PETER GARRISON
Fixed is the new retractable. "Landing gears are made retractable in all modern high-speed airplanes. The drag of fixed 'undercarriages' used in old-type, and still in small and slow airplanes, is avoided in this manner." Thus wrote Sighard Hoerner, the great compiler of drag data, in 1951. ONE OF THE ODDITIES of the present moment is that, of the three swiftest singleengine aeroplanes manufactured in this country, only one has retractable landing gear. A few decades ago, this would have seemed an unimaginable situation. Without exception, retractable aeroplanes outperformed ones with fixed gear. It was simply understood, without dispute, that an aeroplane with fixed landing gear was aerodynamically handicapped.
Retractable models often came with slightly larger engines and constant-speed props that made it impossible to assess how much difference retractable gear really made. Results, such as they were, were mixed. If POH numbers could be believed – and manufacturers had every reason to exaggerate the gains – the Piper Arrow was 11 knots faster than its stifflegged counterpart; the Piper Lance 9; the Beech Sierra 15; the Cessna Cardinal RG 8; the Skylane RG 14; the Cutlass more than 20. (I have adjusted some of these figures when the retractable version had more horsepower than the other; the effect of a constant-speed rather than a fixed-pitch prop is more difficult to guess, and I didn’t try. Very large unexpected disparities, for instance between the speed gains for the Cardinal RG and the Cutlass, may be due to wheel pants (spats) being taken into account in one case and not the other.)
it is simpler to add power than to subtract drag
Perhaps the barrier separating retractables from non-retractables began to crack in the late 1960s when several manufacturers, beginning with Piper, brought out retractable versions of traditionally fixed-gear models, I suppose to colonise a perceived niche halfway between fast aeroplanes and slow ones and to capitalize upon the perception that real pilots fly retractables.
26
September 2021
