Renault 70 hp
| Company type | Aircraft engine |
|---|---|
| Industry | Aerospace |
| Founded | 1910 |
| Headquarters | France, United Kingdom |
| Products | Aircraft engines |
The Renault 70 hp (also known as 8Ab or 8C) is a French-developed V-8 aircraft engine that debuted in 1910. It was utilized in early military airplanes including the Farman MF.7 Longhorn and the Royal Aircraft Factory B.E.2. Manufactured both in France and the United Kingdom, this engine powered the majority of British planes deployed to France at the outbreak of WW1.
Design and development
This engine incorporates an early variant of reduction gearing, wherein the propeller is mounted directly on the camshaft, rotating at half the crankshaft's speed. This arrangement allowed for optimized propeller and engine RPM without the additional mass of a conventional gearbox. Versions designed for pusher aircraft were equipped with a centrifugal blower to provide cooling airflow over the finned cast iron cylinders.
When compared to contemporary air-cooled rotary engines such as those from Gnome et Rhône, the Renault 70 hp exhibited a lower power-to-weight ratio but delivered enhanced fuel economy. Aircraft powered by this engine established records for both distance and flight duration during 1912.
Military procurement began in 1911, with an initial batch of 81 units supplied to the French army for Farman reconnaissance aircraft. By 1912, two out of five French squadrons were outfitted with Farman planes powered by this engine.
In Britain, Renault’s subsidiary alongside licensed manufacturers—Rolls Royce, Wolseley, and Airco—produced the 70 hp unit. Prior to WW1, Renault chose not to grant licenses to German companies.
Variants
Information sourced from Wolseley Motors' 1917 service manual. Weights account for flywheel, exhaust manifolds, cowlings, and propeller hubs.
Type W.B - Model featuring an internal lubrication oil pump. Dry weight:
Type W.C - Model equipped with an external lubrication oil pump. Dry weight:
Both W.B and W.C variants were offered in configurations for pusher (rear-mounted propeller) and tractor (front-mounted propeller) aircraft. Tractor versions included a cowl scoop directing airflow over the cylinders, whereas pusher models incorporated a centrifugal blower mounted at the rear, increasing power output by and consuming .
Type W.X - An enhanced 75 hp model featuring an increased bore size of 100mm and redesigned connecting rods employing a two-stud system compatible across cylinder banks. This variant was produced exclusively in tractor form. Dry weight:
Applications
- Airco DH.1
- Armstrong Whitworth F.K.2
- SS class airships
- Blackburn Type E
- Breguet Type IV
- Bristol B.R.7
- Central Centaur IVA
- Farman MF.7 Longhorn
- Farman MF.11 Shorthorn
- Flanders F.4
- Royal Aircraft Factory B.E.2
- Royal Aircraft Factory F.E.2
- Royal Aircraft Factory R.E.1
- White & Thompson Bognor Bloater
Surviving Examples
- Norsk Teknisk Museum, located in Oslo
Related Topics
Additional Resources
- Image "Flymotor Type 70 hk Renault" (side perspective), Norsk Luftfartsmuseum
- Image "Flymotor Type 70 hk Renault" (front perspective), Norsk Luftfartsmuseum