De Havilland Digby
| Industry | Aviation |
|---|---|
| Founded | 1923 |
| Headquarters | United Kingdom |
| Products | Fighter-reconnaissance and army cooperation biplanes |
Template:EngvarB Template:Infobox aircraft The de Havilland DH.42 Dormouse along with its two derivatives, the de Havilland DH.42A Dingo I and II, were biplane designs featuring a single engine and seating for two. These aircraft were intended for fighter-reconnaissance and army cooperation missions but never entered mass production.
Development
The DH.42 Dormouse shared many design elements with the DH.42A Dingo I, differing primarily in their powerplants.[1] The Dormouse was developed to meet Air Ministry specification 22/22 as a two-seat reconnaissance fighter, whereas the Dingo was designed under Specification 8/24 for army cooperation tasks. Both models featured two-bay biplane configurations with straight, constant-chord wings; however, the lower wing was slightly reduced in span and measured about 73% of the upper wing’s chord. The trailing edges of both wings aligned horizontally, with vertical trailing struts and forward-leaning front struts. Unbalanced ailerons were installed on both upper and lower wings. The vertical stabilizer exhibited the distinctive de Havilland outline with a balanced rudder, while the elevators remained unbalanced. Constructed predominantly from wood, the wings and tail surfaces were fabric-covered, whereas the fuselage was sheathed in de Havilland’s characteristic thin plywood skin. The undercarriage consisted of a single axle with main legs connected to the lower wing roots and braced forward to the fuselage. The pilot’s cockpit was positioned beneath the centre section of the upper wing, with the observer/gunner seated just behind near the trailing edge. In the Dormouse model, an oval cutout in the upper wing provided upward visibility for the pilot, and a V-shaped notch in the trailing edge improved the gunner’s firing arc. For the Dingo, these openings were modified: the pilot’s cutout became smaller and circular, while the gunner’s notch extended across the fuselage width and deepened to reach the rear wing spar, forming a straight edge.[1]
The initial flight of the Dormouse occurred at Stag Lane on 25 July 1923, powered by a 360 hp (270 kW) Armstrong Siddeley Jaguar II radial engine. The Dingo took to the air for its maiden flight on 12 March 1924 equipped with a more powerful 410 hp (305 kW) Bristol Jupiter III radial engine.[1] Due to its larger diameter (53 in or 1.35 m) compared to the smaller double-row, 14-cylinder Jaguar (43 in or 1.06 m), the nine-cylinder Jupiter necessitated relocating the two forward-firing guns externally atop the nose on the Dingo; in contrast, these guns were housed within internal tunnels on the Dormouse. Subsequently, the Dormouse was upgraded with a 420 hp (313 kW) Jaguar IV engine and received an upper wing centre section redesign to mirror that of the Dingo. Both aircraft stored fuel within twin aerofoil-shaped tanks mounted above the inner interplane struts on the upper wing.[1]
The final variant in this series was the DH.42B Dingo II, which made its first flight on 29 September 1926. Although visually similar to its predecessors, this model featured a steel airframe instead of wood.[1] This change resulted in an empty weight increase of approximately 18% over that of the earlier Dingo I.[2] Powered by a slightly enhanced Bristol Jupiter IV engine delivering 436 hp (325 kW), it carried additional fuel yet maintained comparable top speed performance relative to its wooden-framed counterpart.[1]
Operational history
A total of only three units were produced. The Dormouse was assigned to the Royal Aircraft Establishment, Farnborough, operating within the Wireless & Photographic Flight for experimental radio-related tasks from March until December 1925, after which it was retired. The Dingo I was involved in a crash during testing at RAF Martlesham Heath in June 1924, while the Dingo II was delivered to Farnborough in November 1926.
Variants
- DH.42 Dormouse
- Powered by Armstrong Siddeley Jaguar III and Armstrong Siddeley Jaguar IV engines
- DH.42A Dingo I
- Equipped with Bristol Jupiter III engine; featured a modest span increase of 6 inches (152 mm)
- DH.42B Dingo II
- Utilized Bristol Jupiter IV engine; retained the DH.42A dimensions but incorporated a steel frame and had an increased weight
Specifications (DH.42 Dormouse, Jaguar IV)
See also
Notes
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Jackson 1978, pp. 179–82
- ↑ Jackson 1978, pp. 182
References
- Jackson, A.J. (1978). de Havilland Aircraft since 1909. London: Putnam Publishing. ISBN 0-370-30022-X.