P-47: bad at boom and zoom?

[Legioneod]

5 minutes ago, ICDP said:

 

 

So these tests contradict the assumption that a P-47D should leave all 109s and 190s in the dust as soon as or not long after pointing the nose at the ground.

No one is arguing that it should, what we're arguing is that the P-47 losses its energy too quickly in level flight or in a zoom climb. The mass of the P-47 alone would greatly help it hold it's energy once it got it, not to mention that it has 2600-2800 HP to help.

[Tomsk]

6 minutes ago, Raven109 said:

Here you are assuming that the drag is the same for both balls

 

I have actually already explained this. I'm just explaining the physics of why heavier objects, in general, dive and zoom better than light ones. I'm not claiming the P-47 has the same drag as a 109, it clearly doesn't.

[Bremspropeller]

What people seem to fail grasping is that weight is just a force-vector, pointed at Earth's center.

When you start moving the airplane around, that vector might work for or against you.

 

You'll have to add a lot more lift (and that includes induced drag) to convince a diving Jug to recover, or to even go uphill.

[ICDP]

10 minutes ago, Legioneod said:

No one is arguing that it should, what we're arguing is that the P-47 losses its energy too quickly in level flight or in a zoom climb. The mass of the P-47 alone would greatly help it hold it's energy once it got it, not to mention that it has 2600-2800 HP to help.

 

Apologies, I did not mean to introduce a strawman and will edit my post to be less general.  I should have said that any advantage the P-4D would have in maintaining energy was slight and could be easily lost.  So the OP losing any advantage after 1 or 2 passes does not seem that wrong in my opinion, if we take these tactical tests as accurate (which I do).

Edited June 8, 2020 by ICDP

[=621=Samikatz]

23 minutes ago, ICDP said:

Please have a read of the following tactical trials of a P-47D compared to Fw190 and of USAAF fighters compared to an A6M5.

 

http://www.wwiiaircraftperformance.org/japan/zeke52-taic38.pdf

 

I know these figures all say they're estimated, so we can't take them as gospel, but...

 

 

Assuming the test was done to the same standards for both aircraft (I would hope they did that! Surely?) then there isn't a huge difference between the P-47 and P-51 when it comes to climbing after a dive. The test also says that the P-51 is a better accelerator, so it probably climbs better too, so I imagine a lot of the P-47's advantage does come from its energy retention.

[Raven109]

28 minutes ago, Tomsk said:

 

I have actually already explained this. I'm just explaining the physics of why heavier objects, in general, dive and zoom better than light ones. I'm not claiming the P-47 has the same drag as a 109, it clearly doesn't.

 

Ok, but so as weight helps with acceleration, it doesn't help while climbing since that weight is pulling back on the aircraft. (I think this is what the poster you answered to was hinting at)

 

Also, please consider maneuvering, a heavier object needs a bigger force to change course than a lighter object needs (due to its bigger inertia). The force which is used to change course of an aircraft is lift. Bigger lift means bigger drag. Bigger drag means more speed loss while maneuvering. Also, a change in AoA for an air frame which is already draggy at SL in horizontal flight will mean even more drag when turning, when compared to a lighter, less draggy air frame. 

Edited June 8, 2020 by Raven109

[ICDP]

Just now, =621=Samikatz said:

 

I know these figures all say they're estimated, so we can't take them as gospel, but...

 

 

Assuming the test was done to the same standards for both aircraft (I would hope they did that! Surely?) then there isn't a huge difference between the P-47 and P-51 when it comes to climbing after a dive. The test also says that the P-51 is a better accelerator, so it probably climbs better too, so I imagine a lot of the P-47's advantage does come from its energy retention.

 

I think the point is people need to remember that any performance advantage in contemporary WWII fighters was marginal.  So a P-47D could retain energy better if it had it to spare in the first place, but it would be very easily and quickly lost.  So it's a fine line between having an advantage, squandering it within seconds and then being inside the other fighters sweet spot.  If you were at 350 TAS in a P47 you have a big advantage a against an A6M5 but a few marginally aggressive manoeuvrers will soon have you at 250 TAS and the A6M5 is going to eat you for breakfast.

[ICDP]

1 hour ago, Raven109 said:

The weight of the P-47 should matter more higher up, where the air density is reduced, and even more considering that it can hold it's output power much better at higher altitudes than the opposition. But at SL, it can only hold the same speed as a less powerful aircraft.

 

Something must be holding it back, don't you agree?

 

I don't think the low level performance of the P-47D in BoX is actually wrong.  Every flight test I have seen shows the P-47D getting ~340-345mph at SL, even at higher boost.

 

 

http://www.wwiiaircraftperformance.org/p-47/p-47.html

 

So marginally slower than a contemporary Fw190A8.

http://www.wwiiaircraftperformance.org/fw190/fw190a8.html

Edited June 8, 2020 by ICDP

[Raven109]

5 minutes ago, ICDP said:

 

I don't think the low level performance of the P-47D in BoX is actually wrong.  Every flight test I have seen shows the P-47D getting ~340-345mph at SL.

 

 

http://www.wwiiaircraftperformance.org/p-47/p-47.html

 

Yes, I agree. I don't think it's wrong either.

 

The point I was trying to make is that the drag of a P-47 is much higher than that of the 109G-14. I tried to do this by comparing max speeds at sea level. The speeds are somewhat similar, but the power of the P-47 is much bigger than that of the 109. Which leads me to think that the drag of the P-47 is bigger than that of the 109, so much so that even a difference of ~1000HP cannot help the 47 overtake the 109. As such, drag becomes an important factor when comparing accelerations while diving, climbing and maneuvering, and most likely offsets the weight advantage in a dive.

Edited June 8, 2020 by Raven109

[Tomsk]

1 hour ago, Raven109 said:

Ok, but so as weight helps with acceleration, it doesn't help while climbing since that weight is pulling back on the aircraft. (I think this is what the poster you answered to was hinting at)

 

So there are two main forces we are interested in that are acting on the plane: gravity and air resistance. As explained the acceleration caused by gravity does not depend on the mass (the mass "cancels out" of the equation), a heavy mass accelerates due to gravity the same as a light one (at roughly 9.8 m/s^2). The force of air resistance, however, only depends on shape not on mass: so the force of air resistance is the same for both the light and the heavy object of the same shape, but for the heavy object it causes less acceleration because F = ma (and hence a = F/m, same force, higher mass, less acceleration).

 

So when the plane is diving gravity is accelerating the plane and air resistance is decelerating it. The heavy plane and the light plane have the same acceleration due to gravity, but the heavier plane has less deceleration due to air resistance so it accelerates faster and so dives quicker.

 

Now the planes take their speed from the dive and zoom upwards. Now both gravity and air resistance are both decelerating the plane, eventually the planes will have no speed left and will reach the top of their zoom. Gravity is the same for the heavy plane and the light plane, so it produces the same deceleration for each. Air resistance produces less deceleration for the heavier plane, and so it loses speed more slowly than the light plane and will zoom higher.

 

Quote

Also, please consider maneuvering, a heavier object needs a bigger force to change course than a lighter object needs (due to its bigger inertia). The force which is used to change course of an aircraft is lift. Bigger lift means bigger drag. Bigger drag means more speed loss while maneuvering. Also, a change in AoA for an air frame which is already draggy at SL in horizontal flight will mean even more drag when turning, when compared to a lighter, less draggy air frame. 

 

So this is complicated. It is true that maneuvering a heavier object requires more force .. but it also has more energy with which to do it (KE = 1/2 * mass * v^2). This is why, in general, heavier planes (like the F-15) are no less maneuverable that lighter ones (like the F-16).

 

 

Edited June 8, 2020 by Tomsk

[Atomic_Spaniel]

If we summarise -

 

The real-world accounts and data describe an aircraft that has a poor climb rate compared to other aircraft except at high altitude, that needs elevator trim to pull out of a dive because the controls are getting heavy, that bleeds energy on pulling g noticeably more than other WWII warbirds and has a marginal advantage in diving c.f. light-weight aircraft like the Zeke. I have absolutely no problem in accepting this is how the aircraft behaved in real life.

 

However, it also goes like absolute stink at 20,000'+ and is thus an excellent weapon if your task is to break up and drive down formations of LW fighters that are trying to assemble in groups prior to attacking formations of B-17s and B-24s.  

Edited June 8, 2020 by Atomic_Spaniel

[ICDP]

Just now, Atomic_Spaniel said:

If we summarise -

 

The real-world accounts and data describe an aircraft that has a poor climb rate compared to other aircraft except at high altitude, that needs elevator trim to pull out of a dive because the controls are getting heavy, that bleeds energy on pulling g noticeably more than other WWII warbirds and has a marginal advantage in diving c.f. light-weight aircraft like the Zeke. I have absolutely no problem in accepting this is how the aircraft behaved in real life.

 

However, it also goes like absolute stink at 20,000'+ and is thus an excellent weapon if your task is to break up and drive down formations of LW fighters that are trying to assemble in groups prior to attacking formations of B-17s and B-24s.  

 

Pretty much sums it up really.

[Tomsk]

32 minutes ago, Atomic_Spaniel said:

If we summarise -

 

The real-world accounts and data describe an aircraft that has a poor climb rate compared to other aircraft except at high altitude, that needs elevator trim to pull out of a dive because the controls are getting heavy, that bleeds energy on pulling g noticeably more than other WWII warbirds and has a marginal advantage in diving c.f. light-weight aircraft like the Zeke. I have absolutely no problem in accepting this is how the aircraft behaved in real life.

 

No disagreement on the climb rate: the plane couldn't climb well at all. However, every source I've read suggests the high speed performance of the aircraft was considered absolutely top-notch at all altitudes.

 

I can't find the exact quote but there was an account made by Robert Johnson (a P-47 ace) of a mock dogfight with a Spitfire Mk IX, RAMJB describes it nicely here. The 4th fighter group had been training on Spitfires but were then forced to move to the P-47: they didn't like it, it couldn't climb, it wasn't a great turner at slow speeds like the Spitfire and so on. Eventually many of them asked to be moved back to the Spitfire. So Robert Johnson did a mock dogfight against a Spitfire expert: he used the high speed handling of the P-47 to beat the Spitfire each and every time, forcing the fight into a high-speed regime where the P-47 shined and the Spitfire could not compete. They repeated the test several times and each time came up with the same result: at high speeds the P-47 totally dominated. The 4th fighter group apparently never complained about the P-47 after that, having seen the strength of the plane.

 

And this is how it is modelled in other sims I have flown: it can't climb, it's not the best at low speed turning, but it can dive, it handles well at high speeds and it is a very capable BnZ plane. Now maybe IL2:GB is right and all the others are wrong and the P-47 was just a bad plane ... but honestly my money is on the IL2:GB FM being wrong for the P-47, especially with it being such a new plane. As such I'm expecting it'll get corrected eventually in some later update, as most FM issues do.

Edited June 8, 2020 by Tomsk

[Raven109]

1 hour ago, ICDP said:

 

I don't think the low level performance of the P-47D in BoX is actually wrong.  Every flight test I have seen shows the P-47D getting ~340-345mph at SL, even at higher boost.

 

Offtopic, but since you mentioned things that I might find wrong about the P-47:

 

One thing I did find awkward about the in-game P-47 was something that I could only do once.

 

I took it for a vertical dive, got it to somewhere around 500mph+ at around 10000ft, throttle set to 0. Managed to pull it out at around 1500ft, and started doing a lazy barrel roll, while still at high speed. Then I suddenly applied maximum throttle. The plane entered a violent horizontal spin. When I applied maximum throttle I noticed that the RPM went way over the red line, something like the 12 o'clock position on the gauge. 

 

I've never seen such sudden reaction to torque in any of the GB planes, especially at high speeds. The only way I could see it happening is if I had lost the rudder during the dive, but as I was doing the lazy barrel roll nothing seemed to be missing.

Edited June 8, 2020 by Raven109

[Legioneod]

1 hour ago, ICDP said:

 

I don't think the low level performance of the P-47D in BoX is actually wrong.  Every flight test I have seen shows the P-47D getting ~340-345mph at SL, even at higher boost.

 

 

http://www.wwiiaircraftperformance.org/p-47/p-47.html

 

So marginally slower than a contemporary Fw190A8.

http://www.wwiiaircraftperformance.org/fw190/fw190a8.html

Yep it's not far off when it comes to top speed (at lower alt) still havent tested all the various power settings though. One thing to keep in mind is that not all of those test were conducted in the same way, they had various weights/configurations and this is one of the reasons for the similar speeds at low altitude.

The speed for 65" and 70" was at 13,200 lbs with wing racks. In a lighter and clean setup it would be faster.

 

Also, (in response to another post) the climb of the P-47 wasn't poor, it was average and in some cases superior depending on the altitude.

P-47 can outclimb the P-51, 109, 190, etc depending on the situation.

 

Top Speed/Climb for P-47 13,200lbs 70" MAP.

 

One thing that is incorrect about the P-47 is it's power at higher altitude, the critical altitude for 64" is pretty close (around 24,000ft)  but after that the power drops off too rapidly. At 29,000ft we should be able to achieve 56" with a top speed of around 435-443mph when using WEP but in game we can only achieve 52-53"WEP and we only get around 418 mph iirc.

Edited June 8, 2020 by Legioneod

[Lusekofte]

I think the P 47 in this game lack:

•Well trained pilots and squadrons

•The historical fact of Luftwaffes situation late war in terms of few expirienced pilots, bad fuel, not enough serviceable airfields and planes and logistical problems

[ICDP]

46 minutes ago, Tomsk said:

 

No disagreement on the climb rate: the plane couldn't climb well at all. However, every source I've read suggests the high speed performance of the aircraft was considered absolutely top-notch at all altitudes.

 

I can't find the exact quote but there was an account made by Robert Johnson (a P-47 ace) of a mock dogfight with a Spitfire Mk IX. The 4th fighter group had been training on Spitfires but were then forced to move to the P-47: they didn't like it, it couldn't climb, it wasn't a great turner at slow speeds like the Spitfire and so on. Eventually many of them asked to be moved back to the Spitfire. So Robert Johnson did a mock dogfight against a Spitfire expert: he used the high speed handling of the P-47 to beat the Spitfire each and every time, forcing the fight into a high-speed regime where the P-47 shined and the Spitfire could not compete. They repeated the test several times and each time came up with the same result: at high speeds the P-47 totally dominated. The 4th fighter group apparently never complained about the P-47 after that, having seen the strength of the plane. RAMJB describes it nicely here.

 

And this is how it is modelled in other sims I have flown: it can't climb, it's not the best at low speed turning, but it can dive, it handles well at high speeds and it is a very capable BnZ plane. Now maybe IL2:GB is right and all the others are wrong and the P-47 was just a bad plane ... but honestly my money is on the IL2:GB FM being wrong, especially with it being such a new plane.

 

I found this on another forum.  I can't find any reference to the story you posted but there was a scenario Johnson described in a mock combat against a Spitfire he encountered by chance.

 

"The following episode, found in Thunderbolt! by the World War II USAAF ace Robert S. Johnson, is one of the best examples available of the use of energy tactics (diving extension/pitch-back) to defeat a double-superior opponent. The encounter described is a mock combat engagement over England between Johnson (P-47C) and an unidentified RAF pilot in a new Spitfire IX. the Spitfire had about a 25 percent better power loading and nearly a 25 percent lower wing loading. The Thunderbolt's only performance advantages were faster top speed, greater acceleration in a dive (because of the P-47's heavier weight and higher density), and better roll performance.

I opened the throttle full and the Thunderbolt forged ahead. A moment later exhaust smoke poured from the Spit as the pilot came after me. He couldn't make it; the big Jug had a definite speed advantage. I grinned happily; I'd heard so much about this airplane that I really wanted to show the Thunderbolt to her pilot. The Jug kept pulling away from the Spitfire; suddenly I hauled back on the stick and lifted the nose. The Thunderbolt zoomed upward, soaring into the cloud-flecked sky. I looked out and back; the Spit was straining to match me, and barely able to hold his position.

But my advantage was only the zoom--once in steady climb, he had me. I gaped as smoke poured from the exhausts and the Spitfire shot past me as if I were standing still. Could that plane CLIMB! He tore upward in a climb I couldn't match with the Jug. Now it was his turn; the broad elliptical wings rolled, swung around, and the Spit screamed in, hell-bent on chewing me up.

This was going to be fun. I knew he could turn inside the heavy Thunderbolt; if I attempted to hold a tight turn, the Spitfire would slip right inside me. I knew also, that he could easily outclimb my fighter. I stayed out of those sucker traps. First rule in this kind of fight: don't fight the way your opponent fights best. No sharp turns; don't climb; keep him at your own level.

We were at 5,000 feet, the Spitfire skidding around hard and coming in on my tail. No use turning; he'd whip right inside me as if I were a truck loaded with cement, and snap out in firing position. Well, I had a few tricks too. The P-47 was faster, and I threw the ship into a roll. Right here I had him. The Jug could outroll any plane in the air, bar none. With my speed, roll was my only advantage, and I made full use of the manner in which the Thunderbolt could roll. I kicked the Jug into a wicked left roll, horizon spinning crazily, once, twice, into a third. As he turned to the left to follow, I tramped down on the right rudder, banged the stick over to the right. Around and around we went, left, right, left, right. I could whip through better than two rolls before the Spitfire even completed his first. And this killed his ability to turn inside me. I refused to turn. Every time he tried to follow me in a roll, I flashed away to the opposite side, opening the gap between our planes.

Then I played the trump. The Spitfire was clawing wildly through the air, trying to follow me in a roll, when I dropped the nose. The Thunderbolt howled and ran for earth. Barely had the Spitfire started to follow--and I was a long way ahead of him by now--when I jerked back on the stick and threw the Jug into a zoom climb. In a straight or climbing turn, the British ship had the advantage. But coming out of a dive, there's not a British or German fighter than can come close to a Thunderbolt rushing upward in a zoom. Before the Spit pilot knew what had happened, I was high above him, and the Thunderbolt hammering around. And that was it--in the next few moments the Spitfire flier was amazed to see a less-maneuverable slower-climbing Thunderbolt rushing straight at him, eight guns pointing at his cockpit." (Fighter Combat, Robert Shaw)

 

Now reading this Johnson makes at least one claim that is simply not remotely true and easily proved to be wrong (see attached roll chart).  The Jug cannot out-roll any plane "bar none", the Fw190 was better in a roll and isn't remotely disputable.  Johnson also forgets the part of the "dogfight" where the Spitfire had him in a guns solution long before Johnson "finished" the fight.  Apologies but this account proves nothing other than in that particular 1 on 1 Johnson knew the advantages and disadvantages of his and his opponents plane and concluded he "won".  The other pilot probably thought he (or even she if it was a ferry flight) had also "won" considering how they climbed past the Jug like it was standing still.

 

 

Edited June 8, 2020 by ICDP

[Tomsk]

33 minutes ago, ICDP said:

Now reading this Johnson makes a lot of claims that are simply not remotely true.  The cannot out-roll any plane "bar none", the Fw190 was better in a roll and isn't remotely disputable.  Johnson also forgets the part of the "dogfight" where the Spitfire had him in a guns solution long before Johnson "finished" the fight.  Apologies but this account proves nothing other than in that particular 1 on 1 Johnson knew the advantages and disadvantages of his and his opponents plane and concluded he "won".  THe other pilot probalby thought he had also "won" considering how he zoomed past the Jug like it was standing still.

 

Thanks that's very interesting. I guess it's hard to know what really happened in the past but to my reading of this Johnson is talking about a rolling scissors rather than a simple aileron roll:

 

Quote

As he turned to the left to follow, I tramped down on the right rudder, banged the stick over to the right. Around and around we went, left, right, left, right. I could whip through better than two rolls before the Spitfire even completed his first

 

This sounds like a rolling scissors defence: high-speed rolling scissors involves ailerons, elevators and rudders and is more about overall high-speed maneuverability than straight degrees per second of roll. It's a tactic I've used defensively a lot in the FW-190, P-51 and P-47 which all excel at high-speed rolling scissors. I guess we cannot know who "won" the encounter for certain, but it certainly seems from reading it is that Johnson's view (as one of the US's leading aces of WWII) was that the P-47 had distinct advantages in dive, zoom climb and high-speed maneuverability.

 

Ultimately, as I say it's about weight of evidence. The P-47 was known for being a good BnZ aircraft, in IL2:GB it's not. The P-47 was known for having strong high-speed maneuverability, in IL2:GB it doesn't. In every other sim the P-47 doesn't have these problems (including some with very advanced flight models) but in IL2:GB it does. Now maybe that's because IL2:GB is right and all of those other sources are wrong .. but the more likely explanation to my mind is that the FM has a bug in it. Many people seem to have the same observation of the P-47 in IL2:GB: the FM is not quite right yet. This wouldn't be so surprising after all: we've had plenty of FM corrections over the years.

Edited June 8, 2020 by Tomsk

[kalbuth]

On 6/6/2020 at 3:05 AM, -=PHX=-SuperEtendard said:

I made some zoom tests with different airplanes, basically starting from 3500 meters, diving down to the deck leveling out then waiting until the speed decreased to 710 km/h and then zoom up for a 90º climb trying to say around 3G while pitching up.  I took note of the altitude reached when down to 300 km/h, and finally the max altitude reached as the plane stalled downwards. I took the 300 km/h value as the planes with very good power to weight ratios can prop hang for some time at the edge of the stall gaining some extra alt so it wouldn't be that representative to just take max altitude achieved only.

My conclusion is that basically good aerodynamics and power to weight ratio are key for good zoom abilities in game, the best zoomer is the Bf 109 K-4 specially with DC engine, followed closely by the P-51 with 150 octane fuel. The worse that I tested was the Yak-1 s69.  The P-47 in this regard doesn't have good aerodynamics (a big plane so it has lots of drag compared to the smaller fighters) and the power to weight ratio isn't good at low altitudes compared to the rest, so it's sits in the mid-lowmid part of the stack.   P-47 fuel level was at 50% and P-51 fuel level was at 70%, the rest of the fighters had 100% fuel.

You can see how the aerodynamics and power to weight ratio affects the planes when comparing similar variants like the G-6 vs G-14, or A-5 vs A-8 vs A-8 1.58 ata.

Yak-1 s69                  altitude at 300 kmh:       1351 m       max altitude:       1910 m

Spitfire IX                  altitude at 300 kmh:       1400 m       max altitude:       2040 m

Spitfire IX 150 oct   altitude at 300 kmh:       1438 m       max altitude:        2110 m

P-47D-28                   altitude at 300 kmh:       1431 m       max altitude:       2070 m

Bf 109 F-4                 altitude at 300 kmh:       1484 m       max altitude:       2137 m
Bf 109 G-6:               altitude at 300 kmh:       1364 m       max altitude:       2001 m
Bf 109 G-14:             altitude at 300 kmh:       1482 m       max altitude:       2116 m
Bf 109 K-4                altitude at 300 kmh:        1577 m       max altitude:       2221 m
Bf 109 K-4 DC          altitude at 300 kmh:        1630 m       max altitude:       2245 m

Fw 190 A-5                altitude at 300 kmh:       1476 m       max altitude:       2055 m
Fw 190 A-8 1.42       altitude at 300 kmh:       1438 m       max altitude:      2035 m
Fw 190 A-8 1.58       altitude at 300 kmh:       1464 m       max altitude:       2027 m

P-51D-15                   altitude at 300 kmh:       1502m       max altitude:       2115 m
P-51D-15 150oct      altitude at 300kmh:        1550m       max altitude:       2172 m


The P-47 sits closer to the Fw 190s, better than the Yak, the 109 G-6 and normal Spit IX.    The more aerodynamic/high power to weight ratio 109s (F-4, G-14, K-4) and P-51 are better.

I did 2 additionnal planes following your specs, D9 & Tempest :

Fw 190 D-9 , combat settings, no MW50 :      altitude at 300 kmh:    1550 m   max altitude : 1960 m (test error?)

Fw 190 D-9 , combat settings, with MW50 :   altitude at 300 kmh:    1610 m   max altitude : 2070 m

Tempest, emergency power :                            altitude at 300 kmh:    1606 m   max altitude : 2010 m

Tempest, emergency power, Sabre  IIA :         altitude at 300 kmh:    1635 m  max altitude : 2055 m

 

There's something fishy in my discrepancy for max alt with your tests, I probably did something a bit different, I didn't double check with a plane in your set to see if we were aligned, yet.

I didn't start from 0 ASL, obviously, tests would have ended prematurely ? I substracted the altitude at the start of the pull from the altitude at 300 and max.

I think there's a definite group of energy retention kings, the "above 1500m" group here, of which the Jug is absent (no clue if that's true to life).

That said this is testing with 90° zoom climb, kinda not a general thing done in B&Z

Edited June 8, 2020 by kalbuth

[Raven109]

52 minutes ago, ICDP said:

Now reading this Johnson makes at least one claim that is simply not remotely true and easily proved to be wrong (see attached roll chart).  The Jug cannot out-roll any plane "bar none", the Fw190 was better in a roll and isn't remotely disputable.  Johnson also forgets the part of the "dogfight" where the Spitfire had him in a guns solution long before Johnson "finished" the fight.  Apologies but this account proves nothing other than in that particular 1 on 1 Johnson knew the advantages and disadvantages of his and his opponents plane and concluded he "won".  The other pilot probably thought he (or even she if it was a ferry flight) had also "won" considering how they climbed past the Jug like it was standing still.

 

 

 

According to the graph, the 47 does out-roll the Spit (normal wing) at speeds above 285mph, but I agree that "bar none" is an overstatement. Perhaps he never met an enemy aircraft that was doing max rate rolls, either because the pilot was not applying enough force or other reasons. Without context, it's hard to say what he means by "bar none"

 

This is why I don't like pilot accounts, they either don't contain enough technical information or don't tell the whole story:

 

"I opened the throttle full and the Thunderbolt forged ahead. A moment later exhaust smoke poured from the Spit as the pilot came after me. He couldn't make it; the big Jug had a definite speed advantage."

 

What's stopping the Spit pilot from just shooting the 47 down while it was "forging ahead"? You don't need to keep up with an aircraft that's close to you to shoot him down.

 

"With my speed, roll was my only advantage, and I made full use of the manner in which the Thunderbolt could roll. I kicked the Jug into a wicked left roll, horizon spinning crazily, once, twice, into a third. As he turned to the left to follow, I tramped down on the right rudder, banged the stick over to the right. Around and around we went, left, right, left, right. I could whip through better than two rolls before the Spitfire even completed his first. And this killed his ability to turn inside me. I refused to turn. Every time he tried to follow me in a roll, I flashed away to the opposite side, opening the gap between our planes."

 

Let's assume that the Spit could not keep up with the rolls that the 47 was doing. What's stopping the Spitfire pilot to just disengage and do a max rate climb above the P-47? It will climb faster than the P-47, and will have an energy advantage once the 47 is done rolling around. Of course, this only works if the P-47 chooses to recommit to a fight where now the Spit has an energy advantage. He could simply run away, but that was not the point of the demo.

 

"Barely had the Spitfire started to follow--and I was a long way ahead of him by now--when I jerked back on the stick and threw the Jug into a zoom climb."

 

So, If I read this correctly, if the Spit doesn't have the nose pointed at him the P-47 can get away. Does this say anything about relative aircraft performance? I think it says more that if you compare two aircraft which are at different states in their flight envelope you will get different results. It's like you'd be flying in your F-16 past a landed F-15 and you'd say "look at me get away, my F-16 is so much faster".

 

Oh, and last but not least: where is the side of the story from the Spitfire PoV? It's easy for the P-47 pilot to say this and that about what the Spit did and didn't, but I'd rather also have the other pilot's account, you know, for the purpose of not having a one sided account.

 

BTW ICDP, my questions are aimed at people who take pilot accounts at face value, not at you. 

Edited June 8, 2020 by Raven109

[ICDP]

47 minutes ago, Tomsk said:

 

Thanks that's very interesting. I guess it's hard to know what really happened in the past but to my reading of this Johnson is talking about a rolling scissors rather than a simple aileron roll:

 

 

This sounds like a rolling scissors defence: high-speed rolling scissors involves ailerons, elevators and rudders and is more about overall high-speed maneuverability than straight degrees per second of roll. It's a tactic I've used defensively a lot in the FW-190, P-51 and P-47 which all excel at high-speed rolling scissors. I guess we cannot know who "won" the encounter for certain, but it certainly seems from reading it is that Johnson's view (as one of the US's leading aces of WWII) was that the P-47 had distinct advantages in dive, zoom climb and high-speed maneuverability.

 

Ultimately, as I say it's about weight of evidence. The P-47 was known for being a good BnZ aircraft, in IL2:GB it's not. The P-47 was known for having strong high-speed maneuverability, in IL2:GB it doesn't. In every other sim the P-47 doesn't have these problems (including some with very advanced flight models) but in IL2:GB it does. Now maybe that's because IL2:GB is right and all of those other sources are wrong .. but the more likely explanation to my mind is that the FM has a bug in it. Many people seem to have the same observation of the P-47 in IL2:GB: the FM is not quite right yet. This wouldn't be so surprising after all: we've had plenty of FM corrections over the years.

 

Herein lies the problem, form the tactical tests and my own experience in sim, I find the P47D pretty much matched what the tactical trials find.  So you are saying it's wrong but have given nothing to prove this to be an accurate assessment.  91 meters ahead of a Zero after 30 seconds in a dive is NOT "leaving it standing" and the Zero is pretty much regarded as a horrible diver.

 

Dive Acceleration

From 10,000 feet.  The P-47D was approximately 100 yards (91 metres) ahead after 30 seconds.

From 25,000 feet.  The P-47D was approximately 300 yards (272 metres) ahead after 30 seconds.

 

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.

Edited June 8, 2020 by ICDP

[312_Lazy]

Looking at basic parameters I see that P47 has wing loading very similar to Fw 190 A. Yes, P-47 is very heavy but it's density seems to be quite similar to that of its adversary. So I cannot see a reason why its weight alone should give it any special qualities.

 

Moreover, all aircraft designers try hard to make their planes as light as possible (after providing enough durability, engine power, equipment etc.). Weight is always bad. It's very easy to increase weight but very difficult to decrease it (without sacrificing other qualities). I believe weight advantage in combat is just a myth.

[Raven109]

59 minutes ago, Tomsk said:

Ultimately, as I say it's about weight of evidence. The P-47 was known for being a good BnZ aircraft, in IL2:GB it's not. The P-47 was known for having strong high-speed maneuverability, in IL2:GB it doesn't. In every other sim the P-47 doesn't have these problems (including some with very advanced flight models) but in IL2:GB it does. Now maybe that's because IL2:GB is right and all of those other sources are wrong .. but the more likely explanation to my mind is that the FM has a bug in it. Many people seem to have the same observation of the P-47 in IL2:GB: the FM is not quite right yet. This wouldn't be so surprising after all: we've had plenty of FM corrections over the years.

 

Well, we are at page 3 of this thread, and no hard evidence whatsoever was posted that supports the idea that the P-47 is not according to what it was IRL, when it comes to BnZ. On the contrary, as I see it, much more evidence was posted to support the opposite. I'm sure that if enough evidence is gathered to support the fact that the 47 should be different, the devs will change its FM. Pilot accounts are not evidence for a technical sim, because it's very hard to quantify them, if indeed they are objective.

 

There are several documents posted to support the idea the the behavior of the 47 is correct, but they are completely ignored for whatever reason. 

 

Just out of curiosity, is the other game DCS? The P-47 there is not final.

Edited June 8, 2020 by Raven109

[ICDP]

17 minutes ago, Raven109 said:

 

Well, we are at page 3 of this thread, and no hard evidence whatsoever was posted that supports the idea that the P-47 is not according to what it was IRL, when it comes to BnZ. On the contrary, as I see it, much more evidence was posted to support the opposite. I'm sure that if enough evidence is gathered to support the fact that the 47 should be different, the devs will change its FM. Pilot accounts are not evidence for a technical sim, because it's very hard to quantify them, if indeed they are objective.

 

There are several documents posted to support the idea the the behavior of the 47 is correct, but they are completely ignored for whatever reason. 

 

Just out of curiosity, is the other game DCS? The P-47 there is not final.

 

This mirrors my thoughts as well.  All we have (no offence intended) is some opinions based on anecdotes that the P-47 excelled at B"n"Z.  Yet any factual and objective documents show that while it did indeed have an B"n"Z advantage it was only marginal and only as both aircraft approached VNE.  the scenario the OP describes of loosing his energy advantage after 1 or two passes seems accurate.

Edited June 8, 2020 by ICDP

[Talon_]

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.

[Sublime]

You foolish fools!

Its OBVIOUSLY b17s and b24s that are flyable.

 

 

 

Cof cof (anyone notice.microprose is remaking the mighty 8th? And u can fly b24s in the upcoming version!!!)

[Tomsk]

People are really good at getting distracted ...

 

37 minutes ago, ICDP said:

Herein lies the problem, form the tactical tests and my own experience in sim, I find the P47D pretty much matched what the tactical trials find.  So you are saying it's wrong but have given nothing to prove this to be an accurate assessment. 

 

[snip stuff about dive and zoom]

 

27 minutes ago, Raven109 said:

Well, we are at page 3 of this thread, and no hard evidence whatsoever was posted that supports the idea that the P-47 is not according to what it was IRL, when it comes to BnZ. On the contrary, as I see it, much more evidence was posted to support the opposite. I'm sure that if enough evidence is gathered to support the fact that the 47 should be different, the devs will change its FM. Pilot accounts are not evidence for a technical sim, because it's very hard to quantify them, if indeed they are objective.

 

There are several documents posted to support the idea the the behavior of the 47 is correct, but they are completely ignored for whatever reason. 

 

I have never made any claims about the dive or zoom capabilities of the P-47. My claim is that the high-speed maneuvering is off, specifically energy retention in high speed maneuvering and overall high-speed handling.

 

No one has posted documents supporting that it is correct in IL2:GB as is, because there are none. High-speed maneuvering capability and energy retention are difficult to measure and are somewhat of a subjective quality: there really is no data. I cannot prove this is wrong for the P-47 in IL2:GB, but I can say with some certainty it is noticeably worse than other similar planes that specialized in the BnZ style, and that it is worse than the P-47 in other simulations.  

 

My reason for posting this in the first place was not to get into a flame war about evidence or lack thereof. Rather it is a qualitative assessment: to my eye the P-47 is performing really badly in this role at the moment, and I think this is surprising given the history of the plane. I was looking for feedback from other people who are experienced with flying in a boom-and-zoom style to see if they have the same assessment. Fortunately it's quite easy to tell who is posting on the basis of experience having flown this style extensively, and who is not.

Edited June 8, 2020 by Tomsk

[Talon_]

6 minutes ago, Tomsk said:

No one has posted documents supporting that it is correct because there are none. High-speed maneuvering capability and energy retention are difficult to measure and are somewhat of a subjective quality: there really is no data. I cannot prove this is wrong for the P-47 il IL2:GB, but I can say with some certainty it is noticeably worse than other similar planes that specialized in the BnZ style, and that it is worse than the P-47 in other simulations.  

 

 

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.

Edited June 8, 2020 by Talon_

[ICDP]

5 minutes 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.

 

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

[Tomsk]

11 minutes 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.

 

Thanks, that's interesting, I haven't really tried the P-47 up that high yet, will have to give it a go some time.

[ICDP]

47 minutes ago, Tomsk said:

People are really good at getting distracted ...

 

 

 

I have never made any claims about the dive or zoom capabilities of the P-47. My claim is that the high-speed maneuvering is off, specifically energy retention in high speed maneuvering and overall high-speed handling.

 

No one has posted documents supporting that it is correct in IL2:GB as is, because there are none. High-speed maneuvering capability and energy retention are difficult to measure and are somewhat of a subjective quality: there really is no data. I cannot prove this is wrong for the P-47 in IL2:GB, but I can say with some certainty it is noticeably worse than other similar planes that specialized in the BnZ style, and that it is worse than the P-47 in other simulations.  

 

My reason for posting this in the first place was not to get into a flame war about evidence or lack thereof. Rather it is a qualitative assessment: to my eye the P-47 is performing really badly in this role at the moment, and I think this is surprising given the history of the plane. I was looking for feedback from other people who are experienced with flying in a boom-and-zoom style to see if they have the same assessment. Fortunately it's quite easy to tell who is posting on the basis of experience having flown this style extensively, and who is not.

 

I'm sorry but the title you chose for this thread is "P-47 bad at boom and zoom".  I know you do elaborate that the P51D seems much better by comparison but that does not prove anything because the P51D was even more renowned for its high speed manoeuvrability and of course having substantially less drag.  There is ample objective evidence out there that does not rely on anecdotal evidence.  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.  So I don't see any problems with your finding the same in sim.

 

America's Hundred Thousand rankings by late war fighter type (as chosen by those who tested and flew them during controlled tests)

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

 

Edited June 8, 2020 by ICDP

[Talon_]

11 minutes ago, ICDP said:

Best ailerons at 350 MPH

1 P51D

2 F4U-1D

3 P-38L

4 F5F-5

5 P-47D

 

AFDU testing found the P-47C had a higher rate of roll than the Mustang X (Merlin 65) in dives.

 

 

Later testing in July 44

 

 

Edited June 8, 2020 by Talon_

[ICDP]

Just now, Talon_ said:

 

AFDU testing found the P-47C had a higher rate of roll than the Mustang X (Merlin 65) at high speed.

 

Please remember best ailerons are not the same as best roll.  This test was specifically about lightness, smoothness and ease of changing direction with the ailerons.

[Talon_]

3 minutes ago, ICDP said:

 

Please remember best ailerons are not the same as best roll.  This test was specifically about lightness, smoothness and ease of changing direction with the ailerons.

 

I don't think pilot anecdote should be given priority over test data.

[ICDP]

6 minutes ago, Talon_ said:

 

I don't think pilot anecdote should be given priority over test data.

 

The AHT tests weren't anecdotal.  They tested multiple pilots in each type with identical conditions and asked them to rank each fighter from best to worst in each carefully controlled category.

11 minutes ago, Talon_ said:

 

AFDU testing found the P-47C had a higher rate of roll than the Mustang X (Merlin 65) in dives.

 

 

Later testing in July 44

 

 

 

The max roll rate on the P51B is showing as higher in the table?  Maybe the quote was for lower speeds?  AHT states the P47D had better low speed ailerons than the P51D

Edited June 8, 2020 by ICDP

[Atomic_Spaniel]

34 minutes ago, Tomsk said:

My claim is that the high-speed maneuvering is off, specifically energy retention in high speed maneuvering and overall high-speed handling.

 

Sometimes I think my posts must be invisible

 

I have posted a link to an article by a pilot who flies a P-47 at speed in air displays. He specifically says that if you pull g it loses more energy compared to other warbirds. He actually quantifies this and states (IIRC) 2 g = 10 knots lost.  

 

[ICDP]

10 minutes ago, Atomic_Spaniel said:

 

Sometimes I think my posts must be invisible

 

I have posted a link to an article by a pilot who flies a P-47 at speed in air displays. He specifically says that if you pull g it loses more energy compared to other warbirds. He actually quantifies this and states (IIRC) 2 g = 10 knots lost.  

 

 

I could have swore someone typed something there. ?

[SAS_Storebror]

10 knots would be nothing to argue about.

We've had an online session yesterday and since I decided that it's time to die, 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.

 

I'm not a real life Jug pilot, as most of us, and I'm not here for splitting hairs.

All I want to get across is that the Jug, much different to any other IL-2 Great Battles plane, in each and every situation, at each and every altitude, flies like a fully loaded concrete mixer, and that's what I'm wondering about whether any successful WW2 fighter would have realistically been like that.

 

@edit: Needless to say that my comrade doing the same thing with a Pony in parallel, had no issues in following me through my bnz attempt and regain altitude back to 25k with negligible speed loss. The only thing where he's been having difficulties with was to follow my Jug on a straight line at 25k ft. in nominal power settings - but only after a full 5-minute acelleration run for my Jug; only when the Jug gained speed (which takes forever), it slowly started to extend away from him.

When that happened, I started to climb @200ft/min, and voilá: All my speed advantage was gone within the glimpse of an eye!

 

Mike

Edited June 8, 2020 by SAS_Storebror

[Tomsk]

50 minutes 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.  So I don't see any problems with your finding the same in sim.

 

So my argument is the P-47 is bad at boom and zoom in IL2:GB, I don't argue it is slightly worse than the P-51: I argue that it is a lot worse. If it was slightly worse I wouldn't complain, I'd expect the P-51 to be a little bit better as well, the P-51 is an amazing plane (my favourite actually). Indeed I've also tried using the Spitfire Mk V and Mk IX to BnZ, and they are also much better at it than the P-47 which is really odd.

 

17 minutes ago, SAS_Storebror said:

All I want to get across is that the Jug, much different to any other IL-2 Great Battles plane, in each and every situation, at each and every altitude, flies like a fully loaded concrete mixer, and that's what I'm wondering about whether any successful WW2 fighter would have realistically been like that.

 

Right and this is exactly my assessment. It's not slightly worse than other IL2:GB planes, it is just flat bad and it's very weird. As SAS_Storebror says: you get one or maybe two passes, that's it, then you are basically co-E. No other plane is like that. It's also really bad at high-speeds: it locks up hard and is very stiff. It's exactly the same as trying to use high-speed tactics in a 109, which is plane known to be totally unsuited to high-speed maneuvers.

 

People are perfectly free to ignore my assessment, I have no evidence for it, there really can be none. But as someone who flies this style all of the time (focused on high-speed maneuvers), with a lot of practice at it in many different airframes, my view is the P-47 seems really off at the moment.

Edited June 8, 2020 by Tomsk

[ICDP]

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".

Edited June 8, 2020 by ICDP