Flight, January 1920
The Paris Aero Show 1919
The de Marcay Engines.
The smallest of the de Marcay machines is known as the "Passe-Partout." As already mentioned in our preliminary report on the show this machine has an engine of 10 h.p. only - a British
A.B.C. two-cylinder opposed air-cooled. From the table of particulars published in our issue of January 1 it will be seen that the loading per horse-power is very heavy, 41,7 lb., and one, therefore, somewhat doubts the practical utility of the machine, as there would appear to be no reserve power for climbing. In several respects, however, the machine is very interesting, and with an engine of about 20 h.p. and slightly larger wings to keep down the landing speed, should prove a very serviceable little 'bus.
As in the case of the other two de Marcay machines, the fuselage is of monocoque construction, but the section is rounded rectangular rather than circular. The A.B.C. engine is mounted above the nose of the fuselage, presumably to get the propeller shaft as high as possible so as to allow of getting sufficient propeller clearance. It would be possible to cover in the upper part of the engine, but on the machine shown this had not been done. The main planes are straight without dihedral, and the bracing is of the simplest possible type, one lift cable and one anti-lift cable. Lateral control is by warping the upper plane. To allow of doing this the interplane struts, of which there is one on each side, are tapered towards the top while they are wide at the bottom so as to reach both lower spars. The warp cables pass from front and rear top spars down over pulleys in the bottom plane and hence to the control lever. This would appear to be quite a neat way of arranging the lateral control in a small machine, as the fitting of ailerons entails a considerable amount of extra work, and also adds somewhat to the weight.
The tail plane, as on the other machines on this stand, is of the lifting type, and is covered with three-ply wood. The elevators are fabric-covered, but both fin and rudder are covered with ply wood. The tall skid is very simple and neat, consisting of a laminated spring of wood. A diminutive vee under-carriage, with rubber shock-absorbers, is fitted.