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The HD 44 was commissioned by the DVL in Berlin-Adlershof and was intended to serve as a test vehicle for aircraft engines. The only example built with the serial number 332 was developed and completed in 1929. It was designated HD 44a and registered in May 1930 with the registration number D-1762. Not much is known about its subsequent use as a “motor test aircraft”; According to information in the print media of the time, drives from 300 to 1200 hp of both air and liquid-cooled designs were tested. After expanding the measuring equipment, the HD 44 could also be used as a transport aircraft for smaller goods.

The HD 44 is a braced double-decker of mixed construction. The fuselage consists of a welded tubular steel frame, covered with light metal from the engine to the pilot's cabin and the rest covered with fabric. Behind the firewall is the cargo hold, which is 2.7 m long and 1.8 m high and accommodates the measuring devices and operating personnel. Behind it is the crew cabin, under which there is an additional small cargo hold. The supporting structure is formed from the strongly staggered upper and lower wings of different spans, which are connected with N-pillars. The wings consist of a wooden frame with two box spars, between which there are plywood push plates. The leading edge of the wing is made of plywood, the rest is covered with fabric. All wings have ailerons connected by bumpers. The normal tail consists of a metal frame covered with fabric, the horizontal fin is supported towards the fuselage with I-struts and is adjustable in flight, the vertical fin is only on the ground. The undercarriage is not retractable and consists of the large track-width main wheels connected to each other by an axle with rubber cable suspension and a grinding spur at the rear.