DH Aircraft

When my father retired, we travelled to museums to rediscover his career at de Havilland. The Mosquito is infamous, but I had not appreciated the the scale and breadth of their operations in the 1950s. I decided that the Comet was their greatest post-War achievement: there was no precedent, and the problems that had to be solved were staggering. Every airliner designed after it benefitted from de Havilland's research and experience.

As my fascination with the Comet grew, I looked for a model I could “fly” on my computer. If I had owned a PC, I would have used David Maltby’s superb Comet 4 for Microsoft Flight Simulator and that would have been that. Instead, I had an Apple Mac and X-Plane, by Laminar Research. When I discovered there was no Comet for X-Plane, I decided to make one. How hard could it be?

The flight model was straight forward: I had the correct dimensions, weights and aerofoils, and X-Plane made a very reasonable job of it "out of the box". The only real disappointment was engine thrust at high altitude. This was fixed with a Rolls-Royce Avon plugin by David Plunkett.

The exterior started as a Plane Maker model in X-Plane v8. It looked awful. X-Plane 9 was a colossal leap forward, enabling complex geometry to be created outside Plane Maker and attached to compared with 1,500 nm for the Comet 1. This made the Comet 4 an easier aircraft to fly.

Navigation
The Comet 4 was equipped with ADF, VOR and DME navigational aids. The automatic pilot was integrated with the radios, and was capable of performing coupled ILS approaches. By contrast, Comet 1 instrumentation was hardly any more advanced than a World War Two bomber; fixing position still relied on an optical sextant, and yet it flew twice as fast and twice as high, which made navigation a full time and stressful responsibility. The Comet 4 is an altogether more practical proposition for a flight simulator.