THE JOYS OF FAST

Recently, a Belgian friend of mine, who will forgive me for guessing his age to be not far from mine, was expressing regret at never having flown the F104 Starfighter.

THE FASTEST MACHINE which I’ve flown is the Lear 25, which is a horrible little gremlin, and had a reputation for killing anybody it didn't like. It was based on a Swiss-designed fighter which never made it into production.

The Lear 25 had a straight wing and a Mach limiter set for Mach 0.84. At that speed, power would be reduced and the control column would be eased back automatically to keep the aircraft below Mach 0.84. The Mach limiter could be disabled simply by pulling its circuit breaker.

The vicious nature of the Lear 25 was demonstrated dramatically at Mach 0.87, where it fell foul of the phenomenon known as 'Mach tuck'. At that speed the wave of compressibility moves the centre of lift aft across the chord of the wing, until the effectively stalled horizontal stabiliser no longer has the authority to keep the nose up and it stalls, thus pitching the aircraft into a nose-over of such ferocity that the wings fail downwards and the occupants exit through the roof.

Read more in our latest edition..