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For the sake of the war effort, would it have been more practical or more effective to concentrate development at de Havilland, and/or have Lockheed build Vampires under license?
Some sources for the Arado 234C say 540mph with 1/2 fuel and no bomb load.
Ducts are probably not as heavy as engines, all things considered.
The Lockheed L-1000 (J-37) was a vastly over-complicated dream that would only see comparable engines 12-20 years later. NO amount of funding in WW II would have seen it turned into usable hardware. The first one didn't even run until 1946, not 1942.
The Isotta Fraschini engine, IF it was the Isotta Fraschini L.121 RC.40, sometimes reported, had a supercharger. Just a single stage one but the critical altitude was 4000 meters. That is what the "RC.40" means. On Italian engines the RC is followed by a two digit number and those two digits are the critical altitude in hundreds of meters as in Fiat A.74 R.C.38 used in Macchi 200. Critical altitude in 3800 meters.
The motorjet sounds a lot better in theory than it it ever turned out in practice. Some those early turbo jets actually used several thousand HP to drive the compressor. So a motorjet equivalent to a 2-3000lb thrust turbojet would weigh quite bit more.
It appears that the 234 does not have an internal bomb bay which means it would be unable to obtain these speeds prior to weapon delivery. And it is doubtful if these changes were ever made but was probably proposed.This mach limitation was raised slightly be re-profiling the nacelles which raised the Mach limited speed to 555mph-560mph.
I believe these were proposed upgrades. I could find no indication this engine was ever run.The Ar 234C was scheduled to receive the 900kP thrust BMW 003C but initially received the 800kP BMW 003A2 although the aircraft was still Mach limited. The BMW 003C had the same hot section but had a new 50% reaction compressor of higher efficiency and flow, in fact it had two: one developed at Brown Boverie and Cie and another at BMW and the DVL to choose from.
There is no doubt that the Germans had a decent lead in advanced aerodynamics such as swept wing. However, the allies could quickly recover and had more powerful engines to use. Both the Americans and British had 4000 lb thrust engines starting production, with the 5000 lb thrust Nene right around the corner. The largest German engine that had run was not over 3000 lb thrust.A swept wing had been developed and was in the process of being mated with then fuselage when British troops over ran Arado, in fact it was a scimitar or crescent wing, had been chosen as it overcame both span wise flow issues and didn't required new wing mounting points or center of gravity adjustments.
I take your notes on board regarding the campinis supercharger but not that its low power (670hp) and low full throttle height (3800m or about 12000ft) are unimpressive. Put in a 1700hp merlin or a turbo charged radial with two stages and 300lbs jet thrust that is able to maintain say 1450hp to about 22000ft then thrust is much more impressive, especially as unlike a jet the motorjet would not loose much power/thrust at altitude.
I didn't know that. Thanks for the information.I think Eastman Jobs was disgracefully treated by his country: this ingenious man who had made possible the P-51, moreso than anyone at North American because he developed not only laminar profile wings but the computational methods to ensure they have good stall and pitch characteristics was kept out of the loop on jet development and not invoved with the XP-59, which he could have made a success. It's no surprise he retired early in 1944 and opened a restaurant. Most other attempts at laminar flow wings were failures (that of Spitfire variants dubious, Tempest V unpleasant, Me 309 we don't known, Russians seem to have run experiments in 1944 that needed slats)
I have found no source that shows a Me 262 going faster than about 540 mph except one showing proposed design cleanups. This is similar to the top speed of the P-80 and Vampire. The Meteor was slower. There is a proposal for afterburning but was never developed that showed a significant increase in airspeedIt's also worth noting that well built examples of the Me 262 could sustain a level speed performance of 560mph and there were thrust and subtle Mach Limit increases being developed:
Probably not true with bombs.A strike package of Ar 234C and Me 262 would simply outrun any vampire built.
Bottom line this aircraft, likely the fastest of the war (the other contender being the He 162) was beyond any future Vampire's speed clean and certainly beyond the vampire of 1945 with bombs.
I do not share your pessimism in regard to the motor jet. The Campini's primitive implementation and unimpressive performance rather than being a proof of concept acted more as a proof of failure and entered the 'folklore'
The low pressure and exhaust velocity meant it was more like a ducted fan with some burners to warm the air a little as an afterthought. Eastman Jacobs had built a 14 stage compressor indicating he was looking at pressure ratios of around 8:1 and that this would be a real 'reaction engine' rather than a warmed up ducted fan.
I take your notes on board regarding the campinis supercharger but not that its low power (670hp) and low full throttle height (4000m or about 13200ft) are unimpressive. Put in a 1700hp merlin or a turbo charged radial with two stages and 300lbs jet thrust that is able to maintain say 1450hp to about 22000ft then thrust is much more impressive, especially as unlike a jet the motorjet would not loose much power/thrust at altitude.
It's also worth noting that well built examples of the Me 262 could sustain a level speed performance of 560mph and there were thrust and subtle Mach Limit increases being developed:
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I think Eastman Jobs was disgracefully treated by his country: this ingenious man who had made possible the P-51, moreso than anyone at North American because he developed not only laminar profile wings but the computational methods to ensure they have good stall and pitch characteristics was kept out of the loop on jet development and not invoved with the XP-59, which he could have made a success. It's no surprise he retired early in 1944 and opened a restaurant. Most other attempts at laminar flow wings were failures (that of Spitfire variants dubious, Tempest V unpleasant, Me 309 we don't know, Russians seem to have run experiments in 1944 that needed slats)
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as far as p80 vs vampire 1, the p80 had better performance but i believe the vampire was overall more Maneuverable.
The first P-80A was delivered in January of 1945. the first models were grey and they had all structural seams filled in. The "Grey Ghost" was a specially modified P-80 used for speed records. Later P-80As were delivered unpainted. They had a top speed of over 550 mph and I'm sure were flown that fast during acceptance flights.I doubt any WW2 allied jet exceeded 500mph during WW2.
The first P-80A was delivered in January of 1945. the first models were grey and they had all structural seams filled in. The "Grey Ghost" was a specially modified P-80 used for speed records. Later P-80As were delivered unpainted. They had a top speed of over 550 mph and I'm sure were flown that fast during acceptance flights.
EDIT
"The first flight of the XP-80 took place on January 8, 1944 with test pilot Milo Burcham at the controls. The first flight had to be cut short after only five minutes because of undercarriage retraction failure and the pilot's concern over boosted aileron sensitivity. These problems were quickly fixed. Subsequent test flights reached a top speed of 502 mph at 20,480 feet, the XP-80 becoming the first USAAF aircraft to exceed 500 mph in level flight."
Lockheed XP-80 Shooting Star
"The first flight of the XP-80 took place on January 8, 1944 with test pilot Milo Burcham at the controls. The first flight had to be cut short after only five minutes because of undercarriage retraction failure and the pilot's concern over boosted aileron sensitivity. These problems were quickly fixed. Subsequent test flights reached a top speed of 502 mph at 20,480 feet, the XP-80 becoming the first USAAF aircraft to exceed 500 mph in level flight."
Lockheed XP-80 Shooting Star