Wright R-1750 Cyclone 9
The Wright Aeronautical Corporation was formed in 1919, initially to develop Hispano-Suiza engines under licence. The Corporation’s first indigenous design, the R1, was also the first successful high-powered radial in the USA.
A new design was launched in 1926, known as the R-1750 Cyclone. This was a nine-cylinder radial with a displacement of 1750 cu in and internally cooled exhaust valves. It was type-tested at 500 hp in 1927.
The cylinders are composed of a steel barrel over which an aluminium alloy head is screwed and shrunk. Intake ports are at the rear with exhaust ports on the forward side of the cylinders.
The crankcase assembly is composd of five major castings of aluminium alloy. The cam follower ring carrying the tappet guides is cast integral with the main section of the crankcase.
The crankshaft is a two piece single throw with a one piece master rod and “I” section articulated rods.
Aluminium alloy pistons, cross ribbed on the under side of the head, and fitted with full floating hollow pins.
Tulip shaped valves; solid stem inlet valve and hollow stem exhaust valve; the exhaust valve containing a special salt compound which improves valve cooling and prevents warping.
Equipment supplied was air cleaner and heater, nose cowling, complete exhaust manifold, priming pump, ignition switch, tool kit, external oil filter, and instruction book.
Accessories available at extra cost were Ecllipse hand inertia starter, Eclipse generator, Eclipse generator control box, standard steel propeller hub, fuel pump, Eclipse combination hand and electric inertia starter, Eclipse hand starter with booster magneto, Eclipse electric inertia starter, propeller hub for wooden propeller, metal propeller, and hubs for two or three blade props.
Type: 9 cylinder air cooled radial
Military Rating: 525 hp at 1900 rpm
Commercial Rating: 525 hp at 1900 rpm
Displacement: 1750 cu.in
Compression ratio: 5-1
Bore: 6 in
Stroke: 6 7/8 in
Length: 39 1/4 in
Diameter: 53 15/16 in
Weight: 770 lb
Fuel consumption: not more than .60 lb/hp/hr
Oil consumption: not more than .035 lb/hp/hr
Lubrication: Pressure pumps
Ignition: Scintilla Dual
Carburation: Stromberg, double barrel
Spark plugs: 2 per cylinder
Price with 2-1 reduction, no cowl or exhaust manifold: $10,000