Flight, December 1921

The Paris Aero Show - 1921

HENRY POTEZ
14, Rue Clement, Levallois-Perret (Seine)

   Of the two commercial machines shown, the smaller, type "IX," is obviously a development of the two-seater fighter, whose general lines it preserves in spite of the presence of an enclosed cabin for the four passengers who comprise its useful load. In the light of the cross-channel services, the passenger accommodation is too small, but no doubt there are lines in France, or running out of France, on which this is the maximum number of passengers which can be counted upon regularly. It might be added that machines of this type have been used with great success on the Paris-Strasburg-Prague-Warsaw line, and that until the regrettable accident some months ago, no serious mishap had occurred to any of these machines. This is a very good record when it is pointed out that since September 20, 1920, the machines of the Franco-Roumanian Aviation Co. had flown 450,272 kilometres, carried 658 passengers, 19,072 kilogrammes of goods, and 891 kg. of mails.
   The machine is of clean appearance, and the detail construction appears to be very good. The cabin is small, naturally, and on a long journey the passengers might be subject to fatigue, as there is not sufficient room to stand upright. One therefore somewhat doubts the utility - in its form as a passenger carrier at any rate - of the rather long duration of flights which the large tanks make possible, i.e. 5 hours at a cruising speed of 112 m.p.h. Otherwise, the performance is certainly very good, a cruising speed of 112 m.p.h. being probably more than is really required on most routes. The maximum speed at ground level is 125 m.p.h. The pilot is installed in an open cockpit aft of the cabin.
   The rear portion of the fuselage is constructed in the usual way of longerons and struts of wood, with wire-bracing. The cabin portion, however, is built-up with three-ply walls, while the front portion is largely metal construction. The engine bearers themselves are of wood, but rest on four cradles of which the front and rear are of sheet steel, the intermediate ones being of ply-wood. The engine, a 370 h.p. Lorraine-Dietrich, is entirely cowled-in.
   As regards the wings, little need be said, as they are of standard construction. The inter-plane struts are streamline metal tubes, pin jointed to the spars, and the bracing is by cable, the lift cables being in duplicate and with a wood filler between them.
   The main characteristics of the Potez type "IX" are as follows :- Length overall, 32 ft. 2 ins.; span, 46 ft.; height, 10 ft. 3 ins.; wing area, 495 sq. ft.; weight, empty, 2,750 lbs.; weight of fuel, 726 lbs.; useful load, 1,035 lbs.; total weight, 4,511 lbs.; wing loading, 9-12 lbs./sq. ft.; power loading, 12 2 lbs./h.p.; maximum speed at ground level, 125 m.p.h.; at 6,500 ft., 121 m.p.h.; at 10,000 ft., 116 m.p.h.; climb to 6,500 ft., in 7 mins. 56 secs.; to 10,000 ft. in 19 mins. 42 secs.; ceiling, 20,000 ft.