James Hay Stevens, European Technical Editor, reports on progress with Piaggio P.166
The European executive race is on! While in Czechoslovakia the Aero 45 is in production and enjoys limited sales west of the Iron Curtain and while in France several interesting executives, including the jet powered Dassault Mediterranee, are coming along; in Italy that most original of private-venture constructors Piaggio & C. has already flight tested the P.166 six-eight seater and has started production.
This aeroplane is a direct development from the well known P.136L amphibian, which has had such great success in the USA, and which was fully described from the design, structure and flying points of view in AIRCRAFT for February 1957. The new aeroplane made its first flight on November 26 last and by the middle of February, when I visited Italy, it had carried out about 30 hours flying. The basic idea was to produce a rival to the Aero Commander and similar size American executive aircraft by taking the well-tried P.136L gull wing and Lycoming pusher installation as it stood, adding a new fuselage and working into the result as many common components as could be managed. In the event, the wing is interchangeable, as is the complete main undercarriage and its retraction assembly, which forms a basic unit. The nosewheel is, of course, completely new as are the wingtip fuel nacelles, while the tail unit has also had to be completely redesigned with different areas. The strength built into the wing to take tip float loads has enabled the structure to carry a larger weight as a landplane and the wings themselves now have internal fuel cells in addition to the tip tanks, so that there are relieving moments from the fuel. Overall it is a slightly larger aeroplane and in consequence the empty weight is up a few hundred pounds, but the landplane configuration has permitted the wing loading to be raised by more than 25% so that the disposable load is now well over a long ton as opposed to being a little short of 2000lb.
The layout chosen of a high mid-wing monoplane was more or less inevitable with the cranked wing inheritance from the amphibian and, or course, it produces a most convenient aeroplane, with the cabin set low to the ground without the need for entry steps. Carried well ahead of the wing, the cabin has large windows offering a fine all-round view and the occupants should have the benefit of quiet from the distance away of the pusher engines and the shielding effect of the wing itself. Incidentally, these pusher installations always have a particular droning tone when heard from outside - rather louder, if anything, than a tractor installation with the same engines- but this noise is, of course, left behind by the aircraft so far as the occupants are concerned. Although the prototype P.166 was on test flying when I visited and was an empty, unsilenced shell, the knowledge of the pleasant conditions in the cabin of the P.136L lead me to expect the new aeroplane to be particularly pleasant and comfortable.
By raising the cabin roof in relation to the wing, while retaining a bottom line not too much different from that f the flying boat hull, the designers - the team under Ing. Alberto Faraboschi and directed by Prof. Dolt. Ing. Giovanni Casiraghi - have provided cabin headroom of 69 in. on the centreline and a volume of approximately 300cu. Ft.
The floor at the front of the cabin is raised slightly (over the nosewheel bay) for the two pilots and behind is the main space with three large windows each side for six or eight seats and behind the wing spar bulkhead is a galley and a toilet space. The main cabin door, to port, is 54 in. high and 26 in. wide, while the pilot's door, to starboard, is 43 in. high by 27 in. wide. The central opening in the spar bulkhead which gives access to the toilet (starboard) and galley (port) is 59 in. high and 19.5 in. wide. Aft of this there is a closed compartment in the lower half of the fuselage containing the undercarriage and also the hydraulic and electric servicing bays which are accessible through external doors. There is ample luggage space on top of the undercarriage compartment and there is a freight floor aft of it, which is reached through a hatch 35.5 in wide by 21 in. high in the port side of the rear fuselage. A number of individual accommodation schemes have been tried, but basically the idea is to have two pairs of seats, one on each side of a central passageway - and these are full size airline seats, not Rapide ones- with a removable centre seat section. This latter is a properly sprung item, but with a folding back so that access is retained right through from front to rear of the cabin. To allow the insertion of the central section the inboard arms of the main seats hinge down and out of the way, the finished result being a comfortable three-seater bench 58 in. wide.