Magni PM.1 / PM.2 Vittoria

Flight, September 1925

THE PIERO MAGNI "VITTORIA 1924" SESQUIPLANE
A Novel Italian Sport 'Plane.

   WE give this week some particulars and illustrations of an extremely novel type of "sport plane" designed by Sig. Piero Magni, of Italy. This machine was constructed in Sig. Magni's own factory, the "Laboratorio Costruzzioni Aeronautiche Pietro Magni," at Meda, near Milan, which was founded in 1921 and where a considerable amount of experimental and constructional work has been carried out.
   The "Vittoria 1924" - named after the designer's sister - was produced primarily for the designer's private use as a touring and "laboratory" machine, and, as will be seen later, possesses several interesting and original features.
   The first conception of this machine dates back to 1919, when scale models on the same principle, designed round a pre-war 50-h.p. Gnome engine, were exhibited in the Italian section of the Paris Salon of that year, while models were also tested in the Eiffel Auteuil Laboratory, when it was a private enterprise. The original models are shown in the accompanying illustrations.
   Fundamentally, the "Vittoria" is a "sesquiplano a triangolo afinezza variabili" - or, in other words it is a dorsal-wing, single-strut, semi-cantilever monoplane in which inclined struts supporting the brings from the fuselage also form small auxiliary wings which contribute a certain amount of lift. While the wing structure is of the "thin-wing" type, it is nevertheless "wireless." The most original feature of the machine however lies in the fact that the auxiliary wings are movable, i.e., their angle of incidence may be varied during flight from the pilot's cockpit, either simultaneously or independently. Thus, by setting simultaneously the two auxiliary wings at a large angle, a powerful air brake is obtained.
   Again, any variations in the angle of incidence of these planes give, it is claimed, much the same conditions as those obtaining with variable camber systems, thereby facilitating landing in restricted areas. The control of these auxiliary planes, it should be noted, its quite independent of the usual control of the machine, although the two controls may be partially interconnected for special purposes. We understand that this system of control, as first devised by Sig. Magni, was the first of its kind, although a machine embodying a similar idea was produced in America after the design of the first Piero Magni machine.
   Another important feature of the "Vittoria" consists of the improved range of vision its design offers. As will be seen, the main plane being level with the pilot's eyes, the maximum range forward and above is obtained as in the high-wing type monoplane, while the position and small size of the auxiliary planes does not restrict the vision downwards to any considerable extent.
   A second experimental machine, "Vittoria 1925" - also for Sig. Magni's private use - is now nearing completion, but it differs from the "1924" in details only. There is also a commercial production model of the "Vittoria" which will be placed on the market in a few weeks. Sig. Magni is also developing new commercial and military machines on similar lines, especially as regards deck-landing ships' 'planes, while designs are being prepared of machines embodying new devices, such as variable camber wings, etc.
   Now as to some particulars regarding the construction of "Vittoria 1924." The main plane is entirely of wood construction, consisting of a framework of longerons and ribs built up in the form of a box, the covering being of plywood. There are five longerons, of which the first and fifth are auxiliary. As will be seen from one of the accompanying illustrations the spars run parallel from the fuselage attachment up to the wing-strut attachment. Thence they curve back, converging together at the extreme wing tip.
   The thin main longerons are divided into one primary (the third) and two secondary (the second and fourth); they are built up of two spruce strips separated by a triangulated lattice of battens of the same material, the whole being boxed in by plywood. The ribs are of similar construction. The wing section employed is known as "P.M.14."
   The ailerons for lateral balance are mounted on the rear spar of the main wing, and are of similar construction. For lateral control they are interconnected, but are independent of the auxiliary wings. Each aileron is provided with two steel operating levers, faired by plywood. The control cables, also doubled, pass through the wings and the fin-like cabane supporting the wings on the fuselage. Inspection doors are provided for the cables and pulleys.
   The main wings, which are in two portions, are attached to a fin-like cabane projecting from the fuselage by means of three detachable metal fittings, corresponding to the three main longerons of the wings. The attachment at the central, or primary, longeron is of the articulated spherical type, while the two other attachments are of the fork type, adjustable as to height and thus allowing the wings to be set at any desired angle of incidence. It is of interest to note that the central attachment on the cabane is formed on a triangular transverse member of the fuselage, of metal tubes, to the bottom of which are attached the main wing struts (which also carry the auxiliary wings). All wing loads are thus centred on this transverse triangular metal frame, thereby relieving the fuselage of any heavy wing loads. Of course, all wing joints or attachments are designed so that they allow for all variations of incidence setting.
   The auxiliary wings are similar in construction to the main wings, and each consists of a main wooden box spar through which passes the main wing strut, a secondary spar at the rear, spruce ribs, and a plywood covering. The main spar is mounted on the wing strut by means of special bearings which allow the auxiliary wing to rotate through a range of incidence between -3° to 90°.
   At the lower end of each auxiliary wing is a steel crank lever, faired with wood, working in a recess formed in the side of the fuselage and to which is attached the operating rod from the pilot's control lever - there being a lever for each wing situated on either side of the pilot.
   The fuselage is composed of two main portions, the engine section constructed entirely of metal, and the body proper constructed of wood and carrying the wings, pilot, chassis tanks, instruments, tail surfaces, etc.
   The body proper is of the "coque" type and is built up of circular hoops, diaphragms, and longerons of wood, and to the framework thus formed is attached, by brass screws, a covering of special plywood. At the rear of, and built integral with, the fuselage are the fixed tail surfaces, comprising a vertical fin, to which is hinged the rudder, and two small triangular horizontal surfaces (one each side of the fuselage) carrying the comparatively large one-piece balanced elevator.
   The forward or engine section of the fuselage is constructed of metal and forms a self-contained unit entirely separate from the fuselage, from which it is divided by a fireproof partition. This engine section can easily be detached, enabling, if necessary, another unit with similar or different type of engine to be as easily substituted. The engine fitted is an Anzani 50 h.p. type 6A.20 air-cooled radial, but we understand that a rotary engine such as the 50 h.p. Gnome can be fitted. The engine is mounted in a metal frame attached to the fuselage by four detachable fittings in such a way that the whole engine unit can pivot on two of these fittings and swing clear of the fuselage, thus greatly facilitating repairs, inspection, etc. A quickly detachable aluminium cowling encloses the engine, and forming a continuation of the cowling is a spinner, also of aluminium, mounted on the airscrew.
   The pilot's cockpit is located at the rear of the main wings where, as previously stated, he has a remarkably good all-round range of vision. In front of the pilot is a wind shield, of Triplex glass, and behind is a fairing for his head. This fairing also contains the parachute, for use in case of accidents.
   The landing chassis is composed of two faired inverted L-struts carrying two large-diameter Palmer aero wheels mounted on a steel axle, sprung by "Sandow" shock absorbers.
   The principal characteristics, for normal flying, of the "Vittoria 1924" are :-
   Span 26 ft. 3 ins.
   O.A. length 18 ft.
   Height 7 ft. 4 ins.
   Wing area (total) 118 sq.ft.
   Wing area (effective) 107-6 sq.ft.
   Weight (empty) 623 lbs.
   Weight (laden) 905 lbs.
   Useful load 282 lbs.
   Wing loading 8-4 lbs./sq. ft.
   Power loading 17-08 lbs./h.p.