Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: Wilbus on September 12, 2002, 09:31:24 AM
-
It's got almost the same speed as a Ta152 at the deck with wep (bout 5mph slower) it is much faster without wep (both planes without wep of course.
At all altitudes above 10k it climbs better. It is as fast as the Ta152 at 31k (best alt for AH Ta152).
It accelerates far better at all altitudes. It dives better and it turns FAR better and is easier to hit enemies with although the guns make FAR less dammage.
You can no longer see the 30k+ charts which is bad so you can't really check the speed there but can always try it.
Ok, well, actually, I don't want the P51 B perked but I think ya'll understand why I wrote this post, it's got the same/better performance then the Ta152 at almost all alts except for the Ta152 being slightly faster and slightly better climb bellow 10k.
Basicly these 2 planes are good at the same things but one is perked. Why? because it was a late war plane? Does that matter AT ALL when it comes to a very NON historic arena such as the MA?
-
Be nice to see how many people come in here and yell :D
-
Wilbus I think ur right but I think also it has a to do with the production numbers.
Don't know if the same argumentation could be made with F4U-4.
-
OK..if you give 2 mg151/20s and a mk108 to the pony b
-
Wil,
but they made more then 700 51b's :D
vati
-
Well Pongo, which will you get most kills in do you think? P51B is very good for long range shots, deflection shots and long range delfection shots.
With Mg151's you don't shoot at much more then 400, with Mk108 never more then 300 TOP (if you want a good chance to hit). Ta152 very hard to make delfection shots in because you don't see over the nose.
Should the armament alone perk a plane you think? Then perk the tiffie, 190 A8, La7 etc etc and everything else with 3x20's or more.
Just my argument anyway :)
*Slaps Vati* Go away evil man go away!! *runs away* :D
That's the problem I have vati, production numbers should have NOTHING to do with perks in AH, the F4u-1C wasn't perked because there were only 200 made (ok 4 times as many as there were Ta152 H's)
Same with you Duedel, production numbers shouldn't matter IMO, but they seem to do :(
-
Wil,
You know i'm only pulling your leg :) There seems to be SOME GREY13 area with production numbers on the TA's anyway!!
Vati :)
-
ohhhhhhhhhhhhhhhhh wilbuz I was coming in here to slap you good for even suggesting perking one of my favorite planes. ;)
but I can appreciate your frustration with the Ta-152
-
What you don't mention is the 51b's crap 6 view, propensity for unrecoverable stalls, and 4 50's.
Deflection shots in this plane don't cut it. You need solid bursts.
Damn Wilbus, you gotta have at least 5000 perks. Why all the fuss?
F.
-
Wilbus if you dont see that the 152 has great guns then your missing something. Almost 0 convergence issues on 2 20mms and a 30mm. You only need the 30 if you are about to ram someone..at which time they disapear. Look at the diff between a la7 with 2 20mm and with 3. now imagine the third one is a 30mm...wow.
with the awsome flying qualities of the pony b. that gun load out would rock peoples worlds. Its like a G10 but the 13mms are 20mms...wow.
-
Originally posted by Duedel
Wilbus I think ur right but I think also it has a to do with the production numbers.
Don't know if the same argumentation could be made with F4U-4.
Have you seen the production numbers for the n1k2? There were as many 262s as there were n1k2s.
The F4u4 is perked because it would be used way too much in the main arena. It is essentially a p51d that is better at high alt/high speed, and worse at low speeds. It should remain perked, but really needs to lose it's gangbang tags to have much chance in the MA environment.
The Ta152 isn't a great fighter at any altitude, it's not particularly versatile. If it were unperked, it would probably only see a little bit more use than it does now.
-
Yes, that's why I'd rather see the Ta152 fixed than rather having it unperked, in all mentioned aspects of accel,climb,and top speed at alt. But if it's not fixed or is not intended to be fixed I sure hope it doesn't remain perked for a long time.
-
Why were only 200 Cannon Hogs made? And, if perking is all about numbers, why is the niki not perked?
Also, were more hog-4's made than hog-c's? If so, why the discrepancy in perk points required for each ride?
I would not like to see the pony-B perked, although I doo see the case as to why it should / cold be. Interesting, I did not know that (re: performance specs)
Thanks, and great thread!
-
Hmm, an unperked 152 ? This is not the purpose of this thread, I believe. The plane was extremely rare, close to C-Hog ;). It should be perked.
As for performance, I just can't believe that Kurt Tank considered Dora only an intermediate step until Ta 152 is available. Being as it is in AH, it is like you are given a Ferrari until your Fiat arrives.
Ta 152 is not a bad plane, but isn't terribly good at anything too, except fuel endurance and dive. If that was Kurt Tank's finest, than damn, was he gay afterall ? ;)
-
Just be glad HTC modeled the B so conservatively. Manufacturer's testing yielded top speeds in excess of 450 mph.
-
Yes yes I don't want it perked either, not worth it, but I think you all understand me when the only real difference is the better turn rate of the Pony, and the much better guns (if in close) on the Ta152.
Pongo, in my last post I said the Ta152 has got great guns but compare the eas of delfection shooting and long range shots. Matter of flying and what planes you attack I guess :)
No, this thread isn't really about unperking the Ta152, just to compare it with even NON uber rides of the MA, where the TA still comes out a bit short.
Vati... there are DEFINATLY some GREY13 areas about the Ta152 production numbers
Funked, our B pony does reach 450, at alt :)
What you don't mention is the 51b's crap 6 view, propensity for unrecoverable stalls, and 4 50's.
Deflection shots in this plane don't cut it. You need solid bursts.
The crap 6 view is one thing.
Unrecoverable stalls? No need to get into a stall when a plane turns like it does, even if you don't fly it near the edge it will still outturn a Ta152, specially with the use of a notch flap or two :)
Solid burst can quite easily be done in deflection shots too, whole nother thing with snapshots though where of course the Ta152 beats the living crap out of the B pony :)
Why all the fuss... can't believe you don't understand that :(
I have enough perks, lost alot in discos on 262's etc but still got plenty, takes me 1, maybe 2 sorties to get a Ta152 so no problem with that really but what I want going here is a discussion and to make people somewhat know what it feels like to have his "uber" ride perked, although it's no better then any other mediocre plane AH :)
all keep the discussion going please :)
-
Red Tail,
Perking is not all about the numbers. There were 1,200 Me262s built, 957 Spitfire Mk XIVs and 700 Tempest Mk Vs.
Perking is mainly due to the effect the aircraft would have (or "had" in the case of the F4U-1C) on the MA. Who wants to have one fifth of their fights be against the F4U-1C? Now imagine a free Me262 or Spitfire Mk XIV, they'd make the F4U-1C's usage numbers look tame.
The fact is that the N1K2 simply doesn't have that kind of impact, and so will not be perked.
Before I could say yay, or nay to the Ta152 being unperked I'd want it to be fixed and then let the MA evaluate it. If it still wasn't that good I'd see no reason not to unperk it. Hell, it'll still have the "gangbang me, I'm a perk plane tag" and I think it'll still attract the gangbangs simply due to being a former perk plane.
-
Originally posted by Karnak
The fact is that the N1K2 simply doesn't have that kind of impact, and so will not be perked.
True, it's only roughly tied in the top-four. Right next to the p51d, with how many thousands that saw service?
Right now the p51d is the standard for perking, however by that time, the air war was prettymuch over, leaving the axis fighters lagging behind. Perhaps the performance maximum for free fighters should be lowered a bit, creating more cheap perk planes.
-
It has been said time and time again that performance alone does not determine whether an aicraft is perked or not.
-
Originally posted by Soulyss
It has been said time and time again that performance alone does not determine whether an aicraft is perked or not.
It's also apparent that the criterea for perking a plane is fuzzy at best. There are any number of reasons for perked planes to be unperked, or unperked planes to be perked.
There are free planes which are free for the same reason that a perk plane is perked. There are also perked planes which are perked for the same reason that a free fighter is free.
Let us see a definitive explanation of what determines wether a plane is perked or not. It would solve a lot of these debates.
-
The way I understood it, and correct me if I'm wrong is that those planes which by introducing them in a uncontroled manner would upset the MA arena plane type balance, i.e. Plane X would get 10% or 20% of the kills etc. That's why a plane like the Hitspano CHog was perked.
Now, considering the historical performance of the 152 in speed at hi alt, and acceleration at lower altitudes...compared to its Stopgap the D9 it's about as useful as a 190A8 with the same armament with a slight performance advantage over at 30k. It may have been some mistake in the calcs as to why the 152 has such a mediocre perfromance in the game, which would translate in having an impact on overall gameplay balance as a Ju88.
-
the b pony is a sweet bird to fly, and it's stall is sudden but perdictable. No reason to stall it out at all. Now it will "flip" on you if you push her a bit past the edge looking for a shot...but it's simple to unload and recover before she spins out.
Personally I've always felt the 152 is a pretty useless bird in the MA....cept to uber runstang with. But you cant dance it around like a pony,jug,hog or even a tiffie.
-
Yes the fact that there were maybe 2 or 3 production Ta152-H1's total has nothing to do with the perk status that makes it rare in the arena ;) Nothing at all. If you count the H0's, there were only 42 production Ta152's produced overall.
And while our P-51B is decent at alt, it doesn't compare to the Ta152 in the least.
Since when did the B pony make 450mph? Is this on the guage or on the digital readout you can use in the film?
-
Problem with tha Ta-152 is the acceleration. It should acclerate like a rocket up to 350 mph at any altitude with it's WEP injection systems.
AH didn't model this. :(
-
Originally posted by funkedup
Just be glad HTC modeled the B so conservatively. Manufacturer's testing yielded top speeds in excess of 450 mph.
For the quote below I don't have it's original source. It was posted by Oleg Maddox to the http://www.simhq.com's IL-2 Sturmovik message board. Oleg said that it was from a western historian. I'm just posting it to show a different view on the matter.
"The printed maximum speed in all books for the NA P-51D Mustang is 437 mph at 25,000 ft. Absolute nonsense. The fastest speed ever actually RECORDED for a P-51 ocurred on 20 October 1944, over Henden RAF base, England. Following RAF complaints that the P-51 would not reach the printed speeds, no fewer than 12 Mustangs from various units--two right off the boat, as well--were tested with USAAF pilots. Both theodolite units and radar were used to measure the speed. The fastest run--I should mention after innumerable flights occupying the whole day--
was 416 mph in a P-51B (s/n 36799 "Carolina Hustler"); this speed was sustained only for 10 seconds before the engine became seriously over-boosted. The longest sustained maximum speed recorded was 405 mph for 55 seconds by a brand new P-51D at 23,000 ft. (s/n 472484). Most of the machines in this evaluation were incapable of exceeding 400 mph under any conditions whatever. The NII VVS tested their P-51B (L-L, s/n 35145) to a maximum of 392 mph at 25,500ft, and climb to 5000m of 6.5 mins. (yes, on 100 octane gas). I suspect that this was exactly correct, despite the fact that all Wetserners try to explain it away. These two events are the ONLY scientific evaluation of the Mustang by any non-Company (i.e. North American) entity in the entire history of the aircraft. Both evaluations prove that the Company was inflating their numbers for 'advertising' reasons...."
-
thats gotta be BS wmaker. Its a neat story though.
Published top speeds that I have seen vary from 440-448 MPH TAS at altitude. FWIW, Zeno's has 448 MPH for the P-51D.
http://www.zenoswarbirdvideos.com/P-51.html
-
now...
woudnt that change our little game..lol
-
I'm talking about manufacturer's data, not USAAF or RAF data. If people want to say that NAA was lying then the discussion ends, because we can apply that to any other organization who tested aircraft. Certainly one could construct scenarios the NII-VVS might have a motive to show the inferiority of an American product.
http://yarchive.net/mil/laminar_flow.html
Report: NA-5798
Title: "Flight Test Performance for the P-51B-1
Date: January, 1944
Test Weight: 8,460 lbs
High Speed: 453 mph true airspeed at 28,800 feet at 67" HG and 1298 HP,
war emergency power, high blower, critical altitude.
-
Wasn't Carson that fool who ignorantly lambasted the Bf109, often criticizing it for for features, like the radiator ducting, almost identical in concept to his beloved P51.
-
Originally posted by GRUNHERZ
Wasn't Carson that fool who ignorantly lambasted the Bf109, often criticizing it for for features, like the radiator ducting, almost identical in concept to his beloved P51.
If you can't see the superiority of the P-51 radiator/oil cooler ducting over the 109, you shouldn't be posting here. :)
-
Verm, I said it before and say it again, charts that we had before, that went 30k+, showed the P51 B with a speed of 450 at about 35k.
Karnak, what I want is fot it to be fixed, even then I don't think it would be worth perking, it had a great, actually, exelent rate of climb but that doesn't make it perkable.
-
Originally posted by Wilbus
Karnak, what I want is fot it to be fixed, even then I don't think it would be worth perking, it had a great, actually, exelent rate of climb but that doesn't make it perkable.
It sure made the Spitfire Mk XIV perkable, and its WEP only lasts five minutes.
-
Are we using manufacturers data for all planes?
if the usaaf and the RAF coundt get within 50mph of that number..what does it matter what the russians found?
-
When Pyro decides to fix the Climb, accel, and Speed at altitude like its RL counterpart it will indeed be worthy perked aircraft. The odds of that happening are really slim even with the overwhelming evidence we have from various sources no even LW,but brit tests and numbers.
4.5k per minute at SL for climb rate would indeed make it perkable!!! also considering the LW wep lasts for about 10minutes and the climb to 23k would be made in 8 minutes.
I suspect greatly it has to do something with missing HP for the Ta and torque like Fork has meintioned before that's why it doesn't get its speed nor acceleration.
-
Ha ha ha that quote from Oleg is such pure and utter crap.
J_A_B
-
Originally posted by Glasses
Yes, that's why I'd rather see the Ta152 fixed than rather having it unperked, in all mentioned aspects of accel,climb,and top speed at alt. But if it's not fixed or is not intended to be fixed I sure hope it doesn't remain perked for a long time.
Maybe they should just remove it from the game to stop all the crying about it. In the history of the war, it was a totally insignificant curiosity.
-
I don't think at all it should be removed if it's that way some would have the D9 completely dissapear because of it's "low" production numbers.
For an aircraft that is perked and it's suppossed to have performance greater than that of the D9, it's undermodeled in those aspects if it was put in the game it was done so for a reason so the LW would have an prop driven perk but I think either they put up the climb and HP from the H-0 or it might have been a slight modeling mistake in HP which doesn't give the correct speeds, climb and acceleration. The aircraft is not a problem and will probably not be a problem in the future,why? It's perked,why? because it would unbalance the arena, and indirectly one of the reason it would be chosen for perking it'd be a derivative of an overwhelming advantage over the other unperked aircraft which would lead it to be chosen over any other rides. It'd be frankly a waste if it'd be just erased after I'd have complete support from people like Frenchy and Karnak who have seen with the information posted and agree to its modeling being short of what it is suppossed to be. It was indeed a rarity in the war which almost about over when these aircraft came to action but those aircraft were the Best to come out the design beureu of K.T. and we've had proven with numbers and not just historical accounts the aircraft falls short real short of hitting the numbers,and of course the paint Scheme is that of the Ta152H-0,but IMO that's minimal. If and when and if ever Pyro decides to fix the aircraft, and the use increases with it's improved climb rate acceleration and hi altitude speed I guarantee you this aircraft would be perked higher out of use alone of the regular bunch and some other of the 190 Leather wearers.
I don't want to see it unperked I want to see it fixed,and I implore pyro to take a look at the data that has been brought up to please , please fix the plane because it's one of my fav planes yet there's overwhelming evidence it's falling short of its RL counterpart numbers.
-
The way I understood it, and correct me if I'm wrong is that those planes which by introducing them in a uncontroled manner would upset the MA arena plane type balance, i.e. Plane X would get 10% or 20% of the kills etc. That's why a plane like the Hitspano CHog was perked.
planes arent perk just on anyone thing.
performance alone dont matter
overall numbers alone dont matter
However overall imopact on the main matters. Thats why the chog was perked. Not on performance or numbers but because it got nearly 20% of the kills.
The ta152 needs to be perked because it was very rare in ww2. I dont want a main full of wunderwaffe planes :)
My squaddie moot, last time I checked, was 73 and 1 in the 152.
Its a great plane and a cheap perk. I fly flew in the other night went 6 and 0 in it. And no I wasnt gangbanged because of its icon :)
None of the top 3 killers in ah have the same impact of the main as the chog.
Olegs quote about 51 performance makes you wonder. Doesnt ht model VVS planes based on test of production a/c (more like quality control tests)? Anyway p51b is pos imho.
-
"Olegs quote about 51 performance makes you wonder"
No it doesn't. It's BS. I can understand why he might be of that opinion, but it's still BS. Why would he be of the opinion he is? He'd feel that way for the same reason most Americans assume that Soviet planes were junk--growing up during the cold war.
FYI the 437 MPH figure, although it may match manufacturer's claims (I have never seen manufacturer's data on the 51D), also comes from post-war testing of the plane in war configuration (read: not souped up). The P-51D, of all WW2 planes, probably has the most and best information available. In other tests the P-51 performed even better; several tests such as the Navy's test of a P-51B rate the plane for as much as 450 MPH (and the Navy was if anything biased against an Army plane like the P-51).
Not to mention just a paper comparison of the P-51 to planes like the Spit and 109G should show Oleg to be wrong. But it's a free world; he can be as wrong as he wants to be :)
J_A_B
-
Originally posted by Wmaker
For the quote below I don't have it's original source. It was posted by Oleg Maddox to the http://www.simhq.com's IL-2 Sturmovik message board. Oleg said that it was from a western historian. I'm just posting it to show a different view on the matter.
"The printed maximum speed in all books for the NA P-51D Mustang is 437 mph at 25,000 ft. Absolute nonsense. The fastest speed ever actually RECORDED for a P-51 ocurred on 20 October 1944, over Henden RAF base, England. Following RAF complaints that the P-51 would not reach the printed speeds, no fewer than 12 Mustangs from various units--two right off the boat, as well--were tested with USAAF pilots. Both theodolite units and radar were used to measure the speed. The fastest run--I should mention after innumerable flights occupying the whole day--
was 416 mph in a P-51B (s/n 36799 "Carolina Hustler"); this speed was sustained only for 10 seconds before the engine became seriously over-boosted. The longest sustained maximum speed recorded was 405 mph for 55 seconds by a brand new P-51D at 23,000 ft. (s/n 472484). Most of the machines in this evaluation were incapable of exceeding 400 mph under any conditions whatever. The NII VVS tested their P-51B (L-L, s/n 35145) to a maximum of 392 mph at 25,500ft, and climb to 5000m of 6.5 mins. (yes, on 100 octane gas). I suspect that this was exactly correct, despite the fact that all Wetserners try to explain it away. These two events are the ONLY scientific evaluation of the Mustang by any non-Company (i.e. North American) entity in the entire history of the aircraft. Both evaluations prove that the Company was inflating their numbers for 'advertising' reasons...."
as to OLEG's information. I queried some folks in a newsgroup to th validity of OLEG's response in the IL2 thread.
here as follows FWIW--
Gruenhagen's book on the Mustang shows a max. level speed of 441 mph @ 30kft for
the P-51B with V-1650-3 (and probably no rear fuselage tank). I'd really want
to know what the atmospheric conditions were on the day in question, as all test
results are supposed to be normed to Standard atmosphere, and whether this was
done. The claim that "these two events are the ONLY scientific evaluation of
the Mustang by any non-Company entity in the entire history of the a/c" is
patently incorrect. For instance, there used to be a web link which had the
results of the speed and climb tests performed on the Mustang Mk. I (AG 351) at
Burtonwood by the RAF. Unfortunately that link's no longer active, but
Gruenhagen states that the a/c managed a top speed of 382 mph at its best
altitude of 14,000 feet (engine critical altitude of 11,300 ft.) during those
tests, reduced from the 390 achieved in company tests because the a/c had gotten
its camouflage paint as well as having other operational equipment added.
Elsewhere he lists the same speed at 13,700 feet, which may be the value
corrected to ISA. Either way the best speed altitudes were a hell of a lot
lower than the Merlin-powered models in high blower, which were also more
powerful. Higher altitude = thinner air = less form drag = higher speed, until
the power starts to fall off or mach effects (on the prop or airframe) become
significant.
The P-51A, with a more powerful engine (Allison V-1710-81 vice -39) is credited
by Gruenhagen with 409 mph at its best altitude of 10,000 feet, mainly because
the -81 has a War Emergency MP rating of 57"/3000 RPM at that altitude, vs. the
-39 engine's military rating of 44.2"/3000 RPM at 11,300 feet; the -81 can
maintain the 44.2"/3000 RPM up to about 17 or 18,000 feet (eyeballing the
graph). Again, both of these are well below the critical and best speed
altitudes of the Merlin models in high blower, as well as being down a couple of
hundred hp compared to the Merlin. The Merlin V-1650-3 engined models made
their best speed at 30kft (give or take a few hundred, allowing for the usual
variation), while the V-1650-7 models made theirs at 25,000 feet.
Guy
-
Well Jab sometimes it happens across these boards aswell what you think of what oleg said.
-
Pongo AFAIK HTC are not in the business of revealing research sources. However if you "reverse engineer" the climb and speed curves you will find they almost always come very close to some set of customer test data (e.g. USAAF, NII-VVS, AFDU) as opposed to manufacturer's data. Manufacturer's data is often more optimistic than customer data, for many more reasons than advertising.
-
I don't want to see it unperked I want to see it fixed,and I implore pyro to take a look at the data that has been brought up to please , please fix the plane because it's one of my fav planes yet there's overwhelming evidence it's falling short of its RL counterpart numbers.
Exactly, couldn't have said it better myself.
The ta152 needs to be perked because it was very rare in ww2. I dont want a main full of wunderwaffe planes
My squaddie moot, last time I checked, was 73 and 1 in the 152.
Wotan, the Ta152 has got worse performance, in all ascpect at all altitudes below 25k, except for turn rate then the D9. It is only slightly faster then the P51B, and the 190 A8 aswell as many many other planes. It's about 25mph slower then the La7 at the deck, bout 20mph slower then a tiffie and a good 15mph slower then a D pony, 20mph slower then a Dora (cirka).
It climbs worse then all of those except the tiffie. What makes it a wunderwaffle plane bro? :)
When it's fixed (if) it would sure be worth the perking, as it is now, hell, it's hardly worth flying unperked as the Dora beats it hands down aswell as many other planes even from 1943. I was chased down, in a dive followed by along "on-the-deck-run" by a P47 D-11! He didn't lose any distance on my although we were on the deck for 3 minutes.
-
Hi Funked,
>If you can't see the superiority of the P-51 radiator/oil cooler ducting over the 109, you shouldn't be posting here. :)
You shouldn't dismiss it so lightly :-)
The Me 109 radiator, after it was completely redesigned for the Me 109F, featured a boundary layer bypass duct and continuously variable intake and outlet cross sections, and that's technologically very similar to the P-51's radiator system.
The actual layout of course differed, but the late-series Me 109 radiators were quite sophisticated and much more efficient than the early-series underwing "boxes" :-)
Regards,
Henning (HoHun)
-
Hi Ammo,
>as to OLEG's information. I queried some folks in a newsgroup to th validity of OLEG's response in the IL2 thread.
As an additional info, I remember reading a comment on some board that provided an explanation for the low numbers Oleg posted.
It seems like the British tests he refers to were using British standard procedures which had top speed tests done with radiator flaps in closed position. This gave the best short-term top speeds for most British aircraft, but the Mustang of course relied on its variable outlet to provide a jet effect, which was negated by British procedure. As a result, drag increased and cooling deteriorated, leading the the poor speeds and quick overheating pointed out by Oleg.
I can't comment on how accurate this information is, however, and couldn't find the original post again when I searched for it.
Regards,
Henning (HoHun)
-
I still don't seem to see anyone with an effective counter-explanation for the top speed of the P-51D. ammo's post is very informative, but its basically a "guess" based on the P-51A. Hohun's post seems logical, too, but yes, it's basically an explanation on why the P-51D was slower than the factory charts... you can't conclude on how fast the P-51D was based on that.
Don't get me wrong, I find it hard to believe what Maddox disclosed, too... The image of the "lightning-fast P-51D" is still hard embedded into my brain, too. :)
I'm just stating that these different views and interpretations are pretty interesting to watch. :) I remember the heated debate when IL-2 first came out concerning the roll-rate performances of the 190. One thing for certain is, like many things, there are different views on flight modelling of a certain plane.. and since IL-2 is probably the first case where the developers use research data that is not primarily based on Western tests, it is very interesting to note that maybe, just maybe some of the perceptions and images of a certain plane we held for so long might not be right. It's a possibility I guess :)
Whatever it is, I don't think we can just dismiss it as "roadkill".
...
Would there be any other instances of "real tests" concerning the P-51D other than the case Maddox refers to? :) It'd be interesting to know...
-
Then again, when Il2 first came out the roll speed of all planes were total BS, specially the 109 and P39. (thinking about the Demo now)
Think they've got it pretty good now though.
-
hohun/kweassa--
I have been promised more information forth coming.
-
Another thing crossed my mind as I read Hohun's post.
Would the radiators on some planes effect the plane so much as drag down nearly 20mph from its top speed, and make the engines overheat up to such dangerous levels?
If so, maybe modelling some of the more various aspects of the planes in AH might be farely enjoyable. :) Things such as engine overheat(not as drastic as IL-2 though..), management of radiators, a bit more profound RPM control, opening/closing cockpits for the planes known to fly them open in some situations.. and maybe supercharger gears and stuff..
If such management issues were put into AH, I have a feeling a lot of planes would feel totally different than we're used to :D It'd be very cool to watch how managing the more detailed aspects of the plane would work on our normal sense of "dogfight"..
...
Oh dear. I've done it again.. I've hi-jacked the thread.. :D
-
Kweassa, this sounds like a similar idea I posted some time back. I suggested random parts/equipment failures to simulate the real life aspects of planes at the time. How many times have you read stories of P51's taking 48 fighter with 4 extra, and then when some planes had 'technical difficulties' the extras would fill in. This aspect of realism would greatly hamper the MA, but I think in the combat theater or as an option for something like H2H would challenge everyone greatly. Another example, in real life, the original P51b's couldn't fire while turning because the belt loaders for the .50's were at a 45 degree angle inside the wings, or else some guns would jam? How about gun jamming or overheating? That would be a VERY interesting aspect added to AH. I'm not saying we need these things, I'm just suggesting it as an addition once HTC creates most of the WWII planes. Hope HT is reading this thread, great posts guys!!!
Jason
-
Funked.
Thats why I thought those numbers were interesting. they were USAAF and RAF numbers where they not?
The cooling system for the pony was supposedly heavily influenced by a visit of the designer to the ME factory.
I think that was in planes of fame volume one...
-
Hi Kweassa,
>If so, maybe modelling some of the more various aspects of the planes in AH might be farely enjoyable. :) Things such as engine overheat(not as drastic as IL-2 though..), management of radiators, a bit more profound RPM control, opening/closing cockpits for the planes known to fly them open in some situations.. and maybe supercharger gears and stuff..
I'm not sure it would make much of a difference for performance or even for pilot work load. The late-war planes had many automatic controls, and thermostatically controlled radators were pretty common too. Often, you'd only override the automatic to get full fuel economy.
The early-war planes varied a bit more in their degree of user-friendlyness, I think the Me 109 for example was quite good while the F4F required a lot of manual attention, with most other planes somewhere in between.
Still, it would be nice to have the "character" of an aircraft reflected in the way you describe, even if it might not impact performance very much :-)
I'd actually be ready to hit the "raise gear" key 28 times after each takeoff in the Wildcat to simulate cranking up the wheels manually! ;-)
Regards,
Henning (HoHun)
-
Originally posted by funkedup
I'm talking about manufacturer's data, not USAAF or RAF data. If people want to say that NAA was lying then the discussion ends, because we can apply that to any other organization who tested aircraft.
I generally agree that if we start throwing lying accusations around with out any proof we could easily do that in every direction. Mr. Gruenhagen obviously thinks he has the proof to say so. Personally I'm not going to judge if it's true or not. But I can understand if a purchaser has doubts on manufacturers data. But as I said: I see what you mean.
"Report: NA-5798
Title: "Flight Test Performance for the P-51B-1
Date: January, 1944
Test Weight: 8,460 lbs
High Speed: 453 mph true airspeed at 28,800 feet at 67" HG and 1298 HP, war emergency power, high blower, critical altitude."
HTC's help pages show Normal loaded weight of 9245 lbs for the P-51B-15. That's 785 lbs higher than the P-51 in NAA test. Weights of P-51B vary 9200 lbs to 9400lbs depending on the source. So they are well inline with HTC's weight. Also I doubt the NAA-test a/c had its wing hardpoints attached. This is just a guess based on various pics I've seen of P-51B-1 test a/c. Since your quote on the test doesn't have a a/c serial number it's hard to determine if any of those pics match the plane in NAA test. F4UDOA said somewhere on this board that to his knowledge F4U-1 is the only plane in AH where hardpoint drag is taken into account because it was almost always attached in operational planes. I don't remember seeing pictures of operational P-51Bs without their wing hard points. So I don't know if they are calculated in the FM or not. I think they should be though.
I tested AH's P-51B's top speed at 29000ft (altitude where HTC's speed chart shows the highest speed). I got a result of 440mph with WEP on.
So, the difference is 13mph which well inline with the weight difference and the hard point drag IMO.
Originally posted by funkedup
Just be glad HTC modeled the B so conservatively.
I'm feel very tempted to use the big W-word here but since the discussion has been very civil and interesting here so far I'll try to cool it.
-
"Would there be any other instances of "real tests" concerning the P-51D other than the case Maddox refers to?"
This is why Oleg's case is BS....his claim of "lack of real tests" is simply false. It just isn't true.
If you want, look up for example tests in 1957 of the last ANG P-51D before it was donated to Wright-Patterson's museum. Those tests were done with the airplane in normal WW2 config and matched the 437 MPH figure. The Navy tested the P-51B and did a fair amount of work with the "D" too. There are numerous Army tests available for different versions of the P-51. If all that wasn't enough there is information available from other countries that used the P-51D as well as from private collectors, although in the case of private colectors you must take note of what modifications have been made to the airplane (a few surviving P-51D's are kept very close to WW2 condition). There is more good data available for the P-51D than for any other WW2 fighter that I know of.
Why aren't I looking it all up and posting it myself? I don't feel like wasting several hours of my life refuting a claim as obviously false as Oleg's claim. The fact is, Oleg's "material" is nothing more the the absolute worst data he could find. Whether it is left over Russian propaganda from the cold war or just an attempt to get attention (free advertising) I don't know. I suspect it's a combination of both though.
(I read Oleg's quote, then think of a lot of players in AH who complain about the Yak-9U and LA7..."Russian planes couldn't have been THAT good!")
J_A_B
-
The P-51B was aerodynamically cleaner than the later D model Mustang. The bubble-canopy imposed a drag-penalty, although it was slight. Therefore the B model was a few mph faster than the D model. Top speed of the D model, depending on loadout, would be above 440mph.
Comparing the performance of the P-51D to that of the Ta-152 is like comparing apples and oranges. The Ta-152 was designed for high-altitude interception, it's main targets being Allied bombers. It's engine was maximized for operation beyond the reach of any Allied fighter. This made it ideal for its main role, and for photo-reconnaissance. While it would out-perform the P-51 at altitudes above 35,000 feet the Ta-152's wings proved to be too fragile for high-speed dives, limiting it's usefulness in combat.
Regards, Shuckins
-
Ta-152's wings proved to be too fragile for high-speed dives, limiting it's usefulness in combat.
Sorry but the wing had no proeblems what so ever with high speed dives, it couldn't handle as much G loading as the earlier 190's due to longer wing but the wing was greatly strenghtened and could handle a good amount of G's.
It was actually on par with, if not superior with the P51 D at all altitudes not only above 35k. Combat reports also report it being on par with or superior the Spit 14 and Tempest at most alts aswell, except for the tempest greater low alt speed and spits better climb at the deck (not much better) and it's better turn rate.
Will post a nice little comparion "chart" (text only) which was made in Germany near the end of the war.
-
Hi Shuckins,
>Comparing the performance of the P-51D to that of the Ta-152 is like comparing apples and oranges.
The original comparison at the beginning of this thread was between the P-51B and the Ta 152, and I think this is a fair comparison as the P-51B had the engine that was originally developed to give the Spitfire IX superior high-altitude performance.
Of course, the Ta 152 was highly specialized and used more advanced technology as it came out much later, but the P-51B was a very good high-altitude fighter too, and if it outperforms the Ta 152 at the latter's best altitude in AH as Wilbus claims, I'd say there's no fruit mix-up problem involved ;-)
>the Ta-152's wings proved to be too fragile for high-speed dives, limiting it's usefulness in combat.
I don't think speed was the problem, but the Ta 152's long wings were G limited. I think they were designed for around 6.5 G, meaning that it had a safety margin for up to 9.75 G by standard design practices. The P-51 could be stressed quite a bit more, so it really had the edge in instantaneous turns. The Ta 152, however, undoubtly had the edge in sustained turns.
At high altitudes, high G situations aren't much of a concern as the thin air just doesn't provide enough lift to overstress the wings. The Ta 152H-0's climb & combat power top speed of 720 km/h @ 10.7 km work out to just 400 km/h IAS, which just isn't enough for more than (maybe) 6 Gs.
Accordingly, the (comparatively) low G resistance of the airframe didn't matter much in the role it was designed for. At lower altitudes, this might have been different, and I think a Fw 190D-12 with the D-9's sturdy airframe and the Ta 152H's engine might actually be a better overall compromise :-)
Regards,
Henning (HoHun)
-
Originally posted by HoHun
Hi Funked,
>If you can't see the superiority of the P-51 radiator/oil cooler ducting over the 109, you shouldn't be posting here. :)
You shouldn't dismiss it so lightly :-)
The Me 109 radiator, after it was completely redesigned for the Me 109F, featured a boundary layer bypass duct and continuously variable intake and outlet cross sections, and that's technologically very similar to the P-51's radiator system.
The actual layout of course differed, but the late-series Me 109 radiators were quite sophisticated and much more efficient than the early-series underwing "boxes" :-)
Regards,
Henning (HoHun)
Good point, you are right. I thought of Me radiators and pictured an Emil.
-
Hohun said it pretty good, for the Ta152 H-0/1 the max G was said to be 6.5, all designers use a safety margin of, usually 50%.
Another thing was that pilots during WW2 never pulled 9 G's, nor did they hardly ever pull more then 6, maybe 7 tops so losing a wing due to high G's wasn't common. The Ta152 DEFIANATLY did not have any problems what so ever with high speed dives, it was designed for high speed at all altitudes and could dive just as good, if not better, as any other 190.
Btw, here's the old speed chart that goes above 30k. Only have it for the Ta152 though :(
(http://www.webspawner.com/users/wilbus/ta152hspeed.gif)
-
Wow,
Of all of the A/C in A/H I would actually question the real life performance of it would be the Soviet built fighters ala the La-7 and Yak-9. If I'm not mistaken aren't the AH models flown on pre-production no-combat loaded test planes??
The most undermodeled I believe would be the Japanese plane set. When tested they virtually all were superior to commonly accepted test data albeit with better fuel that the Japanese had at the time.
As far as allied A/C go the Brits tested Navy and AAF birds while the Navy was tested the Mustang, FW190, Zero and others repeatedly.
(http://www.geocities.com/slakergmb/23d60700.jpg)
-
Nope, F4UDOA its the exact opposite. AH uses quality control test flight data that is quite inferior to the data to which you are referring.
-
by inferior you mean that the planes dont rate as well as the factory stats..not that the data is inferior...right?
-
Verm,
Your saying that the VVS a/c had better stats than what are used here?
That is not my current understanding. Do you have this data anywhere viewable?
-
"In his flight report Major Kubyshkin stated that compared with the standard La5FN, the La7's rate of climb had improved considerably. A maximum speed of 680 kmh (422mph) at an altitude of 6000 meters (19,685 feet) was recorded with the La7 prototype - at the time the best performance for a soviet fighter."
Also on the prototype, flown by test pilot G.M Shiyanov on the second of Feburary 1944.
"A maximum speed of 597 kmh (371 mph) was recorded at sea level. This was markedly superior to the La5FN's speed of 546 kmh (339 mph) and the Focke Wulf Fw-190A-8's speed of 560 kmh (347 mph) at the same altitude."
Both those speeds were with the prototype.
Reading further...
"The Standard production La-7 had a top speed of 592 kmh (367 mph) at sea level - 46 kmh (28.5 mph) more than the La-5FN and 72 kmh (44.7 mph) more than the Focke Wulf Fw 190A-3. The improved performance was due to the aerodynamic refinements of the airframe and a weight reduction of some 82kg (180 lbs). At 6100 --ters (20,000 feet) the La-7 had a top speed of 655 kmh (407 mph), 35 kmh (21.7 mph) more than the La-5FN. The La-7 was also 15 kmh (9 moh) faster then the Focke Wulf Fw 190A-8, the latest version of this German fighter to be deployed of the Eastern front"
To me it seems like the low alt modelling for the La7 is in the "prototype" Stage while the 20k modelling is right on with 407mph.
A speed of 380 mph level at the deck was obviously never reached with the La7, prototype nor the production series.
Source of information: La 5/7 Fighters in action.
ISBN: 0-89747-392-2
-
This book (http://www.amazon.com/exec/obidos/tg/detail/-/1857800834/) has comparisons of top speeds, maximum climb rates, and other data for prototype and production Soviet fighters. I haven't looked at it for a while but last time I checked the HTC Soviet planes were closer to production figures than prototype.
-
"The flight tests conducted at the LII in July 1944 showed that the mazimum speed had fallen to 344 mph at sea level and 397 mph at 6000m, which meant that the la7s speed was not signifigantly greater than that fo th a production la-5fn..
..
lists production reasons why...
When tested at the LII a production La-7 with these defects remedied reasched 361mph at sea level and 418mph at 6000m;figures conforming to the prototype. It only remained to realise this performance in the production aircraft, but as it transpired this was not an easy task. Both plants had built about 400 la-7s when productoin aircraft made by plants 21 and 381 where flight tested at NII VVS in eafly sptember 1944. At a weight of 7164 pounds the readched a speed of 355.4 to 359 mph at sea level (with augmented power speed increased to 380mph and 407 to 408 at 6000m.
"
From Soviet Combat Aircraft of the second world war, Volume 1 single engine fighters.
seems like these numbers suport the AH numbers..for a late 1944 production La-7.
-
Sigh :(
-
Originally posted by Pongo
"The flight tests conducted at the LII in July 1944 showed that the mazimum speed had fallen to 344 mph at sea level and 397 mph at 6000m, which meant that the la7s speed was not signifigantly greater than that fo th a production la-5fn..
..
lists production reasons why...
When tested at the LII a production La-7 with these defects remedied reasched 361mph at sea level and 418mph at 6000m;figures conforming to the prototype. It only remained to realise this performance in the production aircraft, but as it transpired this was not an easy task. Both plants had built about 400 la-7s when productoin aircraft made by plants 21 and 381 where flight tested at NII VVS in eafly sptember 1944. At a weight of 7164 pounds the readched a speed of 355.4 to 359 mph at sea level (with augmented power speed increased to 380mph and 407 to 408 at 6000m.
"
From Soviet Combat Aircraft of the second world war, Volume 1 single engine fighters.
seems like these numbers suport the AH numbers..for a late 1944 production La-7.
Yep that's how I remember it from last time I looked at that book. The key is augmented power AKA WEP.
-
That's a big if. Is augmented WEP or over boost. Because as we know WEP is modeled but overboost is not.
And frankly most of what I have just read says top speed on the deck is about 360MPH. And the comment about the La-5 top speed mentioned as 339MPH. It is clearly about 350MPH in AH. What is that based on??
It's not like these A/C never had a chance to prove themselves against the western world. In fact the La-7/11 and Yak-9 saw plenty of action in Korea. Frankly I see nothing to support the claims of performnce seen here.
I have made the request to see some of the AH source data if it could be scanned or faxed/Emailed on request (I would pay for this). But some of the data in here is a little suspicious to say the least.
Doesn't anyone have a chart for the VVS a/c tested by a non soviet block country??
-
the top speed of the production la7s is listed in the tabels in the back of the book at 380 on the deck..why is that so hard to believe with the post I made above. production la7s went 380 on the deck...say it 3 times...
lol
-
Originally posted by F4UDOA
That's a big if. Is augmented WEP or over boost. Because as we know WEP is modeled but overboost is not.
WEP and overboost and augmented power are the same thing dude.
-
Cool, it's an La7 thread now :D
-
Originally posted by F4UDOA
And frankly most of what I have just read says top speed on the deck is about 360MPH. And the comment about the La-5 top speed mentioned as 339MPH. It is clearly about 350MPH in AH. What is that based on??
Doesn't anyone have a chart for the VVS a/c tested by a non soviet block country??
I didn't keep a copy of the link, but a translation of a German test of an La-5 (Rechlin Test Centre, Test No. 90014) was posted to allaboutwarfare.com's forums a while back.
The La-5's speed was given as follows:
323 mph TAS @ SL, emergency power
304.5 mph TAS @ SL, rated power
335.5 mph TAS @ 1 km, emergency power
348 mph TAS @ 5 km, rated power
338.7 mph TAS @ 6.5 km, rated power
-
Umm, La-5 or La-5FN ? There is quite a difference, so I have heard.
-
Originally posted by Hristo
Umm, La-5 or La-5FN ? There is quite a difference, so I have heard.
Thanks for catching that. The La-5 in the report is listed with an 1 850 hp M-82FN engine, which would make it an La-5FN.
-
Yep the La-5FN and La-7 have the Ash-82FN motor with direct injection and very macho overboost WEP aka "augmented power" in the translations from Rooskie.
-
Quite frankly, I would be suprised if any of the prop driven aircraft used by the North Koreans, were aicraft in peak condition and maintenance.
These were used up rejects sent to bolster what was to them, a third world country.
-
Funked,
WEP and Overboost are not the same thing as modeled in AH. WEP is use of water/meathonal to keep cylinder head tempetures down at higher MAP.
Overboost IMHO is the use of higher octane fuels to sustain higher MAP ala the V-1 chasers using 150octane or the F4U-4/P-47M using 150octane because thay had R2800C engines that could handle sustained higher temps.
Also any A/C with a multistage super-charger could overboost at will. And F4U-1 had a two stage mechanical supercharger with Neutral, low blower and high blower. Any pilot could swith to high blower at lower below 10K instantly OVERBOOSTING his engine into higher MAP. He took the chance of blowing up his engine but for limited time he could run at excess of maximum boost.
So was the La-5/7 running in WEP or overboost?
-
Originally posted by Vermillion
Quite frankly, I would be suprised if any of the prop driven aircraft used by the North Koreans, were aicraft in peak condition and maintenance.
These were used up rejects sent to bolster what was to them, a third world country.
Don't forget that the pilots flying them would most likely be worse than second-rate. From my readings, I get the impression that the average North Korean MiG-15 pilot was pretty mediocre; how much worse would be the crews assigned to less modern aircraft?
-
From my readings, I get the impression that the average North Korean MiG-15 pilot was pretty mediocre; how much worse would be the crews assigned to less modern aircraft?
A lot of them were USSR or Chinese pilots which is becoming common knowledge now-days. In fact, the Soviets were told they cannot bail anywhere near Allied lines for fear of being found out.
-
well this thread took an abrupt detour:D
as far as the Korean War. In reading Gabreski's book, he stated that on one occasion a N Korean fighter pilot bailed from his downed fighter and a member of the 4th FG in the area buzzed the guy in the chute. He was pale skinned, red haired, and very angry:) Didnt look orienetal in the least.
-
WEP is use of water/meathonal to keep cylinder head tempetures down at higher MAP
Just a point of contention ( :) ) WEP in AH is not always the use of a water/methanol injection system. None of the production P-51's in WW2 had a water/methanol system according to America's Hundred Thousand. At least in the -51 WEP seems to model a combat power setting on the throttle that is a step above military power and that's why I imagine that P-51 runs out of WEP so quickly, it's because of the lack of water injection to help cool the engine.
-
Soulyss,
I didn't mean it was water and methonal. I meant water or methonal. And the P-51 did have a water tank for WEP. It was for cooling so the engine so it could be temorarily overboosted without overheating. Once the water ran out the engine would overheat rapidly hence the 5 minute limit. Some A/C had larger water tanks and had longer WEP time. Like the P-47 had a very large water tank. The F6F had 10 minutes worth and the F4U-1D had 8.5 minutes. Of course AH only gives you 5 minutes in the game. The German A/C used combinations of water and methonal I believe. I am no expert on German A/C for sure. However they are given far more WEP time in AH.
However it should be said that most American aircraft could be overboosted by the pilot at his own risk because of the manual blower controls. I know the FW190A series had automatic controls and would not allow the pilot to do this.
-
Hi Guppy,
>I didn't keep a copy of the link, but a translation of a German test of an La-5 (Rechlin Test Centre, Test No. 90014) was posted to allaboutwarfare.com's forums a while back.
I'm afraid that the La-5 in queston had an unrecognized engine problem. The test pilot Hans-Werner Lerche mentions elsewhere in his book (which has the report in the annex - unfortunately, the rest of Lerche's reports didn't survive the war!) that operational Luftwaffe pilots did believe that Rechlin had faked the numbers to make the German fighters look better.
Lerche considered his tests to be thorough and accurate, but one more indication for an engine problem was that he almost suffered carbon monoxyde poisoning in that La-5. That hints at problems with the exhaust system, which can have quite a negative effect on performance.
Lerche had to fly with oxygen mask as a result, but noticed that the original Soviet system fitted to the La-5 obviously had never been used. This might indicate that the exhaust leak had only occurred after the capture.
In short, I think Rechlin tests were generally realiable, but occasionally failed to give realistic results. Testing captured equipment is not easy, and I think all major air forces failed to get the best from a prize aircraft occasionally.
Regards,
Henning (HoHun)
-
just a question, has anyone seen so far an original flight test report of ´44/45 backing up those 380mph sealevel speeds for La-7?
-
Ammo, similar stories abound from pilots. My interest is the Vietnam War and not WW2, but in my readings I do come across some Korean War stuff and it seems to me that lately the Russian military is admitting more and more to having flown for the North Koreans during that war. There has also been some talk of UN pilots shot down in Korea having been seen in the USSR but never returned after the armistice. That's probably common in all wars though. In fact, this even goes for one USN pilot from the Desert Storm war.
(To get us back on topic...) The P-51B is a beautiful bird. But between it and the LA7 and TA, the 51B seems to me to be the least lethal. It's still a good weapon and very deadly in capable hands though. Also, the last time I flew I got into chasing a 51D around and he seemed to out accelerate my 51B (or maybe he just outflew me since I'm still getting used to the Mustang.)
-
Originally posted by HoHun
Lerche had to fly with oxygen mask as a result, but noticed that the original Soviet system fitted to the La-5 obviously had never been used. This might indicate that the exhaust leak had only occurred after the capture.
)
more likely it was because the soviets flew with open cockpits to make up for poor venting in the cockpit and lack of trust in being able to get the canopy open in case of an emergency.
The venting in the La7 was even worse then the la5-fn. they had removed some to increase speed.
"At maximum power the cockpit tempreture rose to 104 f even when operating in the bitter cold of the russian windet. the tempereture rise was casued by the elimination of the cockpit air inlets and poor thermal insulation between the cockpit and the engine bay. The situation was worsend by the hot oil liines running between the oil cooler and the engine and passing directly beneath the pilots feet. Additionally, poor internal sealing allowed exhaust gases to enter the cockpit. The lack of proper venilation also increased the condensation in the cockpit."
thats from the La in action book.
I have read Czeck preports on the LA7 that basically confirm all those points. The planes were often flown with cockpits open..
The Germans did not have a plane with a mystery engine problem..they had a typical production quality La5...they didnt perform anything like thier prototypes.
-
WEP and Overboost are not the same thing as modeled in AH. WEP is use of water/meathonal to keep cylinder head tempetures down at higher MAP.
Overboost IMHO is the use of higher octane fuels to sustain higher MAP ala the V-1 chasers using 150octane or the F4U-4/P-47M using 150octane because thay had R2800C engines that could handle sustained higher temps.
Whether we are talking about aviation terminology or AH terminology, WEP does NOT always imply injection of anything special like water/methanol. It's just an emergency power setting that allows increased performance for a brief period.
Overboost just means you are running more boost than normally permitted. You don't need fancy fuel to do this if you are willing to sacrifice long term durability and overhaul intervals. Hence the short time limits.
I didn't mean it was water and methonal. I meant water or methonal.
AFAIK no production aircraft in WW2 used pure methanol injection. ADI (anti detonant injection) aka Water Injection aka MW 50 was used. The primary ingredient was water. Methanol was only added to lower the freezing point of the solution so that it would remain liquid even after flight at high altitudes or in very cold weather.
And the P-51 did have a water tank for WEP. It was for cooling so the engine so it could be temorarily overboosted without overheating. Once the water ran out the engine would overheat rapidly hence the 5 minute limit.
That's false. The only production P-51 with ADI was the P-51H. Get the manuals for the P-51D (they are available through many online shops or just read AHT to enlighten yourself.
However it should be said that most American aircraft could be overboosted by the pilot at his own risk because of the manual blower controls. I know the FW190A series had automatic controls and would not allow the pilot to do this.
The part about the Fw 190A is false. The Fw 190A-8 had a boost control override system. And earlier A models (A-3 through A-7) had an emergency power setting (which increased boost and RPM) that could only be sustained for a few minutes.
Nothing personal F4UDOA, I just don't want people to get bad information.
-
F4UDOA will be very interested in this, if he hasnt already see this. This website has several detailed reports of tests of several navy birds. I was turned on to this information on a newsgroup by someone else. I appreciate it Guy if you are reading this.
some more information in regards to the orginal subject, the P-51B true top speed. Pllease review this report of a comparison between a P-51B and a F4U-1A. From what I understand. The pony's were both slightly modified from production condition. The racks were removed and some sanding of the wings was accomplished. Additionally, the F4U was modified to some extent. Details in the report.
(http://home.satx.rr.com/pointblank/films/p-51%20f4u-1%20comparison%20chart.jpg)
As you can see, this test shows a 450 MPH pony. Also it is quite revealing in the regards to the relative performance difference between the pony and the corsair, wit the evauator s giving the f4U the nod as the better AC below 25K.
report http://www.geocities.com/slakergmb/id95.htm
-
Can't believe it! The discussion is still civil and calm and organized!
Ok, sure, it's organized about the La7 now instaed of the Ta152 and P51 B but hey, gotto make some sacrifices :D
All!
-
Just for giggles, here is RAF results of the Mustang Mk III, Spitfire Mk XIV and Tempest Mk V with 150 octane fuel:
(http://www.fourthfightergroup.com/eagles/spit14+25lbs.jpg)
-
Now THAT would be a perk Mustang. :)
-
LoL, those would serious perks overall! :D
-
Nahh..... if we get a perk mustang, we need the P-51H :) Now THAT was a beautiful beastie !! :)
-
Perhaps this is not so much an argument to perk the pony B as it is an argument to unperk the Ta152.
-
And the P-51 did have a water tank for WEP.
I'm looking at America's Hundred Thousand and on page 362 under "Engine and Water Injection System" is says:
"No water injection system was used on any production models prior to the P-51H"
-
No Fancy but you understand my argument :)
This is actually more fix the Ta152 then unperk it or perk the P51 B.
-
I asumed at was kinda obvious from the start when you said
Ok, well, actually, I don't want the P51 B perked
but I guess that got a little over looked. :D
-
just wanted to add this info that I got froma newsgroup. I had posed the topic there and was given some great info. Basically, the following information puts the p-51 speed issue to bed IMO. Be advised, alot of you know and understand all that isn said in this post, and the majority (me included) do not. Thx Peter.. In several parts--
This is going to be redundant for a lot of people, but I've reviewed
the Bulletin Board thread that's been referenced as part of this
question, and, if you don't mind, I'd like to take the opportunity to
do a small bit of teaching for those who'd like to learn where these
numbers come from. A lot of you know this stuff, so please bear with
me, and if I've typo'ed or Thinko'ed something, please jump in and
correct me.
Let's start with a Glossary. Some of it's pretty basic, but we'll
need it to get all the ducks in a row. These are the things you need
to know if you want to figure out if a performance report is valid:
Flight is a balance of four forces: Weight, Lift, Thrust, and Drag.
When the sum of Weight and Lift is 0, you are in level flight. When
the sum of thrust & drag is 0, you are at the maximum speed.
The Air: Air, of course, is vital to making an airplane work. For
our purposes, there are 3 properties of the air that are important.
The Pressure, (P), the Density (Rho), and the Temperature (T). These
values change as altitude increases. How these values change can vary
from day to day, and from location to location. To get past these
differences, the "Standard Atmosphere" was developed. This is a
mathematical representation of the atmosphere's changes from a given
set of start conditions, how they vary with height, and from this can
be determined the changes due to, say, a difference in temperature or
pressure at ground level. This definition has changed through time,
in order to reflect our better understanding, and better ability to
measure these conditions. For this purpose, I'm using the ICAO 1979
Standard Atmosphere, which does vary somewhat from the 1930s NACA
Standard Atmosphere. (It's not that significant at these altitudes)
The thing that affects an airplane's flight the most is the Dynamic
Pressure, or 'q', This is the pressure generated by the movement of
air. q varied with the square of the velocity, so if you go twice as
fast, q is increased by 4 times.
Because the Pressure, Density, and Temperature of the air decrease as
you travel higher in the atmosphere. (Actually, temperature is
constant about 36,000' or so, but that's not relevant here), the q
generated by a particular airspeed is less than it is at lower
levels. This has led to the definition of several different measures
of airspeed. These are:
True Airspeed - the actual speed of movement through the air.
Equivalent Airspeed - the airspeed at sea level corresponding to a
particular q.
Calibrated Airspeed - the Equivalent Airspeed corrected for the
compressibility of the air at that height and speed. At the speeds
we're talking about, it may amount to 3 or 4 mph.
Indicated Airspeed - The airspeed that shows on the pilot's Airspeed
Indicator. This can be affected by the location and orientation of
the pitot tube used to measure 'q', and internal system peculiarities.
The difference between CAS and IAS is called Position Error, and
varies with the speed of the aircraft. It can be as high as 10-15
mph. We're not actually concerned about it here.
Weight: How much an airplane weighs. Weight doesn't necessarily
affect speed much, but it has big effects on Excess Acceleration, and
therefore Excess Power, and thus Rate of Climb and Maneuverability.
There's a whole bunch of weights, though. There are:
Empty Weight: The weight of an airframe without fuel, oil, crew,
Ammunition, Bomb load, or removable equipment.
Basic Weight, or, sometimes, Empty Equipped Weight. This is the
weight of the airframe with crew, removable equipment, oil, and
unusable fuel. (More or less the true minimum weight that an aircraft
can have.
Normal Loaded Weight: The Basic Weight, plus full internal fuel, and
ammunition.
Maximum Weight: The absolute most weight that you can have without
exceeding some limit. (Like Landing Gear Strength, or strength at some
G load, or engine-out rate of climb, etc.) This usually, for fighters
requires some amount of external load.
Note that there can be a big difference between a
After World War II, the U.S. Department of Defense, in order to help
make sense of it all, came up with the idea of "Combat Weight", Combat
Weight is a stylized representation of what the weight of an airplane
will be as it may be actually engaged in combat. It is defined as the
Basic Weight, + 60% of the Internal fuel (In most cases), plus, in the
case of some bomber aircraft, internal bombs.
This affects some aircraft more than others. In a World War 2
context, there's a lot more difference between a P-51B's Basic Weight,
and its loaded weight, than, say, for a Spitfire or an Me 109.
Most of that difference is fuel, or course.
Here's a quick comparison, with weights expressed as a percentage of
Basic Weight:
P-51B Spitfire IX Me 109G-6
8190# 6650# 6550#
Basic weight 100% 100% 100%
Loaded Weight 120% 110% 110%
Combat Weight 112% 104% 106%
When you consider the difference that a relatively small weight change
can make on maneuverability and climb, you'll see that there's a lot
more difference between a Mustang at it's loaded weight, and a Mustang
over the target area than there is for its contemporaries. (Just for
the record, a P-51B carried about 1600# of gas internally. The Spit 9
and 109G both could squeeze i about 650-660# of gas. You can see why
the idea of Combat Weight was considered important.
Lift: What's required to keep you separate from the ground. This is
done by, if you will, "fooling the air" into generating a lower
pressure on the top of the wing vs. the bottom of the wing. For a
given weight, in level flight, Lift is the same as the weight. How
hard the wing has to work to achieve this lift is measured by the Lift
Coefficient, Cl. Lift is defined as Cl * S (Wing Area) * q. As you
can see, since q decreases for a particular True Airspeed with
altitude, the higher you go, the harder the wing has to work. There's
a maximum limit for CL for each airfoil, called Clmax. This limits
how much lift a particular wing can generate. For purposes of Maximum
Speed, Clmax isn't important.
Drag: Drag is the resistance to something moving through the air
generated by pressure on the front parts, friction over the surfaces,
vacuum (low pressure) over the back parts, and drag produced by
generating lift. Basically, for the speeds involved in this
discussion, this can be divided into 2 components, the Profile Drag
(Drag due to shape), and the Induced Drag (Drag due to Lift).
These are expressed as the Induced Drag Coefficient (CdI), and the
Profile Drag Coefficient (CdF). The forces that these produce are
defined, similar to lift, as Coefficient * q * S, where S is a measure
of surface area. There's some difference of opinion over whether to
relate the Profile Drag coefficient to Wing Area (Easy to measure,
usually) or Wetted Area, which takes into account wing, tail, and
fuselage area exposed to the airstream. (Easier to determine the
effects of changes to clean up an airframe aerodynamically) We can
get past that by relating profile drag as an Equivalent Profile Area,
which expresses the drag in terms of an imaginary flat plate with a
Drag Coefficient of 1.0 - basically, the draggier the airplane, the
bigger the plate.
Induced Drag is the drag that's generated by the lift that the wing is
producing. The Coefficient of Induced Drag is defined as:
CdI = (Cl*Cl)/(pi * AR * e)
[pi is of course, pi, as in 3.14157..., AR is the Aspect Ration of the
wing, best calculated as (span * span)/Wing Area, and e is an
efficiency factor related to the shape of the wing.]
As you can tell, Induced Drag, depending on how hard the wing is
working to generate a certain amount of lift, is small at large values
of q. (In other words, it's less as you go faster and/or lower).
Thrust: How much force is being exerted by the aircraft's powerplant
to push it through the air. This is a toughie. Reciprocating engines
don't produce thrust directly, they produce power. (Which is defined
as Torque * rotational Speed - don't sweat that). Power doesn't
directly translate into thrust, so we'll have to do a bit of
arithmetic:
1 HP = 550 ft-lb/sec. Now, thrust is lbf (pounds force), since we're
on Earth, we can safely assume 1G - 32.2 ft/sec^2 and not sweat it)
So, to get lbs out of a horsepower number, we divide by 550
ft/sec. (Hey ft/sec, that's speed!) so, if we do a bit more figgering,
to get the speed part down, we end up with T (Thrust in lbs) = HP *
550/v (v in ft/sec). As you can see, at low speeds, we get bags of
thrust per horsepower. At high speeds, the thrust decreases.
Here's another table that shows this: (remember that 550 ft/sec = 375
mph)
Speed Thrust (1 HP) HP (1# of thrust)
100 mph 3.75# 0.266
200 mph 1.88# 0.533
300 mph 1.25# 0.800
400 mph 0.94# 1.067
500 mph 0.75# 1.333
-
continued--
As you can see, as speed goes up, thrust drops off alarmingly. But,
of course, there's more to it. A reciprocating engine generates its
thrust by turning propeller, which is basically a set of rotation
wings, which turn torque into thrust by moving a large volume of air
from in front of the propeller disk to behind it. This of course,
isn't 100% efficient. While the propeller can be considered a set of
wings, it moves through a complicated airmass. The airspeed that a
propeller's airfoil sees is defined by the rotational speed of the
propeller, and by the forward motion of the airplane. There are also,
of course, altitude effects. An airplane propeller stalls at low
speeds, and has transonic problems at higher airspeeds. The
efficiency of a propeller isn't constant. At low speeds, it can be
rather poor, and it drops off at high speeds. The altitude effects
also mean that a given propeller setting is only most efficient at a
particular combination of Torque, RPM, airspeed, and altitude. This
led to problems in the 1930s, when airplanes with wide speed ranges
were beginning to be developed, and supercharged engines, which
produced their best power at higher altitudes, were introduced. As an
example, the Boeing Monomail transport prototype, with a supercharged
Pratt & Whitney Hornet engine, couldn't take off with its propeller
set for the cruising design point of the airframe/engine combination -
the propeller efficiency was too low. When the propeller was set for
takeoff performance, there was a hefty hit on cruise speed. This was
resolved by producing variable pitch and constant speed propellers.
Basically, the pitch change allows the peak efficiency to be
maintained over a wide combination of engine power/ airspeed and
altitude combinations. What this means for this analysis is that the
thrust produced for a particular horsepower isn't dependant on
altitude.
Oh, yeah, there's one other factor as well. Because the combination
of airplane airspeed and the propeller's rotational speed can get
quite high, there's a loss of efficency as the propeller's blades
approach the speed of sound. To get past that, the propeller shaft is
geared down to keep the total speed low. The Mustang's V1650 had a
gear ratio of 0.479. For every 1000 engine RPMs, the propeller turned
479.
The efficency of an airplane propeller is best referenced by the
Advance Ratio, or 'J'. 'J' is defined as J = V(true airspeed) /
n(rotational speed)* d (diameter). For a typical WW 2 fighter airplane
propeller, the highest efficiencies are reached at Js between 1.5 and
3.5.
Now that we've got the propeller out of the way, we need to take a
look at what is driving it. All WW 2 fighter engines were
supercharged. Most airplanes started the war with single-stage (one
compressor) single-speed (one peak altitude) superchargers. This
gives the maximum engine performance at a particular height. There
are two problems with this combination - It takes engine power to run
the supercharger, so the more you want it to compress (better at
higher altitudes), the less power is available for the propeller.
This leads to less power being available for takeoff, and at lower
altitudes. There were basically 2 ways to get around this. One was
to have multiple ratio gear drives, like a car's manual transmission,
to drive the supercharger. With a slower drive speed, the peak power
was developed at low altitude, and less power was used to drive the
supercharger. Another possibility was to have a variable speed drive
for the supercharger, like the torque converter on a bulldozer or
tank. This meant that the supercharger used only as much power as
needed to produce a certain engine power, but at a cost in
efficiency.
There is also a limit for how much a single compressor can squeeze
the air. This limited just how high an airplane engine could go and
produce peak power. (Typically about 20,000'). This was solved by
using multi-stage superchargers, basically using two superchargers in
tandem so that the main stage (engine stage) supercharger is working
on the already compressed air of the initial (auxiliary stage). This
could take a number of forms. Turbosupercharged engines, such as the
Allison V1710 on the P-38, and the Pratt & Whitney R2800 of the P-47,
are one form. The turbosupercharger delivered "sea level" air
pressures to the single-speed engine supercharger at heights ranging
from Sea Level to over 25,000', with no additional cost of shaft
horsepower to run th auxiliary stage. There are drawbacks in that
the turbosuperchargers were fairly heavy, took up a lot of volume, and
required tens of yards of ducting to move air all over the place
within the airframe. Another approach was to have a separate
Mechanical supercharger, that could be shifted when appropriate to
deliver the best power. This was the type used on the F4U Corsair and
F6F hellcat. The drawbacks to this type are also the weight of the
system, and that the power consumed by the supercharger reduces the
power available to the propeller. (For example, at 20,000', for the
same RPM and Manifold pressure, the R2800 on an F4U produces about
1650 HP, while the turbosupercharged R2800 on a P-47 produces 2000
HP. The missing 350 HP is driving the supercharger.
Another possibility, which saved weight and bulk, was to have s ingle
supercharger drive that ran both compressors. This was the type used
on the V1650 Merlin on the Spitfire and P-51. The advantages are that
the engine wasn't much bigger or heavier than the single-stage
Merlin. The disadvantages were that it still consumed Shaft
Horsepower, and required very careful design to match the performance
of the two compressors. Luckily, Rolls had Stanley Hooker, who was
able to sort this all out.
Oh, yeah, and still another thing! If you design the intake system to
you superchargers right, you can take advantage of thy dynamic
pressure you're generating to basically fool the engine into thinking
its at a lower altitude. This is referred to as "Ram Recovery", and,
for typical airplanes is in the range of 65-80%. Well designed
systems can give recoveries higher than 90%. This is why an
airplane's max speed can occur at altitudes higher than the engine's
best altitude, and for purposes of finding an airplane's maximum
speed, can be critically important.
The data that is presented in the popular references is not a good
basis for accurately determining what the true performance of an
airplane is. While the data reported is correct, as far as it goes,
context information, which is vital to determining if the numbers are
valid or not, is lacking. You've basically got to have the following
data before an airframe's performance can be determined - Airspeed,
Specific Excess Power, Altitude, Weight, and Power produced by the
engine(s) . (Note that Max Speed is a case where Specific Excess Power
= 0.)
You'll generally get a Max Speed Number, sometimes an Altitude to go
with it, and, very rarely, a weight. Power setting information is
almost impossible to find. In fact, in most references, anything
other than the takeoff power of the engine is impossible to find.
Now to the subject of testing.
Well, there was (And still is) a _lot_ of non-contractor testing that
is performed for any military aircraft. This testing takes the form
of flying instrumented aircraft over instrumented ranges, wind tunnel
testing, systems testing, the whole gamut. After acceptance, the
aircraft are often run through test series other times, in order to
provide, for instance comparisons to other aircraft.
The date provided in these tests is normalized, or corrected to
whatever the Standard Atmosphere of the era is, so that comparisons
can be quickly and accurately made.
The data from these tests goes into developing the performance tables
in the Pilot's Operating Handbooks, and also into the data presented
in the (In the U.S. case), Standard Aircraft Characteristics (A
distilled summation of aircraft performance data used as a Staff
Reference ).
Now, for some time, I've been a bit leery about the P-51s Standard
Aircraft Characteristics data. (A reasonable source for some of these
numbers is Ray Wagner's _American_Combat_Planes_ (Doubleday, several
editions). The performance numbers he presents are apparently taken
from the "Basic Mission" table of the current "Standard Aircraft
Characteristics". I've found this correspondence in about 40 test
cases, so it's fairly safe to presume that the data is from a reliable
source.)
At that time, the USAAF performed their testing at, basically, 5,000'
intervals, measuring the performance at SL, 5,000', 10,000, etc. These
numbers in themselves are accurate, but they don't necessarily
represent the actual points of peak performance of the airplane.
Not a big deal, really, unless you're an obsessive gearhead/Wing Nut
who plays with CFD for fun. (Guilty)
-
continued--
Now, to the case of the P-51.
I have immediately available to me a number of reports, or data from
reports, that include P-51B/C performance. These are the Central
Flying Establishment graphs that Guy mentioned in another post, the
comparison report of the P-51B and a pair of F4U-1s made by the Navy
Flight Test Center at Pax River, Also mentioned by Guy, although I'd
obtained my copy from the Navy Historical Office in DC a few years
back. It, BTW, provides excellent context, describing what was done
to clean up the airplanes before the tests. (And, yes, the Corsairs in
the tests definitely were cooked.)
Other reports are from a test series at Eglin Field as part of the
P-51B acceptance trials, and performance test series EE393 conducted at
Wright Field in early 1943. I'm not counting the Tactical Reports by
the British Air Fighting Development Unit at Farnborough, but they
make interesting reading. If Mike Williams is listening in, Thank
You! The work that you've done obtaining and putting the A&AEE
reports on the web have been invaluable.
Another useful resource is the NACA Technical Reports Server. Some of
the good folks at NASA have been spending a not inconsiderable amount
of time digitizing and cataloging thousands of the older Tech Reports,
Research Memoranda, and Wartime Reports from 1921 onward, covering
everything from determining the turning circle of a Los Angeles class
rigid airship to Anti-Satellite vehicle trajectories.
Wartime Report L-108 was most useful. This was a study of a number of
mid-war aircraft tested in the Langley Full Scale Wind Tunnel to
determine the effects of cleaning up these airframes.
As a cross check of these numbers, Rate of Climb figures were
calculated and compared to test figures, if they were available. The
rate of climb, and best speed for rate of climb crosscheck the drag
and thrust calculations at a mid-point in the performance, rather than
just at the end points.
Anyway, here are the performance numbers
CFE Report, Mustang III (P-51B/C with V1650-7 engine at 61" MAP/3000R
Test Weight 9200#
Max Speed 438 mph @ 27500'
412 moh @ 14000'
Rate of Climb 2600'/min @ 23000'
3420'/min @ 11100'
The rate of climb numbers match within 5%, and the best climb speed is
175 mph IAS.
These numbers yield an equivalent Profile Area of 4.1702 sq ft, and a
Ram Recovery of 95%
U.S. Navy Patuxent River Comparison Tests V1650-3 engine at 67" MAP/3000R
Test Weight 9423#
Max Speed 450 mph @ 29200'
426 mph @ 12600'
No Climb data specifically called out.
Equivalent Profile Area is 4.1812 sq ft, with a Ram Recovery of 95%
Best Rate of Climb speed is also 175 IAS.
Eglin Field tests V1650-3, 67"/3000RPM
Test Weight 9640#
Max Speed 435 mph @ 27000'
420 mph @ 13100'
No Climb Data
Equivalent Profile Area 4.3315 - note - this aircraft had the wing
pylons attached. Ram Recovery 85%
Wright Field EE 393 tests V1650-3 67"/3000RPM
Test Weight 9200#
Max Speed 450 mph @ 28200'
420 mph @ 15300'
Rate of Climb 2666'/min at 28550'
3450'/min at 11857
Equivalent Profile Area 4.0763 Ram Recovery 95%
Note - Calculated Max Rate of Climb at 12000' is 3400'/min at 175 IAS.
NASA Wartime Report data on P-51B
"Beat Up" CdF, 0.0208, for an E.P.A. of 4.84 sq ft.
"Cleaned up" CdF 0.0173, for an E.P.A. of 4.0309 sq ft.
So, the numbers I'm getting fall into the middle of the range,
corresponding to polishing the airplane and sealing up the gun ports.
As a check, I ran data for an "Average" P-51B with a CdF of 0.01800,
and a Ram Recovery 0f 90%. At a weight of 9200#,
With a V1650-3, this gave me the following numbers:
Vmax, 67"/3000R (Emergency Power) 450 mph @ 30000'
427 mph @ 19000'
350 mph @ Sea Level
Vmax, 61"/3000R (Military Power) 445 mph @ 31000'
425 mph @ 20500'
335 mph @ Sea Level
Vmax, 46"/2700R (Normal Power) 415 mph @ 34000'
380 mph @ 22000'
300 mph @ Sea Level
The logic I'm using for when the supercharger speeds should shift may
need some tuning.
All in all, I'd say that the numbers that are in the reports quoted
above are valid. They match with NACA's drag data, and they are
internally consistent.
Note that it's rather pointless trying to pin things down too
closely. Individual airplanes vary, and engine performance varies as
well. Even coming off the factory floor, a variation of about 5% or
more in the performance numbers is to be expected.
As for the Soviet numbers, I'd be interested in more detail. From
reading reports from Soviet Pilots flying Merlin Engines Hurricanes
and Spitfires, they seem to have had some trouble getting the full
amount of oomph from their Merlins. Although the slightly over 400 mph
number at 22,000' sounds pretty close for a V1650-3 airplane in low
blower/Max Cont. Power. As for limits using 100 Octane rather than
100/130, I had an opportunity to ask a P-51 owner about that way back
when. (Don Davidson, when he owned "Double Trouble II") about running
his airplane on 100LL rather than 100/130. He limited his power to
61" for takeoff. (Which was the usual value.) Of course, he didn't run
it at more than 46"/2700 very much. Since at that time, a Merlin only
cost a quarter of a million bucks, we can safely assume that he
wouldn't risk it needlessly.
and there is more--
Lots of testing gets done on any aircraft by the customer before
acceptance. Anybody who believes that the U.S. Army doesn't wring out
an aircraft before selecting it for service should check out the
history of the Curtiss P-46, the annointed successor to the P-40, and
an immediate precurser to the NA-73 (P-51 prototype), This failed
testing so miserably that Curtiss decided that they's start with a
clean sheet of paper (And did no better with the P-60 series), and
sold the engineering data to North American, who used it as an example
of what not to do. The Brits had been testing P-51s before the
U.S. had. After all, it was designed to their specifications. There
was some disbelief on the part of the RAE about the Mustang's
performance numbers as reported from California, but testing of the
first examples to reach the U.K. showed that the numbers were valid.
(The stuff that Guy's pointed out was part of that testing) It's
possible that the story you've had posted was a conflated version of
that.
There were, of course, a number of tests run on every model of the
P-51 throughout its career.
I've been able to pull useful data from 4 test series, and use them to
reverse-engineer the basic aerodynamics of the airplane.
I'll digress a bit here and there, to bring up a few interesing bits
about sources, and other such stuff.
What I've done was to take information from official tests and
technical literature, apply all the basic rules of aerodynamics to
them to determine the basic coefficients that define how an airplane
is going to perform, and then recalculate the airplane's performance
through it's entire flight envelope. (This allows me to crosscheck the
date vs. things like Rate of Climb, Cruise Speed, and Ceiling data.
If they match as well, then the numbers I'm generating are
consistant.)
The tests that I'm using are:
Appendices E and F of a report by the British Central Flying
Establishment, 1946. These are charts comparing the speed/altitude
and climb/altitude performance of a Mustang II with a V1650-7 engine,
a Spitfire XIV, a Hornet I, and a Meteor III. The tests were done in
early '46. (In fact, they're the same ones that Guy pointed out. Mike
Williams has done some great work by ferreting out these reports, and
should be recognized.) The second set of numbers comes from a test
series flown at Eglin Field in early 1943. The third set is from Test
Series EE 393, performed at Wright Field in early mid '44, The last
numbers come from comparison tests of the P-51B vs. two versions of
the F4U-1 Corsair, performed by the U.S. Navy at Patuxent River.
(Guy also managed to find an online copy of this report as well. I
got mine from the Navy History Office a few years back)
I also cross-checked this data with NACA Wartime Report WR-L-108,
which was a series of tests performed in the Langley Full Scale Wind
Tunnel on various mid-war aircraft with a view to improving their drag
coefficients.
Here are the numbers, and the results of the run. (The data for each
test run turns out to be about 80-100 pages, so I'll just distill it
down a bit. The data points are at the critical altitude for both
supercharger gear ratios for the appropriate power setting.
CFE: Mustang III with V1650-7 engine, Military Power (61"/3000R)
Test Weight: 9200#
Vmax: 438 mph @ 27500'
412 moh @ 14000'
These numbers give a CdF of 0.0179, and a Ram Recovery of 95%
Eglin: P-51B with V1650-3 engine, Emergency Power (67"/3000R)
Test Weight: 9690# (Pylons attached)
Vmax: 435 mph @ 27000'
420 mph @ 13100'
This gives us a CdF of 0.0185, and a Ram Recovery of 85%
EE 393: P-51B with V1650-3 engine, Emergency Power
Test Weight 9200#
Vmax: 450 mph @ 28200'
430 mph @ 15300'
This gives a CdF of 0.0175, and a Ram Recovery of 95%
Pax River: P-51C with V1650-3 engine, Emergency Power
Test Weight 9423#
Vmax: 450 mph @ 29200'
426 moh @ 15600'
CdF 0.017945 Ram Recovery 97%
CdF is the profile drag. Ram Recovery is the efficency of the
supercharger inlet duct in capturing the dynamic pressure of the air
moving through it. This can increase the critical altitude of an
engine by, in this case, 6000'.
-
lastly---
So, we've got 4 tests, with these results for CdF:
0.0179
0.0185 - with wing pylons.
0.0175
0.0179
The NACA Wartime Report L-108, "A Summary of Drag Results From Recent
Langley Full-Scale-Tunnel Tests of Army adn Navy Airplanes", 1945,
shows the P-51B to have an initial CdF of 0.0208 (Beat-up condition)
which was reduced to 0.0173 (Cleaned up, with cowling gaps sealed.)
The drag coefficents seen above are consistant with aircraft having
had a moderate clean up, basically a wax job and taping the gun ports.
I can go into much more detail later, if you'd like. But, I'd have to
say that the numbers reported here are correct. They check out
mathematically, and are within the basic coefficents are in line with
what NACA determined as part of their testing.
Again, thx to Peter for providing this information.
-
Please define cooked? As in the F4U's were cooked?
I am always curious to hear how test were cooked to change a flight simm 60 years later??