Häfeli DH-3

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DH-3

Cutaway replica of a Häfeli DH-3.
Type Reconnaissance biplane
Manufacturer K + W
Designed by August Häfeli
Introduced 1917
Retired 1939
Primary user Swiss Air Force
Number built DH-3 24
DH-3a 83
DH-3b 3
Developed from Hafeli DH-2

The Häfeli DH-3 was an 1910s Swiss two-seat reconnaissance aircraft, built by the aircraft department of the Federal Construction Works (Eidgenössische Konstruktions-Werkstätte, K+W) at Thun, Switzerland.

Contents

[edit] Development and design

Following the poor performance of the DH-2, August Häfeli designed an improved version the Häfeli DH-3. It was basically the same airframe as the DH-2, the upper wing had a cut-out to give a greater field-of-fire for the pivoted machine-gun. It was a two-bay of wood and fabric construction, powered by a 120 hp (89 kW) Argus As II water-cooled inline engine. Initial problems with the landing gear and the engine cooling system led to modifications. Further developments were the re-engined and improved DH-3a, and the DH-3b used for engine trials. Following successful trials with an installation of the Handley Page slats all surviving DH-3as were modified in 1932.

[edit] Operational history

On 8 January 1919 a DH-3 inaugurated the firsts Swiss air mail service between Zurich and Berne. A DH-3 aircraft failed a structural test in 1923 which caused the DH-3 to be withdrawn from service. The DH-3a following modification remained in service until 1939.

[edit] Variants

DH-3
Initial production version with Argus As II engine, 24 built.
DH-3a
Improved version with Hispano-Suiza HS-41 8Aa engines, four aircraft ordered in 1919. A second order of 30 aircraft was placed in 1919 with licence built engines, a third order for 49 aircraft was placed in 1925. Survivors were modified at Thun in 1932 with Handley Page slats and changes to allow crew to wear parachutes.
DH-3b
Three aircraft powered by the indigenous 150 hp (112 kw) LFW 0 engine developed by the Swiss Locomotive and Machine Works were built in 1918.

[edit] Operators

Flag of Switzerland Switzerland

[edit] Specifications (DH-3a)

Data from The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985)

General characteristics

  • Crew: Two
  • Length: 26 ft 1 in (7.95 m)
  • Wingspan: 41 ft 0 in (12.50 m)
  • Height: 10 ft 2 in (3.10 m)
  • Wing area: 409.04 m² (38 m²)
  • Empty weight: 1,587 lb (720 kg)
  • Max takeoff weight: 2,447 lb (1110 kg)
  • Powerplant: 1× Hispano-Suiza HS-41 8Aa 8-cylinder Vee piston engine, 150 hp (112 kW)

Performance

Armament

  • one pivoted machine-gin in the rear cockpit

[edit] References

  • The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985). Orbis Publishing. 

[edit] External links

[edit] See also

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