de Havilland DH 108

https://en.wikipedia.org/wiki/De_Havilland_DH_108

The de Havilland DH 108 "Swallow" was a British experimental aircraft designed
by John Carver Meadows Frost in October 1945. The DH 108 featured a tailless,
swept wing with a single vertical stabilizer, similar to the layout of the
wartime German Messerschmitt Me 163 Komet rocket-powered point-defence
interceptor. Initially designed to evaluate swept wing handling characteristics
at low and high subsonic speeds for the proposed early tailless design of the
Comet airliner, three examples of the DH 108 were built to Air Ministry
specifications E.1/45 and E.11/45. With the adoption of a conventional tail for
the Comet, the aircraft were used instead to investigate swept wing handling up
to supersonic speeds. All three prototypes were lost in fatal crashes.

Employing the main fuselage section and engine of the de Havilland Vampire mated
to a longer fuselage with a single tailfin and swept wings, the de Havilland DH
108 was proposed in 1944 as a test "mule" for the DH 106 Comet which had
initially been considered a tailless, swept-wing concept. Despite the Comet
design taking on more conventional features, the value of testing the unique
configuration to provide basic data for the DH.110 spurred de Havilland to
continue development of the DH 108. Selecting two airframes from the English
Electric Vampire F 1 production line, the new aircraft had unmistakable
similarities to its fighter origins, especially in the original forward fuselage
which retained the nose, cockpit and other components of the Vampire. The
Ministry of Supply named the DH 108 the "Swallow", a name that was never
officially adopted by the company.

The new metal wing incorporating a 43° sweepback was approximately 15% greater
in area than the standard Vampire wing. Control was based on the conventional
rudder in combination with elevons that were part elevator and ailerons, fitted
outboard of the split trailing edge flaps. Although the Vampire fuselage was
retained, as development continued, a revised nose and streamlined, reinforced
canopy were incorporated.


Role
experimental

Manufacturer
de Havilland

Designer
John Frost

First flight
15 May 1946

Introduction
Experimental programme only

Status
Cancelled

Primary user
Royal Aircraft Establishment

Produced
1946–1947

Number built
3

The first DH 108 prototype, serial number TG283, utilising the Vampire fuselage
and a 43° swept wing, flew on 15 May 1946 at RAF Woodbridge. Designed to
investigate low-speed handling, it was capable of only 280 mph (450 km/h). The
de Havilland Chief Test Pilot Geoffrey de Havilland Jr., son of de Havilland
company owner-designer Geoffrey de Havilland, gave a display flight in the DH
108 during the 1946 Society of British Aircraft Constructors (SBAC) airshow at
Radlett.

The second, high-speed prototype, TG306, with a 45° swept wing incorporating
automatic leading-edge Handley Page slats and powered by a de Havilland Goblin 3
turbojet, flew soon after in June 1946. Modifications to the design included a
more streamlined, longer nose and a smaller canopy (framed by a strengthened
metal fairing) facilitated by lowering the pilot's seat. While being used to
evaluate handling characteristics at high speed, on 27 September 1946 TG306
suffered a catastrophic structural failure that occurred in a dive from 10,000
ft (3,050 m) at Mach 0.9 and crashed in the Thames Estuary. The pilot, Geoffrey
de Havilland Jr., was killed in the accident.

In 1949, the third DH 10...VW120...put on an aerial display at Farnborough and
scored third place in the Society of British Aircraft Constructors Challenge
Trophy Air Race before being turned over to the Ministry of Supply and test
flown at RAE Farnborough. It was destroyed on 15 February 1950 in a crash near
Brickhill, Buckinghamshire, killing its test pilot, Squadron Leader Stuart
Muller-Rowland. The accident investigation pointed to a faulty oxygen system
that incapacitated the pilot.

Finally, on 1 May 1950, during low-speed sideslip and stall tests, the first
prototype, TG283, was lost in a crash at Hartley Wintney killing the pilot, Sqn
Ldr George E.C. Genders AFC DFM. After abandoning the aircraft at low altitude
in an inverted spin, his parachute failed to open in time. In all, 480 flights
had been made by the three Swallows.

Specifications (DH 108 VW120: third prototype)

General characteristics
•Length: 29 ft 9.5 in (9.081 m)
•Wingspan: 39 ft (12 m)
•Wing area: 327.86 sq ft (30.459 m2)
•Empty weight: 8,940 lb (4,055 kg)
•Powerplant: 1 × de Havilland Goblin 4 centrifugal compressor jet engine, 3,738
lbf (16.63 kN) thrust

Performance
•Maximum speed: 677 mph (1,090 km/h; 588 kn)
•Range: 730 mi (634 nmi; 1,175 km)
•Service ceiling: 35,425 ft (10,798 m)
•Wing loading: 27 lb/sq ft (130 kg/m2)
•Thrust/weight: 0.42




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