Snautzer01
Honourably banned
- 42,548
- Mar 26, 2007
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No way the P-40 was superior to the P-39 in speed climb ceiling or range.If they had axed the P-39 and ordered the XP-51 right away, could Bell have also built more P-40's for Curtis? Not that it didn't have it's own quirks and flaws, but it was still a far better aircraft than the P-39 especially when flown with significant overboost.
No way the P-40 was superior to the P-39 in speed climb ceiling or range.
The "early 2 stage Spitfire MkIX" was a 1942 aircraft. Only 4 squadrons active with the Mk IX before Sept '42, basically test batches. Real production of the Mk IX was in 1943.
By 1943 the engines had improved.
Do you think the P-39N is actually a match for the P-51A? The P-51A being faster and longer ranged. Charts for the P-51A and P-39Q (no wing guns) below. P-51 is about 10mph faster even though with a sanded and polished finish. Climb is almost identical even though the P-51 weight was reduced to 8000lbs (from 8600) and carried only 105gal fuel (normally 180). Hard to believe they climbed at the same rate when the P-39 was 400lbs lighter with the same engine. P-39N tests showed an additional 600fpm climb. Performance of these two planes, even with the P-51 finish being sanded and weighing 600lbs less than normal, was about even. I would consider them a match.
What about the Spitfire XII? Sure only 100 made, but top speed about the same as the P-39N, best performance in a similar altitude band, but better climb rate than the P-39N. You said it, only 100 made. Griffon engine was 30% larger than the Allison and had a two stage supercharger. Not really any faster and didn't climb as well as a P-39N.
Typhoon Ib? Faster, with more firepower. And range. According to wwiiaircraftperformance.org the Typhoon 1b had about the same speed at 20000ft but a lot slower below. Climb was 2000fpm at 20000ft when the P-39N would climb at 2650fpm at 20000ft. Not a bad plane, about like a 1943 Corsair, Hellcat or FW190.
Fw190A (not sure which subvariant was best by 1943)? By your own reckoning, the P-39N was no match for the Spitfire IX, the Fw190A was, or was close. Surely that would mean the Fw 190A outmatched the P-39N? You can compare a 190 with a Spitfire V but not a Mk IX. Mk IX would climb away from a 190 at any altitude, would climb almost THREE times as fast at 26000ft. No comparison, especially when the 190 couldn't use full power through most of the war. Against the P-39N the 190 was about the same speed but climbed 600fpm slower at 20000ft. And a lot less maneuverable than the P-39.
The 1942 P-39 (D/F/K/L) was way too heavy when compared with contemporary fighters power/weight ratio. Delete the unnecessary/redundant wing guns, nose armor plate and IFF radio and those P-39s weigh 7150lbs.
No plane will meet these specs until the Merlin P-51 in 1944. A 1943 P-39N was very competitive with any other 1943 fighter. Except the early two stage Spitfire MkIX.
I'm wrong that a 20% larger engine should make more power?
Yes, with 20% less displacement.
Never said any P-39 had the two stage engine (except the P-39E), just said it would fit with minor modifications. The engine was in production in April '43 but the first P-63 airframe wasn't ready until October '43. Put the engine in the P-39 until the P-63 was ready.
The P-40 used a similar engine that was rated mostly at about 1,325 hp. Some had engines of 1,425 HP or so. Two variants of the P-40, the P-40F and P-40L, had Packard-Merlin V-1650 engine, but the Merlins so used were single-stage engines and the resulting P-40s performed almost the same as with the Allison engines. The Merlin-powered units were very slightly faster and had very slightly better altitude performance, but not enough to make much of a difference. They were still low-altitude fighters. You can tell the Merlin units because they airscoop on top of the nose is missing.
My doctors advice is I am no longer allowed to partake in any discussion regarding the P-39.On doctors advice, I am no longer allowed to install or remove fuel tanks, armour or weapons, at any time.
I got the same but from my anger management consultant, and mental health awareness self help group.My doctors advice is I am no longer allowed to partake in any discussion regarding the P-39.
According the the pilot's handbooks for P-40E and P-39K/L (same engine power above 12000ft):P-40E Range: 716 mi (1,152 km, 622 nmi) at 70% power
P-39Q Range: 525 mi (845 km, 456 nmi) on internal fuel
Is this some kind of new math where 525 is actually greater than 716?
Of course the P-39's range can be increased by the addition of the external drop tank...but that reduces its speed to below that of the P-40.
My doctors advice is I am no longer allowed to partake in any discussion regarding the P-39.
Still does not do things required by USAAF Pacific (the area USAAF was mostly fighting in 1942). In best part of 1942, it required the -83 engine (so it can compete above 15000 ft) and at least 50% more fuel (so it can cover the area better).
It wasn't so. In 1942 the AAF was in a defensive position. Only thing the P-39 had trouble doing was intercepting IJN bombers at 18000-22000ft headed for Moresby. Could intercept them about half the time. At 7150lbs it could intercept them all the time. Otherwise the escort of medium bombers and transports was no problem.
P-47 has certainly a potential to do 500 mile escort with wing tanks in 1943. P-38 - ditto (and a bit longer). P-39 can do how much of the escort job at 25000 @ 300 mph TAS? 250-300 miles? P-47 could only escort about 350mi radius in 1943 and then only after drop tanks introduced in August. I have a range chart but can't seem to make it attach.
You've answered your own question there. A larger engine will make more power.
P-39E required major modifications of central and rear fuselage in order to the cooling systems and the 2-stage engine to fit inside. Once all of that was done, the P-39E was found to have dangerous spin characteristics - no wonder with the extra weight added aft the CoG. I'm not talking about an 8900lb P-39E. I'm saying put the -93 engine in a standard P-39, offset the weight of the auxiliary stage with a larger four blade propeller. The -03 engine would fit into a standard P-39, I've shown the drawings on here many times. Whole thing would have weighed about 7900lbs.
I used that same P-40D/E chart for my calculations.Flight Operation Instruction Chart
P39FOIC.pdf (zenoswarbirdvideos.com)
P-40FOIC.pdf (zenoswarbirdvideos.com)
Nope - P-39 Faster (under 18K vs P-40F, then P-40F faster by 20mph), better acceleration (under 18K vs P-40F/K) and better climber (except vs P-40F/K from 18K ), much slower roll rate than P-40 (any model), less terminal dive speed, shorter range, less external load, less practical armament than P-40E and Subs, for most strafing and all air to air due to the issues with M-4 37mm cannon. Nobody in USAAF, RAF, Commonwealth, French and Italians were crying for more P-39s.According the the pilot's handbooks for P-40E and P-39K/L (same engine power above 12000ft):
Clean:
P-40 12000ft 148gal less 28gal warmup&climb = 120net gallons divided by 41gph = 2.9hours x 235mph = 681mi.
P-39 12000ft 120gal less 20gal warmup&climb = 100net gallons divided by 33gph = 3.0hours x 241mph = 723mi. P-39 cruised faster than P-40 at a lower power setting.
We can do this at any altitude with any external tank. P-39 was faster, climbed faster and cruised farther then P-40.
Only 4 squadrons active with the Mk IX before Sept '42, basically test batches. Real production of the Mk IX was in 1943.
You said it, only 100 made. Griffon engine was 30% larger than the Allison and had a two stage supercharger. Not really any faster and didn't climb as well as a P-39N.
Nope - P-39 Faster (under 18K vs P-40F, then P-40F faster by 20mph), better acceleration (under 18K vs P-40F/K) and better climber (except vs P-40F/K from 18K ), much slower roll rate than P-40 (any model), less terminal dive speed, shorter range, less external load, less practical armament than P-40E and Subs, for most strafing and all air to air due to the issues with M-4 37mm cannon. Nobody in USAAF, RAF, Commonwealth, French and Italians were crying for more P-39s.
Don't depend on your calculations -use USAAF Published Tables as reproduced on page 599 of AOHT, Table 100. Boundary conditions are 10 minutes of fuel for warm up, taxi, takeoff and landing. It allows for fuel used to climb to 10,000 feet, cruise and 10% of net ideal range for other factors - at more economical power speed. Below table values are for pure straight line range from take off to reserve point..
Pilot Handbook values were contractor developed and the USAAF tables were developed from flight testing - and averaged across multiple ships same type.
P-39D/F/K (VERY best P-39 range performance w/120 gal and TO weight of 7650) = 600 mi. The P-39N w/87gal TO wt of 7550 =350 mi; =550mi for 120gal.
The P-39N is probably the best comparison as it was most widely produced
P-40E (149gal and TO weight of 8700) = 650mi
P-40F/K (157gal Merlin 1650-1, TO weight of 8800) = 700mi
According to wiki there were 6 squadrons of Spitfire Mk IXs at Dieppe, 4 RAF and 2 RCAF.You mean the 4 squadrons hat took part in the Dieppe landings?
I have moved all the P-39 vs P-40 talk into this thread about the P-39 vs. the P-40.
P-39 Expert stop hijacking threads and turning them into P-39 threads. It's getting really tiring...