Quote:
Originally Posted by T. A. Gardner
While this (the loss of knowledge / information) does occur, in this case it is far more one of making what clearly is a very extraordinary claim; that is, that the Germans in early 1945 had a flying aircraft capable of exceeding mach 2.
According to what we know of the Lippsich project the aircraft weighed between 2 and 4 metric tons loaded. This would require a rocket booster given extant technology on the order of a small V-2 to get the aircraft aloft and to a speed where its ramjet would work. That is, the rocket alone would have to boost the aircraft to near mach 2 (say 2000 kph minimum, and more like 2500 kph) just to get the ramjet to run.
To complicate things powdered coal is used as a fuel. How was this stored and moved to the engine? Mechanical means such as a screw conveyor? Aeolian means?
There are just too many questions that pose huge obstacles to this project ever reaching a flying prototype, particularly in 1945 as Germany was collapsing. Think, when Kurt Tank describes a problem with the engine on a Ta 152 prototype requiring a replacement part and the only available means to get the part was to send a technician with special passes on a bicycle to the factory to get it and pedal it back taking a week to do so, as but one microcasum in the bigger picture of what transportation was like in 1945 Germany, it does not bode well that the P 19 could have progressed so rapidly to a flying aircraft....particularly given its novel propulsion systems and extreme predicted performance.
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Sorry, but many ramjets work perfectly well at speeds as low as 200km'hr.
You are mistaking the higher efficiency of ramjets at supersonic speed for the idea that they need to go supersonic to work at all. That is far from the case.
They are far less fuel efficient at subsonic speeds than a turbine but they can still produce considerable thrust to propel aircraft at subsonic speed.
The Eugene Sänger designed Lorin ramjet and Skoda-kauber ramjets worked successfully subsonically. Both were fitted in separate tests to a Dornier 17 and were able to mightily thrust the unstreamlined beast to more than 150km'hr faster than its normal maximum top speed.
The P13 was intended to have a flattened version of these ramjets.
The French Leduc ramjet fighter had a derived version of the Lorin engine and flew under ramjet power in 1952 reaching a maximum sustained speed of mach .85.
So that's a large heavy german Dornier 17 being given a sizable kick along, plus a manned, working jet fighter prototype scooting through the sky and climbing under ramjet power only and there's no Mach 1, let alone Mach 2 anywhere in sight.
If the coal gas and catalyst system was airworthy, then a walter rocket could have easily helped a P13 reach ramjet operation speed.
Whether a powered P13 actually flew is another matter. Lippisch did successfully test the design in the Berlin supersonic tunnel and his freeflying test models worked beautifully. He later designed for Convair and his German colleagues led the teams that produced the Delta dagger, convair seadart and B58 Hustler.
Despite the bicycle factor mentioned, they still almost completed the sweep wing Me P1101, flew the Natter, DFS 228, flew 4 or 5 flights of the Horten lX (Go 229)version 1, flew the fieseler Reichenberg, the 4 engine Junkers 187, 4 engine Arado 234, TV guided missiles etc etc and fielded 3 types of Helicopters in Combat. A hypothetical completed p13 even if subsonic is in rather extraordinary company of genuine aircraft.
Btw The Münich computational fluid dynamics tests confirmed the ME262 could exceed Mach 1 for a few seconds without area rule. Not well or effortlessly but it was possible and the characteristics exactly match what was reported by Mütke and the British test pilots.
The engines flamed out of course during the transonic period and the plane needed previously to be dived steeply and with full power to minimise the duration of buffeting. A slow approach to Mach 1 would mean a long period of instability and severe down pitching leading to uncontrollable negative gs and loss of aircraft. After a few seconds above mach 1 with dead engines the craft would then drop back and begin shaking madly again with high deceleration and high likelyhood of structural failure and total loss of control. Not pretty, but still supersonic, even if only for a few brief moments.
Like the X1, the 262 had a fully trimable all moving tailplane rather than just an elevator flap. The 262 was tubby in the middle but had very thin swept wings. Similarly, neither the Bell X1, the F86 nor the Convair Seadart seaplane had area rule either but all were able to exceed Mach 1.