GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
It'll pass in time.
Every so often this sort of thing comes up - before the P-39, it was a P-40 discussion if I remember right, that ran well past it's point of being useful.
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It'll pass in time.Damn straight. Is there a way to filter out P-39 chat within a thread?
Regarding Post #1059:
The top fighter in the Pacific flown at military power loaded for combat against the bottom fighter flown at WER and light enough to be useless on a mission?
That's useful! Thanks!
You'd be a lot better off and a lot more believable if you stick to the numbers from the Pilot's Oprating Handbook rather thanh lightweight WER tests. The P-39N was nowhere NEAR what you posting when it was flown at normal weihgts and Normal power settings.
P-39 weight was listed at average weight for a flight, fully loaded with half fuel. Took off with full fuel, landed with minimum reserve. British used 95% of gross weight to allow for fuel burn. Hellcat flown at WER, as was P-39 except no WER above 17000ft. Standard tests for AAF and USN.Regarding Post #1059:
The top fighter in the Pacific flown at military power loaded for combat against the bottom fighter flown at WER and light enough to be useless on a mission?
That's useful! Thanks!
You'd be a lot better off and a lot more believable if you stick to the numbers from the Pilot's Oprating Handbook rather than lightweight WER tests. The P-39N was nowhere NEAR what you posted when it was flown at normal weihgts and Normal power settings.
P-39 weight was listed at average weight for a flight, fully loaded with half fuel. Took off with full fuel, landed with minimum reserve. British used 95% of gross weight to allow for fuel burn. Hellcat flown at WER, as was P-39 except no WER above 17000ft. Standard tests for AAF and USN.
Pilot's manual was a guide for pilots, not the results of a performance test. Climb (and range) almost always lower in the manual than on an official test to give the pilot a reserve. Hellcat manual had no similar climb chart, only listed time to climb with no feet per minute figures at different altitudes.
Doesn't the P-47 have the same issue? I'd probably drop my Big League Chew into the bowels of the aircraft.F4U Corsair: floorboards under cockpit and some seat adjustments so somebody shorter than a 75th percentile male would fit properly
You're doing this the hard way. Straight from the pilot's manual. If range is important then use the full 120gal internal, we're in the Pacific, not the Russian steppes. And lets cruise at 20000ft just in case we do get jumped by Zeros. Deduct 20gal for takeoff and climb to 5000ft, 32gal for a full 20minutes of combat at 20000ft, and a 10gal reserve for landing. That leaves us with 58gal for cruise out and back at 35gph or 1.7 hours at 224mph TAS is 380miles. Not 193. That's with a full 20 minutes at combat power at 20000ft.Hi P-39 Expert,
OK, P-39 Expert, let's take a look at it.
I'll use a P-39N-1 at 7,514 lbs. That's basic airplane plus full internal fuel (87 gallons) and no center tank. Let's say we cruise at 15,000 feet.
1) Takeoff and climb to 5,000 feet uses 20 gallons and gets you 5.42 miles from brake release. You can do the math.
2) Climb from 5,000 feet to 15,000 feet takes 4.7 minutes at 142 gal/hrs and uses another 11.12 gallons. It also gets you another 11.714 miles from brake release.
3) Let's say you have an action sorties in which you are at combat power for 6 minutes. You basically don't go anywhere, but you use 13.80 gallons of fuel.
4) Now, instantly, you go from combat to cruise flight and you choose to cruise at 2,200 rpm, 31" MAP, for a fuel burn of 59 gallons per hour. That means you have 42.79 minutes of flight at 247 mph, which means another 176.15 miles.
5) So, the total range is 193.28 miles from brake release, or less than 100 miles out and back. In the Pacific, that means the P-39 was a viable airplane on full internal fuel and no aux fuel if it was flying between the islands in Hawaii. If you don't engage in any combat, the range goes up to 251 miles under the above conditions. The conditions do not allow for fuel reserve.
Not very useful. You can get out 300 – 345 miles if you cruise at absolute economy power. But, getting caught cruising at 194 mph by a Zero means you are right in the middle of his best-performance airspeed range. Not a good place to be if you are the P-39 pilot. If you cruise at 250 mph, your range is less than 250 miles one-way, which means a 125-mile mission range.
Again, not very useful when the Pacific Ocean is your playground. You can get as many as 430 statute miles, but you'll be cruising at 160 - 194 mph, so don't get caught by a Zero (or any other Japanese fighter). If you DO happen to need 5 minutes of combat, and you are out at the max range, you won't get back home before running out of fuel. The range tables don't allow for combat.
With the 75-gallon aux tank, you can get out to 694 miles, but that is at best economy power and low-speed (160 – 194 mph) cruise, with no allowance for combat. To actually get to the max range, you'd have to basically fly the entire mission at best economy cruise power (2,000 rpm). Nobody who wanted to live would go into a potential combat area where he expected to see enemy aircraft at economy cruise. So, the max range is basically a ferry flight with no combat.
So, the P-39 looks like it could be a useful fighter for local defense and short-range attacks. That only helps offensively if there are short-range targets around. In the Pacific, there were in some island chains, notably around Port Moresby and similar island chains. Not so much if you were flying out of an island with nothing around for hundreds of miles.
In total, it doesn't look very useful, and it didn't prove to be so in real life during WWII in the Pacific.
In the Russian steppes, the targets could be only a few miles or a few tens of miles away, so it wasn't range-limited and the space between the launch airfield and the target was ground and not water. That meant if you had to get out of the P-39, you could walk home if you had to. A completely different scenario from the Pacific where going down might mean a LONG swim. Heck, in a flight suit a 100-foot swim was a long one.
The above come from the POH, not the lightweight WER test report.
You're doing this the hard way. Straight from the pilot's manual. If range is important then use the full 120gal internal, we're in the Pacific, not the Russian steppes. And lets cruise at 20000ft just in case we do get jumped by Zeros. Deduct 20gal for takeoff and climb to 5000ft, 32gal for a full 20minutes of combat at 20000ft, and a 10gal reserve for landing. That leaves us with 58gal for cruise out and back at 35gph or 1.7 hours at 224mph TAS is 380miles. Not 193. That's with a full 20 minutes at combat power at 20000ft.
Now virtually every mission was a drop tank mission so let's use the 110gal external tank most common in the Pacific. And let's go on up to 25000ft in case we meet any Zeros. Start with 230gal (120+110) less the same 20gal for takeoff, 24gal for combat at 25000ft and landing reserve of 10 gal. That leaves 176gal for cruising at 62gph or 2.8hours of cruising time at 276mph or 772miles. Full 20min combat at 25000ft and a 10gal landing reserve.
The F6F-3 stat sheet shows a combat radius of 335mi with a 150gal drop tank, but the USN figured theirs differently. Figured like an army mission use 400gal (250 internal and 150 drop) less 45gal takeoff and climb to 5000ft, 93gal for 20 min combat at 25000ft and a 20gal reserve for landing. That leaves 242gal for cruising at 93gph (max cruise) or 2.6hours. About the same as the P-39N at 2.8hrs. Max cruise is not max continuous (normal) which used 250gph at 25000ft, that would give you less than 1hr.
Now virtually every mission was a drop tank mission so let's use the 110gal external tank most common in the Pacific. And let's go on up to 25000ft in case we meet any Zeros. Start with 230gal (120+110) less the same 20gal for takeoff, 24gal for combat at 25000ft and landing reserve of 10 gal. That leaves 176gal for cruising at 62gph or 2.8hours of cruising time at 276mph or 772miles. Full 20min combat at 25000ft and a 10gal landing reserve.
And let's go on up to 25000ft in case we meet any Zeros.