A Royal Navy flounder

by Dr. Marshall Michel
52nd Fighter Wing historian

One of most widely developed jet fighters of World War II (though it never saw combat) was the Royal Air Force’s diminutive, single-engine, twin boom de Havilland Vampire. The Vampire was continually developed, and a two seat radar equipped variant, the Sea Venom, became the Royal Navy’s first carrier based all-weather jet interceptor.

The basic twin boom design was so successful that de Havilland used it to develop an advanced fighter, the DH.110, to meet a requirement by the British Air Ministry for a high performance, twin-engine, all-weather interceptor for both the RAF and Royal Navy.

The DH.110 was an entirely new aircraft that only retained the twin-boom general configuration of the Vampire/Venom, and it had a starting appearance. It was very large, with swept wings carrying large fences on the wings’ leading edge, and swept tail fins with a straight, all moving tailplane mounted on the top of the fins.
The fuselage compartment also had a very distinctive feature, a fighter-type bubble canopy for the pilot offset to the left side. The offset cockpit gave the DH.110 a “one eye” appearance and led to its informal name, the “flying flounder.”

The radar operator/navigator sat completely inside the fuselage on the right with a small rectangular window above and another small rectangular window on the side. The belief was he could see the displays better from inside his dark “coal hole” than from under a clear canopy.

The prototype first flew on Sept. 26, 1951, and, powered by two Rolls-Royce Avon 208 engines, showed scintillating performance. It had excellent acceleration and a rapid rate of the climb and was soon regularly exceeding the speed of sound.

However, the DH.110 program’s progress was rudely halted when, on Sept. 6, 1952, it was performing at the Farnborough air show and its wings came off over the crowd. Both aircrews were killed and one of the engines hit an area crowded with spectators at the end of the runway, killing 27 and injuring 63. This incident led to a major restructuring of the safety regulations for air shows in the U.K.
The second prototype’s wings were reinforced and the flight test program continued, but the RAF, probably influenced by the airshow disaster, selected another aircraft, the Gloster Javelin, to fill its all-weather fighter requirement.
Nevertheless, Fleet Air Arm needed a replacement for its Sea Venoms, and in 1955 de Havilland produced a navalised prototype of the DH.110 called the Sea Vixen. It proved very successful and the first production version flew on March 20, 1957.

On July 2, 1959, the first Sea Vixen version, the FAW.1, entered service with the Fleet Air Arm. It was well liked in service because it had twice the rate of climb of the Sea Venom, a much higher service ceiling and much greater range. Importantly for carrier operations, it handled well and the twin boom scheme put the two engines close together, reducing the problems of asymmetrical thrust if one engine failed.

The Sea Vixen was armed with four de Havilland Firestreak air-to-air missiles and two unguided rocket pods, but no cannon. It was the first British fighter to be armed solely with missiles and rockets.

A later version, the FAW.2, had an enlarged tail boom with additional fuel tanks, making the boom extend forward over the leading edge of the wings. Twenty-nine were built and a further 67 FAW.1s were upgraded to FAW.2 standard. The last Sea Vixen ended its Navy service in 1972.

After its service, one Sea Vixen was painted in bright colors to advertise Red Bull and appeared at air shows for many years.

(For questions or comments, contact Dr. Michel at marshall.michel@spangdahlem.af.mil.)