Heinkel He 46
During the early 1930s, the German military was beginning to build up in strength - the RLM (German Air Ministry) wanted aircraft that could be rapidly built and would be able to swell the Luftwaffe's inventory with large numbers of aircraft for training. Ernst Heinkel designed many of these early aircraft, with the He 46 being created to fill this short-range reconnaissance and army co-operation role for the Luftwaffe.
The prototype flew for the first time toward the end of 1931. Although following the general Heinkel biplane configuration it did have an abnormally large upper wing with marked sweepback and a very small lower wing. It was otherwise a conventional biplane, with a mixed construction consisting of metal framework and fabric covering, and a slightly swept back (10°) upper wing, powered by a 450hp Siemens-built Bristol Jupiter radial engine. The tailplane was mounted high and braced by struts. The undercarriage was fixed, and the tail was fitted with a skid rather than a wheel. The observer's view of the ground was considerably restricted and the aircraft was subsequently altered to a parasol monoplane design by removing the lower wing and increasing the span of the upper by 2.5 m (8 ft 2.5 in) and braced to the fuselage with strut-braces: the second prototype, the He 46B was built to this design (overall the upper wing area was increased by 22%). Both machines were initially powered by the Siemens‑built 450‑hp Bristol Jupiter engine, but trials proved that this had insufficient capacity and in 1932 the 650‑hp Siemens SAM 22B nine‑cylinder radial was installed. This was considered satisfactory during trials on the third (and first preproduction) aircraft, the He 45C, which was equipped with radio and fitted with a 7.9‑mm (0.311‑in) MG 15 machine‑gun in the observer's rear cockpit. The He46b first flew in early 1932.
By 1934, the He 46C had been ordered in sufficiently large numbers to improve the now rapidly‑expanding Luftwaffe. Production began with the He 46C-1 in 1933. This was similar to the 46c, but with the ability to carry either a camera or 440lb of small bombs under the rear cockpit. The He 46C-1, similar to the He 46C but having a bay beneath the observer's cockpit to carry photographic equipment or up to 20 10‑kg (22‑lb) bombs.
Heinkel's order book for 1933 included 478 of these aircraft, including exports to Hungary and Bulgaria, and in order to fulfil these obligations licence‑production was undertaken by Siebel Flugzeugwerke (159 C‑1s), MIAG (83 C, E and F series), Gothaer Waggonfabrik at Gotha (24 CA/C‑2s), and the Fieseler Flugzeugwerke (12 C‑Is). Two hundred (194 of which were C‑1s) were built at Heinkel's Warnernfinde factory, in addition to the three prototypes.
A prototype conversion of the He 46C-1 in 1934 was made for the D series, with only minor improvements over its predecessors. This was followed by six pre-production C-1 conversions to the He 46D-0s, with a number of minor changes. One D‑1, fitted with the NACA engine cowling and designated He 46e, became the prototype for the E series. Built for the Luftwaffe in E‑1, ‑2 and ‑3 variants, they differed slightly in equipment installations, but the ‑2 was the only one to be fitted with an engine cowling that increased maximum speed by 16mph but that made maintenance rather more difficult and was often removed. An He 46C fitted with a 560‑hp Armstrong Siddeley Panther cowled engine became the prototype (He 46f) for a new unarmed observer trainer series F‑1 and ‑2 (14 built).
The original total of 478 ordered had been completed by 1936 when production ceased, but a few continued into Second World War service, until eventually replaced in the short‑range reconnaissance role by Henschel Hs 126s. Some of those remaining during the war were in service with Nachtschlachtgruppen (night attack groups) on the Russian Front, along with their Hungarian counterparts.
By the time production finished in 1936 the He 46 was the main equipment of the Luftwaffe's Auflärungsstaffeln (H), but early in 1938, at the time of the Ilmavoimat’s evaluation, it had begun to be replaced by the Henschel Hs 126A-1. As such, the aircraft was cheap and readily available and there had already been export sales to Bulgaria and Hungary (eighteen He 46C-2s (C-1s but with engine cowling) were sold to Bulgaria, while Hungary purchased a number of He 47E-2s.
The Bulgarian batch of 18 aircraft were designated He 46C2, and fitted with a NACA engine cowling, which increased the maximum speed by 26 km/h (16 mph). Hungarian aircraft were designated He 46E‑2, and gave useful service as late as 1942‑43, in bombing operations and as attack aircraft against the USSR. In September 1936, during the civil war, 20 He 46C1s had also been sent to Spain.
At the time the Ilmavoimat / Maavoimat evaluation team looked at the He 46, it was already largely phased out of front-line service with the Luftwaffe. The aircraft were offered for sale “as is” at an attractive per-unit cost far below any of the newer aircraft on the market and available. Serious consideration was in fact given to this offer, particularly as delivery was immediate.
A few were still in use in September 1939 two units were still equipped with the He 46 at this stage), and saw service in Poland. By the time Germany invaded France in 1940, all He 46 aircraft had been withdrawn from operational service, although they did continue service in training units. A final period of front-line service came in 1943, when a shortage of more suitable aircraft meant that the Luftwaffe was forced to take the aircraft from the training units and used a number of He 46s on night harassment missions on the Eastern Front. The He 46 saw service in Spain, twenty He 46C-1s given to the Spanish Nationalists in September 1938. The Hungarian aircraft took part in the invasion of the Soviet Union in 1941, equipping the 1st Short-Range Reconnaissance Squadron, and with the 3/2 Short-Range Reconnaissance Squadron in 1942. The Hungarian aircraft were also used as bombers, before being replaced with the Focke-Wulfe 189 during 1943.