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 (2,900 cu in) and produced up to 940 hp (700 kW). 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.
| Asso 750 | |
|---|---|
 | |
| Preserved Asso 750 | |
| Type | W 18 piston engine |
| National origin | Italy |
| Manufacturer | Isotta Fraschini |
| First run | 1934 |
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 (700 kW) 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 (700 kW).
- Asso 750 R.C.
- Asso 750 R.C.35
- The 750 R. fitted with a supercharger, rated altitude of 3,500 m (11,500 ft).
- Asso 750 M
- A 57.25 l (3,494 cu in) racing development with 150 mm (5.9 in) bore and 180 mm (7.1 in) stroke, for the Macchi M.67, re-designated Asso 1000 Ri.
Applications
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.
Specifications (Asso 750)
Data from Il motore Isotta Fraschini Asso 750[1][2]
General characteristics
- Type: W-18 liquid/water-cooled
- Bore: 140 mm (5.5 in)
- Stroke: 170 mm (6.7 in)
- Displacement: 47.6 l (2,900 cu in)
- Length: 2,196 mm (86.5 in)
- Width: 1,060 mm (42 in)
- Height: 1,060 mm (42 in)
- Dry weight: 630 kg (1,390 lb)
Components
- Valvetrain: Overhead valves 2x inlet and 2x exhaust per cylinder
- Supercharger: No supercharger fitted to this variant: supercharger available in other variants - (R.C.35 rated to 3,500 m (11,500 ft)).
- Fuel type: Gasoline 87 Octane
- Oil system: pressure
- Cooling system: Liquid/water
- Reduction gear: Not fitted to this variant: reduction geared variants available (0.658:1 R. and R.C.35).
Performance
- Power output: Normal 800 hp (600 kW) at 1700 rpm; Take-off 850 hp (630 kW) at 1750 rpm; Max 900 hp (670 kW) at 1900 rpm
- Compression ratio: 5.6:1
- Specific fuel consumption: 0.485 lb/hp/h (0.295 kg/kW/h)
- Oil consumption: 0.00187 lb/hp/h (0.00114 kg/kW/h)
- Power-to-weight ratio: Normal 0.95 kW/kg (0.58 hp/lb) max 1.129 kW/kg (0.687 hp/lb)
References
- "Il motore Isotta Fraschini Asso 750" (PDF) (in Italian): 655–657. Retrieved 6 November 2018. Cite journal requires
|journal=(help) - "Aero Engine Data Sheets:Mechanical Data tables:Italian Aero Engines". oldengine.org. Retrieved 7 November 2018.
Further reading
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Wikimedia Commons has media related to Isotta Fraschini Asso 750. |
- Cei, Leoniero; Fiore, Amedeo (1934). Il motorista d'aviazione (in Italian). Milan: Ulrico Hoepli.
- "Jotti da Badia Polesine". Annuario dell'Aeronautica Italiana. Milan.: Libreria Aeronautica: 222. 1934.
- "Foreign Aero Engines at Olympia". Flight. Vol. XXI No. 30 (1074): 761–778. 25 July 1929. Retrieved 8 November 2018.