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P47 Performance Stats

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30 minutes ago, ICDP said:

 

Your post below stated quite clearly that in BoX the P-47 loses control surfaces sooner than the 109 and that the P-47 should not lose control surfaces at all.  That can be read as P-47D should not lose controls and the Bf109 should lose them sooner.  Diving until controls come off in game proves nothing, because it is a game limitation that applies to all aircraft sooner or later.

 

 

Had you said neither aircraft should lose their controls then your point wouldn't look so biased.  I am not claiming you are biased, I am saying your post can be interpreted that way.

 

 

 

 

I have read that report, and to be honest at 350MPH IAS the P-47D in BoX feels very controllable.  I have not tested if I can blackout at those speeds but I will.  This is the kind of info we should be using to test in game and reporting back to the devs if there are discrepancies in game.

 

I can understand the frustration but having rants without empirical evidence to back them up is not going to get us anywhere in my experience.

Sorry that you misinterpreted what I said but I never claimed the 109 should lose any surfaces, most metal covered aircraft should not lose surfaces.

 

What they need to do is model compressability more accurately and remove the loss of control surfaces on aircraft that never had this problem.

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1 hour ago, ICDP said:

I have read that report, and to be honest at 350MPH IAS the P-47D in BoX feels very controllable.  I have not tested if I can blackout at those speeds but I will.  This is the kind of info we should be using to test in game and reporting back to the devs if there are discrepancies in game.

 

I can understand the frustration but having rants without empirical evidence to back them up is not going to get us anywhere in my experience.

 

Well, I don't think we have been having rants about this subject (at least I personally didn't intend to) if anything, I have kept bringing up this NACA test to sustain my reasoning and, at the same time, I tried to make clear that (proper) ingame testing was necessary to confirm or deny the point.

 

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1 hour ago, HR_Zunzun said:

 

Well, I don't think we have been having rants about this subject (at least I personally didn't intend to) if anything, I have kept bringing up this NACA test to sustain my reasoning and, at the same time, I tried to make clear that (proper) ingame testing was necessary to confirm or deny the point.

 

 

Absolutely agree.

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I did a few tests in the P-47D at 400 mph IAS and was able to black out at around 360mph IAS.  This was with trim at 40% back.

 

In a few test dives, 90deg from 32,000 feet to 15,000 feet, I compared to P-47D to Bf109-K4.  The idea here is to test how long it takes to dive from 32,000ft to 15,000ft and how long it takes to get there.  I also wanted both aircraft to survive the tests intact.

 

Neither aircraft could use full throttle or the engine would die, engine was eventually at almost idle for both aircraft.  Both aircraft entered the dive at 180mph IAS.  I found both aircraft were unable to pull out of the dive without use of full trim, though the 109 was able to pull out earlier.  I assume this is because it had all moving tail for trim.

 

At 15,000 feet the P47-D was usually at ~500mph IAS

At 15,000 feet the 109-K4 was usually at ~500mph IAS

Both aircraft took around 28 seconds average to get from 32,000 to 15,000

 

So at the moment from this test it looks like the P-47D is unable to dive straight down to evade a 109-K4 and that the 109-K4 will recover from the dive easier.

 

It's not a perfect test but it's enough to raise concerns about the P-47D lack of dive advantage.  It's certainly better than just diving until bits start falling off.

Edited by ICDP

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1 minute ago, ICDP said:

I did a few tests in the P-47D at 400 mph IAS and was able to black out at around 360mph IAS.  This was with trim at 40% back.

 

In a few test dives, 90deg from 32,000 feet to 15,000 feet, I compared to P-47D to Bf109-K4.

 

Neither aircraft could use full throttle or the engine would die, engine was eventually at almost idle for both aircraft.  Both aircraft entered the dive at 180mph IAS.  I found both aircraft were unable to pull out of the dive without use of full trim, though the 109 was able to pull out earlier.  I assume this is because it had all moving tail for trim.

 

At 15,000 feet the P47-D was usually at ~500mph IAS

At 15,000 feet the 109-K4 was usually at ~500mph IAS

Both aircraft took around 28 seconds average to get from 32,000 to 15,000

 

So at the moment from this test it looks like the P-47D is unable to dive straight down to evade a 109-K4 and that the 109-K4 will recover from the dive easier.

 

It's not a perfect test but it's enough to raise concerns about the P-47D lack of dive advantage.

It is remarkable that you could keep up with k4 in a p47. Generally speaking, k4 is one level above p47d in tech. But you could keep up never the less.

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Do we have any records of P-47's reaching 600mph corrected IAS? The only ones I've seen were tge two 700mph dives that were attributed to erroneous readings on the pitot tubes. Beyond that, I've only seen references to a test limit of 520mph IAS, reports of control reversal at ~550, and an, as yet, unsourced reference to wind tunnel testing indicating a terminal velocity of 600mph.

 

http://joebaugher.com/usaf_fighters/p47_3.html

 

It really sounds like, aside from the engine not supporting control reversal, some debate about the exact critical mach number, and questions about the turbo power drain above 20,000 ft, that the P-47 is pretty solid. 

 

That leads me to question whether the 109's dive performance is inordinately good instead. Have we wrung that plane out to this degree? 

 

So potential things to check on the 109: G limits, elevator and rudder authority at pre compression speeds and what it's critical mach number is. 

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48 minutes ago, ICDP said:

So at the moment from this test it looks like the P-47D is unable to dive straight down to evade a 109-K4 and that the 109-K4 will recover from the dive easier.

It's in line with my yesterday tests. I've taken P-47 and K-4 (with DC engine) to 8.000 m (or 26.000 ft) and dove near vertically to the ground with engines all out at entry but later gradually closed when approaching Vne, and with a speed check aproximately at 5.000 m (16.400 ft). At 5.000 m I've reached 745 km/h in K-4 and 716 km/h in P-47 D. Exiting dive was easier in K-4 was easier for me and took less trimming / stab rotating than in P-47.

Initial dive speed was equal for both - 220 mph / 350 km/h.

 

I've raised another question, how K-4 dive characteristics compare to G-14 and earlier G models. As far as I was told, K-4 was equipped with rudder spring tab to improve rudder controls, elevator was provided with larger trim tabs and entire stab was geared a bit different to older G models. But it doesnt sound like K-4 dive and controlability characteristics should be very different to what older 109s represent. 

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18 minutes ago, =362nd_FS=Hiromachi said:

It's in line with my yesterday tests. I've taken P-47 and K-4 (with DC engine) to 8.000 m (or 26.000 ft) and dove near vertically to the ground with engines all out at entry but later gradually closed when approaching Vne, and with a speed check aproximately at 5.000 m (16.400 ft). At 5.000 m I've reached 745 km/h in K-4 and 716 km/h in P-47 D. Exiting dive was easier in K-4 was easier for me and took less trimming / stab rotating than in P-47.

Initial dive speed was equal for both - 220 mph / 350 km/h.

 

If you done the test at 2700rpm in the P-47 then set it to (or lower even) 2500rpm and try again. There is a nice boost in level speed doing so (except when close to 9000m alt); and should reduce the drag considerably.

Another thing to consider is the fastest descent curve. It could be you pulled too late and too hard in the Thunderbolt. In practice there is not need to go totally vertical; it's dangerous even.

Edited by Ehret

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Running low RPM and high MP is not exactly realistic. As for dive, I've said it was near vertical, not exactly vertical. I assume not more than 70 deg, judging by the relative position of the ground to my cockpit. 

And Im not sure whats the point of those "it could be" ? If I pulled too hard Id most likely stall it and then I'd repeat test, as far as P-47 handling I know to treat her gentle. And there's no "too late" since exact point was to pull when set entry speed is achieved, otherwise with uneven speeds entire test would be meaningless. 

 

The above matches my online experience when I dove from a K-4 from about 6.500 m, reaching 520 mph and K-4 could keep up with me. The moment I started leveling off, K-4 immediately got into gun range and started scoring hits. 

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26 minutes ago, =362nd_FS=Hiromachi said:

Running low RPM and high MP is not exactly realistic.

[...]

 

As your True Air speed increases you need to reduce RPM to prevent the prop tips from going super sonic and having a big drag spike. As I believe the P-47 has a much larger prop than the Bf-109K-4 it will have a lower Max RPM. 

 

http://www.epi-eng.com/propeller_technology/selecting_a_propeller.htm

 

That atypical references an issue the author had when a lost speed from bumping the prop speed from 2400rpm to 2700rpm. We can expect this to be more pronounced in a high speed dive. 

 

This does bring up the question of, can we drive even faster by using even lower RPM? The Thunderbolt has a very big prop, and I can see that turning into, effectively, a very large dive brake as the blades start breaking the sound barrier. 

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1 hour ago, =362nd_FS=Hiromachi said:

Running low RPM and high MP is not exactly realistic. As for dive, I've said it was near vertical, not exactly vertical. I assume not more than 70 deg, judging by the relative position of the ground to my cockpit. 

And Im not sure whats the point of those "it could be" ? If I pulled too hard Id most likely stall it and then I'd repeat test, as far as P-47 handling I know to treat her gentle. And there's no "too late" since exact point was to pull when set entry speed is achieved, otherwise with uneven speeds entire test would be meaningless.

 

I started dive from 8000m, initial speed 350km/h indicated, settings: 50% fuel, no mods, oil rad to 0%, cowls to 0%, inter-cooler 50%, initial rpm about 2500 (85% in tech-chat), throttle and boost levers to 100%, water-injection on and mixture to 100%. The diving angle was no less than 45 degree but I'm not sure of exact amount. At the 5000m I had 740km/h IAS every time at 5000m and full recovery was still possible (but barely) without resorting to tabs. Two times I managed to exceed the 750km/h but don't know how. It should be noted that at the step dive the engine can seize momentarily due the free-fall and lack of positive G. At the attempted 90 degree it stops completely and I noted speeds under 720km/h at the 5km mark. The latter could explain few things.

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Except I did not enter dive by pushing the stick, but by rolling on the back and pulling on the stick and then rolling again when sufficient angle was achieved. Again, it was near vertical and as I;ve further explained, about 70 degrees, not more. Not vertical, not sure why do you cling to that. Regardless, I might try shallower angle but in actual combat I look for every option to hide under opponents nose to avoid being shot. Shallower angle with his superior initial acceleration just reduce chances of escapting unscathed.

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Neither I was doing "full" vertical for most runs. The engine in the P-47 interrupted most in the middle of dives before pitch approached 90 degree; few moments past the initial pitch-down and when velocities exceeded 440km/h.

Just tried using the split-S and indeed it seems to be slower about 20km/h. Probably due to unloading the frame weight a bit later.

Quickly checked (relatively) shallow dives at about 4000ft/m (20.32m/s), too. For the first 1000m of descent the K4 has an advantage but speeds seem to equalize after that. Considering the later is the LW's last (and very rare) prop fighter that's no fault for the P-47D-28. If you got K4 on your close six you have to defeat the enemy's gun solution first before trying anything else.

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10 hours ago, Voyager said:

Do we have any records of P-47's reaching 600mph corrected IAS? The only ones I've seen were tge two 700mph dives that were attributed to erroneous readings on the pitot tubes. Beyond that, I've only seen references to a test limit of 520mph IAS, reports of control reversal at ~550, and an, as yet, unsourced reference to wind tunnel testing indicating a terminal velocity of 600mph.

 

http://joebaugher.com/usaf_fighters/p47_3.html

 

It really sounds like, aside from the engine not supporting control reversal, some debate about the exact critical mach number, and questions about the turbo power drain above 20,000 ft, that the P-47 is pretty solid. 

 

That leads me to question whether the 109's dive performance is inordinately good instead. Have we wrung that plane out to this degree? 

 

So potential things to check on the 109: G limits, elevator and rudder authority at pre compression speeds and what it's critical mach number is. 

 

Critical mach changes with altitude (air density) iirc. There are multiple CM that I've seen listed for the P-47,  0.7 , 0.75, and 0.8. 

The P-47D suffered from aileron reversals at around 540 mph iirc, this wasn't a huge concern for the most part.

 

Whats odd to me is the ability for the 109 to pull out of the dive so easily compared to the P-47, not sure if this is accurate or not but it seems off based on everything I've read about the 109s high speed authority.

 

Here's a good video about P-47s dive performance and mach numbers. He explains things much better than me.

 

Edited by Legioneod

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Get ready for the "P-47 out diving its opponents was just a myth"

When diving in a P-47 you should make sure the P-47 is at a reasonable speed before entering the dive to neglect any advantage in power to weigh ratio. So I started my dive from 8000m @ 435kph IAS. There are no means to telling the dive angle so I used the top of my canopy framing against the horizon for the P-47. I measured reticle on both planes to the horizon to make sure I was diving at the same angle for the Bf-109K4.

Fuel    100%  10%    K4 50%
7000m 571    558    565

6000m 645    658    655

5000m 736    720    715

4000m 782    765    759

3000m 821    803    796
1000m 895    873    861

It took the P-47 @ 100% 33 seconds to get to 1000m from 5000m while the K4 took 40 seconds. The K4 was yawing to right slowly during the entire dive.

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17 hours ago, ICDP said:

 

Your post below stated quite clearly that in BoX the P-47 loses control surfaces sooner than the 109 and that the P-47 should not lose control surfaces at all.  That can be read as P-47D should not lose controls and the Bf109 should lose them sooner.

 

He's not saying that at all - you're saying something could be read into his post that isn't remotely there.

 

I have made statements about the P-47 and it losing control surfaces as well.

Not because I think that the 109 losing them is correct necessarily ( have no idea) but I don't have that information - unlike the P-47.

If it's not correct with regard to the 109, then let those who have access to that info post about it.

 

 

Edited by Gambit21

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6 hours ago, Gambit21 said:

 

He's not saying that at all - you're saying something could be read into his post that isn't remotely there.

 

I have made statements about the P-47 and it losing control surfaces as well.

Not because I think that the 109 losing them is correct necessarily ( have no idea) but I don't have that information - unlike the P-47.

If it's not correct with regard to the 109, then let those who have access to that info post about it.

 

 

 

Sorry but read what I said again, I said it could be read that way, not that it should be read that way.  All aircraft in BoX lose their flight controls in a prolonged dive.  It is simply a limitation of the game from before compressibility was modeled.  I believe the devs need to introduce a less arbitrary dive limit that is modelled on compressibility and controllability rather than bits just falling off at X speed.

 

 

6 hours ago, DSR_T-888 said:

Get ready for the "P-47 out diving its opponents was just a myth"

When diving in a P-47 you should make sure the P-47 is at a reasonable speed before entering the dive to neglect any advantage in power to weigh ratio. So I started my dive from 8000m @ 435kph IAS. There are no means to telling the dive angle so I used the top of my canopy framing against the horizon for the P-47. I measured reticle on both planes to the horizon to make sure I was diving at the same angle for the Bf-109K4.

Fuel    100%  10%    K4 50%
7000m 571    558    565

6000m 645    658    655

5000m 736    720    715

4000m 782    765    759

3000m 821    803    796
1000m 895    873    861

It took the P-47 @ 100% 33 seconds to get to 1000m from 5000m while the K4 took 40 seconds. The K4 was yawing to right slowly during the entire dive.

 

This is a good test, thanks.  It is quite similar to the results the USAAF got when comparing P-47D to Fw190-A in a dive.  The Fw190-A pulled away initially and  it took 7,000ft of alt (from 10,000 to 3,000ft) the P-47D caught up and passed the Fw190-A.

 

I have read RAF tactical trials of captured earlier model Bf109F and G and both tests state the trim controls in a Bf109 become impossible to move at high speeds.

 

So part of the problem with the BoX 109 (and possibly other aircraft" is that trim adjust is always available and extremely easy to use.  Maybe the devs should introduce a trim scale that changes with speeds making trim adjust at higher speeds considerably slower.

 

It should also be worth remembering that the P-47D got dive brakes for a reason.  It was incredibly easy to enter compressibility and crash during high speeds dives.

Edited by ICDP

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4 hours ago, ICDP said:

 

Sorry but read what I said again, I said it could be read that way, not that it should be read that way.  All aircraft in BoX lose their flight controls in a prolonged dive.  It is simply a limitation of the game from before compressibility was modeled.  I believe the devs need to introduce a less arbitrary dive limit that is modelled on compressibility and controllability rather than bits just falling off at X speed.

 

 

 

This is a good test, thanks.  It is quite similar to the results the USAAF got when comparing P-47D to Fw190-A in a dive.  The Fw190-A pulled away initially and  it took 7,000ft of alt (from 10,000 to 3,000ft) the P-47D caught up and passed the Fw190-A.

 

I have read RAF tactical trials of captured earlier model Bf109F and G and both tests state the trim controls in a Bf109 become impossible to move at high speeds.

 

So part of the problem with the BoX 109 (and possibly other aircraft" is that trim adjust is always available and extremely easy to use.  Maybe the devs should introduce a trim scale that changes with speeds making trim adjust at higher speeds considerably slower.

 

It should also be worth remembering that the P-47D got dive brakes for a reason.  It was incredibly easy to enter compressibility and crash during high speeds dives.


I also noticed in my test the Bf-109 despite its legend to have troubles pulling out of a high speed dive did it considerably easier than the P-47 without the use of trim. Yes and the dive brakes weren't just slapped on to some random batch of P-47, it was added on the most produced P-47. I couldn't added the Bf-109G-14 to my test as it couldn't achieve 435kpg IAS.

Energy retention on the deck.

After the dive I pulled out on the deck and timed the speed lost from 850kph to 700kph.


10% 19s
100% 19s
K4 23s

So a 2000lb weight difference between full and minimum fuel contributes nothing to energy retention. 🤐

 

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1 hour ago, DSR_T-888 said:

So a 2000lb weight difference between full and minimum fuel contributes nothing to energy retention. 🤐

 

Maybe it did but any gain just got eaten by wings extra induced drag in level flight as they had lift that 2000lb. The weight is most beneficial when you unload the engine+frame in a fall. At least it looks like a likely explanation.

Edited by Ehret

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Let's not call them "dive brakes" please, they are compressibility recovery flaps to be deployed for recovery purposes - you don't have them to keep the speed low, you have them to pull up because you're overspeeding so easily.

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13 hours ago, Ehret said:

 

Maybe it did but any gain just got eaten by wings extra induced drag in level flight as they had lift that 2000lb. The weight is most beneficial when you unload the engine+frame in a fall. At least it looks like a likely explanation.

 

From my knowledge the extra weight should assist in energy retention. The speed difference should be marginal but the addition 2000lbs of fuel weight should help It significantly. Other simulators seem to have this modeled.

 

Unless again inbox before "the P-47 was a poor zoom climber"

 

12 hours ago, Talon_ said:

Let's not call them "dive brakes" please, they are compressibility recovery flaps to be deployed for recovery purposes - you don't have them to keep the speed low, you have them to pull up because you're overspeeding so easily.

 

Dive brakes

Dive brakes

Dive brakes

 

😎

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2 hours ago, DSR_T-888 said:

Unless again inbox before "the P-47 was a poor zoom climber"

I guess everything the P-47 was good at was just propaganda? At least, that's what some people would like us to believe.

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On 12/9/2018 at 2:05 PM, Voyager said:

It really sounds like, aside from the engine not supporting control reversal, some debate about the exact critical mach number, and questions about the turbo power drain above 20,000 ft, that the P-47 is pretty solid. 

 

That's probably due to lack of understanding what critical Mach means. It just means that at the given AoA, some part of the airstream around the wing reaches sonic speed.

Trim-changes are only going to happen beyond Mcrit - but that depends on a lot of things. That's why the Brits were looking for a "maximum tactical Mach number" in their comparative trials.

It would be interesting to get an exact definition of what is precisely meant by that, though.

 

 

On the whole "outdiving"-matter:

I remember a thread where the whole thing was physically broken down to the issue that most people have a wrong understanding what this means.

"Outdiving" merely means there's a diverging acceleration between the two airplanes, not that one airplane completely vanishes from view.

 

"No hope of catching" does not mean a P-47 will open the distance to 10 miles during the dive, but will get out of firing range (or will get into firing range when in pursuit) during the dive and have a useful margin of additional airpeed to play with over the adversary.

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