Isotta-Fraschini Asso XI.RC
The Isotta-Fraschini Asso XI.RC was an Italian water-cooled, supercharged V12 piston aeroengine produced in the 1930s. It powered the CANT Z.501 and CANT Z.1007, both of which served the Regia Aeronautica, and several prototype aircraft.
Design and development
Isotta-Fraschini produced a long series of engines with the name Asso (Ace, in English). The Asso XI.RC was an upright, liquid-cooled V-12 engine with maximum power output in the range 670-725 kW (900-970 hp) depending on the degree of supercharging. There were two variants, differing only in their supercharger speed: the R.C.40 ran at a little over 10 times the crankshaft speed and enabled the engine to maintain a rated power of 623 kW (836 hp) to an altitude of 4,000 m (13,120 ft) (hence the 40 in the variant name) whereas the R.2C.15 held 655 kW (880 hp) to 1,500 m (4,920 ft) with a supercharger gearing of 7.[1]
All variants of the RC.40 had much in common constructionally with the earlier Asso-750.RC, though they had two, rather than three, banks of 6 cylinders and 4 rather than 2 valves per cylinder. Cylinder barrels were machined from carbon steel with flat-topped heads and valve seatings. Each barrel had a separate sheet steel water jacket. Cast aluminium head blocks were bolted to each of the two banks of 6 cylinders, providing valve ports, guides, coolant passages and camshaft supports. The pistons were also aluminium castings. The crankshaft was a 6-throw design with 8 plain bearings and a double row ball thrust bearing between the front two. The connecting rods had bronze bush little ends and white metal big ends. The crankcase was cast in two parts, the upper one with the housings for the crankshaft bearings.[1]
Variants
- R.C.40
- Supercharger speed 75/7 times crankshaft; rated power at 4,000 m.
- R.2C.15
- Supercharger speed 7 times crankshaft; rated power at 1,500 m.
- L.21 RC.40
- Maximum power 960 hp at 4,000 m.
Applications
Specifications (RC.40)
Data from Jane's All the World's Aircraft 1938[1]
General characteristics
- Type: 12-cylinder supercharged water-cooled 60° V-12 piston aircraft engine
- Bore: 146 mm (5.75 in)
- Stroke: 160 mm (6.30 in)
- Displacement: 32.65 L (1,992 in3)
- Length: 2,128 mm (83.78 in)
- Width: 834 mm (32.83 in)
- Height: 1,106 mm (43.54 in)
- Dry weight: 594 kg (1,310 lb)
Components
- Valvetrain: Two intake and two exhaust valves per cylinder, drive via cams and T-shaped tappets from inlet and exhaust pairs of overhead camshafts geared together, one for each bank of 6 cylinders, each pair driven by its own shaft connected indirectly to the crankshaft bevel gear.
- Supercharger: Single speed, single stage centrifugal, running at 10.714 times crankshaft speed.
- Fuel system: 4×Isotta-Frashini L.70C updraft carburreters, 2 for each bank of 6 cylinders.
- Oil system: Dry sump with single pressure and scavenge pump shaft driven off crankshaft bevel gear.
- Cooling system: Water-cooled, pump shaft driven off crankshaft bevel gear.
- Reduction gear: 0.743 or 0.512
- Compressed air starter
Performance
See also
- Related lists
References
- ^ a b c Grey, C.G. (1972). Jane's All the World's Aircraft 1938. London: David & Charles. p. 72d. ISBN 0715 35734 4.
|
|
|
| Piston engines |
Asso 80 · Asso 100 · Asso 500 · Asso 750 · Asso 1000 · Asso XI · Asso Caccia · Asso A · Asso L · Astro 7 · Astro 14 · Delta · Gamma · V.4 · V.5 · V.6 · Zeta
|
|
|
|
|
| General |
|
|
| Military |
|
|
| Accidents/incidents |
|
|
| Records |
|
|