PDA

View Full Version : P-47 dive test



JtD
09-11-2006, 12:54 PM
Some time ago there was a dive chart for a P-47D-30 floating around on this forum. I took the liberty to compare this data with the P-47D-27 and P-47D-10 from FB 4.05. Same altitude, same dive angle. The result: Dive acelleration in FB for this plane in this test is way higher than it could have possibly been in real life.

http://mitglied.lycos.de/jaytdee/testgraph/p47dive.JPG

faustnik
09-11-2006, 12:59 PM
JtD,

Can you post a link to the original D-30 chart please.

Thanks!!!

MEGILE
09-11-2006, 01:04 PM
Most interesting.

JtD
09-11-2006, 01:49 PM
Originally posted by faustnik:
Can you post a link to the original D-30 chart please.

Can't find it anymore. http://forums.ubi.com/groupee_common/emoticons/icon_frown.gif

Good info gets lost oh so easily around here.

faustnik
09-11-2006, 01:55 PM
OK, I'll look around for it too.

HayateAce
09-11-2006, 02:19 PM
Meaning the P47 in FB does not accelerate fast enough in a dive.

JtD
09-11-2006, 02:31 PM
Originally posted by HayateAce:
Meaning the P47 in FB does not accelerate fast enough in a dive.

I can not believe you fail to understand a simple chart with a written explaination next to it. Are you that dumb or just trying to provoke?

Edit: On a second thought you may just have a very strange sense of humour.

WWMaxGunz
09-11-2006, 02:54 PM
Hayate is both and more. His wank-post acceleration when he thinks of US planes is astounding.

Differences between how the real test was flown and how the game one was flown should account
for very much. Rarely do we see even half of it.

JtD that chart keeps halting on load for me, not that it's real important.

EDIT: got it all after 4x reloading. What version FB were those "tests" flown? Long ago I
think you could get 900+ kph out of P-47 before parts came off but since 4.0? Real test was
with real pilot and no refly button.

Daiichidoku
09-11-2006, 02:57 PM
Originally posted by Megile:
Most interesting.

a spit and 190 comparison next to this WOULD be most interesting...........

robban75
09-11-2006, 03:02 PM
If the P-47 dive acceleration is off, then dive acceleration is off for all planes, by an equally great margin. http://forums.ubi.com/images/smilies/16x16_smiley-sad.gif

majnos64
09-11-2006, 03:04 PM
JtD: WWMaxGunz is right how that tests were made, do you have some more info about it ?

p1ngu666
09-11-2006, 03:06 PM
Originally posted by robban75:
If the P-47 dive acceleration is off, then dive acceleration is off for all planes, by an equally great margin. http://forums.ubi.com/images/smilies/16x16_smiley-sad.gif

yep

JG4_Helofly
09-11-2006, 03:14 PM
Exellent,

Finaly we have a RL vs game test. This should not be an exeption in our discussions about FM but the rule if possible.
Now we can discuss with evidences and not speculation and interpretation.

Very very nice work JtD http://forums.ubi.com/images/smilies/25.gif

I also saw a spitfire dive test chart in the forum. Does anyone still have it? Would be interesting to compare with the p47 especialy for the "energy problem".

WWMaxGunz
09-11-2006, 03:19 PM
For years so far the whine has always been they accelerate too slow or not different enough
or "all the same".

I've looked at over 20 dive tests through devicelink besides my own and find that differences
in starts alone make it very hard to line them up fairly. The best I can do is take planes
that dive within about 2 degrees of each other total spread and compare acceleration at
different speeds and within 200-300 meters alt at the speed points and then I find real
differences.
The big difference is they all lose acceleration as they approach top speed. Ones with less
top speed slow down sooner and the race is decided there. But you compare fastest group of
fighters only there is not much difference nor should there be with much thought at all.

So it is outspeed at the top end or get the head start if you would lose another and there
is more than one way to do the latter but who wants to read into their storybooks to know?

I keep seeing the same Johnson in the P-47 vs Spitfire quote by forum member who ignores
totally the part where through rolls Johnson builds up a large lead on the Spit before he
does his dive and zoom trick at the end. Ignoring the seperation in time and distance
makes it possible to come up with a totally false picture of putting a huge seperation by
dive and zoom alone, but does not make that true.

noace
09-11-2006, 03:24 PM
Hi!

Acceleration up to 750 km/h would be of more interest. At very high speed compressibility and other effects kick in which are not modelled. And if the trend seen on the left side (black curve crossing green/red) stays to lower speed the p47 actually would really accelerate to slow in the game.

noace

FritzGryphon
09-11-2006, 03:37 PM
It's always nice when the game can be compared directly to historical numbers, rather than on subjective accounts.

I'm curious, what are the conditions of the test? Alt, dive angle, power setting, etc.

Here's a chart I made back in early PF, showing difference of power-off dive accel. It is bizarre that some would claim that all planes dive the same.

http://members.shaw.ca/evilgryphon3/dive.jpg

Daiichidoku
09-11-2006, 03:39 PM
Originally posted by noace:
At very high speed compressibility and other effects kick in which are not modelled.

the P 38 more than compensates for this on behalf of all the other types in game, collectively http://forums.ubi.com/images/smilies/disagree.gif

sorry, i couldnt resist...

JtD
09-11-2006, 10:42 PM
This test was done at an altitude of 11000 to 8000 meters at a dive angle of about 15?. The dive was entered at a high level speed, probably top speed. It must have been a high engine power dive.

I did a 15? full power dive at the same altitude with roughly the same inital speed in game.

The airspeed in my chart is TAS. In FB, the P-47 can do 1000 IAS, which at these altitudes is easily supersonic.

The real P-47 would refuse to accelerate any further than mach 0.8some, like hitting a wall. This mach number also more or less was the upper limit of it's flight envelope.

The acceleration at lower speeds would just include the level acceleration figure, the maximum dive related acceleration component at this angle is 2.5 m/s² (physics). If the real P-47 was ahead of the FB P-47's, it would only mean it had a better level acceleration at that height.

I also think that the differences this chart reveales are not limited to the P-47. But the P-47 is the only plane I had a good enough chart for to reproduce the tests.

I will also take a look at the mentioned Spitfire table.

BBB_Hyperion
09-12-2006, 01:51 AM
That is old news search for high speed modeling posted something like this years ago. High speed effects are not modeled . Compression , Terminal dive speed non existing. Oleg knows this "next sim" be sure etc .)

WWMaxGunz
09-12-2006, 02:40 AM
What real WWII plane +could not+ be dived until control lost and plane destroyed?
I have noted in every dive to high speed that acceleration becomes less.

BBB_Hyperion
09-12-2006, 03:37 AM
set prop to windmill pitch 0 turn engine off and try terminal dive , look at the chart from devicelink then concerning acceleration.

Fork-N-spoon
09-12-2006, 04:15 AM
Originally posted by JtD:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by HayateAce:
Meaning the P47 in FB does not accelerate fast enough in a dive.

I can not believe you fail to understand a simple chart with a written explaination next to it. Are you that dumb or just trying to provoke?

Edit: On a second thought you may just have a very strange sense of humour. </div></BLOCKQUOTE>

Well, if you think that the P-47's dive acceleration is too fast, imagine how off other aircraft are...

Xiolablu3
09-12-2006, 05:56 AM
Interesting test!!!

Now we need a test from one of the poorer performing planes in a Dive from 1943, such as the Spitfire IX, to compare.

JG4_Helofly
09-12-2006, 12:34 PM
Now is it possible to do a similar test with the spitfire? I have seen the RL chart in the energy topic. Would be very interessting to compare these two graphics RL vs in-game.

JtD
09-12-2006, 01:09 PM
The table of the Spitfire dive is detailed enough to do a comparable test. I plan to do it, but don't know when.

BBB_Hyperion
09-12-2006, 01:52 PM
Is that the mach test for the spit ?

This test might have some bad instrument errors in it . At that time quick change from high density to low density was too fast for the instruments in so there is a instrument correction needed , compression correction is surely done (hopefully).

WWMaxGunz
09-12-2006, 02:14 PM
Originally posted by Xiolablu3:
Interesting test!!!

Now we need a test from one of the poorer performing planes in a Dive from 1943, such as the Spitfire IX, to compare.

There must be a big difference between rolling a 190 faster than a Spit or nosing a 109 down
when the Spit has to roll and dive to avoid negative G cutout and actual how fast can you go
dive speed since, and get this right -- those Spitfires were used to run world-class record
dive mach speeds at high altitudes under controlled conditions.

What happened in combat with mixed actions does not make every part the same as the end result.

Just compare early plane war dive to late war plane dive should be enough.