Of cource, there were a number of people who recognised
that jet propulsion would supersede piston-engine propulsion
for high-speed flight in the future while the gas turbine,
being entirely rotary, was capable of higher speeds and
powers than the reciprocating piston engine.
Eventually, all
the main aero-engine companies, plus some others, worked
on jet engines in accordance with a programme laid down
by Schelp and his staff in the German Air Minstry. Of these
companies, BMW was the first to begin work on a turbojet
in 1938 (Kurt Loehner’s P.3303 centrifugal engine)
which Bramo followed in the same year by building a
piston-driven ducted fan engine and beginning the design
of an axial turbojet (later designated P.3302). When in
the summer of 1939, Bramo was taken over by BMW, a
complicated counter-rotating axial turbojet project from
Helmut Weinrich was also begun under the designation
P.3304 or 109–002.
HeS 3B
July of 1939 saw the first flight tests, using an He 118, of
von Ohain’s HeS 3B centrifugal turbojet.
Cutaway view of the Heinkel HeS 3B in the Deutsches Museum. Picture shows
a rebuilt example after the war.
In 1939 the HeS 3B produced a thrust of 450 - 500 kp.
The axial low-pressure compressor had
eight blades while the centrifugal-flow
compressor had 16.
He 178
A second HeS 3B was fitted to the He 178 prototype
which made the first true
purely on turbojet power on august 27, 1939. Although no
spectacular performer, the succes of the
He 178
made an enormous impact on the RLM and swelled the ranks of jet
aircraft protagonists.
He 178, seen while taxiing during flight testing
in 1939.
He 178, in flight 1939.
By now, the Junkers engine
division had accepted a contract to develop an axial turbojet
engine (origins of the 109–004) while even the
conservative Daimler-Benz company had decided to enter
the files with paradoxiacally, a complicated counter-rotating,
ducted-fan turbojet (109–007).
BMW’s P.3302 turbojet
evolved into the 109–003 engine and this, with
Junkers 109–004, were to become the two more developed
and therfore most used turbojets for Germany in the later
war years.
Pulsejet & Ramjet
Before leaving 1939, we must
observe that the Argus company had begun making pulsejet
tests (later it was to overtake Schmidt’s work) while
the first unsuccessful firings of Trommsdorf ramjet accelerated
missiles were made. Work at the pionieering Heikel company had
taken a bad turn by 1940, since instead of concentrating on
the pursuance of von Ohain’s ideas, efforts were spread
over a number of other projects including piston-engine
ducted fans (eg HeS 50 and HeS 60) and axial turbojets
(eg HeS 30 and HeS 40) which were under the direction of
Max A. Mueller who had arrived from the Junkers airframe
division at Magdeburg.
The HeS 30 produced a thrust of 820 kp on its test platform
in April 1942.
Drawing of HeS 30.
Drawing of HeS 40.
HeS 8 & Hes 30
Among the new Heinkel projects, specially interesting were
von Ohain’s HeS 8 (or 109–001) centrifugal
turbojet and Muller’s Hes 30 (or 109–006) axial
turbojet; the HeS 8 was the first Heinkel turbojet to
receive afficial backing but both engines were earmarked
as alternative powerplants for the world’s first
turbojet aircraft designated as a fighter, the twin-engined
He 280.
Developed from the previous
HeS 6 of 550 kp (1213 lb) thrust, the HeS 8 was designed
for a thrust of 700 kp (1544 lb) but development was
protracted and this thrust was never reached.
Follow-up development of the HeS 3B, the HeS 6.
Developed from the HeS 6, the HeS 8.
Not until
1941 was the HeS 8 ready for flying when two such engines
powered the He 280 protoype for its maiden flight on april 2.
Another two years were to pass before more HeS 8 engines were
ready for the V2 and V3 prototypes of the He 280 but by
then the engine had been overtaken by other developments.
The Heinkel He 280 V1 taking-off on the first flight on April 2 1941.
The aircraft was designed as a potential
fighter. The two HeS 8 turbojets were left
uncovered on the first flight. Below the
He-280 V3, GJ–CB.
By contrast, the Hes 30
engine made dramatic progress, was
developing some 860 kp (1896 lb) of thrust by october 1941,
and showed every promise of substantially increasing this
thrust. Inexplically, however, the engine never flew since it
was officially abandoned for obscure technical reasons and
because it was considered to small for future requirements.
Instead, the order came at the end of 1942 for the Heinkel
company (which had now absorbed the Hirth engine company)
to concentrate all its jet engine staff upon the development
of a new 1300 kp (2866,5 lb) thrust engine with a diagonal
compressor and designated the 109–011. The idea was
that the 109–011 would be a second-generation engine
leaving BMW and Junkers to develop the first-generation
engines.
Both these companies had prototypes for their engines running
by the end of 1940 but they were far from satisfactory and
enormous difficulties remained to be solved. The nature of
these difficulties encompassed aerodynamic thermodynamic and
mechanical problems and can scarcelly be touched upon here.
The HeS 011 was designed for a thrust output of 1600 kp, by the end of the
second world war the thrust output was 1300 kp.
An abortive attempt was made in
March 1942 to fly the prototype Messerschmitt Me 262 V1 with
two BMW 003
turbojets (P. 3302), still with its nose mounted piston engine.
At an altitude of 165 ft both turbojets
flamed out and it was discovered that the
compressor blades in both engines were broken.
The BMW 003 had
to be entirely redesigned, and the
revised power plant, the BMW 003A with a greater mass flow,
was not destined to fly until October 1943, and then beneath
a Ju 88A test bed.
The Ju 88A-5 illustrated above seen in service as a BMW–003 turbojet
test aircraft
P.3302 experimental engine, which initially (1940) had a thrust
of 260 kp in the test chamber, but due to numerous
improvements this was boosted to 500 kp.
Me 262 V1, werknummer 262 000 01, PC + UA, with Jumo 210 in the nose,
photographed during installation of the BMW P.3302 engines near the end
of 1941.
