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95 years ago: Karl Maybach tests the first modern aircraft engine
In 1917 Karl Maybach set up a test rig at 1,800 meters above
sea level to show that his aircraft engine produced more
power at altitude than its competitors.
Learning to fly
Testing engines to their limits under extreme conditions
before they are sent out to the clients is by no means a new
idea at MTU. Ninety-five years ago, Karl Maybach – one of the
founders of Luftfahrzeug-Motorenbau GmbH from which the
present-day MTU is descended – tested an aircraft engine at
1,800 meters above sea level on a specially constructed rig.
It was an occasion that signaled the birth of the first modern
aircraft engine.
The First World War was raging at the time and Maybach wanted
to show he could supply engines for airplanes as well as airships.
The challenge that had to be overcome is that at high altitudes
the air density is lower, so the engine cannot produce as much
power. Maybach’s solution was to compensate for the power loss
by increasing the cylinder capacity and the compression. So the
engine only developed its maximum output of 184kW (250hp) at
an altitude of 1,800 meters. At ground level, it was throttled back.
To convince the authorities that this engine really was superior
to the competition, Maybach had a special test rig set up on the
Wendelstein, a mountain in Bavaria. And he was proved right. The
tests were a success and Maybach was soon able to try out his
Mb-IVa engine in an airplane. In a test flight, a reconnaissance
plane with the Maybach engine was able to climb to an altitude of
5,000 meters in only 24½ minutes. Using a rival power unit that
was equally powerful on the ground, the aircraft took 42 minutes
to reach the same height. And the Mb-IVa engine had other
advantages too. The oil was air-cooled by means of air scoops
on the crankcase. Plus, it boasted twin fire-safe butterfly-valve
carburetors and altitude-dependent control of the air/fuel mixture
combined with simultaneous ignition timing adjustment – all of which
made sure that fuel economy was efficient. The Mb IVa went into
series production from 1917 and was used in Rumpler and Heinkel
biplanes, among others.
After the end of World War I, the Treaty of Versailles banned German
companies from making aircraft equipment of any kind – which, of
course, included Maybach aircraft engines. The Allies destroyed all
of the plant and equipment for making them. From that point on, the
company started producing high-speed diesel engines.
Words: Lucie Maluck; Pictures: Tognum Group Archive
To find out more, contact: Dr. Heike Weishaupt
heike.weishaupt@tognum.com, Tel. +49 7541 90-3225
50 I MTU Report 03/12