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P-47: bad at boom and zoom?


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Let me rephrase the issue:

When you bnz two times like I did with the Jug at combat power as described in my previous reply, and in parallel you bnz with a Pony with throttle idle, same flight path, you end up at the same altitude, same speed, same energy state - more or less that is.

If anyone out there thinks this was right, fine with me.

I take the liberty to think that it's odd.

 

:drinks:

Mike

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Did you record a track when you conducted this side by side test?  If yes then post it in the technical issues forum because that would indeed be a problem.  It could indicate the P51D is over modelled or vice-versa.

Edited by ICDP
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I surely have a track lying around somewhere, I'm just too tired of providing megabytes of proof for something that's been hair-split, torn apart and negated later on anyway.
If a tiny bit of frustration is showing through in these lines: Yes, that's it, exactly.

Not at least because honestly we're not outlining all the Jug's flight model issues since yesterday, don't we? "Hovering flaps" anyone?

 

:drinks:

Mike

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If at first you don't succeed stop trying right?  If there have been bug reports with data to back up the claims then it will not be ignored.  If on the other hand all you have are threads like this then unfortunately nothing will be fixed.

 

It probably took longer for you to type your replies than it would have done to post a link to your already saved trak.

Edited by ICDP
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Out of curiosity I did a test of what you described.  P47D Kuban Spring.

  • 25,000 feet alt.  200IAS
  • Entered a dive of roughly 30-35 degree and rapidly reached VNE at around 18,000.  I began a roughly 2G pull-out at 20,000 feet.  Speed at ~1600 was ~436 mph
  • Began pulling out at ~2G and levelled out at just over 16,000 feet.  Speed lost during pullout to climb was ~40 mph IAS.  I did need to use trim which matches the manual.
  • Pulled through into a ~40 degree climb.
  • Continued climb until stall speed.
  • Final altitude was 23,000 feet and 145mp IAS

Same test in a P51D

  • 25,000 feet alt.  200IAS
  • Entered a dive of roughly 30-35 degree and rapidly reached VNE at around 18,000.  I began a roughly 2G pull-out at 20,000 feet.  Speed at ~1600 was ~440 mph
  • Began pulling out at ~2G and levelled out at just over 16,000 feet.  Speed lost during pullout to climb was ~40 mph IAS.
  • Pulled through into a ~40 degree climb.
  • Continued climb until stall speed.
  • Final altitude was 24,000 feet and 145mp IAS

 

So the P-51D was marginally better and under no circumstances would have reached this altitude if I were on idle as alleged.  Both aircraft were full power throughout.  I see nothing wrong.

Edited by ICDP
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Fine, so what you experience doesn't match what I experience.

Honestly, given the attitude you've started with, I could have put money on that "result".

 

2 hours ago, ICDP said:

If at first you don't succeed stop trying right?  If there have been bug reports with data to back up the claims then it will not be ignored.  If on the other hand all you have are threads like this then unfortunately nothing will be fixed.

 

It probably took longer for you to type your replies than it would have done to post a link to your already saved trak.

 

What is it that makes you feel entitled to attack me for not doing anything you wish on your command?

Is there anything else I can do for you?

Nice cup of coffee maybe?

Rub your back?

 

Sit back and relax man. The Jug's a flying pig in IL-2 GB, hands down. Believer it or not, I don't give a flying something.

 

:drinks: (and bye to this thread)

Mike

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Then why are you posting about it if you don't care?  The altitude I tested was based on your alleged dive from 25,000 feet to 16,000 with your buddy in a P51D at idle beside you.  Here let me remind you of your post.

 

I took a P-47 for an escort, and later bomber intercept sweep.

The escort was for a group of 4 Pe-2, which were flying at 16k ft.

I took the Jug up to 25k ft (just for sh*ts and giggles) and started a shallow dive to the Pe-2s at almost 500mph (didn't want to check vne tolerance).

On level with the Pe-2s, I pulled out with 2G, planning to extend away from them in a 45° climb and check how far I could climb.

At the end of the 2G pull I had lost more than 100 kts (120 mph according to my speedometer readout, but that might have been slightly imprecise as I was busy with watching my six in parallel), simply from pulling 2G to get out of a ~30° dive and climb away to 45° again, at combat power.

The 45° climb saw me stalling at slightly below 20k ft, so I've lost about 5k ft. from one single bnz dive/climb attempt.

One more and my energy would have been all gone.

 

So I took my testing parameters from your very own post!

 

I also just  tested the P51D in the same test at idle (as you claim your friend did to keep from overtaking you in your pig P47D).  Best altitude was 20,000 so around 4,000 less than with power on and about 50 mph slower at the bottom of the dive.  If you are going to claim that a P51D at idle is better boom and zoom than a Jug at full power then it doesn't help your cause.  Ironically I am not the one who is coming across as entitled, it is people claiming the P47D is a pig and demanding fixes based on "feels".

 

I did not "demand" anything from you, I made a suggestion that would get far better results.

Some more testing results.

 

P47D

  • 25,000 feet alt.  200IAS
  • Entered a dive of roughly 30-35 degree and rapidly reached VNE at around 18,000.  I began a roughly 2-3 G pull-out at 20,000 feet.  Speed at ~1600 was ~430 mph
  • Began pulling out at ~2G and levelled out at just over 16,000 feet.  Speed lost during pullout to climb was ~40 mph IAS.
  • Pulled through into a ~40 degree climb.
  • Continued climb until stall speed.
  • Final altitude was ~23,000 feet and 145mp IAS

 

Bf109G-14

  • 25,000 feet alt.  200IAS
  • Entered a dive of roughly 30-35 degree and rapidly reached VNE at around 18,000.  I began a roughly 2-3 G pull-out at 20,000 feet.  Speed at ~1600 was ~430 mph
  • Began pulling out at ~2-3 G and levelled out at just over 16,000 feet.  Speed lost during pullout to climb was ~40 mph IAS.
  • Pulled through into a ~40 degree climb.
  • Continued climb until stall speed.
  • Final altitude was ~23,000 feet and 145mp IAS

 

Bf109G-6

  • 25,000 feet alt.  200IAS
  • Entered a dive of roughly 30-35 degree and rapidly reached VNE at around 18,000.  I began a roughly 2-3 G pull-out at 20,000 feet.  Speed at ~1600 was ~400 mph
  • Began pulling out at ~2G and levelled out at just over 16,000 feet.  Speed lost during pullout to climb was ~40 mph IAS.
  • Pulled through into a ~40 degree climb.
  • Continued climb until stall speed.
  • Final altitude was ~21,500 feet and 145mp IAS

 

P51D (idle)

  • 25,000 feet alt.  200IAS
  • Entered a dive of roughly 30-35 degree and rapidly reached VNE at around 18,000.  I began a roughly 2-3 G pull-out at 20,000 feet.  Speed at ~1600 was ~386 mph
  • Began pulling out at ~2G and levelled out at just over 16,000 feet.  Speed lost during pullout to climb was ~40 mph IAS.
  • Pulled through into a ~40 degree climb.
  • Continued climb until stall speed.
  • Final altitude was ~20,000 feet and 145mp IAS

 

Oh, and ironic signature quote, very apt in this case considering your wild allegations and attitude.

Edited by ICDP
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4 hours ago, ICDP said:

Then do your best to find the evidence and show that in graphs compared to real data guys.  Nothing will get changed based on "feels".

 

So here are some data points I just collected in the sim to compare high speed handling. The test was quite simple:

  • Start at 9000 ft.
  • Go full power, dive down (about 30 degrees) until we reach 400 mph. This generally happens around 5000ft.
  • Then roll 90 degrees to the right (timer starts when roll is finished).
  • Pull as hard as possible in a level turn (no altitude change), without stalling the plane or blacking out.
  • Complete a 360 circle, this is estimated using an easily visible landmark.
  • Timer stops when 360 circle is complete, measure finishing speed and time.
     

All speeds and times measured using tacview. Three separate runs were taken for each plane (R1, R2 & R3) and averages made. 

  • Start time: time when the 360 circle started, as shown in tacview.
  • Start CAS: speed (in CAS) when the 360 circle started, as shown in tacview.
  • End Time: time when the 360 circle was finished, as shown in tacview.
  • End CAS: speed (in CAS) when the 360 circle was finished, as show in tacview.
  • Time (s): the time to complete the 360 circle, end time - start time.
  • Delta Speed: the speed loss doing the 360 circle, end CAS - start CAS.
=== P-51 ====================

Full power, 50% fuel.

        Start time  Start CAS (mph)     End Time        End CAS (mph)   Time (s)    Delta Speed (mph)
R1:     0:05        412                 0:19            270             14          142
R2:     0:29        413                 0:45            267             16          146
R3:     0:35        412                 0:50            283             15          129 

Average:                                                                15          139

NOTES: P-51 is G limited here, easy to blackout at any point all the way round.


=== P-47 ====================

Full power, 50% fuel, cowl flaps closed.

        Start time  Start CAS (mph)     End Time        End CAS (mph)   Time (s)    Delta Speed (mph)
R1:     0:33        408                 0:51            231             18          177
R2:     0:00        409                 0:17            221             17          188
R3:     0:06        417                 0:23            233             17          184

Average:                                                                17.3        183

NOTES: P-47 can't pull enough G to blackout at this speed, P-47 also loses so much speed that it stalls before completing the turn.

=== P-38 ====================

Full power, 50% fuel, cowl flaps closed.

        Start time  Start CAS (mph)     End Time        End CAS (mph)   Time (s)    Delta Speed (mph)
R1:     0:28        412                 0:43            251             15          161
R2:     0:35        411                 0:50            255             15          156
R3:     0:25        408                 0:41            247             16          161

Average:                                                                15          159.3

NOTES: P-38 is G limited, it can easily reach blackout.

=== Spitfire Mk IX ==========

Full power, 50% fuel.

        Start time  Start CAS (mph)     End Time        End CAS (mph)   Time (s)    Delta Speed (mph)
R1:     0:29        406                 0:46            271             17          135
R2:     0:30        406                 0:48            285             18          121
R3:     0:27        413                 0:45            295             18          118

Average:                                                                17.6        125

NOTES: very very easy to blackout here, have to be very gentle with the stick and ride the blackout.


=== Bf 109 G-14 ==========

Full power, 50% fuel.

        Start time  Start CAS (mph)     End Time        End CAS (mph)   Time (s)    Delta Speed (mph)
R1:     0:23        407                 0:41            285             18          122
R2:     0:23        404                 0:39            280             16          124
R3:     0:29        409                 0:45            281             16          128

Average:                                                                16.7        124.7

NOTES: more elevator limited than G limited.

=== Bf 110 G-2 ==========

Full power, 50% fuel.

        Start time  Start CAS (mph)     End Time        End CAS (mph)   Time (s)    Delta Speed (mph)
R1:     0:02        402                 0:23            281             21          121
R2:     0:33        403                 0:53            281             20          122
R3:     0:31        403                 0:51            291             20          111

Average:                                                                20.3        118

NOTES: strongly elevator limited rather than G limited.

Conclusions:

  •  The P-51 and P-47 both have G suits (other planes do not) which increases the G tollerance for the plane. However, the P-47 cannot pull enough G to blackout at this speed meaning it is elevator limited and cannot make use of the G suit. As a result the P-47 turns no better than the other planes. This supports my observation the P-47 is not handling well at high-speed, it cannot pull enough G to reach the blackout limit at 400mph, unlike the P-51 (or even the Spitfire) which easily can. This is not in keeping with the many reports of the P-47 having strong and responsive controls at high speed.
     
  • The P-47 has much much larger energy loss than all the other planes, even though it is turning no quicker. This strongly supports my original observation: the P-47 bleeds energy much worse than every other plane even though it is turning no quicker and pulling no more G. It is the only plane tested to lose so much speed that it tends to stall during the last part of the turn.
     
  • The data for the P-38 is included. The P-38 is easily able to reach the blackout limit and completes the circle in the same time as the P-51 (G limited). However, despite the P-38 being heavier and larger than the P-47, and pulling significantly more G than it, it loses less airspeed than the P-47. 
     
  • The Spitfire is strongly overperforming: it can easily pull more than enough G to quickly black out, far more than any other plane. This is despite the Spitfire being well known for having heavy and unresponsive controls at very high speeds. The 109 in comparison (a plane that is structurally similar) is elevator limited: you cannot pull enough G to blackout in the 109 at this speed.
Edited by Tomsk
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2 minutes ago, Tomsk said:

 

So here are some data points I just collected in the sim to compare high speed handling. The test was quite simple:

  • Start at 9000 ft.
  • Go full power, dive down (about 30 degrees) until we reach 400 mph. This generally happens around 5000ft.
  • Then roll 90 degrees to the right (timer starts)
  • Pull as hard as possible in a level turn (no altitude change), without stalling the plane or blacking out.
  • Complete a 360 circle, this is estimated using an easily visible landmark.
  • Timer stops when 360 circle is complete, measure finishing speed and time.

All speeds and times measured using tacview. Three separate runs were taken and averages made. 

  • Start time: time when the 360 circle started, as shown in tacview.
  • Start CAS: speed (in CAS) when the 360 circle started, as shown in tacview.
  • End Time: time when the 360 circle was finished, as shown in tacview.
  • End CAS: speed (in CAS) when the 360 circle was finished, as show in tacview.
  • Time (s): the time to complete the 360 circle, end time - start time.
  • Delta Speed: the speed loss doing the 360 circle, end CAS - start CAS.

=== P-51 ====================

Full power, 50% fuel.

        Start time  Start CAS (mph)     End Time        End CAS (mph)   Time (s)    Delta Speed (mph)
R1:     0:05        412                 0:19            270             14          142
R2:     0:29        413                 0:45            267             16          146
R3:     0:35        412                 0:50            283             15          129 

Average:                                                                15          139

NOTES: P-51 is G limited here, easy to blackout at any point all the way round.


=== P-47 ====================

Full power, 50% fuel, cowl flaps closed.

        Start time  Start CAS (mph)     End Time        End CAS (mph)   Time (s)    Delta Speed (mph)
R1:     0:33        408                 0:51            231             18          177
R2:     0:00        409                 0:17            221             17          188
R3:     0:06        417                 0:23            233             17          184

Average:                                                                17.3        183

NOTES: P-47 can't pull enough G to blackout at this speed, P-47 also loses so much speed that it stalls before completing the turn.


=== Spitfire Mk IX ==========

Full power, 50% fuel.

        Start time  Start CAS (mph)     End Time        End CAS (mph)   Time (s)    Delta Speed (mph)
R1:     0:29        406                 0:46            271             17          135
R2:     0:30        406                 0:48            285             18          121
R3:     0:27        413                 0:45            295             18          118

Average:                                                                17.6        125

NOTES: very very easy to blackout here, have to be very gentle with the stick and ride the blackout.


=== Bf 109 G-14 ==========

Full power, 50% fuel.

        Start time  Start CAS (mph)     End Time        End CAS (mph)   Time (s)    Delta Speed (mph)
R1:     0:23        407                 0:41            285             18          122
R2:     0:23        404                 0:39            280             16          124
R3:     0:29        409                 0:45            281             16          128

Average:                                                                16.7        124.7

NOTES: more elevator limited than G limited.

=== Bf 110 G-2 ==========

Full power, 50% fuel.

        Start time  Start CAS (mph)     End Time        End CAS (mph)   Time (s)    Delta Speed (mph)
R1:     0:02        402                 0:23            281             21          121
R2:     0:33        403                 0:53            281             20          122
R3:     0:31        403                 0:51            291             20          111

Average:                                                                20.3        118

NOTES: strongly elevator limited rather than G limited.

Conclusions:

  •  The P-51 and P-47 both have G suits (other planes do not), however, the P-47 cannot pull enough G to blackout at this speed meaning it is elevator limited and cannot make use of the G suit. As a result it turns no better than the other planes. This supports my observation the P-47 is not handling well at high-speed, it cannot pull enough G to reach the blackout limit at 400mph, unlike the P-51.
     
  • The P-47 has much much larger energy loss than all the other planes, even though it is turning no quicker. This strongly supports my original observation: the P-47 bleeds energy much worse than every other plane even though it is turning no quicker and pulling no more G. It is the only plane tested to lose so much speed that it tends to stall during the last part of the turn.
     
  • The Spitfire is strongly overperforming: it can easily pull more than enough G to quickly black out, far more than any other plane. This is despite the Spitfire being well known for having heavy and unresponsive controls at very high speeds. The 109 in comparison (a plane that is structurally similar) is elevator limited: you cannot pull enough G to blackout in the 109 at this speed.

I'm not  sure I have the best understanding of aerodynamics, so you can tell me if this is wildly out to lunch. But the P-47 is much heavier than all the other aircraft tested. A heavier aircraft is going to have a higher amount of induced drag as lift increases (for example, in a hard turn). So would we not expect the P-47 to bleed energy faster than  other fighters, given this higher amount of induced drag? It weighs twice as much as the 109 and the Spitfire, and about 50% more than the P-51, and about the same as the 110 (with higher wing loading). 

And at the altitudes you tested, the P-47 is not generating close its maximum power, so it cannot regain energy as fast as the other planes that generate more of their maximum power at that altitude.

Also the Spitfire I believe did not have a big problem with stiffening elevators, but with Ailerons become stiff and roll rate growing sluggish, making it difficult to follow faster rolling aircraft at high speeds. The 109 had the bigger problem with a stiffening elevator. 

As far as blackouts, the G-suits in game grant 1-2G of tolerance, so the Spitfire pilot is probably blacking out at 6G roughly while the P-47 pilot would have to pull 7-8G to black out.

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Good work and thanks for sharing these test results.  This goes a lot more towards having the devs sit up and listen so we can fix verified FM issues.

 

I don't think those numbers are that outlandish considering the weight and drag of a P-47 compared to the other single engine fighters.  The amount of speed loss from each fighter is right where I would expect it.  P47D, followed by P51D followed by Spitfire and 109.  Also as RedKestrel mentioned above, the Spitfire had very sensitive elevators.

 

It might be worth remembering that not all aircraft start with neutral trim and will be trimmed nose down when the mission starts.  So that will effect how much G you can pull.  Were you using the G meter to ensure all aircraft had the same G load?  If not then the test is not accurate as the less G the less drag and hence the numbers would not be comparable.

Edited by ICDP
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32 minutes ago, Tomsk said:

 

  • This is despite the Spitfire being well known for having heavy and unresponsive controls at very high speeds. The 109 in comparison (a plane that is structurally similar) is elevator limited: you cannot pull enough G to blackout in the 109 at this speed.

 

Spitfire II pilot's notes

 

image.png.eb2b85fd3abc72a2dcd280c7b5e0687a.png

 

Additionally, in near every comparison with captured 109s the RAE made they noted the 109 had heavier controls at high speed

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28 minutes ago, ICDP said:

I don't think those numbers are that outlandish considering the weight and drag of a P-47 compared to the other single engine fighters.  The amount of speed loss from each fighter is right where I would expect it.  P47D, followed by P51D followed by Spitfire and 109.  Also as RedKestrel mentioned above, the Spitfire had very sensitive elevators.

 

It might be worth remembering that not all aircraft start with neutral trim and will be trimmed nose down when the mission starts.  So that will effect how much G you can pull.

 

So I've added the P-38. The P-38 is significantly heavier and larger than the P-47, yet it can pull more Gs (it reaches the blackout limit no problem) but it loses signiciantly less airspeed than the P-47. If a heavier plane loses more speed, why does the P-38, pulling much more G (same speed, less time to complete the circle, more G force), have less airspeed loss?

 

So if I recall correctly, the Spitfire had fabric covered elevators until the Mk 21. This source agrees: Mk IX elevators were fabric covered. Fabric covered elevators were prone to balooning and were much less effective than the metal covered elevators of the P-51 or P-47. There are references that support the claim of the Spitfire having heavy control surfaces at high speeds (The Decisive Duel: Spitfire vs 109).

Quote

Even a superbly responsive fighter like the Spitfire had heavy control forces at high speeds.  Jeffrey Quill, the Supermarine test pilot, flying a Spitfire, had to 'struggle with both hands on the stick at well over 400 miles per hour and sweating and swearing profusely'.

 

I forgot to mention: all planes were trimmed to hold 400 mph for consistency.

Edited by Tomsk
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Because Weight is not the Problem.

 

Power to Weight Ratio is Problem 1

Wing Loading is Problem two

Wing Profile is Problem III (Cw/Drag; Cl/Lift; and Lift to Drag)

 

The Engine is an Energy Adding Device, the Wings are Energy Subtractors. How much Energy the Subtract is determined by their Drag at any given AoA.

Edited by 6./ZG26_Klaus_Mann
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4 minutes ago, Tomsk said:

 

So I've added the P-38. The P-38 is significantly heavier and larger than the P-47, yet it can pull more Gs (it reaches the blackout limit no problem) but it loses signiciantly less airspeed than the P-47. If a heavier plane loses more speed, why does the P-38, pulling much more G (same speed, less time to complete the circle, more G force), have less airspeed loss?

 

Probably that the P-38's acceleration is better - it climbs about 50% better than the Jug. It could be bleeding speed faster but it is also 'adding' speed much faster too, enabling it to have less of a net loss of speed. 

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5 minutes ago, RedKestrel said:

Probably that the P-38's acceleration is better - it climbs about 50% better than the Jug. It could be bleeding speed faster but it is also 'adding' speed much faster too, enabling it to have less of a net loss of speed. 

It simply has lower Wing Loading. So it has to pull less AoA (meaning less Drag) to pull the same AoA as a more highly Loaded Plane.

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10 minutes ago, 6./ZG26_Klaus_Mann said:

It simply has lower Wing Loading. So it has to pull less AoA (meaning less Drag) to pull the same AoA as a more highly Loaded Plane.

 

The P-38 (261 kg/m^2) has a higher wing loading than the P-47 (207 kg/m^2) ...

 

16 minutes ago, RedKestrel said:

Probably that the P-38's acceleration is better - it climbs about 50% better than the Jug. It could be bleeding speed faster but it is also 'adding' speed much faster too, enabling it to have less of a net loss of speed. 

 

Perhaps, but that's still a very large difference to explain. The P-38 is not renowned for it's awesome acceleration. In any case I stand by my claims, now with solid data to back them up:

  • The P-47 does not handle well at high-speeds: unlike the P-51, P-38 or even the Spitfire it cannot pull enough G to reach the blackout limit at 400mph.
  • The P-47 bleeds energy faster than any other comparable plane in high-speed maneuvers: even planes that are heavier, with higher wing loading, pulling more G.
  • It is not like this in any other simulation: only in IL2:GB.

It's possible that this is all entirely explainable, and makes perfect sense but to my mind this seems enough evidence to warrant some investigation by the dev team: it certainly is very odd. This could indeed be correct, but it could also easily just be a simple bug.

Edited by Tomsk
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2 minutes ago, Tomsk said:

 

The P-38 (261 kg/m^2) has a higher wing loading than the P-47 (207 kg/m^2) ...

 

 

Perhaps, but that's still a very large difference to explain. The P-38 is not renowned for it's awesome acceleration. In any case I stand by my claims, now with solid data to back them up:

  • The P-47 does not handle well at high-speeds: unlike the P-51, P-38 or even the Spitfire it cannot reach the blackout limit at 400mph.
  • The P-47 bleeds energy faster than any other comparable plane in high-speed maneuvers: even planes that are heavier, with higher wing loading, pulling more G.
  • It is not like this in any other simulation: only in IL2:GB.

It's possible that this is all entirely explainable, and makes perfect sense but to my mind this seems enough evidence to warrant some investigation by the dev team.

The P-38 climbs very well in this game, climbing with or outclimbing even some 109s. That should pretty much translate to good acceleration at least at low speeds, so it should be better at recovering energy when you are bleeding it in a turn. I don't know if the P-38 is more or less draggy than the P-47 but it very well might be. 

You can't use 'blackout limit' in this game when comparing a plane with a g-suit to planes without it, especially considering that the game does not model a single, hard limit but a complex system that takes into consideration speed of onset, pilot fatigue, etc. You seem surprised the Spitfire can achieve blackout when the P-47 cannot...but the Spitfire pilot is going to black out about 1 or 2 Gs before the P-47 all other things being equal, and it has strong elevator authority, which enables you to cause rapid onset of g-forces which will black you out even sooner than a gradual increase in g-forces. 

There is a G-meter in the HUD now so a more valid test than watching for blackout would be to turn off pilot physiology, turn on the g-meter, and pull a consistent amount of g's and take your results from that. Then we could say how much speed the planes bleed in a consistent 5G turn or something, rather than turning as hard as you can and trying to eyeball it.
 

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The P-38 has a good deal more installed power than the P-47 and it sprays a lot more wing-area with it's own prop-wash, creating additional lift.

It also has a better aspect-ratio than the P-47.

Edited by Bremspropeller
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34 minutes ago, Tomsk said:

 

The P-38 (261 kg/m^2) has a higher wing loading than the P-47 (207 kg/m^2) ...

 

 

Perhaps, but that's still a very large difference to explain. The P-38 is not renowned for it's awesome acceleration. In any case I stand by my claims, now with solid data to back them up:

  • The P-47 does not handle well at high-speeds: unlike the P-51, P-38 or even the Spitfire it cannot pull enough G to reach the blackout limit at 400mph.
  • The P-47 bleeds energy faster than any other comparable plane in high-speed maneuvers: even planes that are heavier, with higher wing loading, pulling more G.
  • It is not like this in any other simulation: only in IL2:GB.

It's possible that this is all entirely explainable, and makes perfect sense but to my mind this seems enough evidence to warrant some investigation by the dev team: it certainly is very odd. This could indeed be correct, but it could also easily just be a simple bug.

 

The P-38 as I posted earlier has the best level acceleration of all USAAF prop fighters in WWII.  The P47D is also not renowned for its high speed manoeuvrability, as posted earlier even the P47D manual mentions aileron and elevator controls stiffening at higher speeds.  What the P-47 was very well regarded for, was dive and zoom abilities.  Though again, as I showed earlier, it was hardly leaving an A6M5 in it's wake during dives and zooms.  So while it had a reasonable advantage compared to contemporaries it was marginal and given the weight and drag, easily lost during aggressive maneuvering.

 

Please forgive me posting these again but they are pertinent to your assessment that the P47D was regarded as having excellent high speed manoeuvrability, or the P38 was not renowned for it's acceleration.  America's Hundred Thousand rankings by late war fighter type and the P47D is not at the top of either list.

 

Dive acceleration

1 P-38G

2 P-51D and F4U-1D (tied)

4 P-47D

 

Best ailerons at 350 MPH

1 P51D

2 F4U-1D

3 P-38L

4 F5F-5

5 P-47D

 

Level Flight acceleration

1 P-38

2 P-47M (note D not tested)

3 P-51D

 

As a suggestion it would be best to focus on a test that can be replicated and verified by existing real life test data.

Edited by ICDP
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9 minutes ago, ICDP said:

As a suggestion it would be best to focus on a test that can be replicated and verified by existing real life test data.

 

I'd like to do a test focused on high-performance maneuverability: specifically energy bleed in high-speed maneuvers and maximum G that could be produced at various airspeeds. What test would you recommend that I could verify against existing real life test data? I ask because to my knowledge, there is no real-life data about these aspects of flight for the P-47.

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1 hour ago, Tomsk said:

 

The P-38 (261 kg/m^2) has a higher wing loading than the P-47 (207 kg/m^2) ...

 

 

Perhaps, but that's still a very large difference to explain. The P-38 is not renowned for it's awesome acceleration. In any case I stand by my claims, now with solid data to back them up:

  • The P-47 does not handle well at high-speeds: unlike the P-51, P-38 or even the Spitfire it cannot pull enough G to reach the blackout limit at 400mph.
  • The P-47 bleeds energy faster than any other comparable plane in high-speed maneuvers: even planes that are heavier, with higher wing loading, pulling more G.
  • It is not like this in any other simulation: only in IL2:GB.

It's possible that this is all entirely explainable, and makes perfect sense but to my mind this seems enough evidence to warrant some investigation by the dev team: it certainly is very odd. This could indeed be correct, but it could also easily just be a simple bug.

 

Why not draw the conclusion that the P-38 is over performing? I mean that would be a valid conclusion, wouldn't it? An aircraft which is more powerful than the P-47 yet only manages to reach the same SL max speed. 

 

Anyway, here is an article about the P-38J, which fortunately also includes information about the P-51 and the P-47.

 

http://www.wwiiaircraftperformance.org/p-38/p-38-wayne.html

 

p-38-wayne-fig1e.jpg

The formula for getting that graph is thrust horsepower (bhp x propeller efficiency) / parasite area (parasite drag coefficient x wing area).

 

At least according to this, it seems that the P-47 is behind the P-51, the P-38 and the FW-190A8 - the BnZers. 

 

What's interesting is that the article is stating that the max power limit for the P-38 was 1150-1240hp, due to inadequate cooling, which makes it a less powerful aircraft than the P-47 at SL. I don't have the P-38 in game, but as far as i can tell, it's the 60inHg, 3000RPM "version". Basically, 1600bhp/engine, so more powerful than the P-47.

Edited by Raven109
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15 minutes ago, Raven109 said:

Why not draw the conclusion that the P-38 is over performing? I mean that would be a valid conclusion, wouldn't it? An aircraft which is more powerful than the P-47 yet only manages to reach the same SL max speed. 

 

I'm not sure why I bother :) It always goes the same .. you point out that you think there is possibly some flaw in one of the FMs based on your experience. You provide data to support that hypothesis. Some people agree straight out, but also lot of people jump on and post either lots of irrelevant things .. or somewhat tenuous explanations for why it must be correct as is. Rather than saying "hmm yeah that's interesting, could be, really we need more data" people get quite defensive: that what is there must definitely be correct, because obviously bugs never happen in software. Then eventually at some point later the devs patch it and the problem is fixed .. seen it so many times.

 

You're right, it could be that the P-47 is fine and the P-38 is over performing .. it could be that somehow everything is correct as is. But maybe, just maybe, there actually is a problem with the P-47 flight model .. that the many people who report the same issue (energy retention, high-speed handling) are actually not making it all up .. right?

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10 minutes ago, Tomsk said:

 

I'd like to do a test focused on high-performance maneuverability: specifically energy bleed in high-speed maneuvers and maximum G that could be produced at various airspeeds. What test would you recommend that I could verify against existing real life test data? I ask because to my knowledge, there is no real-life data about these aspects of flight for the P-47.

 

The NACA roll rate charts also show the P47C was mediocre at max roll rate at high speeds.  This is also backed up by the RAF tests that show the same.  The P47D was mediocre at high speed manoeuvrability according to these charts, the opinion from test pilots who tested all USAAF fighters in controlled tests and of course the fact the pilot manual mentions aileron and elevators stiffening at higher speeds.

 

I don't know how to say this, but when I put all these primary sources together I conclude the P-47 was not special at high speed manoeuvring.  I'm sorry but a pilots anecdotal accounts will never trump actual data from controlled tests.  That doesn't make pilot accounts useless but Johnson claiming the P-47 had the best roll of any fighter "bar none" is not remotely backed up by actual test data.

 

naca868-rollchart.jpg

 

wade-roll.jpg

 

Here is some more data taken from AHT for some of the contemporary USAAF fighters.

 

Turning performance from best to worse (no flaps).

1 FM-2

2 P-63A

3 P-61B

4 F65-5

5 P-51D

6 P-38L

7 P-47D

8 F4U-1D

 

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7 minutes ago, ICDP said:

The NACA roll rate charts also show the P47C was mediocre at max roll rate at high speeds.  This is also backed up by the RAF tests that show the same.  The P47D was mediocre at high speed manoeuvrability according to these charts, the opinion from test pilots who tested all USAAF fighters in controlled tests and of course the fact the pilot manual mentions aileron and elevators stiffening at higher speeds.

 

I have no complaints about the roll speed, seems reasonable enough: a bit weak at low speeds, pretty good at high-speeds but not in the league of the P-51 or FW-190. It's really the elevator effectiveness that seems off for the high-speed regime, is there any quantitive data available on that? On top of the that the much bigger issue in my opinion is the energy bleed, is there data for that?

 

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20 minutes ago, Tomsk said:

 

I'm not sure why I bother :) It always goes the same .. you point out that you think there is possibly some flaw in one of the FMs based on your experience. You provide data to support that hypothesis. Some people agree straight out, but also lot of people jump on and post either lots of irrelevant things .. or somewhat tenuous explanations for why it must be correct as is. Rather than saying "hmm yeah that's interesting, could be, really we need more data" people get quite defensive: that what is there must definitely be correct, because obviously bugs never happen in software. Then eventually at some point later the devs patch it and the problem is fixed .. seen it so many times.

 

You're right, it could be that the P-47 is fine and the P-38 is over performing .. it could be that somehow everything is correct as is. But maybe, just maybe, there actually is a problem with the P-47 flight model .. that the many people who report the same issue (energy retention, high-speed handling) are actually not making it all up .. right?

 

You seem reasonable and should know that loads of people who desperately want something to be true does not make it true.  You state the P47D must be wrong, yet your own tests don't back this up.  Maybe, just maybe, when you are given actual first hand primary test reports that show why your findings aren't wrong, you should simply review your preconceptions?

 

Like I said, tactical reports, pilots manuals, AHT test results, drag and roll-rate diagrams.  All of them point to the fact the P47D did not excel at high speed manoeuvring but was just mediocre.  Are you of the opinion they are all wrong?

 

Edit:  Sorry if I missed your reply, but did you try adjusting the trim on the P-47 yet?  By default I think it is around 26% nose down trim.  So don't be afraid to adjust it to get the elevators to act more responsive in a turn.

Edited by ICDP
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1 minute ago, ICDP said:

You state the P47D must be wrong, yet your own tests don't back this up.  Maybe, just maybe, when you are given actual first hand primary test reports that show why your findings aren't wrong, you should simply review your preconceptions?

 

I have not stated the P-47D must be wrong. I've been very clear, that it is hard to know for sure. I have made the case that I think that it is wrong, and have given my reasons why, but I do not claim infallibility. Without hard data, of which this is very little in this area .. it seems impossible to be certain. As I asked before, could you suggest a test that I could do to verify high-speed elevator effectiveness or high-speed energy bleed that could be verified against known test data? It seems to me there is no data, and we are all scrabbling around in the dark trying to make our best estimates with the limited information available: a fact which I am very happy to admit to.

 

Quote

Like I said, tactical reports, pilots manuals, AHT test results, drag and roll-rate diagrams.  All of them point to the fact the P47D did not excel at high speed manoeuvring but was just mediocre.  Are you of the opinion they are all wrong?

 

As I say, I have no issues with the roll rate it seems fair enough. It's the elevator effectiveness that seems most lacking. The only thing that talks about that is the pilots manual .. and it is pretty vague. Is there hard quantitive data available that could be used to check the maximum G that can be produced at various airspeeds?

 

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4 minutes ago, Tomsk said:

 

I have not stated the P-47D must be wrong. I've been very clear, that it is hard to know for sure. I have made the case that I think that it is wrong, and have given my reasons why, but I do not claim infallibility. Without hard data, of which this is very little in this area .. it seems impossible to be certain. As I asked before, could you suggest a test that I could do to verify high-speed elevator effectiveness or high-speed energy bleed that could be verified against known test data? It seems to me there is no data, and we are all scrabbling around in the dark trying to make our best estimates with the limited information available: a fact which I am very happy to admit to.

 

 

As I say, I have no issues with the roll rate it seems fair enough. It's the elevator effectiveness that seems most lacking. The only thing that talks about that is the pilots manual .. and it is pretty vague. Is there hard quantitive data available that could be used to check the maximum G that can be produced at various airspeeds?

 

 

For what it's worth I do agree your tests do raise some questions.  In my opinion the speed bleed of a P47D should not be more than a Bf110G2 but as said above by RedKestrel try again with the G-Limiter enabled so you can test at identical G loading.  Also use trim if required.  Once you have done that post the findings in the relevant thread for FM issues and see if a dev replies.

 

My dive and zoom tests showed the P47D easily outdive and out zoom a 109G6 and was equal with the higher powerd G14, both slightly behind a P51D.  Though I only tested the stock P51D without 150 Octane.

Edited by ICDP
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8 minutes ago, Tomsk said:

 

I'm not sure why I bother :) It always goes the same .. you point out that you think there is possibly some flaw in one of the FMs based on your experience. You provide data to support that hypothesis. Some people agree straight out, but also lot of people jump on and post either lots of irrelevant things .. or somewhat tenuous explanations for why it must be correct as is. Rather than saying "hmm yeah that's interesting, could be, really we need more data" people get quite defensive: that what is there must definitely be correct, because obviously bugs never happen in software. Then eventually at some point later the devs patch it and the problem is fixed .. seen it so many times.

 

You're right, it could be that the P-47 is fine and the P-38 is over performing .. it could be that somehow everything is correct as is. But maybe, just maybe, there actually is a problem with the P-47 flight model .. that the many people who report the same issue (energy retention, high-speed handling) are actually not making it all up .. right?

 

I'm sorry, but with what you have posted I cannot just go and say "hmmm, interesting" when I go and find other data that confirms my expectations about the P-47. (although I do appreciate that you've started posting some test data, however let me respectfully remind you that you have provided no data about the RL P-47 behavior).

 

It's the nature of public forums. If one can't accept different opinions, then perhaps that person should not be posting on a public forum, and should go straight to the devs, clearly stating his/her case.

 

Allow me to state the obvious, by saying that you don't have to convince anyone here about your findings. All you have to do is provide reasonable, real world proof, to the devs....

 

Not sure how a power vs drag graph is irrelevant to this discussion. 

 

Here, some more irrelevant information:

Republic was doing tests for more streamlined airframes: XP-47H, XP-47J, XP-72. They all got canceled because of the advent of jet powered interceptors.

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9 minutes ago, ICDP said:

For what it's worth I do agree your tests do raise some questions.  The speed bleed of a P47D should not be more than a Bf110G2 but as said above by RedKestrel try again with the G-Limiter enabled so you can test at identical G loading.  Also use trim if required.

 

I'm happy to do that, could you tell me how to enable the G-Limiter I haven't seen that option.

 

7 minutes ago, Raven109 said:

(although I do appreciate that you've started posting some test data, however let me respectfully remind you that you have provided no data about the RL P-47 behavior).


I think this is the key: there basically is no data about the areas of high-speed elevator effectiveness or energy bleed. Everything anyone posts is at best a guess: you could be right and everything could in fact match the real world situation perfectly .. or I could be right and it could be there is a bug in the FM. I am perfectly happy to accept the posibility that I could be wrong, and that to some extent I am guessing ... but then so is everyone else. That is all I really meant.

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8 hours ago, ICDP said:

Zoom from Level Flight

10,000 Feet.  The P-47D was approximately 400 (121 metres) feet above and ahead of the Zeke after a full power zoom from level flight.

25,000 Feet, Results were approximately the same as those obtained at 10,000 feet.

 

Zoom from Dive

10,000 Feet.  After a zoom from 310 IAS to 130 IAS, the P-47D was approximately 600 feet (200 metres) above and far ahead of the Zeke

25,000 Feet, Results were approximately the same as those obtained at 10,000 feet.

 

If those are the numbers a P47D-30 beats an A6M5 by in "boom and zoom" then it will be even less against the 109 or 190.  So the P47D to my mind is perfectly fine in sim given those actual numbers.  Every single dive and zoom scenario tested left the P-47D well inside gun range of an A6M5. If you start with a 100mph speed advantage and do a few 90 degree zoom climbs, or a loop and your advantage is history.  Hell even turn hard to get a lead and you have just flushed most of your energy down the toilet.  Please don't take this wrong but I find your expectations of the P-47D dive and zoom performance may be a bit high.

Keep in mind that above and ahead in this situation are to separate things, it doesn't mean the P-47 was right in front of the Zero the whole time.

P-47 wasn't like this with a direct line of fire from the zero.

141383436_NotThis.thumb.PNG.af37778295e3294f9d4930f1abc82934.PNG

 

It was more similar to this or this: (Thats not a gun solution, the P-47 was safe at that point. Keywords are 600ft above and far ahead) The Zero would of had to pull up to fire and would have lost even more energy which would allow the P-47 to gain even more of an advantage. Not of this actually matters but I notice people seems to ignore the Above vs Ahead part.

977395379_ThisOR.thumb.PNG.09f5ab6886d6b7906f52ec3c718231dc.PNGThis.thumb.PNG.2b04b7daa1d320a08e1c1897df0924b8.PNG

 

7 hours ago, Talon_ said:

I think the P-47's high speed control lockup is too high - it handles like a lawn dart compared to every other plane in the sim - even the 109 at very high speeds doesn't suffer with such a stiff elevator. If that were improved it would become a lot more usable.

I think its a bit too stiff as well but I'm not 100% sure. If anything this report would tell us but I'm not sure how to interpret it or even apply it in-game for test.

 

Measurements of flying qualities of P-47D airplane to determine longitudinal stability and control and stalling characteristics.

http://www.wwiiaircraftperformance.org/p-47/Naca_TN_2899__F-47D-30_Flight_Test.pdf

 

7 hours ago, Talon_ said:

 

I think what's most noticeable is just how much better the P-51 is compared to the P-47 up high. At 10km the P-51 flies like others do at 7km, but the P-47 which arguably has a greater high altitude power reserve even after MAP falloff over critical alt, flies like an absolute bucket up there.

Part of this is because the P-47 doesn't get it's historical power up high, it's only making 52-53" when it should be making 56" at 29,000ft, this would give it around 435-443 mph at 29,000ft. The power available at higher altitudes is incorrect in-game.

 

7 hours ago, ICDP said:

 

Maybe the P47D is correct and the 109 needs fixed?  Here is the relevant section on dive recovery in the P47D manual.

179855958_P47DDive.PNG.86dd7d50428a197d7e5a262e846d588e.PNG

The problem is the P-47 elevator seems to stiffen up too early to the point of not pulling full deflection. This makes it impossible to blackout the pilot at higher speeds unless you use trim. Clearly the elevators get stiff but my question is are they getting stiff too soon and should we be able to pull full deflection at higher speeds.

 

7 hours ago, ICDP said:

GIven the evidence I would conclude the P51D was a better boom and zoomer than a P-47 given it had better high speed controls and had less drag so it could hold its energy better. 

Yet the trials between the A6M5 seems to indicate the P-47 to be on par if not slightly better than the P-51. at least in zoom. Certainly the P-51 wasn't superior by any large margin if at all.

While these test are helpful for getting an idea imo they are too vague sometimes, we don't know all of the conditions.

image.png

image.png

 

 

And just so people can see them again and maybe make more sense out of them than I can, here are just a few reports, There is more but I don't have them right now.

 

Flight investigation of boundary layer and profile drag characteristics of smooth wing sections of P-47 airplane.

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930093001.pdf

 

Flight investigation at high speeds of profile drag of wing of a P-47D airplane having production surfaces covered with camouflage paint.

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930092751.pdf

 

Measurements of flying qualities of P-47D airplane to determine lateral and directional stability and control characteristics.

http://www.wwiiaircraftperformance.org/p-47/Naca_TN_2675__F-47D-30_Flight_Test.pdf

 

 

Measurements of flying qualities of P-47D airplane to determine longitudinal stability and control and stalling characteristics.

http://www.wwiiaircraftperformance.org/p-47/Naca_TN_2899__F-47D-30_Flight_Test.pdf

 

NASA Website so you can look up any other report you want.

https://ntrs.nasa.gov/search.jsp?Nm=17|Collection|NACA||4294059423|Publication Year|1945&N=0&No=30

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55 minutes ago, Tomsk said:

I think this is the key: there basically is no data about the areas of high-speed elevator effectiveness or energy bleed. Everything anyone posts is at best a guess: you could be right and everything could in fact match the real world situation perfectly .. or I could be right and it could be there is a bug in the FM. I am perfectly happy to accept the posibility that I could be wrong, and that to some extent I am guessing ... but then so is everyone else. That is all I really meant.

 

Ok, so if everything here is a guess, whose guess should the developers follow? Yours, mine, some random guy's who's never heard of P-47s? If the guesses are random then they might as well do a coin toss implementation of the FMs - forget manuals, tests (which have been posted and which can be extrapolated to determine high speed performance, btw; I'm sorry, but there are different levels of "guessing" - some "guesses" are better than others) etc.

 

This discussion has actually turned into: if any aircraft is wrong in relation to the P-47, then it must be the P-47 which is wrong - this is even more interesting since the 110 has just been adjusted in the last major update... could it be the 110 which is wrong in relation to the P-47? Look at what the "Duck" can do in a dogfight, pretty impressive for a twin engine, under powered, ground attack airplane, don't you think?

 

I agree, if there is a bug, then it must be fixed, but then the thread should not be called "P-47: bad at BnZ?", but rather "aircraft FMs: are there bugs in them?" - since the initial goal post was that the P-47 was bad when compared to the P-51, FW-190. Now we're at: the P-47 is bad when compared to 110, Spit, P-38.

 

Since we are all guessing here and everything is random, I don't see a problem in posting a power vs drag graph which shows where the P-47 stands. I mean your guess is as good as the guy's who wrote the article.

Edited by Raven109
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2 hours ago, Raven109 said:

 

This discussion has actually turned into: if any aircraft is wrong in relation to the P-47, then it must be the P-47 which is wrong - this is even more interesting since the 110 has just been adjusted in the last major update... could it be the 110 which is wrong in relation to the P-47? Look at what the "Duck" can do in a dogfight, pretty impressive for a twin engine, under powered, ground attack airplane, don't you think?

 

 

 

I'd like to point out, as an avid duckling pilot in game, that the reason this aircraft often does very well in dogfights is because it has excellent survivability and also extremely good and stable handling at low speeds. When fighters get come in slow and get low and slower with me at sometimes less than 220kph, I almost always win. When they are smart and only boom and zoom with plenty of speed to start, all I can do is run for home.

 

Also, it has a big iron under its chin in addition to dual MG151; so when you do get thumped by it, it's often a one and done type of deal 

Edited by II./SG.1-MarkWilhelmsson
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1 hour ago, ACG_KoN said:

DCS - P47 is out could use this as a test bed . 

 

Doesn't have water injection implemented so it can't do full power. I'd also take its FM with a grain of salt in general because I've seen vids of people doing effortless Lomcevaks in it in that sim and... that doesn't seem right

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1 hour ago, II./SG.1-MarkWilhelmsson said:

.

 

What authority can say that the DCS P47 is perfect?

 

I'm gonna go ahead and side with the REAL P47 pilot who OWNED one. He called the FM perfect and only complained about the DM.

 

 

 

DCS worked with real P-47 pilots as well, so who do we believe? I'm not saying one is better than the other but just because one pilot says it's good really doesnt mean anything. Same could be said for DCS.

Edited by Legioneod
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