Ambrose Barber was reminded by Karl Wingett-Smith’s recent pieces in the Newsletter of a test flight he did with Hugh Merewether to investigate a change to the two-seat Hunter’s cabin conditioning system….
    In those pre-computer-prediction days it was called experimental testing with good reason as, after initial slide-rule calculations, much of our work was optimised by honest trial and error. Sometimes one had to see the funny side of it.

The larger cockpit of the two-seater made greater demands on the cabin pressure, temperature distribution and demisting. The plan was to improve the system’s performance by the addition of extractor louvres mounted externally behind the cockpit canopy and a test flight was devised to measure this.

Experimental Flight Testing In The 1950s

After a prolonged ‘cold soak’ at altitude we came plummeting down in a max. rate descent to 1,000 feet. Hugh then hammered across the Sussex landscape at 585 knots while my job, despite the vibration, was to jot down regular readings of cockpit temperatures at head, hands and feet level. On landing back after all this we opened the hood only to find that sometime during our flight the much vaunted louvres had been sucked off without trace!
    This article is an extract from Ambrose’s chapter in ‘Tail Ends of the Fifties’, an anthology of aviation memories compiled and edited by Peter G Campbell, published by Cirrus Associates in 1999.