Brewster F2A Buffalo or P-39 Airacobra?

[FLYBOYJ]

Saburo Sakai claims that he used a dive tactic against pilots in F4Us which involved drawing the F4U pilot into following hi, down in a dive, then pulling up at the last minute. The pilot of the heavier F4U could'nt pull up in time and crashed into the ground. So that was the other side of the coin with having a lighter airframe structure

Yeah, but the F4U would also be able to stand the stress of a high speed pull out. If I remember correctly, Japanese planes, especially the Zero and KI-43 often risked ripping their control surfaces or wings after pulling out of a high speed dive because they were built so light.

I don't know how often he did this or how successful Sakai really was by diving away from an F4U, but I could tell you unless you have target fixation you're going to know your limits in a terminal velocity dive.

As far as pulling wings off of a zero, not going to happen - they are a one piece structure. The Zero's structure was light and strong, it was able to handle aerodynamic loads. What it couldn't handle was having holes shot through it.

[kool kitty89]

Same for the Ki 43, though both the Zero and Oscar had structural problems if they exceeded their max allowable dive speeds, which were low compared to allied planes. (410 mph for the Zero iirc) This wasn't due to G loads though, but high aerodynamic loads from compressibility. This happened to most contemporary a/c as well, but at considerably higher speeds. (though on some planes like the Hurricane for example, usually hit terminal dive before never exceed speed due to the thick wings, the Max dive speed being ~450 mph while the never exceed speed being closer to 490 mph)
But reaching these speeds in the first place wouldn't be all that likely for the Zero/Oscar due to the light airframe and proportionally large ant thick wings. (for their weight)

And of course, some a/c were limited by control reasons in compressibility, not structural concerns, the P-38 probably being the best example. (though once control was lost the increasing speeds would lead to disintegration, particularly as nose-down trim was a usual result, causing excessive -G loads in some cases)

[FLYBOYJ]

Same for the Ki 43, though both the Zero and Oscar had structural problems if they exceeded their max allowable dive speeds, which were low compared to allied planes.

That is the case for any aircraft. When operated within its design parameters both aircraft were actually very strong and were easily able to withstand the traditional plus 6 minus 3 Gs if not a bit more.

[kool kitty89]

Yes, the only thing was that the Zero and Oscar had max allowable dive speeds around 50-100 mph lower than the average allied fighters. More if you include fighters entering in late '43.

But almost any allied fighter will out-dive either anyway though... Except the Hurricane and some older planes being used by China etc. (like some Biplanes and the P-26) And even the Hurricane would win i a prolonged dive.

[FLYBOYJ]

Yes, the only thing was that the Zero and Oscar had max allowable dive speeds around 50-100 mph lower than the average allied fighters. More if you include fighters entering in late '43.

But almost any allied fighter will out-dive either anyway though... Except the Hurricane and some older planes being used by China etc. (like some Biplanes and the P-26) And even the Hurricane would win i a prolonged dive.

Agree - but I think that was due to more structural limitations than compressibility. Even with the Zero's wing I think you're going to have to be pretty high to reach a critical mach number.

[Elvis]

Smokey,

Interesting ancedote. I don't recall ever hearing that one before.
Thanks for posting that.



Elvis

[Juha]

IMHO
P-39N or Q was better than Brewster B.239.

Juha

[kool kitty89]

Yeah, but that plane was more than 4 years newer!

[Juha]

Hello Kool Kitty!
I know, I know, but the question was:
"Imagine you were on some Pacific Island and the Radars tell you that there are Enemy Boggies aproaching to attack your base, and you were faced with the task of Dogfighting perhaps a Zero, Jack, Tony, Hayate, or Shiden and had no other planes on hand but the Buffalo and the Airacobra, which would you pick to intercept the incoming enemy in the air?"

Now Jack, Hayate and Shiden means late war, so P-39Ns and Qs are legitime choices and because of that I would chose them over Brewster. Modified like Soviet usually did, for ex wing guns removed for lightness.

Juha

[kool kitty89]

But by 1944 (at the latest) the P-39 and Brewster had been almost completely phased out in the PTO. The P-40 filling in the gaps when lacking better a/c. Particularly with the commonwealth inventory where the B-339's and Hurricanes were replaced by it in most cases.

But assuming they were still there in in that time frame.

As a pure interceptor the P-39 was certainly better, particularly against bombers, as it's speed would allow evasion of the escorting fighters, which is more important than dogfighting them anyway. The later variants also had a much better climb rate than any of the Brewster versions. (the best climber would probably be an F2A-2 with half fuel load to be fair, since the F2A-2 had more than 2x the range than the P-39 on internal fuel. And the F2A-2/B-339 also carried ~60% more fuel than the earlier F2A-1/B-239)

Even with the added weight of the F2A-2 and even with the lower rated engine of the B-339 the Brewster had better power loading and wing loading than most P-39 models. On top of this the Brewster a/c had a high lift airfoil. (common for Navy a/c) According to Russian and Finnish testing of sustained turns at ~1,000 m the B-239 had a turn time of ~14 sec, while the P-39 was 18-20 sec, depending on model. (the P-39Q w/out wing guns and with 4-blade prop had the best time at ~18.5 sec) The P-39D/D-1/P-400 would have been the most common in the Pacific in the '42-43 period.

However if we're talking about the commonwealth B-339E, Buffalo Mk.I, not all aircraft were up to spec (constructed rather hastily, and sometimes with substitute parts), as sometimes parts were missing and often the fuel pump was not powerful to operated effectively above 10,000 ft. (the proper pump was sometimes replaced with a smaller one for a P&W Hornet engine) They were fitted with external self sealing tanks, and some pilot armor, but lacked head armor (as did many P-39's), reflector sights, and armor glass wind screens.

They required a lot of modification to become fully combat ready. If fully modified to good working order (not very likely to achieve completely) it was a decent a/c, albeit a bit heavy for its 1,100 hp take-off engine. (if working properly) It also carried a heavy ammo load of 500 rpg (for fuselage .50's), compared to 250 rpg on earlier models, of course this added more weight.

[Elvis]

KK89,

That turn rate you quoted for the F2A, was that for a 360 degree turn?
I thought I recently saw a 7 second turn rate posted in another thread.
Was that for a 180 degree turn?
Can't remember the thread off-hand. Maybe the Hurri vs. F4F thread?
Just curious, because I remembered a quicker time being quoted.

I know the test pilots liked the Brewster better than the Grumman, during the '38 Naval trials, (partly) because it seemed more nimble.
How that translates to the P-39 I don't know.
I still say the F2A over the P-39, because the P-39's overall rep seemed more to do with the ground attacK role than a fighter role (only what I've heard, over the years) and I agree with you on the F2A-2, but I still think they should've put the more powerful "-56" version of the Cyclone (along with a properly modified propeller to expound that extra power) in that plane.
I bet the extra 150HP would've offset the weight gain the "-2" incurred.



Elvis

[Juha]

Elvis
it was me who gave the following in from Raunio's book:
"Brewster Model 239
Sustained 180deg at 350kmh (IAS) at 2000m 7sec, no wonder that Finns liked the plane."

[Elvis]

Elvis
it was me who gave the following in from Raunio's book:
"Brewster Model 239
Sustained 180deg at 350kmh (IAS) at 2000m 7sec, no wonder that Finns liked the plane."

THAT'S IT!
Thanks Juha.



Elvis

[kool kitty89]

It was on the P-40 vs 109 thread.

[kool kitty89]

KK89,
I know the test pilots liked the Brewster better than the Grumman, during the '38 Naval trials, (partly) because it seemed more nimble.
How that translates to the P-39 I don't know.
I still say the F2A over the P-39, because the P-39's overall rep seemed more to do with the ground attacK role than a fighter role (only what I've heard, over the years) and I agree with you on the F2A-2, but I still think they should've put the more powerful "-56" version of the Cyclone (along with a properly modified propeller to expound that extra power) in that plane.
I bet the extra 150HP would've offset the weight gain the "-2" incurred.
Elvis

The US used the P-39 mostly in ground attack duties, and seemed to prefer the P-40 overall. (maneuverability being about equal, but easier to fly, 50%+ more range, better bomb load, slightly slower in level flight and climb, better overall armament)

The Soviets used it as a fighter: interceptor, escort, etc. Particularly for top cover for Il-2's. It had better "high" altitude (medium altitude by most standards; 15,000 ft); performance than many contemporary Soviet fighters. (particularly pre '44)



I'm not sure why Brewster didn't use a more powerful engine. (there were more powerful versions than the -56 model. (eventually topping out just over 1,500 HP) But I don't think adding more power would have cured the F2A-3's problems. It was overweight and this exacerbated the landing gear problem, in fact making the gear unreliable even in land based service. The armor had nor been efficiently configured on most US and commonwealth models either with the head and/or sholders often being exposed. (the Finns found an excelent layout though)
Even the F2A-2 was pushing abit much weight (the gear had been improved but the weight gain had negated this), and it probably would have been best to keep the fuel capacity to that of the F2A-1 and keep take-off weight below 6,000 lbs. At that weight 1,200 hp would have been very good, though range would be ~900 mi (compared to 1,400-1,500 mi of the F2A-2/3) but provisions for drop tanks to the wing racks could have helped this. Plus 900 mi was already a bit more than the F4F's 800 mi max clean range.

Some export models, the Dutch B-339D's, got 1,200 hp R-1820-G-205 engines which roughly equivelent to the -40 model of the F2A-2, these engines came directly from Wright and were not refurbished like many of the R-1820-G-105's used. Thus these a/c would have had considderably better performance than the -G-105 powered models.