The first DH 108
prototype,
serial number TG283, had 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. In later low-speed testing designed to clear the rear fuselage at high angles of attack, the first prototype was fitted with longer Sea Vampire landing gear. The second, high-speed, prototype,
TG306, which had a 45° swept wing incorporating automatic leading-edge
Handley Page slats and was powered by a
de Havilland Goblin 3
turbojet, flew soon afterwards, in June 1946. Modifications to the design included a longer more streamlined nose and a smaller canopy (framed by a strengthened metal fairing) facilitated by lowering the pilot's seat. After the loss of the second prototype, a third aircraft was ordered to continue high-speed trials.
VW120 became the third and final prototype. It differed from the first test aircraft in having a more streamlined pointed nose and smaller reinforced canopy (lowering the pilot's seat allowed for a more aerodynamic canopy shape to be employed), with the cockpit redesign allowing an
ejection seat to be fitted. Power-boosted elevators had been specified as a means to control the pitch oscillations at the root of the earlier disaster. A more powerful Goblin 4 of 3,738 lbf (16.67 kN) thrust had the potential to push the DH 108 into the supersonic range.
VW120 first flew on 24 July 1947 flown by
John Cunningham, the wartime
nightfighter ace who became, in 1949, the first person to pilot the
de Havilland Comet jet airliner. Considered an important testbed for high-speed flight,
VW120 was readied for an attempt at the World Speed Record then held by a
Gloster Meteor at 616 mph (991 km/h). The second prototype,
TG306, was a backup for the attempt before it crashed. In 1949,
VW120 put on an aerial display at
Farnborough and was placed third 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 at the time pointed, not to the aircraft, but to a faulty oxygen system that incapacitated the pilot. This theory was subsequently ruled out by the coroner in his report which confirmed that the pilot died from a broken neck. The failure of the left wing as the plane dived occurred just above the garage at Brickhill. This failure was presumed to be the source of a "bang" described by witnesses at Brickhill. Swishing sounds which were reported came from the aircraft spinning at a high rate due to it having only one wing. It came down in the woods, after glancing off an oak tree: traces of the impact were still visible 50 years later. The airframe and right wing were dismantled by the military, and removed very quickly. The left wing was also recovered from the fields just north of Brickhill. A nearby German field worker ran over to the crash site and was met by the mechanic from Brickhill garage who had rushed to the crash site in his car to offer assistance. The pilot was already dead. In 2001, a search at the crash site by a local using a metal detector was successful. He found some of the mounting bolts "cone shaped" that were removed when the remains had been dismantled on-site. The tree that the DH 108 had hit was also found, with the scar still visible. 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 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. ==Legacy==