Description: This is a heavily Illustrated Guide for most U.S. aircraft turbo-superchargers.
Engine manufacturers considered the supercharger their most pressing technical problem.
They added weight, bulk and cost even before you hit boost levels that required
inter cooling. To obtain more power from higher boost levels and maintain
reliability, many engine components have to be replaced or upgraded such as the
fuel pump, fuel injectors, pistons, valves, head-gasket, and head bolts. Yet they were the deal breaker in high performance
The 10 year period prior to World War II saw engine power double and then
triple due mainly to turbo-superchargers advancing substantially.
- The P-47 had the largest fuselage for a
single-engine fighter of the War, in large part because the fuselage
had to be big enough to contain all of the ducting involved in using a
special turbo-supercharger design, the turbo-supercharger was located in
the rear of the fuselage, behind the pilot.
- In the case of the P-38, the twin booms provided a convenient place to
put the turbo-superchargers without a lot of extra ducting. The P38 was the
designated high altitude interceptor.
- The lack of an adequate supercharger made the P-39 useless for
- Adding a turbo supercharger to the engine of the B-17 "Flying Fortress,"
once thought obsolete, had made it a high-speed, high-altitude aircraft.
NACA created an aeronautical research community at Langley, in terms of
equipment for engine research, the laboratory was probably superior to any found
in the world. Interviewed at that time by the laboratory's newspaper, Wing Tips,
Langley's top engineer declared unequivocally that the supercharger was so
essential that his division was looking forward to a not distant future when
they will be asking you not what kind of supercharger have you got on your
engine, but what kind of engine have you got on your supercharger?'"
Supercharger technology was highly guarded. The Americans initially sold
P-38's to Britain, but without the superchargers. That made them very sluggish
at higher altitudes. The British called it the "Castrated Lightnings."
Lockheed wouldn't supply them with the turbochargers, the Americans were afraid
one could potentially end up in German hands.
The impact turbo-superchargers had on the war
can not be understated. Rolls-Royce had been active in the
Schneider Trophy the last couple of times it ran, and used supercharger
boost to achieve the performance. This is also the road they took through
the war, particularly on the Merlin.
High boost dictated lower compression ratios. Allison initially ran higher
compression ratios, which restricted the boost that could be used, and thus
horsepower. Later Allison dropped the compression ratio and increased boost
for turbocharged and two stage engines. When a turbo-supercharger was fitted
to the Allison-engined P-38 Lightning it enabled the heavy fighter to
perform brilliantly at high altitude.
Most, if not all, of the famous warbirds could be reshuffled in order-of-importance simply by the reconfiguration of the installed turbosuperchargers. Advanced superchargers were that essential to the speed, altitude and performance of these aircraft. So competitive was this technology during war, that allowing the information in this manual to fall into enemy hands was considered espionage activity.
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WWII General Electric Turbosuperchargers
Field Service Manual:
General Electric was the sole source for supercharger production in
the United States. The U.S. in the form of General Electric had been
working on turbochargers since the end of WWI.
The USAAF had taken steps to provide all aircraft with advanced superchargers from 1942 onwards,
aircraft like the B-17, B-24, P38 and P47 et cetera. This WWII era manual allows you a rare look into this once classified technology.
A fascinating study into World War II aviation.
View: Original 1944 /45 General Electric turbosuperchargers