Fiat 4700
The Fiat 4700 was an Italian turbo-generator developed by Fiat Aviazione under contract to the Italian Defence Ministry and used to power the experimental Fiat 7002 tip jet helicopter.[1]
| 4700 | |
|---|---|
| Type | |
| National origin | Italy |
| Manufacturer | Fiat Aviazione |
| First run | 1960 |
| Major applications | Fiat 7002 |
| Developed from | Fiat 4002 |
Design and development
The Fiat 4700 was developed to provide power in cold-jet driven helicopters.[1] The 4700 was a turbo-driven air compressor driven by the primary engine, a turbojet engine based on the Fiat 4002.[1] The compressor and primary engine are mechanically independent.[1] The engine is mounted vertically to reduce the length of the compressed-air ducts to the rotor.[1] The engine was used on the Fiat 7002 helicopter which first flew on 26 January 1961 where the Fiat 4700 was used to power the cold tip-jets on the two-blade rotor.[2]
Specification
Data from Jane's All the World's Aircraft 1962-63.[3]
General characteristics
- Type: Gas generator
- Length: 1,300 mm (51.2 in) (height)
- Diameter: 612 mm (24.1 in)
- Dry weight: 152 kg (335 lb)
Components
- Compressor: Single-sided centrifugal flow plus gas generator single-sided centrifugal flow compressor driven by the free power turbine
- Combustors: Annular with 16 burners
- Turbine: 1-stage axial flow (gas turbine power) + 1-stage axial flow free power turbine (gas generator power)
- Fuel type: Aviation kerosene
- Oil system: Re-circulating pressure system with one pressure pump and three scavenge pumps
Performance
- Maximum power output: 450 kW (610 hp) (gas hp for take-off), 377 kW (505 hp) (ghp max continuous)
- Overall pressure ratio: 4:1
- Air mass flow: 5.1 kg/s (11.2 lb/s) at 25,000 rpm at sea level, 3.34 kg/s (7.36 lb/s) (max continuous)
- Specific fuel consumption: 0.758 kg/kWh (1.246 lb/(hp⋅h))
- Power-to-weight ratio: 2.99 kW/kg (1.82 hp/lb)
References
Notes
- "Fiat's New Helicopter - Notes on the 7002 and its powerplant". Flight International: 110. 24 January 1958.
- "Fiat 7002 flies". Flight International: 138. 3 February 1961.
- Taylor, John W.R. FRHistS. ARAeS (1962). Jane's All the World's Aircraft 1962-63. London: Sampson, Low, Marston & Co Ltd.