|Rudolf Neininger (left) with his crewman in front of the D-18 during Challenge 1930|
Design and development
The aircraft was designed by F. Fecher in the Akaflieg (academic group of flyers) of Darmstadt University of Technology. It was a development of the D-16 project, that was designed for a sports aircraft contest organized by Idaflieg in 1926. The D-16 design with a 40 horsepower (hp) engine won the first prize, but was not built as the designer decided to strengthen the construction and fit a more powerful 88 hp Armstrong Siddeley Genet radial engine . The result was the D-18, a single aircraft was built in 1929.
The aircraft featured a quite unorthodox layout, being a cantilever biplane, with an upper wing placed low above a fuselage and ahead of a lower wing. Particular thought was given to aerodynamics and lightness and the aircraft was small, with a streamlined profile. Initially the D-18 had two open cockpits, but by 1930 it had been modified and fitted with a closed canopy covering both cockpits.
The aircraft carried the registration of D-1561. It took part in the Challenge 1929 international tourist plane contest, piloted by Johannes Nehring, being one of the fastest planes in the contest. It was the best aircraft in the fuel consumption trial and, along with two other aircraft, won the first part of the contest - the technical trials. However, the D-18 dropped out due to a forced landing near Września before Poznań on 11 August 1929, during a rally around Europe, because of a fuel pipe clogging. The aircraft turned over and suffered damage, its passenger was injured.
The aircraft was repaired, now fitted with an enclosed cabin it took part in another contest, Challenge 1930, again piloted by Rudolf Neininger. On 26 July 1930, during a rally around Europe the D-18 was forced to ditch in the Mediterranean Sea between Barcelona and Nîmes due to breaking a piston. The crew was rescued by a passing ship, that also recovered the wreckage.
Wooden construction cantilever biplane. A fuselage oval in cross-section, plywood covered. Single-spar wings, plywood and canvas covered. Wings were dismounted and folded. Two crew cockpits in tandem, later covered with a common multi-part canopy. Fixed landing gear with a rear skid. Uncovered radial engine in a fuselage nose, two-blade propeller.
- Crew: 1
- Capacity: 1 passenger
- Length: 6.14 m ()
- Wingspan: 7.20 m ()
- Height: 2.54 m ()
- Wing area: 12.1 m² ()
- Empty weight: 300 kg ()
- Loaded weight: 540 kg ()
- Useful load: 240 kg ()
- Powerplant: 1 × Armstrong Siddeley Genet aircooled 5-cylinder radial engine, 88 hp (64.7 kW)
- Related development
- Marian Krzyżan: "Międzynarodowe turnieje lotnicze 1929-1934", Warsaw 1988, ISBN 83-206-0637-3 (Polish language)
- D-18 photos and drawings at Akaflieg Darmstadt page
- Peter M. Bowers, Darmstadt biplanes- article at General Aviation News