Isotta Fraschini Asso 750

The Isotta Fraschini Asso 750 was an Italian W 18 water-cooled aircraft engine of the 1930s. Produced by Isotta Fraschini the engine displaced just under 48 L and produced up to 940 hp. Together with the Asso 200 and the Asso 500 the Asso 750 was part of a family of modular engines, that used common and interchangeable components to lower production costs.

Technical description
The W-18 Asso 750 had three six-cylinder in-line banks made of chrome-manganese steel, each joined by a single cast aluminum head for each bank of cylinders.

Operational history
A version with an effective power of 940 hp was optimized for the Savoia-Marchetti S.55X used for the trans-Atlantic flight of Italo Balbo.

Variants

 * Asso 750: Direct-drive, unsupercharged.
 * Asso 750 R.: Development with modified crankcase and crankshaft, fitted with a 0.658:1 reduction gear. Maximum power output 940 hp.
 * Asso 750 R.C.:
 * Asso 750 R.C.35: The 750 R. fitted with a supercharger, rated altitude of 3500 m.
 * Asso 750 M: A 57.25 L racing development with 150 mm bore and 180 mm stroke, for the Macchi M.67, re-designated Asso 1000 Ri.

Applications

 * CANT Z.501 (early versions)
 * Caproni Ca.111
 * Macchi M.C.77
 * Savoia-Marchetti S.55
 * Savoia-Marchetti S.62
 * Savoia-Marchetti S.78

Engines on display
At the Italian Air Force Museum two Isotta Fraschini Asso 750 are exhibited: A direct-drive Asso 750 and an Asso 750 R.C.35 with reduction gear and supercharger.