The Bonomi BS.22 Alzavola () was a

training Training is teaching, or developing in oneself or others, any skills and knowledge or fitness that relate to specific useful competencies. Training has specific goals of improving one's capability, capacity, productivity and performance. I ...

motor glider A motor glider is a fixed-wing aircraft that can be flown with or without engine power. The FAI Gliding Commission Sporting Code definition is: a fixed-wing aerodyne equipped with a means of propulsion (MoP), capable of sustained soaring flig ...

, intended to acquaint capable glider pilots with the characteristics of powered aircraft. The sole example was designed and built in

Italy Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...

in the mid-1930s.

Design

The BS.22 was evolved from the earlier Bonomi BS.15 Bigiarella glider, though with the addition of a small

flat twin A flat-twin engine is a two-cylinder internal combustion engine with the cylinders on opposite sides of the crankshaft. The most common type of flat-twin engine is the boxer-twin engine, where both pistons move inwards and outwards at the same ti ...

engine which drove a pusher

propeller A propeller (often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working flu ...

. It also had a retractable wheeled

conventional undercarriage Conventional landing gear, or tailwheel-type landing gear, is an aircraft undercarriage consisting of two main wheels forward of the center of gravity and a small wheel or skid to support the tail.Crane, Dale: ''Dictionary of Aeronautical Ter ...

and a quite different tail. Intended as an inexpensive aircraft, it was Bonomi and Silva's second and last motor glider, the other being the Bonomi BS.19 Alca. The Alzavola was intended to introduce glider pilots with C or B certificates to the complications of powered aircraft. In particular, as well as the retractable

it had a standard glider landing skid so new pilots could take-off on wheels, retract them and land on the skid in the way they were used to. After becoming familiar with the Alzavola they could put the wheels down before landing. The wing had a constant chord, unswept central section and straight tapered outer panels with rounded tips. The outer panels'

trailing edge The trailing edge of an aerodynamic surface such as a wing is its rear edge, where the airflow separated by the leading edge meets.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 521. Aviation Supplies & Academics, 1997. ...

s were entirely filled with the

aileron An aileron (French for "little wing" or "fin") is a hinged flight control surface usually forming part of the trailing edge of each wing of a fixed-wing aircraft. Ailerons are used in pairs to control the aircraft in roll (or movement aroun ...

s. The centre section was supported over the

fuselage The fuselage (; from the French language, French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds Aircrew, crew, passengers, or cargo. In single-engine aircraft, it will usually contain an Aircraft engine, engine as wel ...

on a pedestal, which also supported the small flat twin engine slightly above the wing surface, neatly cowled but with its

cylinder head In a piston engine, the cylinder head sits above the cylinders, forming the roof of the combustion chamber. In sidevalve engines the head is a simple plate of metal containing the spark plugs and possibly heat dissipation fins. In more modern ...

s exposed for cooling. Its pusher propeller rotated in a rectangular trailing edge cut-out, at about 70% chord. On each side an asymmetric V-strut, mounted on the lower fuselage

longeron In engineering, a longeron or stringer is a load-bearing component of a framework. The term is commonly used in connection with aircraft fuselages and automobile chassis. Longerons are used in conjunction with stringers to form structural fram ...

immediately below the forward wing spar, supported the outer ends of the centre section, joining its two spars. The fuselage was flat sided and essentially rectangular, though there was decking to fair in the open

cockpit A cockpit or flight deck is the area, on the front part of an aircraft, spacecraft, or submersible, from which a pilot controls the vehicle. The cockpit of an aircraft contains flight instruments on an instrument panel, and the controls th ...

, which had a small windshield, and a dorsal fairing to merge the rear of the pedestal to the tail. Under the cockpit, where the fuselage was deepest, there was a typical glider landing skid. Its conventional undercarriage had two balloon tyre mainwheels, each mounted on V-form split axles attached to the skid and with a shock absorbing strut fixed to the lower longeron. At the rear there was a tailskid. Both tail surfaces were straight tapered and straight cropped. Both rear control surfaces were much larger in area than their fixed counterparts and

balanced In telecommunications and professional audio, a balanced line or balanced signal pair is an electrical circuit consisting of two conductors of the same type, both of which have equal impedances along their lengths, to ground, and to other c ...

; the

rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, airship, or other vehicle that moves through a fluid medium (usually air or water). On an airplane, the rudder is used primarily to counter adverse yaw ...

extended to the keel and operated in an

elevator An elevator (American English) or lift (Commonwealth English) is a machine that vertically transports people or freight between levels. They are typically powered by electric motors that drive traction cables and counterweight systems suc ...

cut-out as the tailplane was mounted on the

fin A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foils that produce lift or thrust, or provide the ability to steer or stabilize motion while traveling in water, air, or other fluids. F ...

just above the fuselage, braced from above and below. The Alzavola could take off under its own power but could also be launched, with its wheeled undercarriage retracted or removed, by

bungee cord file:Bungee Cord PICT6882a.jpg, Bungee cords equipped with metal hooks A bungee cord (sometimes spelled bungie; also known as a shock cord or an ocky strap) is an elastomer, elastic cord composed of one or more elastic strands forming a core, usua ...

, winch or air-tow.

Specifications

References

{{Bonomi aircraft 1930s Italian sailplanes Motor gliders Aircraft first flown in 1934 Single-engined pusher aircraft