Aces High Bulletin Board
General Forums => Aces High General Discussion => Topic started by: Thor^ on June 26, 2000, 01:17:00 PM
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Hi every one i like to fly the jug and some one put up a link in another thread to zenios warbird drive in. I watched the films on the jug and got to wondering. The film is from 1943 so it couldent have been the same model jug we have now but it stated that a split S in the jug at full powere would lead to compresion and augering. So i went to test this out with the AH jug. I took clean load out and 50% fuel climed to 30k at 250 ias 400 true(got to like that =) ) i did my first split S puling backe enuf to get just a little black around the edges but no where near blacking out i droped 22400 feet. looking at my notes here i forgot to record speed but i rember it was around 5oo ias true? then i dove to 20k leveld and trimed up
at 300 ias 400 true. i split S again i droped to 15k 350 ias 425 true. i dove to 10k leveld and trimed at 350 ias (dident right down true forgot).Again i split s i droped to 4800 feet 450 ias 475 true. i climed to 5000 feet to see what would hapen 300 ias i split S droped to 1000 feet 400ias 400true. i was at full powere during the hole flight. once i puled backe hard enuf to almost black out.At no time did i ever use the dive breaks. so thats my story now my questions. what made the 1943 jug compres like it says in the vido? why dosent the P47 D model have the same problem? is this somthing that AH dident capture in modeling the plain? Or is it somthing that cant be done becus of programing?
note im not complaning about AH i love the game (would pay to play but cant aford it right now long story =( ..) Just so you all know im not squeaking im just wondering and trying to learn. im neather a piolet or a programer im just looking for info =)
[This message has been edited by Thor^ (edited 06-26-2000).]
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Those videos were made to keep new pilots from killing themselves. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif) At 500 Ias the P47 in AH will go into compression badly and the dive flaps must be used to pull it out. That video was likely made before the dive flaps existed, so they had to keep the pilots from split-s ing and hitting 500 IAS or so. If they exceeded 500 they were pretty much dead meat, so you can understand why they built some margin of error into the training films. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
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Lephturn - Chief Trainer
A member of The Flying Pigs
Visit Lephturn's Aerodrome for AH news, resources, and training data.
http://users.andara.com/~sconrad/ (http://users.andara.com/~sconrad/)
(http://tuweb.ucis.dal.ca/~dconrad/ahf/lepht.gif)
"MY P-47 is a pretty good ship
And she took a round coming 'cross the Channel last trip
I was thinking 'bout my baby and lettin' her rip
Always got me through so far
Well they can ship me all over this great big world
But I'll never find nothing like my North End girl
I'm taking her home with me one day, sir
Soon as we win this war"
- Steve Earl
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i can see that they hade some margen of error in there film but i dout it was that larg. I stated in my first post that i did NOT use flaps and i did go over 500 true.
So my guestions still stand and i would like a more in depth reply from thos with the knowlidge on this BBS. thank you all for your time.
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Real pilots didn't pull lots of G in WW2 like we do in sims. Try a split-s at 2 or 3 G and see what happens.
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Thor,
True Airspeed is not relevant. Only your Indicated Airspeed counts when you are talking about compression and dive speed. In your above post you didn't mention going over 500 TAS, and you weren't even close to over 500 IAS.
If you push a Jug past 500 Mph IAS it WILL compress, and badly in AH. Without the dive flap it is VERY hard to recover it in this condition. I was not talking about regular "flaps", but the special "dive recovery flap" that was installed on the later model P-47's, including the version we have here in AH. This film was made before the advent of that flap, so if a pilot got a P-47 into compression, it was very difficult if not impossible to pull out of the dive.
I think if you try gentle 3G split-S's at full throttle in the P-47 starting from a decent cruising speed like 300 IAS you will hit 500 MPH IAS. Notice when you hit that speed in the game your controls will freeze solid and you will be unable to pull out of the dive. If you activate the dive recovery flap in the P-47D-30 that we have in AH, you will regain some control and pull out. The earlier versions of the P-47 did not have this feature, so they would have likely killed a bunch of pilots in training without this kind of warning.
From what I have seen, the AH P-47D-30 is modelled very accurately.
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Lephturn - Chief Trainer
A member of The Flying Pigs
Visit Lephturn's Aerodrome for AH news, resources, and training data.
http://users.andara.com/~sconrad/ (http://users.andara.com/~sconrad/)
(http://tuweb.ucis.dal.ca/~dconrad/ahf/lepht.gif)
"MY P-47 is a pretty good ship
And she took a round coming 'cross the Channel last trip
I was thinking 'bout my baby and lettin' her rip
Always got me through so far
Well they can ship me all over this great big world
But I'll never find nothing like my North End girl
I'm taking her home with me one day, sir
Soon as we win this war"
- Steve Earl
[This message has been edited by Lephturn (edited 06-27-2000).]
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Lephturn, I believe it also depends on the air density, although I dont quite understand it (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif).
(ie it's easier to compress higher up at the same IAS than at lower altitudes).
Daff
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CO, 56th Fighter Group
"This is Yardstick. Follow me"
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This is not meant to be taken as anything but an observartion of an odd occurance but last night in a dogfight with a 109 at A27, after a couple of loops, rolls and turns he dove to escape and I quickly followed right on his tail at 400 yards. He out dove my P-47 handily from an almost equal start and even started pulled away to about 690. This is when I entered compression and even with throttle back all the way and dive flap employed I slow rolled to the right, out of contro and into the ground. The 109 pulled out and up with no problem at all. And the whole time he was pulling away. Not once did I gain on that bugger like I might have had he chopped throttle..
-Westy
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Originally posted by Daff:
Lephturn, I believe it also depends on the air density, although I dont quite understand it (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif).
(ie it's easier to compress higher up at the same IAS than at lower altitudes).
Daff
I am not so sure that this is the complete reason, or that the thicker air at lower altitudes results in a greater control surface force.
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Mino
The Wrecking Crew
"I kinda like it.. and the hell with the cat"
Hangtime
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Was it a G-10?
If so I would expect it to pull away, even in a dive, at least at first. Those suckers are FAST, and accellerate better than a Jug. I would bet the 109 pilot was flying with trim at that point... I know those guys are used to doing it to stay alive. I'll check out the dive speed of the 109 sometime though and see what I find. One would expect it to tear itself to bits before the Jug would lose total control.
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Lephturn - Chief Trainer
A member of The Flying Pigs
(http://tuweb.ucis.dal.ca/~dconrad/ahf/lepht.gif)
"MY P-47 is a pretty good ship, she took a round coming 'cross the Channel last trip.
I was thinking 'bout my baby and lettin' her rip
Always got me through so far"
- Steve Earl
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Mino, yeah, but wouldnt you get the same amount of air hitting the surfaces? (Given that the IAS is the same).
Daff
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CO, 56th Fighter Group
"This is Yardstick. Follow me"
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Thanks Lephturn. I pretty much discounted the initial part of the dive. I had a decent fuel load, who knows what the 109 had - let alone which model it was. And the dive was with an initial full thottle, with wep even used for the first few seconds.
The odd part, imo, is after we both quickly reached the same speed in the dive ( which was steep at about 75-80 deg) and based on the range not changing we stayed that way for a good 10-15 seconds before we I found myself compressed, unable to pull out and I watched him able to do so easily. The P-47 trim didn't help for me, course it could have for him. And the speed flaps didn't seem to make a difference. I'll be filming more now to find my error or anything that might be odd enought to submit to HTC for a look into.
-Westy
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Compression is dependant on your true airspeed in relation to the speed of sound(Mach number), and the speed of sound changes with density(altitude).
Control forces are dependant on indicated airspeed.
As for Westy's anecdote: It sounds like you were at low speed when the 109 dived. It would have a greater acceleration in that case due to its vastly better powerloading. Before you could catch it your Jug was "compressed" and you backed off. The important thing to note is that the P-47 will experience "compression" at a much lower Mach no. than the Me 109. The Me 109 is possibly even better than the P-51 in this regard.
I don't now the critical Mach number for the P-47, but I think it's just over 0.7? For the Spitfire it's about 0.83.
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Hmm..actually sounds sensible.
Guess that at lower density, there's less air obstructing the turbulent flow and vice-versa.
Daff
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CO, 56th Fighter Group
"This is Yardstick. Follow me"
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Haven't have any compressability problems yet, and I love the Jug, but whats with the location of the VSI guage? HT, put the sucker where we can see it with out looking down.
...Weave
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I have been flying the Jug alot and I luv it. I had not experienced any compression untill last nite, the funny thing was that it was not a steep dive but a shallow dive. I was at about 20K and saw a few low dots and stuck my nose down for a 300fpm dive. By the time I had an id on the cons my speed had built up to where my controls locked up, I eased off the throttle and droped the the dive flap and eased the nose up with the trim tab and was able to recover. Odd that is was a shallow dive though.
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JG 2's current cannon magnet
Milo
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That's suprising Juzz (not discounting the info, mind you!) as it does seem to go against pilot anecdotes from both sides on what the P-47 really had going for it, the dive. I'm in no way capable of saying what is right or wrong being that I do not have hand ons experience nor an aeronautical engineering degree. Which is why I usually don't make any ambiguous or spout an uninformed opinion that the FM of the 47 is "porked" in regard to diving - or that another aircraft's FM may be too "forgiving". I tend to always look internally (operator error <G> ) for cause of error first and with the AH P-47 I figure it is a case of having to toss out most of what I learned in other sims to fly this one. Rolls, dives and zoom climb are the usual tricks. I'll have to relearn the dive for starters I think.
Sorry to have hijacked your topic Thor^ (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
-Westy
[This message has been edited by Westy (edited 06-27-2000).]
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Westy, if I recall correctly from the 1.03 readme, compression is not modelled yet for all aircraft. Perhaps HTC hasn't modelled compression on the 109 yet, though clearly it's done so for the P-47. That might explain what happened to ya.
-- Todd/DMF
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reply to Lephturn
>Only your Indicated Airspeed counts when you are talking about compression and dive speed. In your above post you didn't mention going over 500 TAS, and you weren't even close to over 500 IAS.<
(this is what im talking about.i did the tests again at 30k starting at 250ias 400tas.about as fast as i could get it.i did a split S with wep and pulling around 3g
i came out with no problem at 18k 375 ias 500tas and i did NOT use the dive break! i did this prity much all the way to the deck.
starting at 30k and working my way down)
>If you push a Jug past 500 Mph IAS it WILL compress, and badly in AH.<
i have experinced this =)
>Without the dive flap it is VERY hard to recover it in this condition.<
on the deck 600ias 600tas even the dive break dosent help =)
>I was not talking about regular "flaps", but the special "dive recovery flap" that was installed on the later model P-47's,<
sorry i dident make my self clear.i was refering to the dive break.my bad
>This film was made before the advent of that flap, so if a pilot got a P-47 into compression, it was very difficult if not impossible to pull out of the dive.<
>The earlier versions of the P-47 did not have this feature, so they would have likely killed a bunch of pilots in training without this kind of warning.<
If im not using the dive flaps shouldent i get simelar results as the early war P47?
it seems to me that the split S is an importent part of any ACM.I just dont think they would tell them not to use power during the move if they could with ease.It seems to me it would take away a life saving move for no resion at all.
and your right the P47 in AH is the best i have seen yet.im not nocking the game honest =) im just trying to understand the jug a little more.
from the film i always got the impresion that maby the dive acceleration was so suden
that compresion in the split S was otomatic if you dident watch your speed.
has any one watchd the film im refering to?
if not i can get the url for you all=)
wouldent be suprised if you all have watched every film on the site allready =) lol
with respect Thor^
[This message has been edited by Thor^ (edited 06-27-2000).]
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OK, I'm not sure how reliable these figures are, but here they are anyway.
Compression speeds of some AH fighters(Mach number). Generated in Aces High(not RL figures).
P-47D-30: 0.78
P-38L: 0.74
P-51D: 0.80
Spitfire: 0.83
Me 109: 0.83
Fw 190A: 0.81
F4U-1D: 0.81
[This message has been edited by juzz (edited 06-27-2000).]
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Any idea what alt you were at when it started, Westy?
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SnakeEyes
o-o-o-
=4th Fighter Group=
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Originally posted by juzz:
Real pilots didn't pull lots of G in WW2 like we do in sims. Try a split-s at 2 or 3 G and see what happens.
2 or 3G is nothing, it is normal for a fight. Problems for pilots starts at 6+G.
Fariz
XII Legion
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true fariz but if u eat this 2 ,3 g everi day u gona see :-)))
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compression starts based on true air speed not indicated airspeed.
we're talking mach limits here all based on tas
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Good point DMF. About 20-25k Snakeyes.
I'm going to film more for sure. Without a film of what I'd done it makes it hard for me to guess at what the cause was. Thanks!
-Westy
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Fine thor, but I'm saying the film is a bit cautios, but the P47-D-30 is right. The error here is the source material, not the flight model IMHO.
BTW, did the film specify what starting speed? I'd say 250 is a bit slow for a place to start. Who knows.
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Lephturn - Chief Trainer
A member of The Flying Pigs http://www.flyingpigs.com (http://www.flyingpigs.com)
(http://tuweb.ucis.dal.ca/~dconrad/ahf/lepht.gif)
"My P-47 is a pretty good ship, she took a round coming 'cross the Channel last trip.
Just thinking 'bout my baby and lettin' her rip, always got me through so far."
- Steve Earl
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I got the same stuff mentionedin the P-47 Pilots Manual..I'll check it when I get home.
Daff
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CO, 56th Fighter Group
"This is Yardstick. Follow me"
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seen 650knots in a dive in g10 eeerr well around 645 with wings comin off at 650 +)
SKurj
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Ok, found the diagram in the P-47 Manual :
"Pilot's Flight Operating Instructions
For Army models
RP-47B & C and P47D & G
Airplanes
British model Thunderbolt"
AN 01-65BC-1 A.P No. 2381A
November 20, 1943
"P47 Airplanes
Altitude loss and speed attained in Half Rolls Pull Outs at approx 4 G's held constant"
(ed: all split-S's bottom out at 2000'. I will qoute starting altitude, starting speed and end speed (IAS)).
15.100' , 400 IAS, 525 IAS
13.800' , 350 IAS, 490 IAS
12.300' , 300 IAS, 450 IAS
10.400' , 250 IAS, 400 IAS
8.400' , 200 IAS, 342 IAS
6.200' , 150 IAS, 277 IAS
Daff
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CO, 56th Fighter Group
"This is Yardstick. Follow me"
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Citabria, it's neither IAS nor TAS that matters, but the Mach number, Ma. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
FunkedUp
Official Citabria Post Slagger
[This message has been edited by funked (edited 06-28-2000).]
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the film stated 2 starting speeds and had
a dirgam of results for both 150 ias and 350 ias. funny now that i think about it i seem to rember in the take off and landing film on the same site that the jug would almost stall at 150 TAS when landing. if this were
true then would the juge be stalling at 150 ias also?
in the film i cant read all the numbers for alt its cut off eather by my player or somthing else. i have assumed all along that
the alts given were 30k 20k 10k but i may
have been wrong i dont know.
ok another question i have (this is not an insult or any thing ) i just wonder why people somtimes question sorce material?
wouldent the people who made it know more than the people reserching it? ie the origanel manuls?
another thing i read about people geting mad
becus questions like mine devolv in to the (it is ..it isent ..it is ..it isent) kinds of threads i dont want to do that its not my gol.
i do not have access to any real good data just what i can find on the net.
so if thos of you who are good at working the data would give me a hand i would be gratful. Im willing to do any tests but i need to know what to do...and maby how to do it.
Daff i hope you get this fare down my letter here =)
maby im not all that bright could you tell me if i read your info right..or any one who understood it.
are you saying that at a starting alt of 15.100'and a ias of 400 the jug drops to 2000' with a ias of 525? did i read that right? if i have this right than the info on the film may be corect. As i stated i was asuming alt but if tests were dun from 15k
that could explain the film...i am going to asume i read Daffs post right and go do the tests as he has them and see what hapens.
thanks for every ones replys and time given to help me understand things.
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Yups, you understood it right.
Daff
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CO, 56th Fighter Group
"This is Yardstick. Follow me"
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I forgot who, but someone stated that mach number is TAS divided by the speed of sound, which is correct. Also they stated that the speed of sound varies with air density. In fact, air density has little to do with the speed of sound, as it is actually temperature that effects the speed of sound. I forgot what the rate of change per degree of temperature change is, but I know that this is the case. As temperature decreases, the speed of sound decreases, hence while altitude is decreased, temperature decreases, as well as the velocity of sound waves. It is true that the density varies at a proportional rate, but if air were held in a chamber, compressed, and the air was cooled to the original temperature before compression, the speed of sound would be very close to what it was in the original low pressure, but equal temperature state.
Compressability is basically when air starts flowing at certian points along the airframe at over or equal to mach one, forms a shock wave, and disturbs the air flow. This would often cause a seperation of air flow in front of such things as ailerons and elevators, which would have detrimental effects on the controlability of the aircraft. Since the air had to accelerate over control surfaces (such as over the top surface of a wing), it would frequently exceed mach one while the aircraft was at a speed of .7 or .8 mach especially if the aircraft were pulling more than one G. Shock waves would then start forming on other control surfaces, but usually someplace near the high point of the wing first.
hope this helps, and let me know if i messed up (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
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correction for my last post.. as altitude INcreases, temperature decreases. Sorry about that (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
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Ok Daff i followd your stats
i used your starting alt and speed
i added wep as i started the rollover in to the split S and i kept the move at 4G at all times. at no point did i use the dive flap! here are the numbers i got.
15.100' 310 ias +wep i couldent get 400ias even with wep bottom alt 1.800'
13.800' again 310ias +wep was about all i could get bottom alt was 6.900'
12.300' 300ias+wep i maneged to get this speed ok bottom alt 7.900'
10.400' 250ias +wep as i started the rollover bottom alt 6.600'
8.400 200ias +wep as i started the rollover bottom alt 5.700'
6.200' 150ias +wep as i started the rollover bottom alt 4.100'
the first one was close to corect even though i couldent get to 400 ias at that alt
if i had been doing 400ias with wep i might have augerd!
all the rest of the alts and speeds when i had done them dident come as close to the stats you gave me even though the lowere alts and speeds i could match i still came out with a signefcant amount of extra alt.
so i have doen thes tests every one is welcom
to try them. i might have made some mistake.
i dont think i did but who knows. i did thes test from the air feald off line A1?
well im intrested to hear your thoughts and coments im learning and having fun!
never thought i would see that (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
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OK what makes me wonder,
Film shows early production razorback P47 (I'm not even sure it's a D model). In AH we have D-30, which was one of the last D production models. IMO perfomance of these 2 planes should be very different, so why would you compare one to another here?
mx22
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The D-30 is about 2000lbs heavier and got 3-600 more HP (The manual covered P-47's with and without water injection) (It should also be noted that AH's D-30 appears to be 300HP short)
I tried the same test with WB's P-47C some time ago and it was so far off that I gave up.
Daff
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CO, 56th Fighter Group
"This is Yardstick. Follow me"
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Useful ?
from http://www.nasm.edu/nasm/dsh/TRANSCPT/GILRUTH3.HTM (http://www.nasm.edu/nasm/dsh/TRANSCPT/GILRUTH3.HTM)
===================================
The wing-flow tests showed conclusively that a thick wing like you had on the P-47 lost its lift curve slope when you got above a Mach number of about .7 or .8, which caused it to have this so-called stick freezing characteristic. The stick didn't actually freeze; you could still move it the usual amount, but when the wing lost its lift curve slope, it wouldn't do anything for the airplane. It kept going straight down, till it got to the lower altitudes where the drag was great enough to slow it down to a Mach number where the lift effectiveness was restored. Then you could pull it out -- if you could wait that long. It was tough on the pilots the first time it came. They didn't know it was going to stop. To this day I still meet people who flew the P-47 who say, "My God, I never knew why that was."
=====================================
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Hello, I am not as knowledgable as some of you with the technical information of aircraft.
But, I do talk often to a friend of mine who flew the P-47 in the ETO 1944.
This is one of his quote`s from an e-mail he sent me months ago and gave me permission to quote him.
The reason for me posting this was seeing so many comment on this thread that are just NOT TRUE.
Below is a REAL account from a REAL P-47 pilot.
********************************************
"I also remember that on my 50th mission, I was flying element lead & somebody called out the "bandits" & my flight leader turned the wrong direction, or we would have been able to engage them at 26,000`. While in a vertical bank & turning as tight as possible, I saw an Me-109 firing on a B-17. I immediately did a split s & tried to catch him. I went thru the gate on the throttle quadrant, with the turbo lever as well as the throttle, to war emergency power & switched on the water injection. This was also known as "balls out" position. I almost immediately had to decrease power, since I finally was indicating about one needle width over 600 mph. The Jug was red lined for max. permissible speed of 550mph. With the Jug, you had to add power to get out of a dive. If you decreased it, the airplane would tuck under. I got out of this situation with my elevator trim tab. Started pulling out at 15,000` & got level at 5,000`. The german fighter had shot down one B-17 & the 17 gunners got one Me-109. That made 11 parachutes in a wad going down. I spotted them about 5,000` when I saw gray puffs of anti aircraft fire bursting among the chutes. I am certain in my mind that if I had been in a P51, the airplane would have come apart in a dive such as I made. There was NOTHING in the world at that time that would dive with a Jug & NOT disentrigate."
Charlie
********************************************
I hope this answers some of the questions you guys are looking for.
The Jug is poorly undermodeled in WB, I have downloaded it if AH but have not flown it yet.
In WB the Jug starts shake badly at 500MPH, only 100MPH short of what the real one would do. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
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Mavric ~ X.O.
WB 325th FG
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600mph IAS? Didn't factory pilots dive P-47's and see 750mph on the dial or something? Hmmm....
"There was NOTHING in the world at that time that would dive with a Jug & NOT disentrigate."
Spitfire at what was it... Mach 0.92?
Even a flimsy little plane like the Me 109 could manage Mach 0.8... (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
[This message has been edited by juzz (edited 07-02-2000).]
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Mavric your letter kinda sounds like the point im making. with wep in a split S im not geting compresion. Im not using the dive flap im not pulling over 4G and im able to do the split S quite well with wep.
i tested at 30k split s with wep
puling 4g and never turnd off wep and
never usd the dive flap i leveld at 18k
in your letter he had to back off wep (balls to the wall) almost at once and he couldent pull out till he hit 5k
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Thor, it would help to see a film of this if you could make one next time you get a chance..
-Westy
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I don't think the airframe disentigrating is the problem i think it's the fact that the 47 losses use of it's control at mach 0.7-0.8
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I see your point Thor,
Sadly, most of the planes in these sims don`t perform like they did in RL. (http://bbs.hitechcreations.com/smf/Smileys/default/frown.gif)
Notice how he said that you had to ADD power in the Jug to get out of a dive. But since he was "balls to the wall" that was not an option. So his only option at that point was to use the elevator trim and it took him 10k to recover. (damn, that would be scary)
What he also said in his letter that I did not post was he flew the P51, P40 and Spit. He stated that in those planes you could decrease power and recover from a full speed dive, but the P47 was the only one he flew where it did not work and the plane would just tuck under on you if you tried.
Out of all of them the P47 was his favorite. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif) He talks alot about how beautiful it flew, very stable. He hated the P51 because you had to trim the aircraft allmost constantly.
Here it is, found it:
********************************************
"In fact, you could change airspeed 25 or
30 mph with the Jug & not be straining on the controls & without retrimming
the airplane. The 51 had a manifold pressure boost & once you set the power
with the throttle, you didn`t have to keep advancing the throttle when
climbing, etc. like we had to do with the Jug. However, the flapper in the
belly scoop on the 51 would change the trim on the airplane as it changed
position automatically to do the cooling. You had to fly with your left hand
on the trim tabs on the 51 about all the time. Any 25 or 30 mph airspeed
change was extremely hard to hold manually."
********************************************
Anyways, great thread, hope I was able to help out.
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Mavric ~ X.O.
WB 325th FG
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I may have an instructors insight into why the P-47 training material claimed that a split-s with max power would result in "very bad things(tm)".
The T-37 I'm instructing in now has a structural limiting speed of 382 IAS, but a max allowable speed of 275 IAS due to stability and buffeting problems above that speed. As a result of this, we teach students to be very careful when doing split-s or other manuvers that result in a very nose low attitude. The critical parameter at the manuver entry is NOT the power setting (contrary to popular belief and common sense), but the entry airspeed.
The cut-off speed we teach our students when beginning split-s manuvers regardless of power setting is 130 IAS. Above this speed, the airspeed rises fast enough to require the entire manuver be flown at "max performance" limits. At 130 knots or below, the entire split-s can be flown at or below 4 G's with airspeed building to under 250 IAS. Between 130 and approximately 170 knots, the manuver can USUALLY (depending on altitude, fuel weight, throttle setting, and speed brake position) be flown within airspeed and G limits if the plane is "max performed" around the manuver (flown either at the G limit or at the stall buffet, whichever comes first). I haven't had the cojones to do a split-s above 160 IAS, because the last one I did started at 4 G's and ended at approximately 6.5 G's and right at 275 IAS.
Again, the entry speed can be more important than throttle setting depending on the situation and other parameters (if you start slow, idle power isn't much different than max power) and the instructional materials will give new pilots some rules of thumb that allow for a mistake or two without killing anyone or destroying the plane.
As a last note, you might say that the P-47 had enough extra power than the T-37 that power setting WOULD be more important, but my 4 years flying the F-15E taught me differently. In the F-15E the altitude lost and speed gained during loops and split-s manuvers depended on entry airspeed and AOA control more than power setting, and using max afterburners would result in the tightest turn with minimum altitude loss if the entry speed was reasonable (below corner and outside G-limited speed regions).
My $.02
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eagl <squealing Pigs> BYA
Oink Oink To War!!!
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Hi Westy i would love to make you a move but i have never been able to get the movie thing
working (and have no way to know if the film recorder is even on) The Test are easy to
recreat if your interestd in doing it i could try to meet you in the h2h ariena some time we could do the tests or you could filme me whatever works.
Mavric thanks for the info its been a good read Thanks for sharing the letter with us all. I have always wanted to talk to the people that flew thes birds its nice to
know some one gets to (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Hi eagl i never thought of it like that
you have a good point. With that said. i would like to point out that befor Daff
was kind enuf to give me some stats to
work with i did my first set of tests at
the max speed i could get out of the P47
at a given alt. As an example My first
test was at 30k 250 ias 250 was not just
a crusing speed. i dident get to that
speed till i went to wep and held it
there balls to the wall till the speed indacator stoped moving. In my first post all speeds were maxed out and never did
i auger. In the old traning film at zenos
of the P47 it shows what speed and alt
will result in an auger i found it interesting (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
[This message has been edited by Thor^ (edited 07-05-2000).]
[This message has been edited by Thor^ (edited 07-05-2000).]