P-51 FM

[ZachariasX]

2 hours ago, MarderIV said:

but I'm curious what folks thoughts are on the points this person raises.

Nice video.

 

I think he made a good point by singling out what is maybe a general difficulty with the IL2 sim modeling in general, this is about the flaps with resulting plane attitude and related trim change.

 

In the real Spitfire, I notced the same and they corrected flap trim and plane attitude to a degree where I find it matching good enough with the real one (just measuring by eyeball 1.0). Also in the real Spitfire, deploying flaps do very little (but not nothing!) to the plane's attitude, but popping them requires 2 cm pull back on the stick. This is a lot as you will not use 2 cm in regular flight, but it is very little of the entire stick travel range. @Gavrick had that corrected, so I really think our Spit is for our puroses correct there.

 

In the IL2 Mustang, as well as on the P-47, there indeed seem to be things not as they should. It is very nicely shown in the real video, how much flaps mandate a noseup attitude and how much pull/trim is required to hold that attitude. IIRC @JtD made an in game test in the P-47, where also he discovered the attitude changing more than it should upon deployment of the flaps. There should be maybe a general look on how flaps match with expected attitude.

 

It is my impression that flaps (also in the Spit before the correction) can act excessively on the planes attitude, allowing for some "gaming the game" with certain planes when goofing around at slow speeds in MP. And I would speculate that it is probably most of what makes our Thunderbolt a Thunderspit should you decide to abuse this "flaps quality".

 

 

[Guest deleted@50488]

In the IL-2 Spits we still miss the typical "elevator down" as seen from cockpit or outside showing as a result of nose heavy trim being mostly used, for instance while cruising.

Our IL2 Spitfire always shows it's elevator aligned with the horizontal stab, or even showing slightly deflected up. It's maybe a little visual / cosmetic detail, but it's correctly modeled for instance in DCS.

Edited December 14, 2019 by jcomm-il2

[ICDP]

Good video, thanks for posting.  I do love BoX but this comparisons show it is far from perfect in FM.

[unreasonable]

Good video - thanks for linking. FM critique done well.

 

I wonder if the problem with how much power is needed to start the BoX plane rolling relates more to the ground friction rather than the FM per se. AFAICR this was increased from the early days to stop the MP phenomenon of people just taking off from the parking bay. It is now almost impossible to land without nosing over outside airfields, even on dry grass fields, in planes where this should be possible without too much problem. Which is a shame.

 

Agree with jcomm-il2 our Spitfire trim is odd, so it does not surprise me that the narrator finds the P-51 trim is odd too: Spitfire should feel more like the Camel where you need forwards pressure on the stick, whether from trim or by hand: as it is you are constantly having to pull the stick back or use nose up trim to fly level.  

 

 

 

 

 

 

[Bremspropeller]

@Agathos_Deimon Sehr cooles Video! Aber eine Junkers-Uhr in einer P-51? Sakrileg! ?

 

Why do Stallion51 not equip their airplanes with Gopro/ similar HD camers? That would make all their videos much cooler.

 

 

[=RvE=Windmills]

Feel his points are very specific and drawing an overall 'disappointing' from it is somewhat unfair. He only specifically refers to elevator/trim authority and acceleration on take-off.

 

This might be true but there is a lot more to air combat (which is the primary focus of this same after all), where those points are practically irrelevant. At least when compared to stuff like turn-rate/stall/speed/climb. I'm sure it's not perfect, but unless you start debunking actually important things pertaining to air combat I'd be more interested.

 

Unless you are specifically interested in running hyper realistic take-offs, circuit, followed by a landing It's not a very interesting video.

[-=PHX=-SuperEtendard]

It's interesting given @SCG_motoadve really liked the FM and also shared the impressions of a friend of him that flew a real 51 too, don't remember now if he also tried the DCS Mustang. I don't know at which extent this can also be affected by hardware / curves differences.

Edited December 14, 2019 by -=PHX=-SuperEtendard

[RoteDreizehn]

15 hours ago, MarderIV said:

I saw this video recently - looks like a pilot of an actual P-51, going over differences between the real aircraft and it's simulated counterparts. It's pretty long, but I'm curious what folks thoughts are on the points this person raises. And please, I'm not here to start anything with anyone. I'm very interested to learn about this aircraft's performance, as much as anybody else. 

 

 

 

Thanks a lot for this nice comparison between Real World and Sim World. 

 

[69th_Mobile_BBQ]

2 hours ago, =RvE=Windmills said:

Feel his points are very specific and drawing an overall 'disappointing' from it is somewhat unfair. He only specifically refers to elevator/trim authority and acceleration on take-off.

 

This might be true but there is a lot more to air combat (which is the primary focus of this same after all), where those points are practically irrelevant. At least when compared to stuff like turn-rate/stall/speed/climb. I'm sure it's not perfect, but unless you start debunking actually important things pertaining to air combat I'd be more interested.

 

Unless you are specifically interested in running hyper realistic take-offs, circuit, followed by a landing It's not a very interesting video.

 

I think the video was interesting.  It was enough to make me consider downloading DCS. learning how to 'click start' the free P51 and seeing which flight model I prefer.  I don't think it has any chance of taking me away from supporting IL-2 though.    

 

IMO however, the 51 in IL-2 seems too weak in certain aspects of power at realistic manifold pressure settings for the non-150 grade fuel model.  I can't quite put my finger on exactly what so, I guess that's just subjective.  Feel free to write my statement off if you disagree.  

[JG27*PapaFly]

15 hours ago, MarderIV said:

I saw this video recently - looks like a pilot of an actual P-51, going over differences between the real aircraft and it's simulated counterparts. It's pretty long, but I'm curious what folks thoughts are on the points this person raises. And please, I'm not here to start anything with anyone. I'm very interested to learn about this aircraft's performance, as much as anybody else. 

 

 

 

 

 

Awesome find Marder, thanks for sharing!

[zan64]

On 12/15/2019 at 3:06 AM, =RvE=Windmills said:

Feel his points are very specific and drawing an overall 'disappointing' from it is somewhat unfair. He only specifically refers to elevator/trim authority and acceleration on take-off.

he also complains the most about sight picture, which causes him to be not able to fly as he does in real life because of the different perspective , that was his major complaint and why it felt different to him

On 12/12/2019 at 7:24 AM, Legioneod said:

Personally I want the torque and brakes to be modeled accurately but I doubt it will ever happen. From my understanding brakes and torque were intentionally undermodeled to make it easier on players without rudder pedals and joysticks at least thats a rumor that I've read, no idea if it's true or not.

 

I find DCS better in this regard and is the only thing I really like more about DCS, they model brakes and torque more accurately, maybe not perfect but much better than Il2.

whats wrong with the brakes? i think the taxiing in IL2 is reasonable. that video from a few posts before mine is of a real P-51 pilot thinking taxxiing is currently too difficult than the real thing. i always thought il2's old system and DCS (prop) ground ops were stupid hard and cant be true to real life

[Legioneod]

22 minutes ago, Esel_kong said:

he also complains the most about sight picture, which causes him to be not able to fly as he does in real life because of the different perspective , that was his major complaint and why it felt different to him

whats wrong with the brakes? i think the taxiing in IL2 is reasonable. that video from a few posts before mine is of a real P-51 pilot thinking taxxiing is currently too difficult than the real thing. i always thought il2's old system and DCS (prop) ground ops were stupid hard and cant be true to real life

Brakes lack power/responsiveness in Il2. You hit the brake and it produces less braking force than it would irl, the brakes should be more responsive and not so dull like they are in-game. 

Having a more powerful/accurate brake would make taxing alot easier/more realistic.

Edited December 16, 2019 by Legioneod

[[DBS]TH0R]

I've heard this comment already from another real life pilot - that DCS brakes are too effective, whilst IL-2s are too weak.

 

[ZachariasX]

2 hours ago, Legioneod said:

Brakes lack power/responsiveness in Il2.

You‘d be surprised how little braking you‘d do in the real aircraft.

 

Just think of two drum brakes that you can almost hold in one hand each and then think again of how much (and for how long!) they would give you „brake power“ to slow down a three ton vehicle. And think of what happens to those brakes when you hit those brakes at 60 mph.

[Legioneod]

5 hours ago, ZachariasX said:

You‘d be surprised how little braking you‘d do in the real aircraft.

 

Just think of two drum brakes that you can almost hold in one hand each and then think again of how much (and for how long!) they would give you „brake power“ to slow down a three ton vehicle. And think of what happens to those brakes when you hit those brakes at 60 mph.

Yes but I’m talking about taxiing. I expect brakes to fade over high speeds/ long duration use such as in landing but they should be more responsive when taxiing.

[RedKestrel]

8 hours ago, [DBS]TH0R said:

I've heard this comment already from another real life pilot - that DCS brakes are too effective, whilst IL-2s are too weak.

 

Hmmm...I might know this pilot! Curly blonde hair, oatmeal connoisseur, lives with 3 bears?
/this joke is just right

[[DBS]TH0R]

This thread started with FMs, moved to brake discussion and is now turning into a fairy tale. Splendid. ?

 

No, I don't think we're speaking about the same person.

[ZachariasX]

15 hours ago, Legioneod said:

Yes but I’m talking about taxiing. I expect brakes to fade over high speeds/ long duration use such as in landing but they should be more responsive when taxiing.

Brakes in this game are actuated slowly. With the pinky switch, it takes about a second or ore to fully actuate them. Keeps you from nose over in the Spit. Not sure if the brake axis is also delayed somehow, this also takes initial bite.

 

On the whole, personally, I don‘t expect brakes from 70 years ago performing anywhere near what you consider brakes today. Neither in aircraft or in cars. Thinking of brakes as we know them can kill you in vintage cars driving downhill.

 

My bottom line is that the brakes we have are (thank god) on the whole too good. In rainy conditions, water entering you drum brakes (unevenly), you brake and just one wheel „bites“... You wouldn‘t really use those brakes other than for a full stop in the real aircraft. Taxiing on the brakes as we di with our fancy disc brakes of today is simply not an option with them. Upside is, the old brakes are safe to use on the Mustang, while new disc brakes can even make the Mustang nose over. Hence some owners revert to the old brakes I have been told.

 

You know, the Piper Cub and the Tiger Moth didn‘t even have brakes. It‘s a modern mod.

[zan64]

i would like to see that pilot's complaints , elevator trim tab, engine power, and sight picture looked into if not adjusted - sight picture for him seemed the biggest deal he said he couldnt fly it level like he does in real life. 

[Bremspropeller]

18:40

 

 

 

[1PL-Husar-1Esk]

Flaps down - nose down , in the game flaps work as device augmenting the lift , but not the same way as in the video. In the game  plane rise the nose and can be held  there, hanging in high AA and descent. Not as you  extend the flaps to stable descent (lift in slow flight) in nose low attitude in the video.  Other hand to fly level slowly  you need to increase lift by holding nose up but without flaps.

Edited December 17, 2019 by 1PL-Husar-1Esk

[Oyster_KAI]

Descent rate is too fast, the landing is uncomfortable.

Edited December 19, 2019 by Oyster_KAI

[SCG_OpticFlow]

On 12/14/2019 at 8:41 AM, MarderIV said:

I saw this video recently - looks like a pilot of an actual P-51, going over differences between the real aircraft and it's simulated counterparts. It's pretty long, but I'm curious what folks thoughts are on the points this person raises. And please, I'm not here to start anything with anyone. I'm very interested to learn about this aircraft's performance, as much as anybody else. 

 

 

 

 

 

 

Follow-up video:

 

 

[Guest deleted@50488]

Thx for the link for the followup video.

 

Indeed there are at least two major problems with IL-2 FM. One is nose heaviness in some aircraft. I first noticed it in the P-40 E-1, then with the D-9 and a few more, and it ended with the P-51. 

 

The other problem is related to "flaps aerodynamics"...

 

 

Edited December 21, 2019 by jcomm-il2

[CUJO_1970]

I’ve been flying the P-51 online and it gets quite nose heavy in high speed dives.

 

Flaps turn it into a large Yakovlev though, and mercy can it ever take a beating and keep right on flying.

[JG27*PapaFly]

On 12/26/2019 at 5:07 PM, CUJO_1970 said:

I’ve been flying the P-51 online and it gets quite nose heavy in high speed dives.

That is easily corrected by mapping the elevator trim axis to the elevator axis. This effectively, and unrealistically, counteracts the high stick forces, helping to negate yet another genuine Fw-190 advantage. Map the aileron trim to the aileron axis and the mustang gets super maneuverable at high speeds.

[Talisman]

14 minutes ago, JG27_PapaFly said:

That is easily corrected by mapping the elevator trim axis to the elevator axis. This effectively, and unrealistically, counteracts the high stick forces, helping to negate yet another genuine Fw-190 advantage. Map the aileron trim to the aileron axis and the mustang gets super maneuverable at high speeds.

 

I read that folks do this with the Bf 109 too.  Is there a way for the dev's to stop this, or will folks just always come up with a work around?  I suppose the extra advantage of this with the Mustang is that there are anti-g-trousers in play to help as well.

 

Happy landings,

 

Talisman

[ZachariasX]

4 minutes ago, 56RAF_Talisman said:

Is there a way for the dev's to stop this, or will folks just always come up with a work around?

So far it helped that trim wheel rotation is made more realistic, hence the trim cannot follow the stick right away. But I thought they made trim inputs impossible at higher accelleration.

 

The Mustang gets nose heavy due to Mach tuck. Trimming against that in such a way would be an invitation to break up your aircraft.

[CUJO_1970]

3 hours ago, JG27_PapaFly said:

That is easily corrected by mapping the elevator trim axis to the elevator axis. This effectively, and unrealistically, counteracts the high stick forces, helping to negate yet another genuine Fw-190 advantage. Map the aileron trim to the aileron axis and the mustang gets super maneuverable at high speeds.

 

Wait. You mean it's actually possible to make the P-51 more maneuverable? Good grief. I guess that explains some of the nonsense I see online, but was unable to duplicate when I was flying the P-51 on DED.

 

My understanding is that there is also an interesting mixture cheat setting but I've not tried it.

[Jaws2002]

On 12/14/2019 at 1:41 AM, MarderIV said:

I saw this video recently - looks like a pilot of an actual P-51, going over differences between the real aircraft and it's simulated counterparts. It's pretty long, but I'm curious what folks thoughts are on the points this person raises. And please, I'm not here to start anything with anyone. I'm very interested to learn about this aircraft's performance, as much as anybody else. 

 

 

 

 

 

 

 

This video was posted before and it was quickly deleted.

[Bremspropeller]

29 minutes ago, CUJO_1970 said:

My understanding is that there is also an interesting mixture cheat setting but I've not tried it.

 

Which one?

[JG27*PapaFly]

6 hours ago, CUJO_1970 said:

Wait. You mean it's actually possible to make the P-51 more maneuverable? Good grief. I guess that explains some of the nonsense I see online, but was unable to duplicate when I was flying the P-51 on DED

Exactly, and you can adjust the response curves for the elevator and aileron trim axes for a more aggressive response.

The 109 series, the 262, and the P-51 profit a great deal from this.

[1PL-Husar-1Esk]

109 stabilizer was abused in same manner years  ago  , where easy solution would be limiting  axis bind to pitch or roll to work only with one input control.

[357th_KW]

Hopefully we'll see a fix down the road to prevent people from mapping their trim to their stick axis, as it's an obvious and unrealistic exploit.

 

With regard to the Mustang's nose heaviness in the game - that is really a complete 180 from reality.  In game, you need almost full elevator trim and full back pressure to recover from a high speed dive.  The real P-51 had the exact opposite problem, and those control inputs would almost certainly result in airframe damage or worse. 

 

To quote from a test: " 9.   Recovery Technique.- Recovery in any case must be gradual and executed with extreme caution since relatively light elevator stick forces or rapid application of trim may very easily result in the application of excessive load factors. As acceleration is applied at the beginning of the pull-out some increase in vibration may occur. This will gradually decrease as the recovery is completed. In no case is elevator trim necessary to aid recovery. "  Original document here.

 

The USAF F-51D manual from 1954 (T.O. No. 1F-51D-1) say this about Flight Control Effectiveness on page 74: "ELEVATOR CONTROL At normal speeds, elevator control is very good and stick pressure is light.  As speed increases in a dive and pull-out is attempted, you must use caution so as not to overcontrol and pull up too fast; otherwise, undue stress or even failure may result."  This same manual further states under Dive Recover on page 75: "WARNING Care should be taken in pull-outs above 4 G, as the stick forces are relatively light, and an abrupt pull-out may cause rapid uncontrolled increase in G." 

 

[Y-29.Silky]

On 1/10/2020 at 3:21 AM, 1PL-Husar-1Esk said:

109 stabilizer was abused in same manner years  ago  , where easy solution would be limiting  axis bind to pitch or roll to work only with one input control.

 

It's back in full force. I knew people who exclusively fly German would say everything is a UFO once they face planes that are just as good. 

But the 109's stabilizer is more War Thunder than anything else. 

 

https://streamable.com/zpb12

https://streamable.com/pfb9n

https://streamable.com/f4ql2

 

 

On 12/10/2019 at 3:23 PM, CUJO_1970 said:

Wow PapaFLy - you are a brave man, speaking up about community pet plane ?

 

Who doesn't just love those torque-free throttle slams to full power that all real actual P-51 pilots go on and on about in their memoirs? Or the almost complete absence of C.G. issues with full fuel tanks they (real, actual P-51 pilots) just rave about in so many accounts?

 

I'm sure we can dig those up in practically no time!

 

 

 

 

Like this?

 

https://streamable.com/xx4nw

[19//Moach]

One major factor it seems the videos don't consider, is that of density altitude.

 

I have noticed that in BoX, there is a major difference in aircraft performance (all models) depending on the mission season.  This is a natural phenomenon, caused by temperature and pressure affecting air density, and is one which RL pilots take greatly into account before taking to the wild blue yonder. 

 

I have also noticed that most non-winter scenarios in BoX seem to feature somewhat lower-than-standard atmospheric density conditions.  This results in aircraft under-performing, as they normally should in such situations. Yet this is not accounted for in the comparison videos. I do not recall any mention of trying to replicate the flying environment itself with the same attention paid to matching up aircraft-related parameters.

 

 

 

Which then again, just makes us wonder:  Why is atmospheric pressure always so low in IL2?  Most mission briefings note hpa's in the 7~800 range. (22.15"hg, roughly) 

This is quite low, considering the ISA (International Standard Atmosphere) pressure is 1013.25 hpa. (29.92"hg) 

 

 

That kind of weather is more commonly associated with birds hopping near the ground and people carrying umbrellas while looking warily towards a blackening sky.

 

 

 

With summer temps thinning the air even further, there's little wonder planes often feel to fly like bags full of bricks. There's just not enough air.

In the winter, however, it is quite noticeable that one can get away with maneuvers that would leave the exact same airplane dangling precariously off the edge of stalling in hotter days.

 

 

This, obviously, affects all airplanes.   Yet many people doing comparisons seem to neglect this rather major factor in their experiments.

 

 

 

I'm not saying there's nothing amiss with the FMs themselves either. One thing does not necessarily imply another.

 

The fact that the experiment is a bit flawed does not mean it can't still stumble onto something quite revealing. It just means the experiment might benefit from being redone in more controlled conditions, in order to get a more precise set of facts to draw more accurate conclusions upon.

 

It actually raises an even more alarming possibility:   Have all airplanes in the BoX fleet been "tuned" to specs under the exact same atmospheric conditions?

 

This would seem too obvious to have possibly been missed out.  Yet it is the kind of thing that programmers do sometimes forget. (I know, I'm a programmer too, and I've learned the weirdest and most elusive bugs usually result from the stupidest reasons)

In a project as complex as this, there is just too much information to keep in mind.  So even the best minds may sometimes skip something that when pointed out after weeks of troubleshooting causes everyone in earshot to go "D'oh! Of Course!"   

 

Nothing can be safely ruled out as "nobody would neglect THAT" - For that is often the very reason why someone has.

 

Edited January 14, 2020 by 19//Moach

[69th_Mobile_BBQ]

Perhaps the missing air pressure had been siphoned off to account for the over-inflation of both Hitler and Stalin's egos?

[Barnacles]

1 hour ago, 19//Moach said:

 

Which then again, just makes us wonder:  Why is atmospheric pressure always so low in IL2?  Most mission briefings note hpa's in the 7~800 range. (22.15"hg, roughly) 

This is quite low, considering the ISA (International Standard Atmosphere) pressure is 1013.25 hpa. (29.92"hg) 

 

Aren't the pressures in the mission briefings quoting mmHg rather than hPa?

Edited January 14, 2020 by 71st_AH_Barnacles

[Art-J]

^ Quite possible. Can't check it in the game myself at the moment.

 

ISA 1013.25 hPa equals 760 mm Hg.

[357th_KW]

Pressure in the game is in mmHg, and it defaults to 760 in the mission editor when you create a new mission.