Società Leonardo da Vinci Forlanini / P Class
Manufactured by the Società Leonar-do da Vinci in Milan, the ‘Forlanini’ class airships (designed by Enrico Forlanini and the firm’s engineer Luigi Crescentini) may be regarded as the most successful of the Italian semi-rigid vessels, winning a number of re-cords during the years immediately preceding World War 1. Early versions had carried their structural girder externally, but this was eventually placed within the hull as a truss from which the central car with its crew compartment, motors and flotation bags protruded, the leading edge being glazed and an unusual tri-plane set of control surfaces being car-ried at each side of the F.3. To the rear of the car the propellers, arranged as pushers, were carried on outriggers with an extended linkage to the en-gines, the reversible propellers being capable of variable pitch.
An interesting design feature of the envelope was its double surface with a space between the inner and outer fabric, which served as a ballonet to maintain the shape of the envelope. In addition a climbing well was included together with a ladder by which to gain access to a platform on top of the hull.
There were five initial ‘Forlanini’ airships with progressively improved performance, the best showing a rate of climb of 1000 m (3,300 ft) per minute. One such airship setting up an endur-ance record of eight hours, in the course of which the average altitude maintained was 3960 m (12,992 ft) although at one time 5335 m (17,503 ft) was attained.
Perhaps the most unusual feature of the Forlanini was the construction of the tail. This did not terminate in the conventional cruciform pattern but had instead a robust ventral fin of thick section. To each side of this and below the centreline a series of high aspect ratio rudders was carried (five to a side) with biplane horizontal surfaces above and below.
A considerably smaller Forlanini airship was the ‘P’ class (Piccolo, or small) with a fixed vertical fin and out rigged rudders at the ends of very wide span elevators. This model was 63.0 m (206 ft 8.3 in) in length, with a diameter of 12.0 m (39 ft 4.4 in).
Type: sea patrol and bombing airship
Powerplant: two 74. 6-kW (100-hp) Fiat A six-cylinder water-cooled piston
Maximum speed 80 kph (50 mph)
Service ceiling 5480 m (17979 ft)
Range 650 km (404 miles)
Useful lift 2720 kg (5997 lb)
Diameter 20.34 m (66 ft 8.8 in)
Length 9,51 m (296 ft 11.4 in)
Volume 13800 cu.m (487,343 cu ft)