By the time the second World War had ended, the Germans
had achieved many firsts in the field of air-breathing
jet engine and gas turbine technology. Although this
technology was by no means confined to an aerontautical
sphere, it was here that the greatest effort was made and,
amongst other achievements, accounted for the world’s
first turbojet-and pulsejet-powered aircraft and the
first jet fighters, bombers and flying bombs going into
production and operational service. Additionally, the
Germans flew the world’s first jet helicopter and
ramjet missiles. It is proposed here to review some of the
more salient events in German work proceding the operational
debut of Luftwaffe aircraft in 1944, subsequent events
being already recorded elswhere in some measure.
Although, eventually, the Germans worked on vritually
every type of jet, gas-turbine and hybrid engine (not
to mention rocket motors), the prime types were the
turbojet, pulse-jet and ramjet engine.
History
In Germany, the idea of extracting power from hot, expanding
gases by means of a turbine wheel (essential to the
turbojet) went back at least to 1877 when Joseph Wertheim was
granted a patent covering an Atmospheric Gas Engine in which
a mixture of gas and air was to be exploded in a turbine.
Although many ideas followed, it was not until 1908 that
the first German gas turbine, Hans Holzwarth’s
constant-volume type, was actually built. Two decades then
passed before H. Oestrich at the Bramo engine company made
jet propulsion studies but initially rejected such ideas for
the speeds than in view.
At the same time, early experimenters were obtaining
unpromising results due largely to the lack of heat-resisting
materials which would permit operating temperatures high
enough to give the desired effinciency.
Breakthrough
The breakthrough for the turbojet began in the early 1930’s
when Hans von Ohain began studying the problem. Curiously
enough, he did not have a comprehensive picture of the
previous studies of other pioneers (including Frank Whittle)
despite a search through patents made in 1934, but he was in a
position to have a model built around 1935 to demonstrate the
turbojet principle.
Whittle patent from 1930 shows a jet engine wiht axial
compressor followed by a centrifugal flow-stage.
The whittle development resulted in the
Gloster E.28/39
flown for the first time on may 15, 1941.
In the meantime, Paul Schmidt obtained patents and government
support for work on the pulse-jet (1931). Karl Leist had
patented a scheme for a turboprop engine (1934) and Helmut
Walter had initiated studies of the ramjet and suggested a
turbojet with afterburning (1934).
Left to right: Helmut Schelp, Sir Frank Whittle,
Dr. Hans-Joachim von Ohain
and Dr. Maz Bentele during a meeting on 4 May 1978
at the Air Force Museum in Dayton, Ohio.
HeS 1
With the exhausting of his personal funds, von Ohain was
fortunate early in 1936 to obtain the backing of the Ernst
Heinkel AG and he left the University of Göttingen
to begin work on the first demonstration turbojet, the
HeS 1, at Rostock-Marienehe.
Drawing of the HeS 1.
Making extensive use of sheet-metal,
the HeS 1 had a
centrifugal compressor, annular combustion chamber and
radial inflow turbine. With a static thrust of about 250 kp
(551 lb), this engine was succesfully bench-tested in april
1937 and work on the first flight engine, HeS 3, was put in
hand.
Dr. Hans-Joachim Pabst von Ohain standing beside the HeS 3A
jet engine in the Deutsches Museum.
Turboprop and ramjet
Contemporary with these events were the facilities set up
under H. Wagner at the Junkers airframe works to study the
turboprop and the desing made by Helmut Weinrich and Wolf
Tommsdorf for a counter-rotating turboprop and ramjet missile
respectively. However, apart form Walter’s ramjet
work and Schmidt’s pulsejet work, there was no official
or government backing for jet propulsion at that time.
Programme
That Germany eventually had an extensive jet propulsion
programma at all was due to the early efforts of a few men
within the German Air Ministry’s Technical Office.
In august 1937, Helmut Schelp was sent to the research
secton of the Technical Office and given charge of the
pulsejet and ramjet projects of Schmidt and Walter but
he made no headway there with his chief enthusiasm for
gas turbines and turbojests and he had moved by september
1938 to the engine development section of the Technical Office.
Here he found an ally in
Hans A. Mauch who has inspected
von Ohain’s early wordk (the HeS 3 was bench-running
by then) and had conferred with the Junkers airframe company
on its turboprop studies. It was decided, however, not to
back officially either the later company or Heinkel since
Mauch at least felt that such radical developments as jet
engines could not be entrusted to airframe companies. On
the other hand, approaches to engine companies, such as
BMW, Bramo, Daimler-Benz and the Junkers engine devision
with a view to developing a turbojet engine were greeted with
little or no enthusiasme. Partly, the companies considered
solutions to the great technical problems involved to be far
in the future and they were already immersed in the problems
of getting reliable piston engines of high power into
production for a Luftwaffe clamouring to increase its
potential.
