Flight, December 25, 1919.
SOME FRENCH MACHINES AT THE SHOW
Aeroplanes Henry Potez
This firm is a newcomer into the aviation industry, as far as pre-War aviation is concerned. It is one of the firms which had not turned their attention to aeroplane construction until the War demand arose. It will, therefore, be of some interest to watch the future of the firm. At the Paris Show they are exhibiting two machines, one a passenger 'bus to carry four, and the other a little spotting two-seater.
The sporting biplane is a small machine of 26 ft. 3 ins. span and 19 ft. overall length. It is designed as a two-seater, and is built to a large extent of Duralumin. Owing to the peculiar arrangement of the engine (see accompanying silhouette) the fuselage has been placed very low, giving a sturdy undercarriage structure which with its four wheels, in conjunction with a low landing speed, practically precludes the possibility of damage except during an extremely bad landing. The landing speed is stated to be below 25 m.p.h., but, as in the case of the Farman sporting machine, this sounds a little optimistic, in view of the fact that the wing loading is about 4.5 lbs./sq. ft. Probably the landing speed is nearer 35 m.p.h. The undercarriage is provided with a sprag operated from the pilot's seat, by means of which the machine may be pulled up quickly after touching the ground.
Not the least interesting feature of this machine is its engine - a Henry Potez type A 4 - of 50 h.p. It is placed vertically in the machine, with the cylinder heads pointing forward so as to ensure even cooling. (The engine is aircooled.) At the upper end of the vertical crankshaft is a bevel gear which serves the double purpose of transmitting the power to the horizontal propeller-shaft and of giving a 2 to 1 gear reduction. The weight of the engine is somewhat great for its power, compared with modern aero engines, but it is stated by the makers that reliability has been their first consideration, and that they consider this of greater importance than low weight. The engine weighs 220 lbs., or slightly over 4 lbs ./h.p., but it is claimed to be as reliable as a car engine, and to require very little attention. The bore is 100 mm. and the stroke 120 mm., and the full power of 50 h.p. is developed at a speed of 2,200 r.p.m., which give an airscrew speed of 1,100 r.p.m.