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National Museum of Contemporary History of Slovenia

Zoran Jerin Archives

klemm 20

The Klemm 20, which celebrated its premiere in 1924 under the name Daimler L20, is a light two-seater sports

and training aircraft designed by Hanns Klemm. Klemm broke completely new ground after the First World War

by designing an aircraft that would be economical to operate and intended for purely civilian use.


The Daimler L 20 was built between 1923 and 1924 as a low-wing monoplane of wooden construction with an

angular fuselage cross-section and fabric covering. The wings and the elevators could be removed and hung on the

side of the fuselage for road transport. Hanns Klemm was able to win over Ferdinand Porsche, who was working for

Daimler-Motoren-Gesellschaft at the time, to design an appropriate engine. The engine was an air-cooled two-cylinder

boxer engine with 16 kW power, which drove the propeller via a planetary gearbox with a reduction of 1:3.

The intended economy of the Klemm 20 could be achieved by the low empty weight of the aircraft of only 270 kg

(less than the engine of the Hansa Brandenburg alone) as well as the low power and an economical Mercedes F7502

engine. 7 litres per hour was possible from its 884 cc displacement. Like the Hansa Brandenburg, the Klemm 20 was built

on behalf of the Ferdinand Porsche Erlebniswelten fahr(T)raum. The research work turned out to be extremely difficult, as there are no original plans for this aircraft and with only three airframes existing worldwide, it made access to them difficult.

An original Mercedes type F7502 engine is used for propulsion. Under the supervision of Austrocontrol G.m.b.H.,

the aircraft was flight tested and certified as "Experimental" by Craftlab after the necessary plans had been drawn up

and the aircraft subsequently built.

The creation of a true-to-original Klemm 20

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