In the Summer 2007 Issue of
The Junkers Jumo 222
Early
in 1946, the USAAF Power Plant Lab at Wright Field obtained several captured
Junkers Jumo 222A/B and E/F engines from US Navy Engine Test Station in
Philadelphia, Pennsylvania. The Jumo 222 was a 24-cylinder, liquid-cooled engine
with six banks of four cylinders each arranged radially about a common
crankcase. The Navy had performed a cursory examination and planned to test the
engine, but due to the lack of facilities and other difficulties, little was
done. Wright Field personnel began detailed inspection of the engines and
translated several technical papers about the Jumo 222 from German to English.
According to German test information, later versions of the Jumo 222 performed
extremely well at high altitudes. One object of the inspection and testing was
to discover whether this was true and why. There was also considerable interest
in the fuel injection and engine control systems. Pratt & Whitney, Allison and
Lycoming, all with large engine developments under way, wanted information on
the engine.
Aero Engine Drawings by Frank Munger
The Path to the Wright J-5
Part 1: History of Early Radials and Testing of Early U.S.
Cylinder Designs
I was
recently reminded that May 20, 2007 was the 80th anniversary of Charles A.
Lindbergh’s non-stop New York to Paris flight. The engine that got him there
after more than 33 hours of flying time was the Wright Aeronautical
Corporation’s J-5 “Whirlwind” (Fig. 1). By the end of 1927, the J-5 had also
conquered the Pacific from San Francisco to Hawaii twice and Atlantic to Europe
twice again. What made the J-5 an early record setter and what did it take to
design and develop this early air-cooled masterpiece? Was there any one
development that made the J-5 into one of the first reliable, air-cooled
American aircraft engines?
The development of the Wright J-5 is wrought the usual turmoil over new technologies relating to design, metallurgy and manufacturing but specifically with numerous problems concerning cylinder head and valve designs that would cool and be durable. Furthermore, there was a mix of corporate politics and characters along with government research funding for the military after the First World War that is beyond the scope of this article but perhaps food for a later story. The J-5, for the most part, resulted from a purchased design acquired when Wright Aeronautical bought out the much smaller Lawrance Aero Engine Company at the insistence of the U.S. Navy in 1923. But during that time, Wright continued work with the U.S. Army Air Service on larger air-cooled radials (Simoon, P-1, P-2) as well as the R-1 (aka R-1454). In all early air-cooled projects, cylinder cooling and exhaust valve development consumed much of the time toward producing a reliable, air-cooled radial.
Table of Contents
