Häfeli DH-3

DH-3
Cutaway replica of a Häfeli 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

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 1 Development and design 2 Operational history 3 Variants 4 Operators 5 Specifications (DH-3a) 6 References 7 External links 8 See also

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.

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 A DH-3 aircraft failed a structural test in 1923 which caused the DH-3 to be withdrawn from service.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.

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.

Operators

 Switzerland

• Swiss Air Force

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

• Maximum speed: 90 mph (145 km/h)
• Range: 249 miles (400 km)
• Service ceiling: 14,765 ft (4500 m)

Armament

• one pivoted machine-gun in the rear cockpit

References

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

External links

Konstruktion Häfeli DH-3 in Thun

See also

Lists relating to aviation General Aircraft (manufacturers) Aircraft engines (manufacturers) Airlines (defunct) Airports Civil authorities Museums Registration prefixes Rotorcraft (manufacturers) Timeline Military Air forces Weapons Experimental Missiles Unmanned Accidents/incidents Commercial airliners (by location) Fatalities (by death toll) General aviation Military Records Airspeed Altitude Distance Endurance Firsts Most-produced aircraft