Long before his earliest days of flying, David found inspiration in a film about the 1943 ‘Dambusters raid by No. 617 Squadron, RAF, in which Lancaster bombers destroyed the walls of the Mohne and Eder Dams in Western Germany.
The operation used ‘bouncing bombs’ which skipped along the reservoir’s surface. For these to be effective, the pilots needed a way to satisfy the precise and pre-determined bomb release height – above still water and at night. As the barometric altimeters of the day lacked sufficient accuracy, two spotlights were mounted under each aircraft fuselage so that, at the correct height, their light beams would converge on the water’s surface. In other words, height was determined by simple triangulation. The bombsight also used this triangulation principle, applied towards the dam walls.
During 1965, while learning to fly at 18 years of age, that highly effective use of triangulation became David’s inspiration. On closer scrutiny of the ‘Dambusters’ methods, David realised that in a landing situation an accurate flare fix could be derived from a triangulation between a pilot’s eye path and a supplementary, pre-calculated longitudinal point on the runway centre-line, positioned short of the aim point. But that’s as far as it went, at that time.
Much later, in 1985, armed with 20 years experience on both large and small aircraft and using the original inspiration as his working concept, David researched and developed a new flare technique, which he published as a paper for the conference proceedings of the 1987 ‘Australian Aviation Symposium — Innovate or Enervate’ in Canberra. This technique later became known as The Jacobson Flare.
