Retractable Undercarriages: A Historical Review with Descriptions of Examples of the Latest Practice

AMONG the many problems of drag reduction engaging the critical attention of aircraft designers to‐day, that parasitic appendix known as the undercarriage stands out, in more ways than one, as probably the most serious single offender still challenging the ingenuity of the designing engineer in his unceasing quest for aerodynamic refinement. Not so many years ago, however, quite a number of designers were openly sceptical of the mechanical feasibility of retracting the undercarriage unit; at least, in such a manner as to make it economically worth while. One suspects that our devotion in this country to the thin‐wing biplane had something to do with that particular brand of aerodynamic astigmatism, because it was not until the cantilever low‐wing monoplane became an accepted type that the idea of wheel retraction became a fashionable formula.