Häfeli DH-3

The Häfeli DH-3 was a 1910 Swiss two-seat reconnaissance aircraft, built by the aircraft department of the Federal Construction Works (Eidgenoessische Konstruktionswerkstaette, (K+W)) at Thun, Switzerland.

DH-3
Role Reconnaissance biplane
Manufacturer K + W
Designer August Häfeli
Introduction 1917
Retired 1939
Primary user Swiss Air Force
Number built DH-3 24
DH-3a 83
DH-3b 3
Developed from Hafeli DH-2

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 cutout to give a greater field of fire for the pivoting machine gun. It was a two-bay aircraft 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.

Operational history

On 8 January 1919 a DH-3 inaugurated the first 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 A DH-3 aircraft failed a structural test in 1923 which caused the DH-3 to be withdrawn from service.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.

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 for 30 aircraft was placed in 1919 with license-built engines, a third order for 49 aircraft being 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.

Operators
Cutaway replica of a Häfeli DH-3
  Switzerland

Specifications (DH-3a)

Data from The Illustrated Encyclopedia of Aircraft (Part Work 1982–1985)[1]

General characteristics

  • Crew: 2
  • Length: 7.95 m (26 ft 1 in)
  • Wingspan: 12.5 m (41 ft 0 in)
  • Height: 3.1 m (10 ft 2 in)
  • Wing area: 38 m2 (410 sq ft)
  • Empty weight: 1,587 kg (3,499 lb)
  • Gross weight: 1,110 kg (2,447 lb)
  • Powerplant: 1 × Hispano-Suiza 8Aa (HS-41) V-8 water-cooled piston engine, 110 kW (150 hp)
  • Propellers: 2-bladed fixed-pitch propeller

Performance

  • Maximum speed: 145 km/h (90 mph, 78 kn)
  • Range: 400 km (250 mi, 220 nmi)
  • Service ceiling: 4,500 m (14,800 ft)

Armament

  • Guns: 1x flexible machine gun in the rear cockpit

References
  1. The Illustrated Encyclopedia of Aircraft (Part Work 1982–1985). Orbis Publishing.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.