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Glaser-Dirks DG-400

From PlaneSpottingWorld, for aviation fans everywhere
DG Flugzeugbau DG-400
Glaser-Dirks DG-400.jpeg
A 17-metre span DG-400
Type designation DG-400
Competition class 18 metre
Number built 290
Crew 1
Length 7 m
Height m
Cockpit width 0.62 m
Cockpit height 0.81 m
Wingspan 17 m
Wing area 10.57 m²
Aspect ratio 27.34
Wing profile FX 67-K-170
Empty mass ca. 310 kg equipped
Water ballast 90 kg
Maximum mass 460 kg
Wing loading ca. 37 - 43.5 kg/m²
Maximum speed 270 km/h
Maneuver speed 190 km/h
Minimum sink ca. 0.54 m/s
Glide ratio 45
Roll rate ca. 3.5 - 4 s
(-45º to +45º)
Engine type Rotax 505
2 cylinder 2 stroke
Engine power ca. 43 hp
Fuel tanks 20 litres (50 as option)
Take-off run ca. 170 m (460 kg, ISA)
Distance to clear
15 m obstacle
ca. 270 m (460 kg, ISA)
Climb rate m/s (sea level)
m/s (at 3000 m)
Best climb speed 90 km/h
Range in 'saw-tooth' operation 380 km with 20 l

The Glaser-Dirks DG-400 is a single-seat self-launching motorglider that was produced by Glaser-Dirks between 1981 and 1990. It was the first self-launching motorglider with retractable engine and propeller to be produced in large numbers.


The cost of carbon-fibre had fallen enough in the late 1970's to allow its use in the wing spars of high-performance gliders. Glaser-Dirks introduced a carbon wing variant of the DG-200 about this time. The designer, Wilhelm Dirks, realised that the span, strength and very low weight of this wing allowed for a self-launching engine to be carried in the glider without an unacceptable penalty when soaring in weak conditions. The DG-400 was created as a result. Its first flight took place in May 1981.

The DG-400 uses the wings and most systems of the DG-202. It has a modified fuselage with a slightly enlarged boom and carbon fibre reinforcements to accommodate the engine, which is a relatively large unit with electric starter and electric retraction. This powerful installation, associated with a user-friendly engine control unit, ensured that the DG-400 was significantly safer and easier to operate than other self-launching gliders.

As was typical for the time, the engine, propeller and supporting pylon constitute a single unit that extends into the airflow (in more recent self-launchers the engine usually stays inside the fuselage). The type may be flown either with 15 metre or 17 metre wingtips.

The DG-400 was not aimed at competitions, but rather at leisure flying. Nevertheless, several World Gliding Records have been achieved flying this type.