| Potez XVIII | |
|---|---|
 | |
| General information | |
| Type | Three-engine, twelve-seat biplane airliner |
| National origin | France |
| Manufacturer | Henry Potez |
| Number built | 1 |
| History | |
| First flight | 5 December 1922 |
| Developed from | Potez X |
ThePotez XVIII was a French airliner from the early 1920s, a three-enginebiplane carrying up to twelve passengers.
The Potez XVIII airliner, displayed at the 1922 Paris Salon, was a development of thePotez X colonial transport. It was an unequal span biplane largely built of wood, though with metal engines mountings and other fittings, engine nacelles andtail surfaces. The rectangular plan wings werefabric covered. On each side, towards thewing tips a parallel pair ofinterplane struts leaned outwards. Closer to the fuselage a parallel pair of V-form interplane struts formed a cradle for the outboard engines, mounted between the wings. These, and the third in the nose, wereLorraine 8Bds, water-cooled V-8 engines, each producing 201 kW (270 hp); cooled by cylindricalradiators hung beneath each engine nacelle.Ailerons with aerodynamic balances extending past the wing-tips were fitted on the lower wing only.[1][2][3]
The flat-sided and -bottomed fuselage had curved upper decking, dropping towards the tail. Behind the engine cowling back to the rear of the passenger compartment the fuselage wasplywood-covered, with fabric covering aft. Pilot and engineer/navigator/radio operator satside by side in an opencockpit ahead of the upper wing, with an internal door to the passenger cabin. Each passenger had a window, and there was a central passageway between the seats leading to a toilet and luggage compartment at the rear. Theempennage was conventional, with thetailplane mounted on the upper fuselagelongerons. Thefin andrudder together were of broadchord, the rudderbalanced. The Potez XVIII had a conventionalundercarriage with two pairs of underwing mainwheels and a tail skid. Each pair was mounted on two V-formstruts withaerofoil section,duralumin forward legs and rear telescopic,shock absorbing legs.[1][2]
Only one Potez XVIII was built. After its first flight on 5 December 1922, the flight test programme continued into the spring of 1924. It was bought by the French government but never put into production.[4]
The Potez XVIII was developed into the very similar Potez XXII, which differed chiefly in having more powerful, uncowled 283 kW (380 hp)Bristol Jupiterradial engines. It also had an extended nose, increasing the length by 1,300 mm (51.2 in) and an increased maximum weight of 5,400 kg (11,900 lb). The lower-wing, balanced ailerons were replaced with unbalanced ailerons on both upper and lower wings.[5] The type XXII competed in Le Grand Prix des Avions de Transport (Transport Aircraft Prize Competition), held in the autumn of 1923,[6] though without distinction.[7]
Data from Flight 25 January 1923, p.49-50[2]
General characteristics
Performance
