Draft:Focke-Wulf W 7

The Focke-Wulf W 7 was a one-off aircraft model manufactured by the Focke-Wulf factory of a board-based maritime reconnaissance aircraft.

Characteristics
At the turn of 1928 and 1929, the Reichswehr Ministry (RWM) and the Reich Transport Ministry (RVM) began considering a catapult-capable, single-engine on-board reconnaissance aircraft. Due to little monetary flexibility in the budgets from 1929 to 1933, the design was also intended to be used as a light bomber and for liaison and school tasks. At the Reichsmarineamt the RWM/RVM studies for this single-engine seaplane were then supplemented by a catalog of operational requirements:


 * 1) Top speed 235 km/h
 * 2) Range 1100 km
 * 3) Flight duration 5 hours
 * 4) Reaching 3000m altitude in 10 minutes
 * 5) Seaworthiness up to sea states 4–5
 * 6) Double seater (pilot and observer)

The Ernst Heinkel aircraft works in Rostock-Warnemünde responded to the list of demands. The central design department under Reinhold Mewes reduced the design of the twin-engine multi-purpose aircraft Heinkel HD 59 and created a single-engine model with liquid-cooled in-line twelve-cylinder BMW VI 6.0 ZU with 660 hp / 486 kW take-off power: the Heinkel HD 60 (later: He 60).

The Focke-Wulf-Flugzeugwerke submitted another draft, although Henrich Focke was not particularly interested in the tender. Shortly before the tender arrived in Bremen, the engineer Hans Herrmann had moved from Udet Flugzeugbau to Focke-Wulf. Focke reluctantly entrusted the new man with the work. Hans Herrmann convinced the design department in Bremen to create a conventional biplane with floating gear. The special feature of the Focke-Wulf W 7 on-board reconnaissance aircraft were sprung rear float struts to absorb shocks to the airframe when rolling in the water.

The uncertainties of this revolutionary idea and the fact that Heinkel simply reduced an existing design to save time had a negative impact on Focke-Wulf. The shock absorber first had to be developed. A stroke of luck for Heinkel: In August 1930 the HD 60 (W.No. 380, D-2157) went into service, three months later the HD 60 a (W.No. 381, D-2176) at the E-Stelle (See). in Travemünde for testing.

Although Karl Wiborg crashed fatally on December 16, 1931, with the HD 60 a on the apron at Travemünde and in the summer of 1932 the gearbox housing of the BMW VI engine broke on the HD 60, but Heinkel had gotten to this point Events but overall presented convincingly. The first flight of the Focke-Wulf W 7 (work number 116, D-2216) under Hans Herrmann also took place in the summer of 1932. It ended in disappointment: the control around all axes remained defective due to the control cables used.

Focke-Wulf had to make improvements and the transfer of the W 7 to the See testing site was delayed. Although the W 7 used the same engine as the HD 60 or the HD 60 a, Focke-Wulf opted for a higher compression and installed the BMW VI 6.3 ZU instead of the BMW VI 6.0 ZU. This drove a wooden four-blade propeller. The W 7 shared the top speed of around 240 km/h and the landing speed of 90 km/h with its competitors. The design was unarmed; the installation of sMG 08/15 machine guns from Reichswehr stocks as a fixed firearm for the pilot or as a mobile weapon for the observer was taken into account in the planning, but was not implemented.

When the W 7 finally reached the necessary readiness for handover, so much time had passed that the model was actually already outside the tender. Heinkel's third test model, the He 60 b (W.No. 418, D-2325), completed its first flight in August 1932 and was handed over to the E-stelle in September 1932. The designs by Focke-Wulf and Heinkel only flew at the E-Stelle for a short time before they completed testing and voted in favor of purchasing the He 60.