Piaggio Stella P.VII

Piaggio Stella P.VII
Type	Air cooled radial
National origin	Italy
Manufacturer	Piaggio
Designer	Renzo Spolti
First run	1933
Major applications	Caproni Ca.113; Caproni Ca.133; Caproni Ca.310

The Piaggio Stella P.VII was the first P series aircraft engine produced by Rinaldo Piaggio S.p.A. Based on its experience license-producing the Gnome-Rhône 7K, Piaggio sold the engine to be used on a wide range of Italian aircraft before and during World War II, including the record-breaking Caproni Ca.133.

Development

Having built engines under licence from Gnome et Rhône, Piaggio designed a seven-cylinder radial using the same principles.^[1] The engine, named P.VII for its seven cylinders, was one in a series of radial engines produced by Piaggio initially named Stella, meaning star.^[2] The engine was first run in 1933 and was produced in many models.^[3] One notable version was the P.VII Z which was fitted with a floatless Piaggio AS80 carburettor for aerobatic flight. It powered the Caproni Ca.133 flown by Renato Donati that, in 1933, broke the record for the longest duration in inverted flight.^[2]

Variants

P.VII C.15: Supercharged, rated at 331 kW (444 hp) at 1,500 m (4,900 ft); first flew 1933
P.VII C.16: Supercharged, rated at 338 kW (453 hp) at 1,600 m (5,200 ft); first flew 1934
P.VII C.16/35
P.VII C.35: Supercharged, rated at 338 kW (453 hp) at 3,500 m (11,500 ft); first flew 1935
P.VII C.40: Supercharged, rated at 287 kW (385 hp) at 4,000 m (13,000 ft); first flew 1935
P.VII C.45 / 2v: Two speed supercharged, rated at 287 kW (385 hp) at 4,500 m (14,800 ft); first flew 1935
P.VII R.C.10: Supercharged and geared, rated at 1,000 m (3,300 ft).
P.VII R.C.35: Supercharged and geared, rated at 368 kW (493 hp) at 3,500 m (11,500 ft); first flew 1938
P.VII R.C.45: Supercharged and geared, rated at 287 kW (385 hp) at 4,500 m (14,800 ft) first flew 1935
P.VII Z: Normally aspirated, designed for acrobatic aircraft, rated at 272 kW (365 hp), first flew 1933

Applications

Specifications (C.35)

Data from S.A. Piaggio e.C. (1939). Instruzione per l’uso del motore P VII C 35 – D P VII C 35 – S. Rome: Ministero dell’Aeronautica. Retrieved 29 August 2018.

General characteristics

Type: 7-cylinder, single row, air cooled radial engine
Bore: 146 mm (5.7 in)
Stroke: 165 mm (6.5 in)
Displacement: 19.337 L (1,180 in³)
Length: 1,050 mm (41 in)
Diameter: 1,235 mm (48.6 in)
Dry weight: 295 kg (650 lb)

Components

Valvetrain: 2 x overhead valves per cylinder operated by rockers and pushrods
Supercharger: Centrifugal compressor
Fuel type: 87 Octane petrol
Cooling system: Air-cooled

Performance

Power output:
- Take-off: 368 kW (493 hp) at 2100 rpm
- Cruise: 338 kW (453 hp) at 2100 rpm at 3,500 m (11,483 ft)
Compression ratio: 5.5:1
Specific fuel consumption: 292 g/(kW•h) (0.48 lb/(hp•h)) at 1900 rpm
Oil consumption: 9.5 g/(kW•h) (0.015 lb/(hp•h)) at 1900 rpm

References

^ Gunston, Bill (1986). World Encyclopedia of Aero Engines. London: Guild Publishing. p. 125.
^ ^a ^b "PVII C35 engine". Museo Piaggio. Archived from the original on 26 August 2017. Retrieved 29 August 2018.
^ Angle, Glenn Dale (1939). Aerosphere. New York: Aircraft Publications. p. 584.

[1] Gunston, Bill (1986). World Encyclopedia of Aero Engines. London: Guild Publishing. p. 125.

[museo-2] "PVII C35 engine". Museo Piaggio. Archived from the original on 26 August 2017. Retrieved 29 August 2018.

[3] Angle, Glenn Dale (1939). Aerosphere. New York: Aircraft Publications. p. 584.

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