Bristol Taurus
The Taurus was a supercharged multiple radial engine with 14 cylinders that was produced by the Bristol Aircraft Company . It was developed in 1936 as an air-cooled aircraft engine from the already existing seven-cylinder single radial engine Aquila by adding another 7-cylinder star. The Taurus was thus a double radial engine, in which the rear 7-cylinder star was rotated by about 26 degrees so that its cylinders looked through between the front ones. This ensured sufficient air cooling for all cylinders, which was very important for the compact and powerful engine. The Taurus delivered over 1000 HP (750 kW) right from the start of its development.
Bristol did not use valves for gas exchange for the Taurus (but also for other double radial engines like the Hercules and the Centaurus ), but a "Burt-McCollum" slide control . This made it possible to achieve higher compression ratios, the mechanical efficiency was higher than with overhead valves operated via tappets, push rods and rocker arms , the piston temperature was lower than with two-valve engines and higher speeds could be achieved, which benefited the engine's performance. The only disadvantage of this type of construction was the significantly higher construction and manufacturing effort.
Originally, Bristol wanted to build and offer the Aquila and the Bristol Perseus as its two main products in the 1930s , but the rapid increase in size and speed of the aircraft at the time required ever larger and more powerful engines. So Bristol developed corresponding double-star variants from both engines - the Aquila became the Taurus and the Perseus became the Hercules.
The first Taurus engines were delivered shortly before the start of the Second World War . They were in their own Bristol Beaufort - torpedo bomber used. When this aircraft was later fitted with the widely used Pratt & Whitney R-1830 Twin Wasp , its flight performance fell, although the Twin Wasp was lighter and more powerful.
The Taurus was only used for a few years in the Beaufort. The Hercules, on the other hand, was widely used.
Technical data of the Taurus II
- Type: 14-cylinder, compressor-charged four-stroke double radial engine with air cooling and double ignition
- Valve control: "Burt-McCollum" slide control
- Bore: 127 mm (5 in )
- Stroke: 143 mm (5.625 in)
- Displacement: 25.36 liters (1546 cubins )
- Compression: 7.75: 1
- Output: 1010 PS (743 kW) at 3220 rpm (starting output) or 1065 PS (783 kW) at 3220 rpm (short-term output)
- spec. Output: 39.8 PS / l (29.3 kW / l)
- Mass: 590 kg (1,300 lb)
- Power-to-weight ratio : 0.584 kg / PS (0.794 kg / kW)
- Gasoline: 87 octane
- Production: around 3400 pieces (from 1937 to 1943)
Technical data of the Taurus XII
- Type: 14-cylinder, compressor-charged four-stroke double radial engine with air cooling and double ignition
- Valve control: "Burt-McCollum" slide control
- Bore: 127 mm (5 in )
- Stroke: 137 mm (5.4 in)
- Displacement: 24.30 liters (1484 cubins )
- Compression: 7.75: 1
- Output: 1130 PS (831 kW) at 3100 rpm
- spec. Output: 46.5 PS / l (34.2 kW / l)
- Mass: 590 kg (1300 lb)
- Power-to-weight ratio: 0.522 kg / PS (0.710 kg / kW)
- Gasoline: 87 octane
