Flying Laboratories: Two Machines Built in Germany for the D.V.L. Have Been Designed to Try Out Engines and Wings

The Heinkel H.D.44 THE H.D.44 is a development of the newspaper transport Heinkel H.D.40. It is designed to provide a flying engine “test bed,” and its construction, with interchangeable engine fittings, allows the D.V.L. engine department to test out engines from 300/1,200 h.p. It is so arranged that superchargers can also be tested, these being watched by examiners during the flight. As a transport machine the load [which in the case of trial flights with BMW VI U‐engines is 1,070 kg. (2,354 lb.)] can be increased by 500 kg. (1,100 lb.). This heavily staggered, single‐strutted biplane is of mixed construction, fuselage, empennage and wing struts being of steel tubing and the wings of wood. The fuselage is built up on four longerons with welded steel struts and tubular cross‐bracing pieces. The engine cowling and forepart of the fuselage back to the pilot's seat are covered with light metal, the rear being fabric‐covered. The engine is carried on tubular steel bearers detachably fixed to the front framing with four bolts. Immediately behind the engine is a space, measuring 2·7 m. (8 ft. 10 in.) in length, by about 1·8 m. (5 ft. 10 in. in height). This space, which serves as a test or freight cabin, is accessible through a door directly over the lower wing. It is well lighted by several windows of Triplex glass, with a roofing of Cellon. It is covered on the sides and top with aluminium plates, the floor being fitted with fireproofed plywood. All the covering is fixed on the outside, the framework of steel tubing being left exposed to allow of easy attachment of testing gear. Two folding seats are built in on the rear wall. Behind this is the pilot's cockpit with two scats, side by side, and dual control. Below is a small luggage compartment. The instrument board is provided with an opening through which the pilot can see into, and communicate with, the test cabin.