De Havilland DH.67
| De Havilland DH.67 / Gloster AS31 | |
|---|---|
|
|
| Type: | Photographic exploration (flying) |
| Design country: | |
| Manufacturer: | |
| First flight: |
June 1929 |
| Number of pieces: |
2 |
The De Havilland DH.67 was a photographic exploration aircraft made by the British manufacturer de Havilland Aircraft Company from the late 1920s.
history
1926 which sought Aircraft Operating Company a replacement for their outdated, nor of wartime coming Airco DH.9 that she used for tasks in the field of airborne photographic exploration. A twin-engine design was required, with good flight performance in single-engine flight, in order to avoid emergency landings in the event of an engine failure. The airframe should be made of all-metal to simplify maintenance, as it should often be used in tropical zones and far away from the usual workshop equipment. In addition, there was the demand for above-average visibility for both the pilots and the crew who carried out the photographic tasks.
De Havilland was commissioned to design an aircraft to meet the requirements, and the resulting design study was given type number DH.67. The design was very similar to the prototype of the DH.66 Hercules , but should be powered by two Bristol Jupiter VIs . The biggest differences lay in the open tandem cockpits and the position underneath for the lying photographer who was supposed to operate a camera built into the floor of the fuselage. The main cabin had three round windows for the angled images. A simple fin with rudder was chosen as the tail unit, in contrast to the triple tail unit of the DH.66, which also had a "double-decker" horizontal tail unit. There were also attachment points for two interchangeable eight-meter-long swimmers.
In November 1927 the draft - now known as DH.67B - was again heavily revised. The total weight was unchanged at 7000 lb., but the wingspan was significantly increased and the engines were Bristol Jupiter VIII. The tail unit with its double rudders was again closer to the DH.66. The pilot and navigator should sit side by side in the cockpits that are still open, while the camera operator should sit a little below in front of these two in the stepped bow of the fuselage. Both the top and bottom ailerons were provided for the folding wings.
The practical implementation of the design including the missing detailed construction was then transferred to the Gloster Aircraft Company , as de Havilland was already busy with the production of Moth , Hercules and other construction contracts. The resulting Gloster AS31 , which was changed in all dimensions , only showed superficial agreement with the original design. The AS31 was again more similar to the DH.67 than to the DH.67B, so it again had a single rudder unit and ailerons only on the lower wings. The aircraft should be able to take on tasks as diverse as reconnaissance, bombing missions, medical flights and seaplane missions.
Two prototypes were built, the first (aircraft registration G-AADO), with three camera positions according to the original order, was delivered to the Aircraft Operating Company (AOC). The first flight took place in June 1929 in Brockworth. The AOC used the aircraft with great success to map Northern Rhodesia . After further such missions in Central Africa , the machine was sold to the South African Air Force in May 1935 and scrapped in Waterkloof in December 1942 .
The second prototype (RAF serial number K2602) received the Air Ministry, which passed the machine on to the Royal Aircraft Establishment (RAE) in November 1931 for experiments on wireless telegraphy . The last use is recorded in September 1936.
construction
The AS31 ultimately executed was a mixed construction -construction with wing spars from a high strength alloy steel and duralumin ribs. The fuselage structure was made of steel tubes, which, like the wings, was covered with fabric.
Technical specifications
| Parameter | DH.67 | DH.67B | Gloster AS31 |
|---|---|---|---|
| length |
|
14.79 m | |
| span | 17.23 m | 18.30 m | 18.61 m |
| height | 3.97 m | 4.12 m | 5.71 m |
| Wing area | 77.1 m² | 81.8 m² | 95.2 m² |
| Empty mass | 2549 kg | ||
| Max. Takeoff mass |
|
3891 kg | |
| Cruising speed | 176 km / h | ||
| Top speed | 210 km / h | ||
| Service ceiling | 7100 m | ||
| Range | 790 km | ||
| Engines | 2 × Bristol Jupiter VI with 450 PS (331 kW) each | 2 × Bristol Jupiter VIII with 480 PS (353 kW) each | 2 × Bristol Jupiter XI with 525 PS (386 kW) each |
See also
literature
- Aubrey J. Jackson: De Havilland Aircraft since 1909. 3rd, revised edition, Naval Institute Press, Annapolis MD 1987, ISBN 0-87021-896-4 , pp. 275 ff.
Web links
- Photo of DH.67 (accessed November 2, 2011)
- On the concept of flight (accessed on November 1, 2011)