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Didn't matter how they were mounted, the guns were tested with the plane flying straight and level, RAAF .50's didn't work and neither did the same guns fitted to FAA F4 Martlets, we have covered this in other threads.
In 1939-40 the .30's from all nations were a proven gun yet the .50 and 20mm were described by the RAF as underdeveloped, including the ammunition.They had a lot of problems with the .50s in the first few months (for several reason, both aircraft and ammunition), though this was starting to dramatically improve by mid 1942 (not every unit sorted it out at the same time).
They also had quite severe issues with the Hispano cannons particularly in the Tropical conditions, around the same time.
In 1939-40 the .30's from all nations were a proven gun yet the .50 and 20mm were described by the RAF as underdeveloped, including the ammunition.
I love that not the prom queen line!! I talking to a EAA chapter about my own P40k project and I'm gonna use it for sure!Yeah, it did get a Merlin in a couple of models.
As a boy, I read and absorbed the idea that the P-40 was quite craptastic, but in the many intervening years I seem to get that like many overlooked airplanes, in the hands of a decent pilot using good tactics it was a dangerous opponent. Relatively maneuverable, good dive characteristics, limited in altitude performance in most cases, but well-armed and rugged.
Maybe not the prom queen, but a good date to dance with if that's what you've got.
But is it really too draggy to ever be updated to P-51 levels. A fat wing and a whole lot of airframe drag kept even the updated versions from getting real fast. It's kinda like comparing Babe Ruth to modern ballpayers training and equipment. For me personally the tradition and the style of the P-40 will always be an icon like the Colt 1911 and the Fender Stratocaster IMHO of course!
Right but my real point is that they weren't slow compared to their opposition. I would also say, 360 mph in early 1942 (once they are pushing the engines a bit harder) is not slow, it's about average for a fighter. Some were faster but not necessarily in the field.
The -33 impeller was turning at 8.77 times the crankshaft speed, the -39 impeller was turning at 8.80 times. A power of 1040 HP at 13600 ft is always 1040 HP at 13600 ft, whether made by the -33 or the -39.My understanding is that the -33 had a slightly higher ratio, I'd have to go pull down some books to check. But for example according to this Sept 1941 data sheet, it had a critical altitude at military power of 13,600, where it is producing 1040 hp, and performance is usually still pretty good for another 2,000 feet above that. Which puts you at about 15,600
This similar chart from Dec 1942 for the P-40D/E shows a critical altitude at military power of 11,800 ft. Which puts you at 13,800 (but I think that was pushing it!). It's interesting though that the chart does show 56" Hg WEP setting for 1470 HP at Sea Level. I don't think a lot of units in the field got that memo until a bit later (like March).
My understanding is that there were different types of the later generation Allisons, and the variant they put on the 'Interceptor' configurations of the P-40N was the higher boost type, however the 'Fighter Bomber' type P-40N and the P-40Ms were limited to lower boost, this chart for a P-40M with the V-1710-81 shows 1360 for WEP and 1200 for takeoff. The infamous Allison Memo also mentions this, that the higher geared Allisons were going to have more trouble with high boost (due to heat, from what I gather).
Right but without the second speed it would then be relatively a dog down low. As it was the P-40K was considered much faster than the P-40F below 4,000 ft.
But all the single speed superchargers had that problem - you pick where you want to go fast. Down low means poor at high altitude, up high means the reverse. It's just a bit less of an issue with a Spitfire because that is a much lighter aircraft (at least pre-Griffon)
How many threads do we have on things the Japanese could have done differently. (or what the Italians could have done differently)
Got a big engine? Use it. Not got one? License it. Can't license it? You're screwed. Power is the key.
Actually it mattered significantly in P-51B/D. The solution to the B was addition of booster motor (from B-26 top turret IRC) to assist feed continuity uner high G, but realigning the 50 cal upight in the D solved the feed issueDidn't matter how they were mounted, the guns were tested with the plane flying straight and level, RAAF .50's didn't work and neither did the same guns fitted to FAA F4 Martlets, we have covered this in other threads.
The Merlin only had about 1100hp available in 1938/39 so weight was a big issue.It's kind of the perpetual dilemma of the war (and speaks to the circumstances of aircraft like the P-40 and the Hurricane) do you go with what you know works or gamble on something new and potentially much better?
Or you can do like the one communist country I know of, and build stuff without a license. Currently houses the birthplace of the Wuhan Flu...Got a big engine? Use it. Not got one? License it. Can't license it? You're screwed. Power is the key.
AmenOr you can do like the one communist country I know of, and build stuff without a license. Currently houses the birthplace of the Wuhan Flu...
Oh you mean that virus of unknown originOr you can do like the one communist country I know of, and build stuff without a license. Currently houses the birthplace of the Wuhan Flu...
Yes, it still hasn't been confirmed which room it escaped from in the Wuhan Institute of Virology.Oh you mean that virus of unknown origin
With a twin blade fixed pitch prop, only around 66BHP was available on take off, revs had to be limited or the prop was stalled.The Merlin only had about 1100hp available in 1938/39 so weight was a big issue.
I hope you don't actually believe this do you?The P-40 is in my honest opinion the most under rated fighter in the entire war...and there were lots of under rated fighter...F4F anyone? Considering it held the line before the war even started...its kill ratio is amazing...and it was flown against other nations at their peak by inexperienced American airmen unlike the P-51D that got to hold the trophy after the p-47 and Spitfires had already demolished the Luftwaffe.
*SNIP*
If the opposite side has aircraft doing 400 mph, like the Luftwaffe had in 1942 in the field, the 360 mph fighter is a slow fighter. Granted, not as slow as 320-330 mph Hurricane II or F4F.
As indicated on the charts I linked, the Tomahawk types were showing a higher critical altitude at military power.The -33 impeller was turning at 8.77 times the crankshaft speed, the -39 impeller was turning at 8.80 times. A power of 1040 HP at 13600 ft is always 1040 HP at 13600 ft, whether made by the -33 or the -39.
Allison didn't give that blessing until Dec of 1942, the power issues with the Kittyhawks were already resolved by then (for several months) as acknowledged in the memo. But in early 1942 they did not know how far the engines could safely be pushed, and the improved bearings, crank shaft and crank cases were not delivered yet. Hence the problems with the early Kittyhawks starting in Dec 1941.Note the altitude for the WER there - sea level. It will be making more high up, as can be seen at the chart I've previously posted. The ram effect adds another 2500 ft for the rated altitude for WER power setting (57 in Hg at 3000 rpm). The Alison memo indeed warns for not over-boosting the new engines (the ones where impeller turns at 9.60 times the crankshaft rpm), and the power tables and chart show that, the new engines making ~100 HP less at low level vs. 'old' versions that could be run at 60 in Hg down low with blessing from Allison and USAAF. The 'old' S/C will also consume less power to drive, so more power is left to turn the prop.
I believe there was though I don't know if this was just a bureaucratic thing (i.e. orders / policy) or literally a throttle limitation. Some of them had a wire which had to be broken to exceed a certain boost pressure. As Shortround6 often points out, the crew chief would typically know if they had been overboosting the engines (or just using WEP) when the plane landed due to scorch marks, oil leaks etc.There was no such thing as "this is a F/B P-40N, so easy on the throttle, fellas".
As it should be, it had more power there. Trick was finding the answer how to gain performance, altitude and situational advantage over the enemy at all combat altitudes: the P-40 was lacking in that domain vs. the Luftwaffe, and could get at best the parity in Asia/Pacific.
Easy pick - the higher, the better.
FWIW, I was trying to note that 2-speed S/C is not be-all end-all qualifier, when we talk about 1-stage supercharged engines.