Akaflieg Darmstadt D-39
# Akaflieg Darmstadt D-39

The Akaflieg Darmstadt D-39 was a single-seat motor glider derived from the D-38 sailplane. Built in Germany in the late 1970s, it was not intended for production and only one was constructed.

## Design and development

The D-39 was a motorised version of the D-38 sailplane, with wings moved down from the latter's shoulder-wing position to the bottom of the fuselage. A Limbach SL 1700 flat four engine was conventionally mounted in the nose; the propeller could be removed but not folded away in flight. The wings, with 4° of dihedral, tail and monocoque fuselage were formed from glass fibre balsa sandwiches and the ailerons from glass fibre/Klégécel foam sandwiches. The D-38 had an all moving T-tailplane, fitted with a Flettner tab. It landed on a retractable monowheel, fitted with a drum brake and assisted by a small, fixed tailwheel.

The D-39 was first flown on 28 June 1979. By July 1982 it had been modified into the D-39b, with a greater span, revised wing roots and fitted with two-bladed Hoffmann Propeller airscrew and three pitch positions. The „D-39HKW“ was developed on the fuselage of the D-39, using 20-Meter flapped wing V

## Variants

### D-39

    Original version

### D-39b

    Same aircraft modified with greater span, revised roots and a new propeller.

## Specifications (D-39)

Data from Jane's All the World's Aircraft 1981/2

General characteristics

* Crew: 1
* Length: 7.15 m (23 ft 5 in)
* Wingspan: 15.00 m (49 ft 3 in)
* Height: 1.02 m (3 ft 4 in) over fuselage, not tail
* Wing area: 11.00 $m^2$ (118.4 sq ft) gross
* Aspect ratio: 20.5
* Airfoil: Wortmann FX-61-184 at root, FX-60-126 at tip
* Empty weight: 370 kg (816 lb)
* Max takeoff weight: 470 kg (1,036 lb)
* Fuel capacity: 35 L (9.25 US gal; 7.7 Imp gal)
* Powerplant: 1 × Limbach SL 1700E flat four, 51 kW (68 hp)
* Propellers: 2-bladed

Performance

* Maximum speed: 280 km/h (170 mph, 150 kn)
* Stall speed: 80 km/h (50 mph, 43 kn)
* Maximum glide ratio: 36 best, without propeller at 84 km/h (52 mph; 45 kn)
* Rate of sink: 0.7 m/s (140 ft/min) minimum, without propeller at 105 km/h (65 mph; 56.5 kn)
* Wing loading: 42.0 $kg/m^2$ (8.6 lb/sq ft) Maximum
