Flight, January 1921
THE PISCHOF 16 HP. "AVIONNETTE”
IT would appear that the honour of producing the first really practical "aero-scooter" falls upon M. de Pischof, one of the pioneers of aviation in France. His latest effort, which we illustrate and briefly
describe this week, is particularly interesting, not only from the point of view of the small sporting type of machine, but as an example of aeroplane design and construction. The Pischof "Avionnette" is remarkable for its low-powered engine, as well as its small size, the engine being a two-cylindered horizontally opposed Clerget developing but 16 h.p. It is of interest to note in passing that as far back as 1908 M. Pischof carried out some trials with a monoplane also fitted with a 16 h.p. 2-cyl. engine. It seems that this little machine is by no means a freak or toy, neither is it an orthodox type of machine merely cut down in size and weight, but is one designed specially for its purpose - every detail having been carefully thought out, so that it fulfils its particular function in the simplest and most efficient manner possible.
The "Avionnette" has already made several successful trial flights, and in spite of its small size, is claimed to possess remarkable stability and flying qualities. The greatest height so far attained has been 4,000 ft. in 52 minutes, but it is anticipated that a ceiling of 6,000-6,500 can be obtained.
The speed range of the "Avionnette" is 36-60 m.p.h., and it carries sufficient fuel for two-hours' flight, the petrol consumption being 1.3 gals, per hour; oil consumption is said to be "practically-nothing." As regards the machine itself, as may be seen from the accompanying illustrations, it is of decidedly unique design. It is a tractor biplane, with a body that may be described as either of the fuselage or outrigger type. It is of metal construction practically throughout, exception being in the plane covering and interplane struts. The most important feature of this little 'bus is undoubtedly the ingenious method of assembling and dismantling the main planes, and the facility with which either can be accomplished. The main planes are made up of two self-contained units, consisting of an upper and lower plane section, on the port and starboard sides respectively. The upper and lower sections of each unit are separated by a single I interplane strut, which is hinged in the middle - the hinge-joint being locked by a quick-release pin. In dismantling, the removal of four steel bolts at the wing-root attachments, disconnects the wing-units together with the wing bracing, from the body. Removing the hinge-pins in the interplane struts, the latter fold in, bringing the upper and lower plane sections together, so that they take up very little space. Assembling is easily and quickly accomplished. Each wing unit is connected to the body - this being done with little difficulty since, with the interplane strut and bracing "slack," the wings may be more or less freely manoeuvred - after which the interplane strut is "straightened" and locked. This has the effect of tightening up the bracing, and inasmuch as the latter is never disconnected, the adjustment is more or less permanent and the wings need no further rigging once the interplane struts are straightened.
The attachment of the top plane is made to a nacelle-like erection, serving the several duties of engine bearer, fuel tanks mounting, and pilot's "wind shield," above the fuselage or outrigger. The lower sections are attached to the landing chassis - or its equivalent, for, strictly speaking, the latter really comprises a small plane-centre-section the front spar of which forms the axle for the wheels, which are unsprung, it having been found that with such a small and light machine the large-sized tyres are quite sufficient to absorb all landing shocks. It is further claimed that the lower plane being as low as it is, a considerable cushioning effect is produced when landing, which reduces the shock as well as acting as a brake. The wheels being well forward, it is said that it is practically impossible to turn the machine over on its nose.
The fuselage consists of two superimposed steel tubes, connected by vertical tubular members. The tail plane, which is of the lifting type at 0° incidence, carries a load of about 16 lbs. The pilot is located on a species of plough seat mounted on the top fuselage tube, forward of the trailing edge of the top plane. The top plane is cut away in the centre to receive the body of the pilot, who, from his high position, has a very good range of vision. The control stick, which is only some 12 ins. in length, is mounted on the top fuselage member in front of the pilot, whilst the rudder control, consisting of two pedals, is mounted on the lower centre section.
We understand that M. Pischof is now constructing a second "Avionnette" in which several modifications have been introduced. Amongst the most important of these may be mentioned the replacing of the two tubular fuselage members by a streamline fuselage - undoubtedly an improvement.
A cabane is also fitted on the top plane, whilst the area of the main planes has been increased slightly. The tail surfaces also have received certain alterations.
The principal characteristics of the Pischof "Avionnette” are :-
Span 17 ft.
Length 11 ft. 6 ins.
Height 4 ft. 3 1/4 ins.
Wheel track (width folded) 2ft. 7 1/2 ins.
Area of main planes 80 3/4 sq.ft.
Area of tail plane 5 3/4 sq.ft.
Weight of machine empty 225 lbs.
Loading per sq. ft. 2.78 lbs.
Loading per h.p. 14 lbs.
Speed range 56-60 m.p.h.
Climb 4,000 ft./52 mins.