Hamburger Flugzeugbau Ha 137
The Hamburger Flugzeugbau's design team initiated work on a dive-bomber late in 1933. the first project being designated P 6. This was to have had a BMW XV engine, but, as this power plant was not available, the design was modified to take the BMW-built Pratt and Whitney Hornet (which later became the BMW 132) and redesignated P 6a. This project designation was eventually changed to Ha 137, and work was initiated on the construction of two prototypes powered by the Hornet, the Ha 137V1 (D-IXAX) and 137V2 (D-IBGI), and one prototype powered by the Rolls-Royce Kestrel V, the Ha 137V3 (D-IZIQ) or P 6b.
All three prototypes were completed during 1934-35, and tests began at Travemunde during the summer of 1935, after initial trials at Hamburg. The first prototype was damaged at Travemunde in October, 1935, but by this time it was obvious that the rather large Hornet radial was unsuited for a single-seat dive-bomber owing to the severely restricted forward view that it offered, and when the new Junkers Jumo 210 liquid-cooled in-line engine became available in 1936, two further prototypes were built to take the new power plant. Powered by the 610 h.p. Jumo 210Aa the new prototypes were the Ha 137V4 (D-IFOE) and V5 (D-IUXU). The radial-engined and inline-engined versions were referred to respectively as the Ha 137A and Ha 137B, the latter being the proposed production version. The Jumo-powered Ha 137 participated in the dive-bomber contest held at Rechlin in June, 1936, but the aircraft was obviously inferior to the Junkers Ju 87, and no production orders were placed.
Incidentally, the Ha 137 with the Hornet engine was also intended for use by the German Navy, two navalised variants being projected, the P.11 with wheels and the P.lla with floats, and as an assurance against the failure of the Ha 137, the Hamburger Flugzeugbau design team produced an alternative dive-bomber design, the Cyclone-powered P.7 biplane, which was not built.
Ha 137 B Data
|Armament||2 7.9 mm MG 17 over the engine, 4 SC 50 bombs under the wings|
|Performance||Max. speed 330 km/h, max. cruising speed 290 km/h, range 580 km, climb 9 min to 4000 m, service ceiling 7000 m|
|Weights||Empty 1816 kg loaded 2417 kg|
|Dimensions||Span 11.15 m, length 9.47 m, height 2.80 m, wing area 23.50 m2|
|V1 (A)||D-IXAX||P & W Hornet with 3-bladed adjustable-pitch propeller|
|V2 (A)||D-IBGI||P & W Hornet with 3-bladed adjustable-pitch propelle|
|V3 (A)||D-IZIQ||Rolls-Royce Kestrel V with 2-bladed wooden fixed-pitch propeller|
|V4 (B)||D-IFOE||Junkers Jumo 210Aa|
|V5 (B)||D-IUXU||Junkers Jumo 210Aa|
|V6||D-IDTE||Junkers Jumo 210Aa||Crashed July 1937, written off|
|P.6||original project with BMW XV engine|
|P.6a||= V1 and V2|
|P.11||Naval version with wheels and BMW 132 engine|
|P.11a||Naval version with floats|