Flight, May 1925

THE ROUND-GERMANY FLIGHT

THE MACHINES

The Heinkel Machines.

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   The Heinkel H.D.21 is a small two-seater biplane normally fitted with 100 h.p. Mercedes engine. As this machine is shown in the accompanying photograph and scale drawings, there is little need to give a lengthy description of its general lines. Attention may, however, be called to the fact that the wing bracing has only one lift wire and one anti-lift wire on each side.
   The fuselage, of the flat-sided type, is built entirely of wood, and covered with three-ply. The Mercedes engine is mounted on a framework of steel tubes bolted to suitable fittings on the nose of the fuselage proper. The two petrol tanks are carried in the top centre-section, so that direct gravity feed is used and no petrol pumps required. The biplane wings are of normal strength, and the stagger has been so chosen as to bring the rear-spar of the top plane vertically above the front spar of the bottom plane. It is claimed that this arrangement has made the use of the single set of bracing wires possible.
   The under-carriage is a very rigid structure of streamline steel tubes, the front struts forming the letter "M" in front elevation, with a divided axle running across their lower ends.
   The main dimensions of the Heinkel H.D.21 are :- Length, o.a., 7-25 m. (23 ft. 10 ins.); span, 10-6 m. (34 ft. 7 ins.). When fitted with 120 h.p. Mercedes, the empty weight is 710 kg. (1,560 lb.), and the useful load, 270 kg. (590 lb.), giving a total loaded weight of 980 kg. (2,150 lb.). The top speed is 140 km./h. (87 m.p.h.), and the climb to 2,000 m. occupies 5 mins., while an altitude of 3,000 m. is reached in 28 mins.

Flight, July 1926

THE GERMAN SEAPLANE COMPETITION
Many British Engines Used

The Machines

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   The German constructor represented by the greatest number of machines in the competition is Ernst Heinkel, also a pioneer of aircraft design and construction, who has entered no less than five machines of three different types.

   Nos. 11 and 12, the Heinkel H.D.24's, are both tractor biplanes of normal type, and both are fitted with 230 h.p. B.M.W. IV. engines. The type was originally designed for school work, but is presumably thought to meet also the requirements for a postal seaplane. Like the monoplanes, the fuselage is of welded steel-tube construction. The wing area of the H.D.24 is 50-1 sq. m. (539 sq. ft.), the weight empty is 1,350 kgs. (2,970 lbs), and the total loaded weight 1,960 kgs. (4,312 lbs.). The top speed is stated to be 160 km./hr. (100 m.p.h.
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Flight, November 1928

BERLIN AERO SHOW 1928

The Heinkel Machines

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   The second machine exhibited on the Heinkel stand was described as a "sport, travel and courier" machine. It was a heavily staggered biplane, with the works denomination H.D.22. The type is not new, having made its appearance in 1926, and has been sold in fairly large numbers, among those having used it being Major Reinburg of the American Embassy in Berlin.
   The machine shown at the I.L.A. was fitted with one of the Junkers L.5. engines rated at 300 h.p. The fuselage of the H.D.22 is of welded steel tube construction, while the wings are of two-spar wood construction, with the lower surface covered with plywood and the upper with fabric. The petrol tanks, with a capacity of 400 litres (88 gallons), are housed in the top plane, giving direct gravity feed.
   The main dimensions, weights, etc. of the H.D.22 are: Length o.a, 8-3 m. {27 -25 ft.); span upper, 12 m. (39 -4 ft,); span lower, 10-4 m. (33-9 f t ); wing area, 34-8 sq. m. (375 sq. ft.). Tare weight, according to engine fitted, 1,000 kg. to 1,200 kg. (2,200 lbs. to 2,640 lbs.). Permissible load, 500 kg. (1,100 lbs). Gross weight: up to 1,700 kg. (3,740 lbs). Performance figures are not available for the machine as fitted with the Junkers L.5 engine, but with the B.M.W. IV, the top speed is 189 km./h. (117-5 m.p.h.), and the ceiling 5,150 m. (16,900 ft.).