When I'm replying to a message, I quote it.

I made a moderator's statement that should be heard for this thread to avoid locked. And so far, it seems it was.

[unreasonable]

As soon as you get a summer map you will be able to do these tests all over again in something like standard conditions.

 

I wonder whether the BoS FMs read the fundamental inputs (air pressure, temperature) and will hence automatically adjust to a new set of conditions, or if they instead have some "fudge factor" that will have to be recalculated by the devs for each set of conditions. To put it another way, does plane X on the winter map have the same flight model as plane X on a summer map?

[JtD]

The IL-2:1946 FM already took atmospheric conditions into account to some extent. It's simple to make it reasonably accurate.

[unreasonable]

I know RoF takes temperature into account at least as far as engine cooling goes. Not sure if this affects engine power as well: RoF forum down for rebuild for a few days so cannot check. Presumably the FME coming soon will allow the ground level and temperature pressure to be set by human hand, so people can run tests at standard conditions, (just assuming standard altitude changes).

[=362nd_FS=Hiromachi]

Right, I executed the test following Mr. Stepanec and TSAGI instructions how to achieve maximum speed. 

Adjusted IAS to TAS using this : http://www.hochwarth.com/misc/AviationCalculator.html
 

 

Yak-1 – 100 % fuel, Water radiator open at 150mm from full 375mm = 40%, Oil radiator open at 90mm from full 190mm = 48%
My results are as following:

Altitude (m) – IAS (km/h)  – TAS (km/h)
6000              -     428           -  573
3750              -     504           -  601
SL (100)        -     548           -  550

[Crump]

 

 

Right, I executed the test following Mr. Stepanec and TSAGI instructions how to achieve maximum speed. 

 

There is no place to put IAS on that page.  

 

Calibrated Airspeed is not Indicated Airspeed.... CAS is corrected for instrument position error.  

 

That is the whole point of my earlier posting which once again appears to have gotten brushed aside.  

 

Position error is a function of the pitot static system design and airspeed indicator design.  That is why the characteristic curve of the Lavochkin Lagg designs retains the distinctive shape of the curve throughout the series.  Do not brush it aside out of ignorance as to its meaning and importance.  

 

If you read the curve, it makes a huge difference with the VVS aircraft.  Not having that PEC curve could completely throw off your conclusions.

 

Just trying to help you guys and avoid the petty ego arguments.

[=362nd_FS=Hiromachi]

There is no place to put IAS on that page.  

 

Calibrated Airspeed is not Indicated Airspeed.... CAS is corrected for instrument position error.  

 

That is the whole point of my earlier posting which once again appears to have gotten brushed aside.  

That is right Crump and I recognize that issue. I used it mainly because it was used before, to "compare" previous results.

 

But point still stands with values in Indicated Airspeed. They are lower than ones from initial post. 

 

 

 

Position error is a function of the pitot static system design and airspeed indicator design.  That is why the characteristic curve of the Lavochkin Lagg designs retains the distinctive shape of the curve throughout the series.  Do not brush it aside out of ignorance as to its meaning and importance.  

I absolutely "do not brush it aside". 

 

 

 

Just trying to help you guys and avoid the petty ego arguments.

I am absolutely thankful for than Crump

[Brano]

Just created a simple mission in recently released FMB with ISA conditions

1. atmospheric pressure 1013 HPa/760mmHg

2. Outside atmospheric temperature +15C at sea level

 

AC condition

1.Take off from strip and heat up the engine

2. water temp not exceedeng 100C

3.Oil not exceeding 110C

4.rpm 2700

 

Result

TAS at sea level for Yak-1 s69 is 510km/h

[Brano]

TAS at 3850m = 584km/h

 

TAS at 5000m = 544km/h

[JtD]

Could you please share the mission to shave some time off other folks testing attempts? I'm not sure I'll have the time to fiddle with the FME right now, but would like to check other planes as well, particularly the 190.

 

Was 3850m the full throttle altitude in second gear in the Yak?

 

How did you get TAS - map grid or some conversion calculation?

[Brano]

Hi JtD,

 

I am at work right now,not possible to reach my gaming PC.But with absolutly no knowledge of FMB I was able to build simple mission with Yak-1 on airfield at Stalingrad big map.I set map condition to be standard ISA conditions +15C and 1013hPa.Speed at different alts has been recalculated with ISA standard temperatures at given height.Aircraft setup was as written in Stepanec book (he was chief engineer at NII VVS and took part in original testing).

 

Main point was to keep rpm at 2700 and temperature of water/oil at max allowed temperatures (100C water,110C oil).Radiators were set according manual to 40% water and 48% oil (in russian "po potoku).At higher altitudes I could close them a bit as cooling became more efficient,but not much.I did not touch vysotnyi korrektor,as it has no influence on engine above 4k.As I mentioned before,it is either working kind of automaticly or mixture correction is not implemented yet.

[JtD]

I didn't even have time to DL the patch or FMB, so I would still appreciate if you could share the mission. I'd rather spend the next 30mins in game testing performance than fiddling with the FMB (I'd like to do that at some time when I have more time). Unless someone beats me to it, I guess I'd first check the Fw190.

 

I would recommend to check top speeds against the map grid instead of converting IAS to TAS. It should at least be used to check conversion, as we don't know if standard conditions at sea level really mean standard atmosphere at all altitudes.

 

Does Stepanec in his book mention No.15-69 tests, and does he make a statement about the aircraft condition? Does he say if it was tested with radio installed?

[Brano]

Hi JtD,

I could not find Yak-1 N15-69 record in that book.Only s85 (august 42 production) and s99 (october 42).Maybe I overlooked it.Might check again,but not much time for that now.Maybe over weekend.I will get to my gaming PC maybe only on Saturday,so sorry for not sharing the mission now.

Your idea of measuring flown distance in map grids is quite interesting.For that I would have to extend the map area in my mission,cause I used only some default setting which seems to be like Lapino map size.Looking forward to test the Yak according to your suggestion 

[6./ZG26_5tuka]

Made some quick test mission for the Bf 109 F-4 under ICAO / ISA conditions (100% fuel, no winds/turbulences, no extra ordinance/unlocks, autolevel pilot) testing ground level speed (250m AMSL) only. The results with time compression were:

 

- 503 km/h IAS at 1.32 ata

- 521 km/h IAS at 1.42 ata (engine died after 4 min so I'll conduct another one with undestructable engine settings enabled)

 

Interesting results and very different to the ingame winter condition ones. Hopefully this will improve our testing methods and shed some light on the devs mysterious performance gain calculation due to cold weather.

Edited February 26, 2015 by Stab/JG26_5tuka

[303_Kwiatek]

Could somone put map at standart ISA condition  with all planes avaliable ? Im totaly noob with new misison editor

Edited February 26, 2015 by 303_Kwiatek

[Brano]

 Im totaly noob with new misison editor

Myself as well  But it is not so hard to create,only I have no time for that now.Maybe to ask someone with experience of ROF editor to setup such mission.Who is frequently here on forum and can make it in reasonable time.Unfortunately ,as I mentioned before,out of my gaming PC again till Saturday...and maybe longer... 

[6./ZG26_5tuka]

Could somone put map at standart ISA condition  with all planes avaliable ? Im totaly noob with new misison editor

I dont think thats possible. As for as I knwo we can only set up predefined missions, means each plane oyu want to test requires it's own mission.

 

Due to my low expirience - only used terrain editors briefly in RTS games so far - I have lots of stuff to learn about it. I'll try to generate some generic ISA test mission for each plane but I can't promise anything yet.