Rolling performance

[JtD]

I've been looking at rolling performance. My interest was sparked by the most recent flight model overhaul. First off, I'd like to post a couple of things on the theory. What I'm posting here is mostly taken from the NACA "Summary of lateral control research", available b/w as Technical Report 868 or in colour as Technical note 1245.

While it is 70 years old, it is a good source on the issue because the planes we're looking at are also that old. The best known bit of the report is figure 47, roll rates of various aircraft at 10.000 feet. I've attached that one. The curves you see on this one have a distinct shape, their are first increasing as speed goes up, then going down. The increasing part is the speed range, where the pilot is still able to fully deflect the ailerons. So, like a screw, the plane will do a fairly constant rotations per distance travelled, and thus roll faster as speed increases. This screw like behaviour is in fact an important technical quantity, the so called helix angle. It can be defined as both, change of angle over distance, or roll rate over speed. Because it is important, I've also attached the figure 46, which contains the helix angles for the plane for which the roll rates are given.

Back to figure 47, in the right, decreasing part of the curves, the pilot has reached the limit of his physical strength. He cannot fully deflect the ailerons any more. As speed increases, possible aileron deflection becomes less and less and thereby, roll rate (and helix angle) go down.

The top spot, where the pilot can just manage to deflect the ailerons fully, always happens at the same indicated air speed. Indicated air speed is what determines the forces on a plane, no matter which altitude you fly at.

Interestingly, roll rate for a specific aileron deflection (helix angle, as it is) depends on true air speed. Think of the screw again, the faster you drive it forward, the faster it has to turn. In that sense, it doesn't matter if you drive it into soft or hard wood. Just like the plane doesn't care about high density or low density air in this regard.

I've added two formulas to the rolling velocity chart, on the left part, it is the calculation for the helix angle. Fairly straightforward, it is the product of aileron size (relative to the wing) and maximum aileron deflection, and a couple of efficiencies. Most important here are wing twist, induced yaw and possible control tabs. In a first estimate, the aircraft with the bigger ailerons and large aileron deflection rolls faster at low speeds.

At high speeds, the formula is way more complex and I'm not capable of simplifying it to a couple of sentences, but major issues that matter here are aerodynamic balance, control gearing and wing twist. Of course it would be too easy this way, so I'd just like to mention that at high speeds flutter becomes a serious issue. The better the aerodynamic balance (reducing control forces), the higher the risks for flutter or aileron reversal.

To illustrate the impact of wing flexibility, I've added figure 4, which shows the reduction of the roll rate of a P-47C due to wing flex. At 550mph, it can't roll any more, because any aileron impact is compensated by wing flex.
To illustrate the issue of aileron reversal, I've added figure 33, which shows how the stick forces of a modified P-40F develop as speed increases. The lower chart shows that while everything in nice and stable at 250mph IAS, at 400mph the stick force suddenly decreases as the ailerons are getting deflected. A very undesirable behaviour. The upper chart is the same plane, same control, but a stiffer, less stretchable control linkage. Small change, but suddenly the instability is gone.

 

 

So, after this theory I went into the game and started testing. After a couple of pre-tests I decided I wanted to roll aircraft from level flight at basically idle power settings, minium prop pitch and neutral trim - laterally and in yaw. I tried several different elevator trim settings, so I could find one that made my fly less badly.

Anyway, I used the Tacview software to record in game data. Tacview does give you the relevant information here, namely roll rate, true air speed (TAS) and calibrated air speed (CAS), which is essentially indicated air speed minus position error correction (error of display of indicated speed in the cockpit). I've attached a picture of how it looks in Tacview. Pretty crappy, I admit.

From Tacview I just took the data into OpenOffice Calc (Excel, if you work with that), and had roll rate charted over TAS and CAS. From my pre-tests, it is easy to see that when comparing low altitude and high altitude roll, that indeed the peak roll rate will be achieved at the same CAS no matter the altitude, and that roll rate increases with TAS. I've attached two charts showing that. The high roll rate is achieved at high altitude, where at the same CAS, the TAS is higher.

Having established that the theory works (in game), I simply calculated the helix angle (example chart attached, to illustrate how well or poorly measured data was approximated), and from there calculated the roll rates for all fighter aircraft for an altitude of 10000 feet. Roll rates are displayed as angular velocity in degrees per second over true air speed in kilometres per hour.

The I-16 is the low speed king, the La-5 the mid speed king, and at high speed the Fw190 is a touch ahead of the competition. The Mc202 and P-40E are pretty good high speed rollers, too. On the bottom, throughout the speed range, is the Bf109, at low speeds joined by the Yak-1, at high speeds joined by the MiG-3 and Spitfire. Speaking of the Yak-1, I found no difference between S69 and S127.

 

Aside from interesting revelations regarding relative performance, it's also interesting to see how things compare to real world figures.

The Fw190 and the Spitfire are in the NACA chart, so I added my tested performance to that chart. Speed needed to be converted from km/h TAS to mph CAS. Given the limitations of the flight model and the inaccuracies of my testing, I would say that these are pretty good matches. Really good, in fact. Maybe the Fw could be moved a little bit left, but generally, I'm totally happy with these two. Apparently, this was the source the developers used for their FM. It can also be assumed from this, that the force limit modelled in game is 50lb, as the curves match that line very well.

The next one is from a NACA Bulletin, November 16th, 1942. The interesting one is the P-40, which I compared to our P-40E1. As one can see, it's not a that good match. While the low speed performance is quite close, the high speed isn't, but what's most important - the high speed roll shown here is for a stick for of just 30lb, using 50lb would up the maximum deflection speed to 360mph, where we'd get roll rates of 140°/s and resulting higher high speed rolls. Apparently, the developers did not go with the figures. You can find a P-40F in the NACA chart, which is actually not much different than the bulletin. However, roll rate has no clear peak, and in spite of a force limit of 50lb, also appears to decline beyon 280mph. No high speed roll rate is given there.

Finally, I have computed a couple of roll rates from Soviet source, I posted them a while ago. I recall an acceptable match with German figures for the Bf109. Not sure about details, but I corrected my figures to sea level conditions. Comparing to this chart, there's just no good match for anything. The I-16 overperforms considerably, while the Bf109 underperforms considerably. I'd also say the Yak-1 underperforms, but I don't know the details of the Yak-9 used for reference. They are similar, but not the same.

 

Edited September 11, 2017 by JtD

[303_Kwiatek]

La5 and Lagg3 brilant

 

Thx JtD good work as ususally.

 

Do you share these report to devs?

[RoteDreizehn]

and I thought I am the only one who cant believe this damn f...... roll rate in my beloved F4.  

As I saw G2 performance difference on "blad4.jpg" between real and game , I still hope they

will review the patch.

 

Thanks JtD for your research. Hope the Developers will pay attention on these results. 

 

thanks you very much!

 

regards from,

 

Rote

Edited September 11, 2017 by RoteDreizehn

[Holtzauge]

Don't have time to look at this closer for a couple of days but great job and thanks for compiling all the data JtD!

[Venturi]

It in interesting to note Don Berlin made the extremely strong 5-spar wing of the P-40 specifically to give it better high speed rolling ability.

 

It is also interesting to note that the NACA helix angle shows ZERO sharp dropoff at 280mph IAS, unlike the NACA 30lbs force chart shows.

 

In fact, the helix chart shows a smooth run off of roll rate for the P-40 to nearly 310mph IAS. The math obviously precludes any sharp drop off in roll rate to at least that speed.

[silvergun]

A very interesting thread, good work.

 

Nice catch on LaGG-3, La-5 and I-16.

[1PL-Husar-1Esk]

Good that devs give us tacview support thanks to this is easier to verify our fandings by them if they interested in first place. Good work.

[JtD]

You're welcome, everybody.
 

La5 and Lagg3 brilant

Do you share these report to devs?

I'll be getting back to the LaGG/La. Unfortunately, I don't have a good source for them, so it will be a lot of theory. No, I did not share it with the devs, I think they know what they've done. It would be nice to know the sources they used for the figures, though.
 

btw...

We don't know the sources they used, so we don't know how accurate they are. You can see that where a known source is used, it matches fairly well.
 

Don't have time to look at this closer for a couple of days but great job and thanks for compiling all the data JtD!

Counting on you taking a closer look.
 

In fact, the helix chart shows a smooth run off of roll rate for the P-40 to nearly 310mph IAS. The math obviously precludes any sharp drop off in roll rate to at least that speed.

Unfortunately, I haven't been able to find detailed P-40 testing ('unpublished data' is stated somewhere else). However, the maximum helix angle of ~0.008 appears to be a fact and can be found throughout NACA publications. The force limit and the odd shape f the P-40F curve are not that clear. However, the P-40 featured very small aileron angles and sealed, balanced ailerons what would make them fairly efficient, resistant to flutter (thus easy to balance) and easy for the pilot to move.
Spar number doesn't help with wing twist, though, and it is possible that it was a limiting factor NACA didn't consider in their initial test. Another limit apparently was flexible control linkage. In game performance of the P-40E at any speed is as good or better than the NACA chart data for the P-40F.
 

Good that devs give us tacview support thanks to this is easier to verify our fandings by them if they interested in first place. Good work.

Indeed, extremely helpful. Not just for testing, but also for fighting. It's great to know at what point in a fight you won it or lost it, and the 'energy' data available there helps a lot.

Edited September 12, 2017 by SYN_Haashashin
Had to edit the part of deleted posts for attacking the devs...

[303_Kwiatek]

303_Kwiatek, on 11 Sept 2017 - 20:57, said: La5 and Lagg3 brilant Do you share these report to devs? I'll be getting back to the LaGG/La. Unfortunately, I don't have a good source for them, so it will be a lot of theory. No, I did not share it with the devs, I think they know what they've done. It would be nice to know the sources they used for the figures, though.

 

What i remember Han said that they have LA5F or LA5FN roll test and they based on these but i need to see to belive. We know that La5F and LA5FN due to modifications should roll better then LA5 ( i think both at low and high speed) so i if LA5F and La5FN IRL roll even better then our LA5 then they should be king of rollers in WW2.

 

We know that German tested captured LA5FN and they found that its roll rate is between FW 190 A and BF 109 G. So LA5FN wasnt king of roll rate.

Edited September 12, 2017 by 303_Kwiatek

[unreasonable]

Great piece of work.  

 

Is there anything that comes out of that where you are feeling that the game needs to be changed because something is clearly wrong in relative performance or in relation to RL data?    Or are the differences what you might expect with various data sources and testing conditions?

[303_Kwiatek]

Hadn't Lagg3 early series and LA5 soft controls linkage? Haven't it changed since LA5F for stiff control linkage ( airleons) ?

[JG27*Kornezov]

I would like to thank JtD for the information and his huge effort. I did not see data for the 109 f4. I believe they are the same as the 109 g2.

I hope the FM will be further corrected thanks to the efforts of this wonderful community.

 

Every number matters because if you do not have the historical performance you will not use the historical tactics. And all that game is about simulating (recreating) historical encounters.

 

When I flew on Berloga in La 5 and Lagg the FW 190 put more in a close dogfight than the 109s, which were sluggish and completely lacking in the roll department.

Wow what a joy it is to fly the new FM in the La 5 and Lagg.

In the 109 the negative snaprolls are not what they were, I was trying this to compensate for the bad roll rate but it is not enough, with just  aileron roll the la 5 is way better.

Edited September 12, 2017 by JG27_Kornezov

[JtD]

Is there anything that comes out of that where you are feeling that the game needs to be changed because something is clearly wrong in relative performance or in relation to RL data?    Or are the differences what you might expect with various data sources and testing conditions?

Well, as far as feelings go I'd have decreased roll rate for the I-16, LaGG and La-5, and increased roll rate for the MiG and Yak, and for the P-40 at high speed.

 

WRT the Bf109, find attached another chart, compared to German information. Performance in game is obviously simplified, but not wrong compared to this one. In fact it might be the best possible approximation. It appears that, not only here, wing flex and control linkage flexibility is not modelled very accurately. Which means that in some ways, we'll have to be happy with discrepancies, they're just the limit of the possible accuracy.

 

I would like to thank JtD for the information and his huge effort. I did not see data for the 109 f4. I believe they are the same as the 109 g2.

I believe that, too, but will test it. I've already tested the Bf109E, which behaves slightly differently, with higher low speed roll and a lower high speed roll. I'll update the chart some time in the future.

Edited September 12, 2017 by JtD

[Venturi]

Spar number doesn't help with wing twist, though, The spars increased wing stiffness and were intended to reduce wing flex for the simple reason of increasing aileron effectiveness. I can quote Don Berlin, the designer of this aircraft, on this matter directly.

 

and it is possible that it was a limiting factor NACA didn't consider in their initial test. Another limit apparently was flexible control linkage. In game performance of the P-40E at any speed is as good or better than the NACA chart data for the P-40F. You don't superimpose the performance on the NACA helix chart, rather you superimpose it on the NACA 30lb force limit chart. If the game uses 50lbs force limit for the pilot, and you are making comparisons to other aircraft throughout your thread using 50lb limits, which you are doing, then this is obviously the WRONG place to superimpose ANYTHING - it is not honest, and makes me think you have other motives in displaying the data this way.

 

[JtD]

Can you also quote Don Berlin, the designer of the P-40, on the issue as to why he didn't increase the torsional stiffness by increasing the thickness of the load bearing skin, since this would be like 10 times as effective as adding just another spar? Or just increase the strength of the rear spar, as this would still be more beneficial than just adding one more into the wing.

 

Obviously, the P-40F data and the in game behaviour is not a good match. One's got a peak, the other one doesn't. If you don't believe it, feel free to superimpose these two curves by yourself - I gave you all the data you need. How do you know the P-40 in game is indeed modelled to a 50lb force limit, and not just should be? Looks more like 30lb to me, given that the speeds of the peaks match pretty much exactly. And how would you know about that possible issue if I hadn't posted it? Look, what a sinister motive!

 

Anyway, can you explain why the P-40 figures and the P-40F figures look as differently as they do? Do you have any of the actual test reports available? I'd be most curious to know why a plane with 30lb stick force achieves significantly higher peak roll rates than what should be the same plane at 50lb stick force. Why one's peaking, while the other one's not. Feel free to share.

[Farky]

Nice job JtD.

 

 

The next one is from a NACA Bulletin, November 16th, 1942. The interesting one is the P-40, which I compared to our P-40E1. As one can see, it's not a that good match. While the low speed performance is quite close, the high speed isn't, but what's most important - the high speed roll shown here is for a stick for of just 30lb, using 50lb would up the maximum deflection speed to 360mph, where we'd get roll rates of 140°/s and resulting higher high speed rolls. Apparently, the developers did not go with the figures. You can find a P-40F in the NACA chart, which is actually not much different than the bulletin. However, roll rate has no clear peak, and in spite of a force limit of 50lb, also appears to decline beyon 280mph. No high speed roll rate is given there

 

 

Be careful with that NACA bulletin, is it Model 81 (Tomahawk) and according my sources (for example book America's Hundred-Thousand or table below) aileron deflection of Model 81 (18.8° up, 10.7°down) was different than on Model 87 (18.7° up, 10.6° down). Source about P-40F for NACA report 868 is for sure MR No. L5A29a - https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930092941.pdf  , very interesting stuff.

 

 

 

[ACG_KaiLae]

If I recall, the data used for roll of the LA in game was extrapolated from a La-5FN, which also if I recall, does not have wing tanks and therefore should roll better. 

[JtD]

Be careful with that NACA bulletin, is it Model 81 (Tomahawk) and according my sources (for example book America's Hundred-Thousand or table below) aileron deflection of Model 81 (18.8° up, 10.7°down) was different than on Model 87 (18.7° up, 10.6° down).

Yes, but this well within tolerances of actual aileron installation. Question would be - did the stick or linkage change? Must be a reason for that nominal 0.1 deg.

 

Source about P-40F for NACA report 868 is for sure MR No. L5A29a - https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930092941.pdf  , very interesting stuff.

Yes, that's the source. And when I clicked on save to HD it asked me to overwrite. Got it on my disk and totally forgot, but kept searching the NACA server without ever finding it... So, thanks for posting.

 

I think it explains the odd curve shape well enough - the pilot did not manage 50lb stick force, right is 43, left is 36. To the right the plane did also not achieve nominal aileron deflection. The curve in the NACA document is the mean of left and right as shown in figure 14, and therefore includes insufficient aileron travel as well as insufficient force.

Considering these bits of information, for a plane in perfect condition (such as in a computer game) one can assume helix angles of 0.083 at low speeds and still in excess of 0.07 at 300mph. NACA gives less than 0.06 here for the one they tested.

Edited September 13, 2017 by JtD

[JtD]

If I recall, the data used for roll of the LA in game was extrapolated from a La-5FN, which also if I recall, does not have wing tanks and therefore should roll better.

Internal wing tanks have no influence on maximum rolling velocity. They have an impact on roll acceleration, but they don't change the aerodynamic properties of the aircraft, so they don't change roll rate.

[YSoMadTovarisch]

I'd say that initial roll acceleration is way more important that maximum roll rate. Anyway, the early La5 was known to have very heavy ailerons at high speed, and was sluggish in initiating roll, currently it rolls like a 190.

[JtD]

It is important, but then initial roll acceleration is very quite high for these planes in real life, and the difference the wing fuel tanks in the La make would be hard to observe by a pilot. From practical point of view, most important for roll acceleration are rolling moment coefficient (same as for maximum roll rate) and minimum effect of ailerons on anything but roll (well balanced controls). If the plane goes up and sideways while you just want it to roll, you lose a lot. And a poorly set up plane is really hard to coordinate reasonably well at the limit, even for a well trained pilot.

 

A good way to measure roll acceleration is to measure time to bank, with 90° and 45° being typical values tested. For in game testing, you just need a stopwatch and the slow motion function of the game, I'd be curious to see these results.

[Holtzauge]

As YSoMadTovarisch pointed out above, while rolling performance is usually discussed in terms of rolling velocity as in the OP, rolling acceleration is also an important aspect since for practical purposes, rolling in combat is usually a plus minus 90 degrees affair and in those situations a significant portion of the time spent rolling involves the transient acceleration phase before the full rolling velocity is developed.

 

So while wing fuel may not impact the final peak roll rate velocity (w*) as in the fully developed roll speed, getting there requires that you initiate the roll through roll acceleration (w**) and it is in this phase that the moment of inertia around the roll axis is an important aspect to consider. So when it comes to roll acceleration: I’m not so sure that weight in the wings does not have such a large impact:

 

Since w**=M/I where w** designates roll acceleration, M the roll moment and I the moment of inertia around the roll axis, it follows that an increase in I will linearly reduce the roll acceleration.

 

Now since the added moment of inertia around an axis is proportional to the mass times the square of the distance from the axis of rotation as in I=m x d**2 it also follows that fuel tanks situated in the center fuselage and armament close to the roll axis is good while wing tanks full of fuel and wing mounted guns will be detrimental.

 

I don’t have recall seeing any moments of inertia for the Russian fighters, but I do remember seeing numbers posted for the Me-109 based on some Russian measurements. Maybe someone more versed in Russian could dig them up again? If we have those, we could first of all make a ballpark estimate of how the 20 mm gunpods affect the Me-109 roll acceleration which could be interesting to get a feel for things.

 

Data on Russian fighters with wing tanks would be even better since if we have that we could make an estimate of if the wing tanks in say the La-5 had a significant impact on roll performance or not. I’m guessing they did but without data it is difficult to know. Was it less than 5 or more than 20%? If we had a baseline figure for Ixx say for the La-5 with or without fuel in the wing tanks getting a good estimate of the other number would be in reach and would give us an idea about the level of impact on roll acceleration. In addition, this would then raise the question of any measured roll performance value and at what fuel state was the value achieved?

 

My very personal experience is that mass in the wing is bad as in water ballast in a glider wing is bad news for rolling but then the weight added there is proportionally much larger. In a glider you for sure feel the effects of the “fuel” in the wings and while it was nice to have on the straight stretches, thermaling with water was a pain in the @ss.

 

Anyway, if someone could dig up the moment of inertia figures then we would have something to work with. Usually they are designated Ixx, Iyy and Izz and measured in Kgm**2 or something similar.

[Guest deleted@50488]

Excellent, as usual @Holtzauge !

 

And... I fully subscribe the glider ballast note :-)

[Holtzauge]

Well JtD pretty much totally covered the roll speed in the OP so I thought it could be good to look into the acceleration as well.

 

Can't say for sure how much impact it will have without some data to work with but I suspect that the wing tanks are a bit of a nuisance when for example trying to jinx or trying to follow someone who does. In those types of situations you are basically in an roll acceleration phase a lot of the time and wing guns or wing fuel should set you back. Later today if I get the time I'm planing to take an Me-109 up for a spin in BoX to try out flying with and without gunpods. Not to well read up on the Russian crate procedure with wing tanks but I'm assuming they typically feed from the wing tanks first and collect in the central as they go. As far as I can tell the LaGG had a central tank and two wing tanks in each wing: one 120 l and one 65 l. So, if we get a number on the moment of inertia coupled to a fuel state it should be easy to figure out how much impact the fuel has.

 

Edit: Would be good also to try Russian BoX planes with different fuel states: If you go for 20% fuel for example, is that modeled as filled in the central tank? How does it roll with 20% fuel then and what happens if you fill up to 100%? Do you notice it in roll?

Edited September 16, 2017 by Holtzauge

[rel4y]

Hey JtD I think you got something wrong regarding the chart from the german 1944 DVL Rollwendigkeit test. I dont see how your in game curve can peak at 92 deg/s, also the curve in general looks completely off.

 

I posted my test in this thread and all the measurement points I did are seen as dots in the graph. https://forum.il2sturmovik.com/topic/30809-game-version-2012-discussion-hs-129-kuban-map-fm-update-new/?p=507078

 

https://s26.postimg.org/6a8k6l3rt/rollrate_f2.jpg

 

IMO the 109s underperform by about 15% max.

[JtD]

Well, my evaluation is done in accordance with a model I described in post 1. It necessitates peaks. If I was to take a slightly different approach, I could interpret my test data differently to end up with more curvy style results.

 

However, even if I take out as much peak as reasonably possible from the Bf109G-2 data, I still end up with 1.4+ radians per second (80+°/s) in the speed range ~400-500+km/h, making it a very good match. I don't know why you end up at only ~1.2.

[JG27*Kornezov]

Holtzauge Indeed you are into something interesting. The new Russian birds are so fun to fly, by adding rolling inertia will kill much of the fun. In 109 the ailerons rolls are quite painful. I wonder how this can be so. I can maneuver with the russian planes but it requires specific techniques that are more difficult to master and require flying at the very edge of controllable flight. Actually, to keep with their ordinary aileron roll you need to snap roll like crazy in the 109.

When I switched and flew against the Germans in Lagg and La, to my big surprise the FWs pilots put more of a defensive fight than the 109s.

Edited September 29, 2017 by JG27_Kornezov

[rel4y]

I tested at idle power, slip ball center but no input during roll and used the mean of right and left roll. I can get nowhere near 1.4 radians at 3000m. The chart is about sustained roll rate and not initial roll rate btw.

Edited October 3, 2017 by rel4y

[TRA_Rogue]

I've noticed an oddity with the 109 roll rates in the new FM, particularly between the Emil and later 109s. I've taken the E-7 for a quick spin and noticed it rolled a lot faster than it's later models.

As far as I understand it the later 109s should roll better at high speeds and slightly worse at low speeds compared to the Emil.

 

Looking at the patch notes I found no real mention that anything has been changed to decrease the roll rate of the E-7, other than to increase the flight stick load on the roll axis.

 

This begs the question, did the developers made an error and made the later 109s worse in roll rate than they should be? Did they intend to decrease the roll rate of the E-7 but somehow forgot to do it?

 

 

Bf 109 E-7:

10.69. Pitch balance and its dependence on the horizontal stabilizer and flaps have been corrected.

10.70. Flight stick load at any flight speeds has been corrected (increased at low speeds and decreased at high speeds).

10.71. Flight stick load along the roll axis at high flight speeds has been increased.

10.72. Pedals load at medium and high flight speeds has been increased significantly.

10.73. Horizontal stabilizer shift time from end to end increased from 5 to 15 seconds according to the reference video.

10.74. Flaps extension time increased from 15 to 20 seconds according to the reference video.

10.75. The aircraft flight model is corrected to correspond to other aircraft FM (its difference was caused by attempts to fix the roll issues quickly).

10.76. Pushing the flight stick forward abruptly is less likely to cause an inverted snap roll or reverse spin.

10.77. The aircraft stall behavior has been corrected using the data available. The stall danger in a turn if an excessive flight stick input has been given is minimal.

Bf 109 F-2/F-4/G-2/G-4:

10.78. The aircraft roll rate at various flight conditions has been corrected (decreased at medium and high speeds).

10.79. Pedals load at high flight speeds has been decreased.

10.80. Pitch balance and its dependence on the horizontal stabilizer and flaps have been corrected.

10.81. Horizontal stabilizer shift time from end to end increased from 5 to 15 seconds according to the reference video.

10.82. Flaps extension time increased from 15 to 20 seconds according to the reference video.

10.83. Flight stick load along the pitch axis has been increased at low and medium flight speeds.

10.84. Flight stick load along the roll axis at medium and high flight speeds has been increased significantly.

10.85. Pedals load at low and medium flight speeds has been increased.

10.86. Pushing the flight stick forward abruptly is less likely to cause an inverted snap roll or reverse spin.

10.87. The additional research on the aircraft stall has been performed using the data available. It stalls in a turn if an excessive flight stick input has been given. Spin recovery doesn't require much effort.

10.88. The engine die out issue has been fixed (it could happen after a sharp throttle increase with the RPM limiter turned on).

[JG27*PapaFly]

Excellent data!

 

Do we know what stick and pedal force limits are currently implemented? It would also be nice to know whether the limits of pitch and roll axis differ. From a physiological point of view I believe they should.

 

I found another NACA report (Measurements of the flying qualities of a Supermarine Spitfire VA airplane) which stated that the maximum force their test pilot could in practice apply on the Spit's roll axis was 40 lb. In addition, many pilot reports state that the combination of narrow cockpit and control column design limited the lateral force that could be applied and led to the general impression that the planes biggest flaw was the slow roll rate and huge lateral stick forces.

[JV69badatflyski]

roll perfs are only one side of the equation, the other one that's also important , even more, is the roll rate acceleration .
what's so great about having a great roll rate if you need 4 secondes to get to your max continuous roll?

there is a nice video of the P-38 in the cockpit, looks like there is always a lag between the moment the pilot turns the wheel and the moment the plane starts rolling.

Edited November 24, 2018 by JV69badatflyski

[Bilbo_Baggins]

8 hours ago, JV69badatflyski said:

roll perfs are only one side of the equation, the other one that's also important , even more, is the roll rate acceleration .
what's so great about having a great roll rate if you need 4 secondes to get to your max continuous roll?

there is a nice video of the P-38 in the cockpit, looks like there is always a lag between the moment the pilot turns the wheel and the moment the plane starts rolling.

 

4 second roll acceleration phase? There is no fighter that has near such a slow roll acceleration. Lagg 3 with outer wing fuel tanks can do a roll in just under 4 second alone...

 

Being single engine fighters the machines in our sim have near instantaneous roll rate acceleration anyway. Therefore I don't see how it can be more important?

 

Joystick curves and sensitivities/noise filters aside, these single engine machines accelerate to peak velocity in very short time. It only becomes a notable factor at slower speeds once you start slinging heavy bombs on the outside of the wings. 

 

Having said that, the heavy P47 with it's fully loaded 8 gun wings seems to be the first fighter in the sim now where there is a discernable acceleration phase- at lower speeds anyway.

Edited November 25, 2018 by Bilbo_Baggins

[Haza]

I have to agree with the comments about the P-47.  I dropped a single 1000Lbs bomb from the Port mainplane of the P-47, with the other one attached to the Starboard side and you could feel the whole aircraft roll as the first bomb dropped and I had to quickly compensate for this (and it is only a PC flight sim).  To be honest, I really wasn't expecting this as I has assumed that this level of modeling wasn't possible.  Although perhaps I can't add to this discussion, the P-47 and the way that it has been modeled just feels amazing to me regarding the roll and bomb drop! I could argue that the developers have got other aircraft wrong, however, since the P-47, I'm hopeful that everything in time will be addressed, revisited and remodeled, if required!

That said, as there is currently the ability to assign the elevator trim to the elevator joystick inputs, if players were able to assign roll trim (if game aircraft allowed it) to the joystick aileron inputs, I would be interested to see if there was a lag between the movement and the roll rate. 

 

Hopefully, if we have the likes of JtD taking the time to try and ensure that things are accurate and historical and we can all have these adult discussions without the topic being locked, I'm hopeful that IL2 will not just become a Call Of Duty aerial arcade game that my son craves, as I thought we called that WarThunder!?

 

Regards

[Legioneod]

12 hours ago, Haza said:

I have to agree with the comments about the P-47.  I dropped a single 1000Lbs bomb from the Port mainplane of the P-47, with the other one attached to the Starboard side and you could feel the whole aircraft roll as the first bomb dropped and I had to quickly compensate for this (and it is only a PC flight sim).  To be honest, I really wasn't expecting this as I has assumed that this level of modeling wasn't possible.  Although perhaps I can't add to this discussion, the P-47 and the way that it has been modeled just feels amazing to me regarding the roll and bomb drop! I could argue that the developers have got other aircraft wrong, however, since the P-47, I'm hopeful that everything in time will be addressed, revisited and remodeled, if required!

That said, as there is currently the ability to assign the elevator trim to the elevator joystick inputs, if players were able to assign roll trim (if game aircraft allowed it) to the joystick aileron inputs, I would be interested to see if there was a lag between the movement and the roll rate. 

 

Hopefully, if we have the likes of JtD taking the time to try and ensure that things are accurate and historical and we can all have these adult discussions without the topic being locked, I'm hopeful that IL2 will not just become a Call Of Duty aerial arcade game that my son craves, as I thought we called that WarThunder!?

 

Regards

I have to agree with you, P-47 definitely feels like the most advanced flight model, and having the wing drop when dropping bombs is great. First time it happened it took me by surprise.

[Bilbo_Baggins]

On 10/24/2017 at 8:46 AM, Frost- said:

I've noticed an oddity with the 109 roll rates in the new FM, particularly between the Emil and later 109s. I've taken the E-7 for a quick spin and noticed it rolled a lot faster than it's later models.

As far as I understand it the later 109s should roll better at high speeds and slightly worse at low speeds compared to the Emil.

 

Looking at the patch notes I found no real mention that anything has been changed to decrease the roll rate of the E-7, other than to increase the flight stick load on the roll axis.

 

This begs the question, did the developers made an error and made the later 109s worse in roll rate than they should be? Did they intend to decrease the roll rate of the E-7 but somehow forgot to do it?

 

 

I've noticed this as well. The roll rate of Emil at high speeds actually seems no different from F/G models. However, the main oddity in regards to roll rate is the LaGG-3. The thing is spinning around like an Extra 300L. Perhaps it has something to do with the fact it was the very first plane modelled in the sim. I wonder why they chose to model the LaGG-3 first.

Edited November 28, 2018 by Bilbo_Baggins