Roll Rates

[Roland_HUNter]

Greetings,

Can anybody explain to me, with aviation engineering or with historical documentaries: (because I have no clue)
Why the roll rates are "interesting" for some planes:
Example:
Bf-109 4,7-5 sec (by the CLOD sources or some what I found, it should be around 4 sec, but fine)

This video (https://youtu.be/i2aqeALGWL8?t=3005 ) says with historical documents: 109s roll rate should be good as the p51s.

FW-190: 3 sec

La-5FN: 2-2,3 sec Why it is better than the FW-190?

Yaks: 3,5-3,7 sec. Almost good as a FW-190. How and Why?

Spit IX CW: 3,8 sec

Spit IX: 4-4,3 sec

P-51B:4,13-4,27
P-51D:4,13-4,27

 

Please everybody join and discuss this!

 

PS:

Other things:
Turn times/climbing data:

I guess the in game manuals in the future should be upgraded.
Why?
Example:
La-5FN:

Note 4: climb rates and turn times are given for Boosted power.

Climb rate at sea level: 20 m/s

With Boosted, you can climb with 27 m/s.
Maximum performance turn at sea level: 21.0 s, at 320 km/h IAS.

With Boosted, you can make that turn in 18.89 sec.

 

[JimTM]

The last note at this time in Requiem's Flat Scissors videos indicates that a better roll rate is very helpful in a flat scissors fight.

[354thFG_Rails]

I don’t understand what the complaint is. What are you wanting to know?

[Roland_HUNter]

The roll rates.

What kind of historical or aviation document the game values are based on? 

 

And not updated manuals. 

[354thFG_Rails]

Pretty sure they are sourcing multiple flight tests for the different aircraft. I highly doubt they’d be using one single one. Plus flight manuals are not going to tell you how quickly a plane should roll, at least I don’t think they would unless there is a limit. For instances the A4 skyhawk had a limit to how fast it could roll even though the aircraft could potentially exceed it. You should also keep in mind that il2 is modeling stick forces differently compared to dcs. And I’m not certain how clod is modeling them. From what I understand they have it modeled to where the pilot can only put so much force on the stick and depending on speed and load it will change how much the controls deflect. Dcs is 1:1 regardless of speed, if my memory is correct. 

[Art-J]

9 hours ago, 86th_Rails said:

From what I understand they have it modeled to where the pilot can only put so much force on the stick and depending on speed and load it will change how much the controls deflect. Dcs is 1:1 regardless of speed, if my memory is correct. 

 

It isn't. DCS also does it the same way as you explained in previous sentence. But we're getting a bit off topic here in regard to GB series.

[the_emperor]

13 hours ago, Roland_HUNter said:

What kind of historical or aviation document the game values are based on? 

I guess that is a company secret.

If you think some roll rates are off, then you would have to look up the tests that might support that.

But finding tests for roll rates is very hard and most are more anecdotal and comparative in relation to other aircrafts, often coming from captured aircrafts.

And finding good soviet documents is especially hard, even harder if you are not native in the russian language.

[354thFG_Rails]

5 hours ago, Art-J said:

 

It isn't. DCS also does it the same way as you explained in previous sentence. But we're getting a bit off topic here in regard to GB series.

I don’t think it’s that off topic. I just thought dcs did it 1:1 because that’s what I had read a while ago. In any case if they do it the same way then good for them. 

Edited January 16, 2024 by 86th_Rails

[Art-J]

1 hour ago, 86th_Rails said:

I don’t think it’s that off topic. I just thought dcs did it 1:1 because that’s what I had read a while ago. In any case if they do it the same way then good for them. 

Ah, I see. I think what you recall reading was about 1:1 controls movement until reaching airspeed-dependent force "cutoff" point, instead of nonlinear "stiffening" up to the same cutoff point. DCS used to utilize the latter method, like other sims, but switched to the former. Two a bit different approaches to the same problem, each of them having its own pros and cons and both equally crap until FFB controls become mainstream someday in utopian future  

[354thFG_Rails]

3 hours ago, Art-J said:

Ah, I see. I think what you recall reading was about 1:1 controls movement until reaching airspeed-dependent force "cutoff" point, instead of nonlinear "stiffening" up to the same cutoff point. DCS used to utilize the latter method, like other sims, but switched to the former. Two a bit different approaches to the same problem, each of them having its own pros and cons and both equally crap until FFB controls become mainstream someday in utopian future  

It’s why I have FFB now. Has made flying so much nicer, thanks for the info.

[the_emperor]

On 1/16/2024 at 9:04 AM, the_emperor said:

But finding tests for roll rates is very hard and most are more anecdotal and comparative in relation to other aircrafts, often coming from captured aircrafts.

Here is a good example.

http://www.wwiiaircraftperformance.org/me109/me109g6-tactical.html

the 109 rated equal in terms of roll rate to the Mustang, but it is not specified, at which speed and heights.

Additionally the 109 carried the underwing cannon gondolas, so roll rate might even be better and the Aircraft was a captured one, this might contribute to lesser perfomance overall

[354thFG_Rails]

The problem with those test is there aren’t really any numbers to go with them and it’s based on what the pilot is doing to the aircraft. I think they are good to get a general idea of what the planes could do but no good in respect to hard data. 

[354thFG_Drewm3i-VR]

Two words: wind tunnel. That's what we really need to get this stuff mostly right. Personally, I think the 109 is just about right as-is. It really shouldn't roll with a P-51, except at slow speeds and this is exactly what we see in game. The 109 is really an early-war design that stayed competitive because of it's great engine and power to weight ratio, but it retained a lot of the early weaknesses into the K-4 (weak wings, bad landing gear design, small control surfaces, mediocre canopy design, limited range, non-hydraulic flaps, no rudder trim, etc.)

 

With the size of that cockpit and the stiff stick forces, real life pilots would not likely be able to pull off moves like we do in IL-2 as-is. Other planes that are very comfortable, safe, and had more moderate stick forces and larger control surfaces (like the P-40 and P-47) would shine in these areas whereas in IL-2, these factors don't matter. I'm with Rails on this one.

Edited January 30, 2024 by drewm3i-VR

[Roland_HUNter]

12 hours ago, =DW=_drewm3i-VR said:

bad landing gear design

So, the spit had also bad landing gear design?

""109s were so difficult to take off and land that half the 109s lost in the war were lost to take off and landing accidents."
- 5 % of the 109's were lost in take off/landing accidents.

"11,000 of the 33,000 built were destroyed during takeoff and landing accidents - one third of its combat potential!" (direct quote)
"Me-109 had an astonishing 11,000 takeoff/landing accidents resulting in destruction of the a/c! That number represents roughly one-third of the approximately 33,000 such a/c built by Germany." (usual internet claim)
- Source: FLIGHT JOURNAL magazine
- The magazine has it wrong or has misintepretated the numbers. Luftwaffe lost about 1500 Me-109's in landing gear failures. Note that German loss reports often lump destroyed and damaged (10 to 60% damaged) together. It was also a standard practise to rebuild even heavily damaged airframes. While rebuilding/refurnishing these planes were also upgraded to the latest standards and latest equipment. This means that large proportion of these damaged/destroyed planes were not complete losses, but returned to squadron service.

"The specific problem with the Bf 109 was the very narrow / weak undercarriage track."
- Narrow landing gear was not that uncommon at the time - all biplanes also had narrow landing gear. Me 109's undercarriage was connected to the fuselage rather than the wings. This had several reasons. Most importantly the wings were easily and quickly changed if needed, without special preparations or tools. Wings were also one single structure, which made it possible to make them very strong. Because this the plane needed some care when operating. The claim that the narrow undercarriage was a problem is a myth, though. In comparison the undercarriage of Supermarine Spitfire was even narrower - it had its own share of problems from this. Imagine what it was to takeoff and land the Spitfire's carrier version to carriers for example? Especially later marks of Spitfire with enormous amount of installed power were quite a handful to operate. But that is conveniently usually ignored.
- The width of undercarriage in Me 109 E is 1,97 meters; 109 G 2,06 meters and 109 K 2,1 meters. However - Spitifre's undercarriage width was 1,68 meters.
- The real problem was the center of gravity behind the undercarriage. This made it possible to brake unusually hard in landings, but it also required the pilot to keep the plane straight in takeoff and landing. Because this it was easier for a small sideswing to develop into a groundloop or the plane might drift off the runway, if the pilot was not awake. Of course, if the tailwheel was not locked, the tendency would be pronounced and more difficult to counter. As with any plane.
- Contrary to the popular myth, the landing gear could take the plane 'dropping' in from about 8-10 feet. "

12 hours ago, =DW=_drewm3i-VR said:

no rudder trim

There was trim, with red trim you can adjust the trim for the rudder, aileron on the ground.

 

12 hours ago, =DW=_drewm3i-VR said:

shouldn't roll with a P-51

So, the american report is false? They lied to themselves?

 

12 hours ago, =DW=_drewm3i-VR said:

With the size of that cockpit and the stiff stick forces, real life pilots would not likely be able to pull off moves like we do in IL-2 as-is

Yak has the same size canopy as the 109, check out those pulls in Yaks.

Or what about Hans-Joachim Marseille ? The allies reported nobody could pull after him. Yes, he was a rare ace, but the 109 could follow his insane pulls. So the 109 is capable for it.

Still: We need documents instead of opinions. I've my opinion, you have yours, both of us are right and wrong. We need to prove our points.

[ZachariasX]

1 hour ago, Roland_HUNter said:

The real problem was the center of gravity behind the undercarriage.

The problem is the way the wheels are aligned in the 109 together with the suspension.  As soon as the 109 tilts to on side, the outer wheel gets more traction and makes the plane turn in the opposite direction. Together with a small rudder that is not effective at slow speed and tail down, it is easy to create an uncontrolled departure sideways effectively making the pilot a passenger. It all means that there is just little margin for a safe takeoff, far less so than in most other planes.

 

The Spit doesn‘t exhibit such a bevaviour. It goes straight enough to be controllable even with just a swivelling trolley wheel in the back. Given both aircraft were designed to be operated from grass strips with a fair margin to just take off into the wind, it is less of an issue in principle. Still, the 109 will bite you faster and harder on takeoff if you do it wrong, making it a challenging aircraft to operate. Not safe for your common yokel.

[357th_KW]

With regard to roll rates, the Merlin Mustang is probably the worst aircraft to use for a comparison, as they could have their ailerons rigged at +/- 10, 12 or 15 degrees of travel and this kind of detail just isn't mentioned in any roll test I've ever seen.

[LLv34_Flanker]

S!

 

You can find a good chart made by allies having roll rates of several planes compared. The Fw190A should rule ALL planes but clipped wing Spitfire(at a very narrow speed range) and P-51 outrolling 190A only at most extreme speeds. In that same chart maximum roll rate of the Fw190A was given at 160deg/sec. A RAE test comparing 190 vs Spitifre in rolls is also easy to find. Bf109F/G had slightly slower roll rate than E, in the range of 4-5sec depending on speed. Only western document of the LA-5FN roll rate is the Rechlin test from 1944 stating roll rate being slightly better than 109G, but markedly slower than 190A. This is in line with many pilot remarks of the LaaLaa. Yak was said to be better rolling than 109 when comparing against La-5. Again very few USSR documents mention roll rates that I have seen, at least NII VVS and TsAGI ones. No comments on anything else

 

 

[354thFG_Rails]

The problem I have with that chart is it’s only with 50 lbs of stick force. Depending on how much force per g it took to deflect the controls surfaces and how much a typical pilot could put into the stick would either make a plane roll/pitch quicker. In the case of the 109 vs 47 the stick length for the 108 is about 21 inches the 47 is about 29 inches. The 47 pilot should be able to input more force into the stick if the stick forces per g were relatively the same. And considering we don’t know how much force the il2 pilot is inputing. This is really hard to test in my opinion. 

Edited January 29, 2024 by 86th_Rails

[CUJO_1970]

Yep, roll rates are a problem.

 

Yes, we do in fact know how much force it took to deflect the ailerons in most WW2 a/c. There are reams of data on German/British/American aircraft, especially from the RAE. It also helps us to see the NACA chart doesn't really show the FW190 with either full aileron deflection -or- best roll rate:

 

 

 

And yet, this is what we see measured in Great Battles:

 

 

The FW 190 is getting the short end of the stick in this sim as it pertains to roll rate...It should be quite a bit more agile than what we see in the sim. In fact the La5FN was rewarded with the actual FW190 roll rate as La-5FN easily reaches 167 deg/sec roll rate at 250 mph.

 

Finally you have stuff like this going on in the sim as well. (Also benefits A-20 mightily in this regard, as it was forbidden from aerobatics)

 

 

 

Again, in the case of Mosquito like so many other aircraft we do know it's a 30lb load to reach full column displacement. The Mosquito is hideously over-modeled in this regard.

 

It's disappointing that planes like FW190 languish in this sim for years when there is clear data to correct them.

 

 

Plenty of data out there on stick force/aileron deflection. It was studied exhaustively during WW2.

 

 

And yes, the developers are aware of the stick forces being applied in the sim.

 

 

Edited January 30, 2024 by CUJO_1970

[ZachariasX]

19 hours ago, 86th_Rails said:

This is really hard to test in my opinion. 

All I can say is that the charts posted reflect the situation as I could reproduce it in both the Mustang and the Spit. For practical purposes, both aircraft will do almost close to 90° bank from level flight in a second time when you push the stick all the way over, anywhere between ~160 mph to roughly 260 mph. From where on  differences can be felt inasmuch as the Spit getting a progressively slower roll than the Mustang (while starting to require both hands) that can maintain the roll somewhat while giving the pilot a workout. The Spit starts out with markedly less force required. The Mustang always asks for a really strong hand, while the Spit can easily (and best, I find) be controlled with only two fingers when going ~240 mph. Then the Spitfires stick then is even lighter than the one of a Bücker 131 Jungmann.

 

Hence, I'd say most aircraft probably would deliver as a good average of the charts above indicate and they should be the basis to model roll rates.

 

I don't think it is helpful making stick force analogous to what you press at the bench in your local gym when considering what you would manage. You're not pressing the stick, you're controlling it while using that amount of force. Doing aerobatics in the Mustang the way Bob Hoover did it is a throrough workout. It is clear that poorly fed pilots will have an obvious limitation in what they can do with the aircraft.

[354thFG_Rails]

13 hours ago, ZachariasX said:

I don't think it is helpful making stick force analogous to what you press at the bench in your local gym when considering what you would manage. You're not pressing the stick, you're controlling it while using that amount of force. Doing aerobatics in the Mustang the way Bob Hoover did it is a throrough workout. It is clear that poorly fed pilots will have an obvious limitation in what they can do with the aircraft.

I don’t disagree with you. And in fact I would assume they would try to simulate roll rates similar to the charts above. I was merely saying that unless you’d know what the il2 pilot is cable of inputing on the stick, it’s hard to test if they’re off. I don’t think the roll rates for most aircraft are bad in game as well, there are a few that are questionable I think. 

[CUJO_1970]

Test parameters: Kuban Autumn @10,000ft.

 

Lagg-3 rolls essentially same as FW190 in the sim.

 

 

 

 

 

Edited January 31, 2024 by CUJO_1970

[the_emperor]

Hmmmm thanks @CUJO_1970 thats looks at least worth investigating. 
So does any one have any reliable documents of soviet roll rates?

[BubiHUN]

On 1/19/2024 at 8:29 AM, drewm3i-VR said:

Two words: wind tunnel. That's what we really need to get this stuff mostly right. Personally, I think the 109 is just about right as-is. It really shouldn't roll with a P-51, except at slow speeds and this is exactly what we see in game. The 109 is really an early-war design that stayed competitive because of it's great engine and power to weight ratio, but it retained a lot of the early weaknesses into the K-4 (weak wings, bad landing gear design, small control surfaces, mediocre canopy design, limited range, non-hydraulic flaps, no rudder trim, etc.)

 

With the size of that cockpit and the stiff stick forces, real life pilots would not likely be able to pull off moves like we do in IL-2 as-is. Other planes that are very comfortable, safe, and had more moderate stick forces and larger control surfaces (like the P-40 and P-47) would shine in these areas whereas in IL-2, these factors don't matter. I'm with Rails on this one.

109s had the trim tabs man and has been set on the ground. 

[CUJO_1970]

La5FN added - they gave it the roll rate the FW190 really had historically.

 

[LLv34_Flanker]

S!

 

Thanks for posting @CUJO_1970 

[CUJO_1970]

P-47 D22 in game compares very well with P-47C actual tests:

 

 

 

[ZachariasX]

On 2/1/2024 at 5:30 AM, CUJO_1970 said:

La5FN added

What would be historic values?

[CUJO_1970]

2 hours ago, ZachariasX said:

What would be historic values?

This is a million dollar question. There is no publicly available test data. At all. We only have German test by Lerche that says it rolled very similar to the contemporary 109. The La5FN did have wing/aileron improvements that I will post later - over the La5 - which was according to pilots quite heavy on the controls. At any rate, I can’t see anything that justifies its rolling performance in Great Battles at all, and certainly nothing that suggests it so easily out rolls the FW190 as it does in the sim.
 

You would think that pilots might mention that the La5FN was the fastest rolling fighter in the world. 
And the Mosquito…lol.

 

I would like to post more tests but this is a real pain in the ass to do, it takes time to do it right. Because the timeframes are so quick, and you have to test at correct altitude and three speed points of reference. You also have to fly coordinated and not let the plane wander all over the place. I do averages of 10 from three data points (160/260/360) so it takes forever if you want to get it exact. 

Edited February 2, 2024 by CUJO_1970

[354thFG_Rails]

On 1/30/2024 at 12:05 AM, CUJO_1970 said:

Yep, roll rates are a problem.

 

Yes, we do in fact know how much force it took to deflect the ailerons in most WW2 a/c. There are reams of data on German/British/American aircraft, especially from the RAE. It also helps us to see the NACA chart doesn't really show the FW190 with either full aileron deflection -or- best roll rate:

 

 

 

And yet, this is what we see measured in Great Battles:

 

 

The FW 190 is getting the short end of the stick in this sim as it pertains to roll rate...It should be quite a bit more agile than what we see in the sim. In fact the La5FN was rewarded with the actual FW190 roll rate as La-5FN easily reaches 167 deg/sec roll rate at 250 mph.

 

Finally you have stuff like this going on in the sim as well. (Also benefits A-20 mightily in this regard, as it was forbidden from aerobatics)

 

 

 

Again, in the case of Mosquito like so many other aircraft we do know it's a 30lb load to reach full column displacement. The Mosquito is hideously over-modeled in this regard.

 

It's disappointing that planes like FW190 languish in this sim for years when there is clear data to correct them.

 

 

Plenty of data out there on stick force/aileron deflection. It was studied exhaustively during WW2.

 

 

And yes, the developers are aware of the stick forces being applied in the sim.

 

 

That RAE roll chart stated full deflection OR 30lbs of stick force. Unless you have a stick force chart similar to the 190 one you posted, the mosquito might not be making full travel on that chart. Also I’m not saying the mosquito is accurate, I personally think it’s over performing. But again, do we know what the il2 pilot is capable of? I know it seems silly but if the pilot is putting out less or more force than what those test suggest then they could be slightly off. 

[CUJO_1970]

5 hours ago, 86th_Rails said:

That RAE roll chart stated full deflection OR 30lbs of stick force. Unless you have a stick force chart similar to the 190 one you posted, the mosquito might not be making full travel on that chart. Also I’m not saying the mosquito is accurate, I personally think it’s over performing. But again, do we know what the il2 pilot is capable of? I know it seems silly but if the pilot is putting out less or more force than what those test suggest then they could be slightly off. 

The RAE chart is for up to 50lb stick force, not 30lbs. The full report also includes a graph for variation of stick force with speed and aileron angle - part of which is in the first picture I shared: It required 30lbs for the FW190 to roll 160 degrees per second at 250 mph.
 

The RAAF report (which is a separate report) for the Mosquito states 30lbs is full column deflection, so yes it is full travel. The RAAF report shows the maximum rate of roll. 

 

[354thFG_Rails]

Full displacement OR 30lbs? The second chart that shows the 190 roll rate is 50lbs, yes. Also what was the 190’s aileron travel? 

Edited February 3, 2024 by 86th_Rails

[354thFG_Drewm3i-VR]

On 2/1/2024 at 10:17 PM, CUJO_1970 said:

P-47 D22 in game compares very well with P-47C actual tests:

 

 

 

Someone has a Luftwaffe axe to grind...

 

So your contention is: All of the Allied birds are performing as they should or are overperforming, while the 109 and 190 are both underperforming. Sure. You are manipulating the data to prove your pre-existing, overarching premise that German=superior wonder weapon. 

 

If we were being honest, there are likely many minor issues (and some major) with GB planes and it would all depend on what data the devs choose to use for their calculations. Isolated reports from the 1940s are also suspect and would depend on pilot opinion/capability, the reliability of these instruments which cannot be tested, as well as the specific and particular airframe being tested. This is likely why the P-40 has been a turd for so long because Soviet reports during the war at that time, were very suspect. That being said, you are probably right the FW-190 should roll better and the La-5 worse. Bringing the P-47C and Mosquito into it out of nowhere does not help your case though and are red herrings.

Edited February 3, 2024 by =DW=_Drewm3i-VR

[CUJO_1970]

You are out of your element here and your insults don’t deserve a response beyond this: Sit this one out and let the grownups talk.
 

Thanks!

[354thFG_Rails]

I found a link to that RAE report. They confirm similar results to naca. Peak 160 degrees a second. It would probably be safe to assume the devs would try to model 50 lbs of stick force. If the 190 is truly not rolling as quick, I suggest you make bug report.

 

I do find it interesting that the report does suggest that at 300ish mph EAS it can not make full travel due to forces being high. As the other roll chart would suggest it starts to drop off after 250 mph.  Another interesting note is if the devs are modeling wing flex at high speed, also attributing to further loses. 
 

 

Edited February 4, 2024 by 86th_Rails

[CUJO_1970]

On 2/3/2024 at 1:21 PM, 86th_Rails said:

Full displacement OR 30lbs? The second chart that shows the 190 roll rate is 50lbs, yes. Also what was the 190’s aileron travel? 

 

 

Regarding full displacement OR 30lbs, it means that the roll rates were achieved with full column and therefore full aileron displacement. In some cases of course it took less than 30lbs to achieve full column displacement. For example, from other tests notice:

 

 

 

 

 

 

For the FW190, ailerons data from the report:

 

 

 

[354thFG_Rails]

18 minutes ago, CUJO_1970 said:

 

 

Regarding full displacement OR 30lbs, it means that the roll rates were achieved with full column and therefore full aileron displacement. In some cases of course it took less than 30lbs to achieve full column displacement. For example, from other tests notice:

 

 

 

 

 

 

For the FW190, ailerons data from the report:

 

 

 

 

 

 

 

 

 

I figured that’s what it was indicating. I think I was just misinterpreting it. 

[354thFG_Drewm3i-VR]

2 hours ago, CUJO_1970 said:

You are out of your element here and your insults don’t deserve a response beyond this: Sit this one out and let the grownups talk.
 

Thanks!

You literally have made the following claims in this thread: 

 

-The FW-190 roll rate is far too slow 

-The La-5/5N roll rate is far too fast

-Based on data from the P-47C, the P-47 D-22 performs as it should=> so therefore some of the devs upcoming solutions are not warranted?

-The Mosquito rolls/performs too well

 

Your ad hominem also has no place here. I did not insult you, I simply pointed out the logical conclusion of your argument which is to say that all of the Allied birds you mentioned are over-performing, while the German birds are under-performing. You are presenting this as if it is factual and inarguable, yet we don't know what test methods have been used and we don't know if other people can verify and substantiate your in-game tests/reports that are overlaid on the archival reports, which we are also taking at face values as bonafide and verifiably true. The truth is likely much more complicated.

 

Just because I'm not a fluid dynamics expert doesn't mean I am not capable of recognizing a potential bias and agenda, as well as poor logic and reasoning (not accusing you of this, but everything should be questioned and analyzed). I'm not saying everything you have said is invalid: in fact it may all be true, but I am skeptical when someone comes on here with the above four points and do tend to trust professional developers more, although you and others on here like Yak Panther, Rails, etc. make valid points and these changes get investigated and sometimes implemented in-game. 

 

Questioning your expertise and data is part of the process of rational discourse and it should stand up to scrutiny by laymen and experts alike. If it's true, it will be able to stand on its on two feet. 

Edited February 4, 2024 by =DW=_Drewm3i-VR

[CUJO_1970]

28 minutes ago, 86th_Rails said:

I figured that’s what it was indicating. I think I was just misinterpreting it. 

 

The Mosquito had quite low control forces, just not effective when compared to S/E fighters. It was designed to go fast, not perform aerobatics.

 

(In fact it was forbidden to fly aerobatics altogether)

 

 

 

 

[CUJO_1970]

P-51B added.