Author Topic: This looks...fun! (Read 2003 times)

Bronk · « **Reply #30 on:** June 06, 2006, 08:21:11 PM »

Krusty not to start anything but ...
Widewing used" America's Hundred Thousand, page 407-409, and graph 52" as a source.

Now if you want to dispute this please post your source instead of jumping up and down shouting BS.

Because if you have different info it would make a nice read.

Bronk

Widewing · « **Reply #31 on:** June 06, 2006, 10:14:55 PM »

Quote

Originally posted by Krusty
There is no way in hell a 9,000lb plane [edit: with an allison engine] is going to climb 5000+fpm at milpow. It's just not going to happen, EVER. That's like saying the P47 had a 3,500hp engine, and could reach 30k in 6 minutes.

Physics doesn't allow it.

Edit: wait, does "combat power, wet" mean with water injection?

Regardless, 10k in 2 minutes is BS for a single allison engine in a heavy airframe.

Don't belittle the later Allisons, they were excellent engines. This Allison, specifically the 1710-93, was rated at 1,820 hp (WEP) with water injection (75 in/Hg) at sea level. It was a low-drag airframe, second only to the P-51 among American fighters and it had a laminar flow wing. Compared to the Spitfire Mk.XIV, it had a slightly greater wing area and at normal combat load, weighed about 60 lb less than the Spit XIV. If water injection was not used, the rate of climb fell off to about 4,200 per minute (1,500 hp @ 60 In/Hg).

My regards,

Widewing

38ruk · « **Reply #32 on:** June 06, 2006, 10:16:16 PM »

Quote

Originally posted by Krusty
There is no way in hell a 9,000lb plane [edit: with an allison engine] is going to climb 5000+fpm at milpow. It's just not going to happen, EVER. That's like saying the P47 had a 3,500hp engine, and could reach 30k in 6 minutes.

Physics doesn't allow it.

Edit: wait, does "combat power, wet" mean with water injection?

Regardless, 10k in 2 minutes is BS for a single allison engine in a heavy airframe.

Krusty , can you show a formula that proves physics wont allow this, and that it cant be done . I'd like to see what kind of info you have that will discredit this .

DoKGonZo · « **Reply #33 on:** June 06, 2006, 11:28:02 PM »

Just zooming around the web I'm finding numbers for the P63A like 410mph @ 25K, climb to 25K in 7.3min ... which is Spit9 kinds of speed and climb. It weighs about 400 pounds less than a P51B, and if you don't load the 2 under-wing pods with .50cals and 900 rpg, that saves even more weight.

There's an interesting article on the P39 in Soviet service here

The P39 wouldn't get much use in the MA, but would be useful for AvA and events. The P63 looks to be pretty useful in the MA.

Angus · « **Reply #34 on:** June 07, 2006, 04:08:20 AM »

I'd fly it, and the 63, definately.
would be great for vulching. When the tanks start popping out you have the big gun

DiabloTX · « **Reply #35 on:** June 07, 2006, 04:32:22 AM »

Quote

Originally posted by Widewing
P-63A-8 performance from America's Hundred Thousand, page 407-409, and graph 52.

Climb: 2.00 minutes from sea level to 10,000 feet in combat power, wet.
4.80 minutes from sea level to 20,000 feet in combat power, wet.
(Leaves the Bf 109K-4 well behind)

Speed: 378 mph at sea level in combat power, wet (faster than Dora and close to La-7)
421 mph at 17,200 feet, combat power, wet (faster than La-7 and Yak-9U)

Roll rate: 109 degrees/second @ 270 mph (thats Spit16 territory)

Max HP: 1,820 hp @ 75 in/Hg at sea level, combat power,wet.

Acceleration: At sea level, calculated to be better than F4U-4.

Calculated turning performance, no flaps: Expected to be superior to F6F-5, but slightly inferior to FM-2.

In short folks, this baby would be the best low-level fighter in the game, bar none.

Because it offered only average performance at medium to high altitudes, the USAAF did not buy many or deploy those they did buy to combat zones. On the other hand, the Soviets tested the P-63 against the Luftwaffe and found it superlative. There were some issues with a rather weak fuselage near the tail. This was corrected with the P-63A-7 (150 built). The P-63A-8 (200 built) introduced water injection, with the M10 cannon coming into service with the P-63A-9. The largest batch of A models was the P-63A-10, of which 730 were produced. P-63C-1 through -5 constituted the largest block of aircraft (1227 built). Performance was slightly better than the P-63A-8 thru -10.

The Soviets appear to have stockpiled the P-63s in anticipation of declaring war on Japan after Germany was defeated.

My regards,

Widewing

WOW.

I thought the 63 was potent but this is amazing.

bozon · « **Reply #36 on:** June 07, 2006, 06:25:08 AM »

The good thing you can said about american plane designers is that they really tried everything. Wierd stuff like at 12,000 lbs turbo-charger with a fighter built around it, a twin-boom twin-engine fighter and a fighter with a rear engine, tricycle gear and a car door to the cockpit.

American officials killed the P39 with stupid decisions enforced on Bell to change the original design. They could have had a 400+ mph plane back in 1942. Why it took so long to match this airframe with a decent engine and chargers is beyond me. P63 could have happened years earlier when it mattered.

Didn't Chuck Yeager said in his book he really liked the 39?

Bozon

DoKGonZo · « **Reply #37 on:** June 07, 2006, 11:30:05 AM »

Based on what I read online, the Soviets were instrumental in fixing the design flaws in the P-39 (like the tendency to flat spin) and making the P-63 what it was. The top P-39 ace refused to let his squadron be converted to Yaks or La's until the La-7 came out.

Yeah, it'd be great for vultching. Hunting M3's and LVT's. But it also has the climb rate to get up after heavy bombers like a K-4.

With the aft-mounted engine, the CG is almost centerred. So I wonder how this would affect handling.

Debonair · « **Reply #38 on:** June 07, 2006, 07:41:16 PM »

I remember reading an article in Pacific Flyer a couple years ago about a concept ( i forget the term they used, but it was one of those really fancy ones, 'mean dynamic center of momentum' or something like that ).
this article was discussing the benefits of having the average distance from the center of gravity for any unit of mass in an aircraft be low & how this gives a plane better ability to change direction swiftly. the article was about camels & dreidekkers, but it did mention airacobras do well with respect to this measurement. maybe this has something to do with flap spins & weak tails (good ability to apply Gs) in the P-63 too

Krusty · « **Reply #39 on:** June 08, 2006, 05:38:32 PM »

Quote

Originally posted by DoKGonZo

With the aft-mounted engine, the CG is almost centerred. So I wonder how this would affect handling.

Going by Warbirds (another Hitech game) the P39 was slightly unstable and had a nasty snap-stall at moderate speeds when turning tightly.

EDIT: No idea about the 63, though.

DoKGonZo · « **Reply #40 on:** June 08, 2006, 08:20:30 PM »

Quote

Originally posted by Krusty
Going by Warbirds (another Hitech game) the P39 was slightly unstable and had a nasty snap-stall at moderate speeds when turning tightly.

EDIT: No idea about the 63, though.

Yeah ... that's probably about right.

The Russians helped a lot and the 63, and later model 39's, were supposed to be free of those tendencies.

As much as the B17 pilots feared seeing 190's approaching, imagine being a Ju88 pilot and seeing a couple dozen Russian P39's coming your way. Oog.

Angus · « **Reply #41 on:** June 09, 2006, 06:44:47 AM »

From Widewing:
"Compared to the Spitfire Mk.XIV, it had a slightly greater wing area and at normal combat load, weighed about 60 lb less than the Spit XIV"

It's still some 200 hp (?) short of the Spit XIV, so it makes me wonder. More power at lower levels perhaps, so that powerwise there is hardly a difference?
An early Spit XIV will go from start to 20K in 5 mins (J.Quill), - but not in AH.
ROC in low alt is more than 5K.

So, sounds about right to me.

At Duxford I saw a P63 forming with a P40. The 63 was told to be AWESOME and one of the best performers in the area.

Debonair · « **Reply #42 on:** June 09, 2006, 01:43:00 PM »

iirc, they pretty well in the big postwar air races.
i thing i read that in Tony LeVier's book

TimRas · « **Reply #43 on:** June 10, 2006, 09:59:47 AM »

Tilt once posted the VVS speed curves of P-63A-10 (among others). Quite a difference from from America's Hundred Thousand:

Widewing · « **Reply #44 on:** June 10, 2006, 10:54:20 AM »

Quote

Originally posted by TimRas
Tilt once posted the VVS speed curves of P-63A-10 (among others). Quite a difference from from America's Hundred Thousand:

That curve corresponds closely to the USAAF curve for MIL power performance. I'll scan and post the USAAF and Factory performance curves.

Would anyone be surprised that the Soviets would underate any aircraft not built in the USSR? That same chart shows the Fw 190D-9 with a max sea level speed of under well 340 mph and the Spit LF MK.IX (Merlin 66) at well under 330 mph. So, what we see here is MIL power performance, not WEP or WEP with ADI/H20/MW50). For the P-63A-10, the power difference is 1,325 in MIL, and 1,820 in WEP, wet. Huge difference in performance...

My regards,

Widewing