The Heinkel HD 20 was one of the early products of post-World War I aircraft companies after the Allies aviation ban was lifted.[1] HD stood for German: Heinkel Doppeldecker or Heinkel biplane.
The HD.20 had unswept wings of mixed construction with wooden spars, two in the upper wing and one in the lower, and steel ribs; they were fabric covered. Both wings had constant chord over the inner section and semi-elliptical outer panels. The upper wing was considerably the larger, with 45% greater overall span and 17% greater chord over the inner panels. The wings were mounted with slight and equal dihedral and considerable stagger. Only the upper wings carried the long span, narrow chord ailerons. The lower wings were mounted directly onto the lower fuselage structure and the upper wing centre-section was joined to the upper fuselage with a pair of steel inverted V-struts on each side and a central parallel pair arranged transversely. It was a single bay biplane with V-form interplane struts leaning outward strongly from the lower wing below the engines to the upper wings at about 55% span.
It was powered by two 150 kW (200 hp) Wright R-790 Whirlwind nine cylinder radial engines, mounted in streamlined cowlings with the cylinder heads protruding for cooling. They were fed from fuel tanks in the upper wing; oil tanks were in the cowlings. Each engine was bolted to a frame formed of the interplane struts, a nearly horizontal V-strut to the upper fuselage and an N-form strut from the lower wing to the upper fuselage.[1]
The square cross-section fuselage was formed with steel tubes and covered with fabric, with a light, rounded, wooden upper decking. There were three open cockpits: one in the nose, another under the upper wing and the last, from which it was flown, just behind the upper trailing edge which had a shallow, rounded cut-out to aid the pilot's forward view. The tail surfaces were conventional and straight-edged, with angled leading edges and unswept trailing edges. The tailplane, mounted on the upper fuselage, was braced from below to the fuselage with a single strut on each side. Both the rudder and elevators were balanced; the latter were separate, their inner corners cut away for deflections of the deep rudder.[1]
The HD.20 had a conventional tailskid undercarriage. Each mainwheel was mounted on a group of three struts, two to the lower fuselage longeron at points on the wing leading edge and at mid-chord and the third to the upper longeron. There was a solid rubber shock absorber in each hub. The wheels could be replaced with floats.[1]
Operational historyedit
Rather little is known about the history of the HD 20. From the January 1927 date of the Les Ailles article[1] the first flight was probably in later 1926. The number built is also not known. One (D-1157), which appears on a reconstructed civil register, was owned by the Epro advertising agency and was destroyed on 21 November 1929.[2] The HD.20 is also mentioned as a photographic survey aircraft in a 1930 review of the topic, though it does not show the camera positions.[3]
Specificationsedit
Heinkel HD 20 3-view drawing from Le Document aéronautique December,1926
Wikimedia Commons has media related to Heinkel HD 20.
^ abcdef"L'Avion de 'Travail' Heinkel". Les Ailes (290): 3. 6 January 1927.
^"Golden Years of Aviation". Retrieved 2 November 2015.
^Hay, Alfred (1930). Handbuchen Wissenschaftlichen und Angewanten Photographie - Vol VII - Photogrammetrie und Luftbildwesen. Vienna: Verlag der Julius Springer.
December 15, 2023
heinkel, twin, engine, three, seat, german, biplane, built, 1926, civil, survey, work, role, three, seat, photographic, survey, mapping, aircraftnational, origin, germanymanufacturer, heinkel, flugzeugwerkefirst, flight, 1926number, built, least, contents, des. The Heinkel HD 20 was a twin engine three seat German biplane built in 1926 for civil survey work Heinkel HD 20Role Three seat photographic survey and mapping aircraftNational origin GermanyManufacturer Heinkel FlugzeugwerkeFirst flight c 1926Number built At least one Contents 1 Design and development 2 Operational history 3 Specifications 4 ReferencesDesign and development editThe Heinkel HD 20 was one of the early products of post World War I aircraft companies after the Allies aviation ban was lifted 1 HD stood for German Heinkel Doppeldecker or Heinkel biplane The HD 20 had unswept wings of mixed construction with wooden spars two in the upper wing and one in the lower and steel ribs they were fabric covered Both wings had constant chord over the inner section and semi elliptical outer panels The upper wing was considerably the larger with 45 greater overall span and 17 greater chord over the inner panels The wings were mounted with slight and equal dihedral and considerable stagger Only the upper wings carried the long span narrow chord ailerons The lower wings were mounted directly onto the lower fuselage structure and the upper wing centre section was joined to the upper fuselage with a pair of steel inverted V struts on each side and a central parallel pair arranged transversely It was a single bay biplane with V form interplane struts leaning outward strongly from the lower wing below the engines to the upper wings at about 55 span It was powered by two 150 kW 200 hp Wright R 790 Whirlwind nine cylinder radial engines mounted in streamlined cowlings with the cylinder heads protruding for cooling They were fed from fuel tanks in the upper wing oil tanks were in the cowlings Each engine was bolted to a frame formed of the interplane struts a nearly horizontal V strut to the upper fuselage and an N form strut from the lower wing to the upper fuselage 1 The square cross section fuselage was formed with steel tubes and covered with fabric with a light rounded wooden upper decking There were three open cockpits one in the nose another under the upper wing and the last from which it was flown just behind the upper trailing edge which had a shallow rounded cut out to aid the pilot s forward view The tail surfaces were conventional and straight edged with angled leading edges and unswept trailing edges The tailplane mounted on the upper fuselage was braced from below to the fuselage with a single strut on each side Both the rudder and elevators were balanced the latter were separate their inner corners cut away for deflections of the deep rudder 1 The HD 20 had a conventional tailskid undercarriage Each mainwheel was mounted on a group of three struts two to the lower fuselage longeron at points on the wing leading edge and at mid chord and the third to the upper longeron There was a solid rubber shock absorber in each hub The wheels could be replaced with floats 1 Operational history editRather little is known about the history of the HD 20 From the January 1927 date of the Les Ailles article 1 the first flight was probably in later 1926 The number built is also not known One D 1157 which appears on a reconstructed civil register was owned by the Epro advertising agency and was destroyed on 21 November 1929 2 The HD 20 is also mentioned as a photographic survey aircraft in a 1930 review of the topic though it does not show the camera positions 3 Specifications edit nbsp Heinkel HD 20 3 view drawing from Le Document aeronautique December 1926Data from Les Ailes 6 January 1927 1 General characteristicsCrew Three Length 9 45 m 31 ft 0 in Upper wingspan 12 80 m 42 ft 0 in Lower wingspan 8 80 m 28 ft 10 in Height 3 52 m 11 ft 7 in Wing area 39 80 m2 428 4 sq ft Empty weight 1 315 kg 2 899 lb Gross weight 1 965 kg 4 332 lb Fuel capacity 340 L 75 imp gal 90 US gal Powerplant 2 Wright R 790 Whirlwind 9 cylinder radial 150 kW 200 hp each Propellers 2 bladed metal Reed PropellersPerformance Maximum speed 195 km h 121 mph 105 kn at 500 m 1 600 ft Cruise speed 180 km h 110 mph 97 kn Minimum control speed 85 km h 53 mph 46 kn Endurance 4 5 hr Service ceiling 6 000 m 20 000 ft Time to altitude 35 min to 5 000 m 16 000 ft References edit nbsp Wikimedia Commons has media related to Heinkel HD 20 a b c d e f L Avion de Travail Heinkel Les Ailes 290 3 6 January 1927 Golden Years of Aviation Retrieved 2 November 2015 Hay Alfred 1930 Handbuchen Wissenschaftlichen und Angewanten Photographie Vol VII Photogrammetrie und Luftbildwesen Vienna Verlag der Julius Springer Retrieved from https en wikipedia org w index php title Heinkel HD 20 amp oldid 1163613433, wikipedia, wiki, book, books, library,
