Housing of Undercarriage during Flight.
Numerous suggestions, ideas, and patents exist, having as their object the housing of the undercarriage in the fuselage during flight, with a resultant reduction in resistance; and excellent as the principle is, its practical application is difficult of achievement—at least, for machines of the present. In flight the undercarriage is a useless encumbrance, adding weight and head resistance, so that an arrangement whereby this component could be folded into the main structure would apparently effect a saving in resistance. This would mean that the fuselage would be of larger cross-sectional area, the natural sequence being extra weight and resistance. It does not appear that the saving effected in resistance, when the undercarriage is folded during flight, would account for the additional weight of the operating mechanism and the increased head resistance of the fuselage, so that altogether the advantages of any so-called disappearing landing gear are very much more apparent than real. There is also the very great possibility of the undercarriage folding up or disappearing when it would be least required to do so. In the construction of the problematic air-liners of the future it may be possible to economically effect the housing of the undercarriage.
CHAPTER XII.
CONTROL SYSTEMS.
The mechanism by which the aeroplane is controlled in flight forms the connecting link between the pilot and machine, and constitutes a vitally important and somewhat vulnerable item of the complete structure.