P-47 Stall characteristic

[=FEW=N3cRoo]

Hello everyone,

Lets talk about jugs, please keep it limited to the stall behaviour and civil.

 

The long an short, you maintain control authority well into what should be a deep stall without buffeting that should occur 3-5mph over the stall speed.

My tests so where with 50% fuel and default armament which i show in the video. The power off stall doesnt seem that problematic, however power on numbers are.

 

I concluded roughly 75mph stall with medium pwr when not dropping altitude, however if don't hold the altitude you still get the very silly stall speeds of 60mph and lower.

I conclude power on stall has too much control authority and likely a too high L/D ratio, you later on see me doing heavy corrections with the ailerons, which if anything will cause more drag and not effectively help control the planes attitude at these speed ranges/below stall speeds.

I'm neiter a pilot nor somebody studying aeronautics chomping books on the matter. As such I'm going to take this as a reference using figures for P-47 stalls http://www.wwiiaircraftperformance.org/p-47/Naca_TN_2899__F-47D-30_Flight_Test.pdf see fig 31 and following, which are in a different ballpark hence 

 

I dont see the following from the 3.010 game update being implemented or implemetend correctly. I realize the control surfraces are likely another global area of improvement however why a P-47 is lifting itself at 60mph@15°AoA is in my opinion incorrect 

Quote

21. P-47D-28 stall behavior has been corrected;

 

 

 

If you want to get data from .acmi or watch it first hand the recordings are attached

p47_FM.rar

Edited February 6, 2019 by =FEW=N3croo
fixed links

[Heckpupper]

I support the discussion, and I'm also sceptical of quality of stall charasterictics modeled in game.

However, if you're trying to compare that with the NACA document presented it's worth pointing out that you should make sure that the weight of the aircraft that you're flying in your video corresponds with the weight in the diagram which stands at 13,800 lbs. 

Weight affects center of gravity greatly, and center of gravity affects stall behaviour. 

If you want to be thorough with your feedback you should make sure that the weights are the same - unless you did already.

 

Thanks for bringing that up - I'd like to buy Bodenplatte to fly the P-47 (my all time fav) but I've heard mixed opinions regarding aircraft quality so I'm looking forward to some fixes before I purchase.

[=FEW=N3cRoo]

Fair point about the accuracy as i was flying from 3000-600ft instead of 5000ft in some of the tests, however i kinda expedted these results.

As such I deemed fully armed and half fuelled P-47 sufficient to do a check of the charateristics, which still should be ~6 ton bird

Also do not neglect the ease of control compared to the graph which are well beyond stable and smooth conditions.

[=FEW=Hauggy]

1 hour ago, 4./JG26_Onebad said:

I support the discussion, and I'm also sceptical of quality of stall charasterictics modeled in game.

However, if you're trying to compare that with the NACA document presented it's worth pointing out that you should make sure that the weight of the aircraft that you're flying in your video corresponds with the weight in the diagram which stands at 13,800 lbs. 

Weight affects center of gravity greatly, and center of gravity affects stall behaviour. 

If you want to be thorough with your feedback you should make sure that the weights are the same - unless you did already.

 

Thanks for bringing that up - I'd like to buy Bodenplatte to fly the P-47 (my all time fav) but I've heard mixed opinions regarding aircraft quality so I'm looking forward to some fixes before I purchase.

I do know the center of gravity shift is simulated when spending 37mm ammunition in the P-39 which is great but (correct me if Im wrong please) I don't think there is such a feature regarding fuel usage which would be extremely important for a high fidelity 262 since the center of gravity shifts completely when the rear tank is half empty since when the rear tank is full the center of gravity is much farther back as it should be, sadly it's not possible to manage fuel at all right now and not even press the push button to check your wing tank on the Spits of I-16 for example.

Hopefully the devs are already working on that and separate fuel tanks (so that we don't leak everything from one wing) and drop tanks which I believe were announced.

Fingers crossed!

Edited February 6, 2019 by =FEW=Hauggy

[=FEW=N3cRoo]

Alright, since its been requested and will likely put a nail into the coffin of that without even being a super exact test

 

Have it with full fuel and extra ammo and a bit higher altitude.

 

First stall engine off, no flaps 1:50

2nd engine off, 80% flaps 2:55

3rd stall engine on and full flaps 3:50

 

Edited February 7, 2019 by =FEW=N3croo
added timestamps

[Legioneod]

I wouldn't use flaps to determine the accuracy of the base flight model. Flaps on the P-47 are currently over-performing to an extreme degree and using flaps is inaccurate in itself due to asymmetric deployment irl.

 

From what I've read the P-47 had a gentle stall and it gave you plenty of warning before it happened. It also had no tendency to drop a wing unlike what we see in-game, irl it usually just dropped straight down. The video below explains it pretty well.

 

Here's a good video that talks about and shows the P-47 stall. (13:26)

 

Overall I think non flaps, low speed stalls are pretty accurate though maybe not perfect. I know they're much better than the flap modeling and high speed stalls.

[Blackhawk_FR]

Using this topic to ask: Am I the only one thinking P47s flaps are... magic? They are almost turning this heavy aircraft into a Spitfire. 

Those who fly it probably already noticed how easy it is to stand well against a 109 in a tight dogfight.

[Legioneod]

3 hours ago, F/JG300_Faucon said:

Using this topic to ask: Am I the only one thinking P47s flaps are... magic? They are almost turning this heavy aircraft into a Spitfire. 

Those who fly it probably already noticed how easy it is to stand well against a 109 in a tight dogfight.

Yep. Like I said in my post above, the flaps are over performing to a very large degree. Realistically we shouldn't even be using flaps for the most part.

P-47 modeling is pretty bad in some areas imo and it definitely still needs work.

Edited March 24, 2019 by Legioneod

[CountZero]

7 hours ago, F/JG300_Faucon said:

Using this topic to ask: Am I the only one thinking P47s flaps are... magic? They are almost turning this heavy aircraft into a Spitfire. 

Those who fly it probably already noticed how easy it is to stand well against a 109 in a tight dogfight.

ppl noticed that when it got relised, and as there is no word about it or evidance that it could not give that boost in turn it seams its gona stay that way, so its either modeled correctly and in real airplanes it was not used by pilots for who knows what reason, or its wrongly modeled and no one send FM devs evidance that it is. Se how quick D9 engine weard winter behaviod gets fixed, probably someone informed devs with some evidance that is wrong and it seams it will quickly get fix, so that makes me belive that other weard things that stay weard are probably that way as no one send evidance that its not wrong.

For now it is just another weard thing that cant be explained it seams, perfect airplane for fun on berloga while its like this 

[LColony_Kong]

This might be a good time to point out that this appears to be an issue with all of the flaps in the game. 

 

-All plans with plain flaps appear to gain no benefit from them for maneuver.

 

-All planes with split flaps, notably the yak, get an absurd benefit for maneuver.

 

-Given the P-47, slotted flaps seem to continue this trend toward even more bonkers flap behavior.

7 hours ago, Legioneod said:

Yep. Like I said in my post above, the flaps are over performing to a very large degree. Realistically we shouldn't even be using flaps for the most part.

P-47 modeling is pretty bad in some areas imo and it definitely still needs work.

This is not true. Flaps were used quite frequently for dogfighting purposes. Some aircraft had specific settings for this purpose. There is an entire section devoted to pilot accounts of flap use in combat in the link below. And that's just for the P-51. I do agree that the performance some flaps give in game is excessive in the extreme however.

 

http://www.wwiiaircraftperformance.org/mustang/combat-reports.html

 

	Three (3) Fw 190's destroyed. "I dropped 20 degree flap and easily out turned him."
1st Lt. Paul S. Riley, 22 April 1944, 4th FG	"Letting down 20° of flaps, I could get on the inside of the turn and pull deflection."
2nd Lt. Grover C. Siems, 12 May 1944, 4th FG	"Observing that I was overtaking too fast, I pulled up over the right e/a and dropped flaps."
2nd Lt. Frank E. Speer, 24 May 1944, 4th FG	"I had to put down 20° flaps to keep from overrunning him, indicating above 500 m.p.h."
1st Lt. Thomas D. Shank, 19 September 1944, 55th FG	"I dropped full flaps and placed myself directly astern of the e/a on the extreme right of the formation."
1st Lt. Frank E. Oiler, 14 January 1945, 78th FG	"I got into a Luftberry at 1100 feet with the FW 190, and with the use of flaps I got on his tail in two turns."
1st Lt. Chris J. Hanseman, 10 June 1944, 339th FG	"I cut my throttle and turned inside of him, dropping 20 degrees of flaps."
2nd Lt. Chris J. Hanseman, 24 May 1944, 339th FG	"…dropped 20 degree flaps…"
Harold W. Scruggs, 24 May 1944, 339th FG	"I lowered about 10 degrees flaps and made two 360 degree turns in which I gained rapidly on the E/A…"
Capt. Bradford V. Stevens, 12 September 1944, 339th FG	"…I was able to turn inside the Me 109 after dropping 20° flaps."
2nd Lt. Myer R. Winkelman, 6 August 1944, 339th FG	"I put down 20° flaps and got on his tail."
2st Lt. S. K. Moats, 29 July 1944, 352nd FG	I dropped 20 degrees flaps and after 2 more turns I was closing on the tail of the E/A."
Lt. Glennon T. Moran, 27 May 1944, 352nd FG	"We fought for about 20 minutes and it was necessary for me to put down combat flaps three times in order to turn with him."
Major George E. Preddy, 21 June 1944, 352nd FG	"He turned into me and I dropped 20 degrees of flaps, out turning him."
1st Lt. Arthur C. Cundy, 14 January 1945, 353rd FG	"With throttle pulled back and full flaps down, I overshot this 190."
1st Lt. William J. Cullerton, 2 November 1944, 355th FG	"I started to overshoot so I dropped full flaps and gave him another long burst just as he was leveling off to land."
Capt. Walter V. Gresham, 15 August 1944, 355th FG	"I downed 40 degrees of flaps and got in another burst which hit him hard."
Capt. Fred R. Haviland, 21 June 1944, 355th FG	"At 1,000 feet, I dumped 20 degree flaps and made a turn inside him and started to get within firing range, when the E/A made an abrupt turn, snapped over and crashed into the ground, exploding as he hit the ground."
2nd Lt. Esward Moroney, 2 November 1944, 355th FG	"...I put down full flaps and closed on the E/A."
1st Lt. Harold W. Spencer, 16 August 1944, 355th FG	"I dropped full flaps to keep from overrunning and fired from dead astern at about 100 yards and as I went over him, the Jerry popped his stick forward and crashed."
Capt. Clarence E. Anderson, 30 April 1944, 357th FG	"By using 20° flaps and full throttle I pulled around on their tails in one turn and started firing…"
Capt. Leonard K. Carson, 2 November 1944, 357th FG	"I chopped my throttle and dropped flaps."
1st Lt. Leonard K. Carson, 30 May 1944, 357th FG	"I dropped flaps and turned back behind him."
Capt Robert W. Foy, 18 November 1944, 357th FG	"I lowered flaps and gave E/A a short burst."
Capt. Robert W. Foy, 25 July 1944, 357th FG	"He suddenly pulled into a sharp right turn and I put down 20° flaps and followed giving several bursts with about two radii lead."
1st Lt. Gilbert M. O’Brien, 27 May 1944, 357th FG	"I slid right up beside him with my flaps down. He bailed out as I was alongside of him, at about 12,000 ft. His chest was covered with blood and he hit the rudder."
Capt Richard A. Peterson, 6 October 1944, 357th FG	"I realized I was over running him and lowered flaps as I pulled along side of him."
1st Lt. James R. Sloan, 24 December 1944, 357th FG	"In the ensuing combat I was unable to turn inside the E/A until I dropped 10 degrees of flaps."
F/O Boyd N. Adkins, 24 October 1944, 359th FG	"I dropped flaps and slid in trail with him at close range."
1st Lt. George F. Baker, 11 September 1944, 359th FG	"I dropped flaps to stay astern of E/A."
Capt. William C. Forehand, 30 May 1944, 359th FG	"I dropped twenty degrees of flaps and cut my throttle and closed in behind him firing from approximately 100 ft.”
1st Lt. Frank O. Lux, 16 August 1944, 359th FG	"I closed on him, dropped about 10 degrees of flap, and started to fire."
1st Lt. James L. McCubbin, 2 December 1944, 364th FG	"The e/a then dropped his wheels and I dropped 20° flaps to stay behind."
Lt Elmer A. Taylor, 24 August 1944, 364th FG	"I dropped 20° Flaps and outturned him."

Edited March 24, 2019 by Fumes

[Legioneod]

8 hours ago, Fumes said:

This might be a good time to point out that this appears to be an issue with all of the flaps in the game. 

 

-All plans with plain flaps appear to gain no benefit from them for maneuver.

 

-All planes with split flaps, notably the yak, get an absurd benefit for maneuver.

 

-Given the P-47, slotted flaps seem to continue this trend toward even more bonkers flap behavior.

This is not true. Flaps were used quite frequently for dogfighting purposes. Some aircraft had specific settings for this purpose. There is an entire section devoted to pilot accounts of flap use in combat in the link below. And that's just for the P-51. I do agree that the performance some flaps give in game is excessive in the extreme however.

 

http://www.wwiiaircraftperformance.org/mustang/combat-reports.html

 

	Three (3) Fw 190's destroyed. "I dropped 20 degree flap and easily out turned him."
1st Lt. Paul S. Riley, 22 April 1944, 4th FG	"Letting down 20° of flaps, I could get on the inside of the turn and pull deflection."
2nd Lt. Grover C. Siems, 12 May 1944, 4th FG	"Observing that I was overtaking too fast, I pulled up over the right e/a and dropped flaps."
2nd Lt. Frank E. Speer, 24 May 1944, 4th FG	"I had to put down 20° flaps to keep from overrunning him, indicating above 500 m.p.h."
1st Lt. Thomas D. Shank, 19 September 1944, 55th FG	"I dropped full flaps and placed myself directly astern of the e/a on the extreme right of the formation."
1st Lt. Frank E. Oiler, 14 January 1945, 78th FG	"I got into a Luftberry at 1100 feet with the FW 190, and with the use of flaps I got on his tail in two turns."
1st Lt. Chris J. Hanseman, 10 June 1944, 339th FG	"I cut my throttle and turned inside of him, dropping 20 degrees of flaps."
2nd Lt. Chris J. Hanseman, 24 May 1944, 339th FG	"…dropped 20 degree flaps…"
Harold W. Scruggs, 24 May 1944, 339th FG	"I lowered about 10 degrees flaps and made two 360 degree turns in which I gained rapidly on the E/A…"
Capt. Bradford V. Stevens, 12 September 1944, 339th FG	"…I was able to turn inside the Me 109 after dropping 20° flaps."
2nd Lt. Myer R. Winkelman, 6 August 1944, 339th FG	"I put down 20° flaps and got on his tail."
2st Lt. S. K. Moats, 29 July 1944, 352nd FG	I dropped 20 degrees flaps and after 2 more turns I was closing on the tail of the E/A."
Lt. Glennon T. Moran, 27 May 1944, 352nd FG	"We fought for about 20 minutes and it was necessary for me to put down combat flaps three times in order to turn with him."
Major George E. Preddy, 21 June 1944, 352nd FG	"He turned into me and I dropped 20 degrees of flaps, out turning him."
1st Lt. Arthur C. Cundy, 14 January 1945, 353rd FG	"With throttle pulled back and full flaps down, I overshot this 190."
1st Lt. William J. Cullerton, 2 November 1944, 355th FG	"I started to overshoot so I dropped full flaps and gave him another long burst just as he was leveling off to land."
Capt. Walter V. Gresham, 15 August 1944, 355th FG	"I downed 40 degrees of flaps and got in another burst which hit him hard."
Capt. Fred R. Haviland, 21 June 1944, 355th FG	"At 1,000 feet, I dumped 20 degree flaps and made a turn inside him and started to get within firing range, when the E/A made an abrupt turn, snapped over and crashed into the ground, exploding as he hit the ground."
2nd Lt. Esward Moroney, 2 November 1944, 355th FG	"...I put down full flaps and closed on the E/A."
1st Lt. Harold W. Spencer, 16 August 1944, 355th FG	"I dropped full flaps to keep from overrunning and fired from dead astern at about 100 yards and as I went over him, the Jerry popped his stick forward and crashed."
Capt. Clarence E. Anderson, 30 April 1944, 357th FG	"By using 20° flaps and full throttle I pulled around on their tails in one turn and started firing…"
Capt. Leonard K. Carson, 2 November 1944, 357th FG	"I chopped my throttle and dropped flaps."
1st Lt. Leonard K. Carson, 30 May 1944, 357th FG	"I dropped flaps and turned back behind him."
Capt Robert W. Foy, 18 November 1944, 357th FG	"I lowered flaps and gave E/A a short burst."
Capt. Robert W. Foy, 25 July 1944, 357th FG	"He suddenly pulled into a sharp right turn and I put down 20° flaps and followed giving several bursts with about two radii lead."
1st Lt. Gilbert M. O’Brien, 27 May 1944, 357th FG	"I slid right up beside him with my flaps down. He bailed out as I was alongside of him, at about 12,000 ft. His chest was covered with blood and he hit the rudder."
Capt Richard A. Peterson, 6 October 1944, 357th FG	"I realized I was over running him and lowered flaps as I pulled along side of him."
1st Lt. James R. Sloan, 24 December 1944, 357th FG	"In the ensuing combat I was unable to turn inside the E/A until I dropped 10 degrees of flaps."
F/O Boyd N. Adkins, 24 October 1944, 359th FG	"I dropped flaps and slid in trail with him at close range."
1st Lt. George F. Baker, 11 September 1944, 359th FG	"I dropped flaps to stay astern of E/A."
Capt. William C. Forehand, 30 May 1944, 359th FG	"I dropped twenty degrees of flaps and cut my throttle and closed in behind him firing from approximately 100 ft.”
1st Lt. Frank O. Lux, 16 August 1944, 359th FG	"I closed on him, dropped about 10 degrees of flap, and started to fire."
1st Lt. James L. McCubbin, 2 December 1944, 364th FG	"The e/a then dropped his wheels and I dropped 20° flaps to stay behind."
Lt Elmer A. Taylor, 24 August 1944, 364th FG	"I dropped 20° Flaps and outturned him."

 

That's the P-51 though not the P-47.

I'm not saying flaps were never used by aircraft, I'm saying the P-47 rarely if ever used them in combat.

 

The P-47 had asymmetrical flap deployment from what I've read and this problem was never resolved iirc. I have never heard of a single use of flaps by a P-47 pilot in combat, I'm not saying it didn't happen but it wasn't the norm like the P-51.

Edited March 25, 2019 by Legioneod

[LColony_Kong]

1 hour ago, Legioneod said:

 

That's the P-51 though not the P-47.

I'm not saying flaps were never used by aircraft, I'm saying the P-47 rarely if ever used them in combat.

 

The P-47 had asymmetrical flap deployment from what I've read and this problem was never resolved iirc. I have never heard of a single use of flaps by a P-47 pilot in combat, I'm not saying it didn't happen but it wasn't the norm like the P-51.

Ok fair enough, I misunderstood your point.

 

Out of curiosity though, is there any specific evidence of the issue you mentioned preventing their use in combat or is it a conjecture. Admittedly I am not super well versed in the woes of asymmetric flaps,  but to my imagination, it seems like something that would not necessarily be the end of the world. Surely they still used the same flaps for landing? If the flaps deployed a little out of sync, why would this be any worse then essentially a trim issue? 

[Legioneod]

27 minutes ago, Fumes said:

Ok fair enough, I misunderstood your point.

 

Out of curiosity though, is there any specific evidence of the issue you mentioned preventing their use in combat or is it a conjecture. Admittedly I am not super well versed in the woes of asymmetric flaps,  but to my imagination, it seems like something that would not necessarily be the end of the world. Surely they still used the same flaps for landing? If the flaps deployed a little out of sync, why would this be any worse then essentially a trim issue? 

I'm trying to find the source that I read it from but iirc it just stated they were not used much or at all in combat.

The different between using flaps for landing and using them for combat is that when you are landing you are on a steady course/speed, and you aren't making any sudden movements for the most part.

In combat however you are constantly moving and making changes in speed and movement so asymmetric deployment could be harder to counteract in the moment and could cause trouble with maneuvering which could end up losing you the fight.

I could be wrong about all of this of course on I'll need to do more research on the matter.

 

Having said all this, one thing is certain and that is flaps are over performing and need to be adjusted.

The stall speed of the P-47 with flaps is ridiculously low and turning ability is the best in game (for the most part) when flap are fully deployed.

[LColony_Kong]

4 minutes ago, Legioneod said:

I'm trying to find the source that I read it from but iirc it just stated they were not used much or at all in combat.

The different between using flaps for landing and using them for combat is that when you are landing you are on a steady course/speed, and you aren't making any sudden movements for the most part.

In combat however you are constantly moving and making changes in speed and movement so asymmetric deployment could be harder to counteract in the moment and could cause trouble with maneuvering which could end up losing you the fight.

I could be wrong about all of this of course on I'll need to do more research on the matter.

 

Having said all this, one thing is certain and that is flaps are over performing and need to be adjusted.

The stall speed of the P-47 with flaps is ridiculously low and turning ability is the best in game (for the most part) when flap are fully deployed.

I definitely agree that the flaps, in general, are over-performing.  P-47 in particular. It has been toned down a little, but it is still almost as agile as a spit. Before it was turning at 24deg a second, which is obscene.

 

Not really sure what is going on with flaps in il2. But none of them seem to work right. Plain flaps seem to do practically nothing, and split flaps are incredible. In reality, they should be similar in general performance. Slotted and fowler flaps should indeed be in their own ballpark but right now they are somewhere outside the stadium.

 

Additionally, the flap behavior appears to function in an almost magical fashion. For example, plain flaps do indeed reduce stall speed in game for plane that have them, but they only degrade turn performance, essentially acting only as airbrakes. I wonder where the additional lift went all of a sudden in those circumstances. Meanwhile, split flaps might as well be filled with helium. And the P-47s slotted flaps allow it to do unusual cartwheel maneuvers. 

[Legioneod]

3 hours ago, Fumes said:

I definitely agree that the flaps, in general, are over-performing.  P-47 in particular. It has been toned down a little, but it is still almost as agile as a spit. Before it was turning at 24deg a second, which is obscene.

 

Not really sure what is going on with flaps in il2. But none of them seem to work right. Plain flaps seem to do practically nothing, and split flaps are incredible. In reality, they should be similar in general performance. Slotted and fowler flaps should indeed be in their own ballpark but right now they are somewhere outside the stadium.

 

Additionally, the flap behavior appears to function in an almost magical fashion. For example, plain flaps do indeed reduce stall speed in game for plane that have them, but they only degrade turn performance, essentially acting only as airbrakes. I wonder where the additional lift went all of a sudden in those circumstances. Meanwhile, split flaps might as well be filled with helium. And the P-47s slotted flaps allow it to do unusual cartwheel maneuvers. 

 

P-47 has fowler flaps but I agree with everything you said about them overperforming. It allows the P-47 to just float in the air and to ridiculous things.

 

The turn performance of the P-47 irl wasn't as bad as people think, but it couldn't turn with a spitfire for long and it most certainly couldn't outturn it.

[Legioneod]

I know this thread is about stalls but I'm still very disappointed by the P-47 FM. It needs work imo more than any other aircraft.

 

Was doing some dive test to see if anything changed and unfortunately the P-47 still loses surfaces early in the dive.

I dove in the K-4, D9, and P-47. K4 didn't loses anything until 600+ mph, D9 lost controls at around 570 and the P-47 was similar at around 570-575 mph.

 

In reality the P-47 should be able to dive around 600+ indicated without losing any surfaces yet it's still shy of this mark by around 30 mph.

 

Nothing serious, just a small rant.

[Voyager]

Asymetric flap deployment under high g load can cause one wing to stall and kick you into a spin. There was a pair of NACA reports on the P-47 stability, including a plot of the pilot control inputs needed to keep the plane level as the flaps dropped. It was all over the place until they stabilized. 

 

I did a series of L/D plots of the P-47 with flaps in an earlier thread. Basically the flaps give you a worse L/D ratio but a higher stall AoA than without, so you get a lower stall speed. It's only under high g loads that we get unexpected behavior, which, given the aforementioned asymmetry issue, may not have been tested. It is a big airplane yes, but it also has big wings, very large flaps and the most powerful engine with biggest airflow in the game operating in an untested flight regime. We cannot reply on pilot accounts or our own intuition for how it should behave.