Raab Krähe
The Raab Krähe (English: crow) is a West German high-wing, single-seat, pusher configuration motor glider that was designed by Fritz Raab for amateur construction. The Krähe first flew in 1957, shortly after powered flight was again permitted in the Federal Republic of Germany. The most widespread problem was that engines proved unreliable when restarted in flight after being switched off for lengthy periods. Inevitably, there was a great deal of trial and error, and the Krähe was fitted with engines from various manufacturers. The aircraft was never commercially manufactured.
The Krähe is constructed from wood, with the fuselage made from a wooden structure covered in doped aircraft fabric. The 12.0 m (39.4 ft) span wings are built with a wooden structure and covered in plywood and fabric. The wings feature spoilers and a custom Raab-designed airfoil. The tailplane is braced with four cables to the wing trailing edge. The landing gear is a fixed monowheel.
The engine is mounted in the rear of the cabin area, with the propeller in between the top and bottom tail boom tubes. Motors used are usually of an output of about 30 hp (22 kW).
Raab designed the Krähe specifically for homebuilders. About 30 examples were reported completed by 1974.
Initial model with monowheel landing gear and propeller in between top and bottom tail boom tubes.
Austria Krähe
Later model with tricycle landing gear and propeller rotating around the upper tail boom tube.
Engine: 1 × Steyr , 20 kW (27 hp)
Propeller: 2-bladed wooden fixed pitch
Wingspan: 12 m (39 ft 4 in)
Wing area: 14.3 m2 (154 sq ft)
Aspect ratio: 10:1
Airfoil: Raab
Empty weight: 238 kg (525 lb)
Gross weight: 333 kg (735 lb)
Fuel capacity: 8 U.S. gallons (30 L; 6.7 imp gal)
Fuel burn: 1.2 U.S. gallons (4.5 L; 1.00 imp gal) per hour
Wing loading: 23.3 kg/m2 (4.77 lb/sq ft)
Cruise speed: 121 km/h (75 mph, 65 kn)
Endurance: 10 hours loiter
Maximum glide ratio: 18-20:1 at 77 km/h (48 mph)
Rate of sink: 1.2 m/s (240 ft/min) at 68 km/h (42 mph)
Crew: one
Krähe IV
Engine: Hirth F 10, 19 kW
Wingspan: 12.0 m
Take-off weight: 340 kg
Best glide ratio: 20 : 1 at 78 km/h
Minimum sink rate: 1 m/s at 65 km/h
Maximum rate of climb: 1.7 m/s