More Testing Times by Brooke Mike

Author:Brooke, Mike
Language: eng
Format: epub
ISBN: 9780750981880
Publisher: The History Press

1. A naval aviation term for the man in charge of flying and support facilities.

2. The Specialist Aircrew career option for RAF aircrew was introduced in the late 1970s. It gave those who wished to stay on in the service beyond the age of 38 (or sixteen years’ service) the option of continued flying but with promotion limited to the rank of squadron leader; there were enhance salary scales attached.

17 THE YANKS ARE COMING!

June 1989 was the month during which elements of the USAF’s 27th Tactical Fighter Wing would exercise their deployment from Cannon Air Force Base in New Mexico to the cooler and cloudier climes of Boscombe Down and the UK. They would bring with them eight General Dynamics F-111D bombers. I was allocated the job of liaison officer for all their flying operations and to be the man who delivered the arrival briefing.

The F-111’s prime claim to fame was that it was the first production aircraft to go into full operational service with variable-sweep wings, known more prosaically as ‘swing-wing’. The history of engineering variable-sweep wings goes back to 1931, with the British Westland Hill Pterodactyl design, whose slightly swept wings could vary their sweep through a small angle during flight. This allowed longitudinal trim in the absence of a separate horizontal tailplane. During the Second World War a German design, the Messerschmitt P.1101, was able to vary the sweep of its wings, but only on the ground. Post-war research on variable-sweep wings followed in the UK, the Soviet Union and France. After much experimental test flying some variable-sweep operational aircraft eventually emerged – among them the European Tornado, and no less than six Soviet bombers and fighters. The French Mirage G-8 variable-sweep fighter never went into production; the French preferred to stay with the elegant delta-wing solution.

In the USA the Bell X-5, which was based on the Me P.1101 design, could sweep the wings in flight. However, the rearwards movement of the centre of lift engendered some difficult control problems. Undeterred by the challenges, US research continued with the swing-wing Grumman XF10-F that flew in the early 1950s; however, it possessed extremely poor flying characteristics and rather vicious spin tendencies. But what was the rationale behind achieving in-flight variable sweep despite all the control problems?

The main motivator was to rationalise the ever-increasing need for speed, conferred by swept wings, with the increasing weight of aircraft and the resulting very high landing speeds. One solution was to introduce air tapped from the engines blown over the wings to fool it into behaving as if it was flying safely at lower speeds. The British Blackburn Buccaneer and the McDonnell F-4 Phantom were two aircraft that used this technique, known as boundary layer control. The other solution was to have the wings swept for high-speed flight and then bring them forward for the low-speed events of take-off and landing. A beneficial spin-off was that highly swept wings on fighters and bombers operating at low altitudes give a much better ride in turbulent conditions.

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