The Bristol Pegasus is a 9 Cylinder Poppet-valve radial air-cooled engine. It was a development of the Jupiter and Mercury engines of the 1920's. The original version of the engine produced 590 bhp, but the last version in 1937 produced 1,010 bhp. The Pegasus was used in many military aircraft, including the Fairey Swordfish, Vickers Wellington, Short Sunderland, and Bristol Bombay.

The Collections example was recovered from the sea bed, and is on display unrestored. It still has the remains of a two-blade propeller attached, and is probably from a Fairey Swordfish.

This engine should not be confused with the later turbojet engine called the Pegasus, which powers the Harrier.

The Bristol Hercules has 14 cylinders in two rows, and is a sleeve-valved radial air-cooled engine. It was used in many large aircraft from World War 2, including the Handley Page Halifax, Short Stirling, Avro Lancaster, Vickers Wellington, and Bristol Beaufighter. It was used in several post-war aircraft such as the Bristol Freighter, Nord Noratlas and Vickers Varsity. Over 50,000 Hercules engines were built up to 1966.

The Hercules on display is a Mark 216. It was originally built in 1945 as a model 106 for a Handley Page Halifax bomber. It was subsequently modified to a model 216 and fitted to a Handley Page Hastings, giving much more power.

The Bristol Centaurus has 18 cylinders in two rows, and is a sleeve-valved radial air-cooled engine. The first version produced 2,000 bhp, and the most powerful variant produced 3,200 bhp. It was the ultimate Bristol piston engine, and was developed primarily for heavy bomber and transport aircraft. Over 8,000 were produced.

The Centaurus powered the Hawker Tempest, Hawker Fury and Sea Fury, Airspeed Ambassador, Blackburn Beverley, Bristol Brigand and Vickers Warwick. The Centaurus was also used on the Bristol Brabazon prototype, which had four pairs of 2,500 bhp Centaurus engines, each pair driving a set of contra-rotating propellers. The Bristol Centaurus is still in use today on a small number of surviving Sea Fury aircraft.

The Collections example was built during World War II in the underground shadow factory near Corsham in Wiltshire. The bomb-proof factory was a network of huge tunnels, that had previously been an underground quarry for Bath Stone.

The Bristol Proteus was a radical design. The revolutionary turboprop engine has a 'reversed-flow' layout - the air enters through in-lets at the back of the engine, is passed forward, and doubles back through the combustion chambers. The original Mk.600 produced 3,780 brake horse power (bhp), but the 700 series became the production standard. The Mk.765 delivered 4,445 bhp.

It was primarily used on the four-engined Bristol Britannia airliner, but was also intended for the Bristol Brabazon and Saunders-Roe Princess, of which only the prototypes flew. It was also used in many industrial and marine installations.

The Collection has two Proteus turboprop engines on display. One of these, which was recovered from a scrap yard, has sections removed to show how the engine works, in particular the unique air flow system.

The Avon is an axial flow turbojet, developed in the late 1940's to replace the Nene. It was used on the Hawker Hunter, English Electric Canberra, de Havilland Sea Vixen, and Vickers Valiant. It was also used on early airliners, such are the de Havilland Comet and Sud Caravelle. The BAC 221, a high speed research aircraft that was modified at Filton from a Fairey Delta, also used the R-R Avon.

The original version of the Avon produced 6,500 pounds of thrust, but the final variant produced up to 16,360 lbs with reheat.

The Collections Avon engine has been sectioned to show the basic principles of jet engine design. Air is drawn into the front of the engine and is then compressed by a large number of 'rotor' blades, attached to a rotating central shaft. Between the rotor discs 'stator' blades are fixed to the outer casing of the engine. The air flow bounces off these blades, following a more or less straight path through this 'axial compressor'.

At the end of the compressor are the combustion chambers, where a spray of kerosene fuel is burnt, adding energy to the air flow. Part of this energy is used in driving the turbine wheel, which causes the engine shaft to rotate, the rest of the energy goes into expansion of the burnt gas, to form the high-speed jet exhaust which drives the aircraft forward.

The Viper was used in the Hunting Jet Provost, Aermacchi MB326 and MB339, the HS.125 series 600 business jet. In all around 5,000 Vipers were built.

The de Havilland Gyron jet engine was the first British engine to be designed for supersonic flight. A scaled-down version of the engine, the Bristol Siddeley Gyron Junior, was used on the Bristol 188 stainless steel research aircraft, which was designed to investigate the effect of supersonic speeds on airframe structure. The Gyron Junior was also used in the Blackburn Buccaneer.

The Olympus was Bristols first production pure jet engine. With 20,000 lbf thrust, it powered the Avro Vulcan delta-winged bomber. The Olympus was flight-tested in an English Electric Canberra, which broke the world altitude record several times in 1955.

The Olympus 104, including this example, was used in the Avro Vulcan B.1. A later version, the Mark 320, was intended for use in the TSR-2, but this project was cancelled with only a few prototypes ever flying.

The Olympus was continually developed, with 593 model powering the BAC/Aerospatiale Concorde. The engine was developed in Bristol, and was air-tested from Filton in the 1960's, fitted underneath an Avro Vulcan flying testbed. The ultimate model of the engine produced about 39,000 pounds of thrust, without reheat. Other variants of the Olympus are used to power warships, and for mains electricity generation.

The Collection has a complete Olympus engine, and another which has been broken down into sections, so each part of the structure can be seen.

The Leonides engine was used to power the Bristol Sycamore helicopter, as well as other fixed wing aircraft from the 1940's and 1950's.

The Collection has an exhibition example, and features the reduction gearbox (black dome on the top of the engine) used in the Westland Dragonfly, which was a derivative of the Sikorsky S.51 Helicopter. The model used on the Bristol Sycamore did not have the reduction gearbox, which improved its performance.

The Leonides Major engine was a derivative of the Leonides. It was mainly used in the Bristol Type 173 twin-engined helicopter. The sole surviving example of the Bristol 173 is also in the Collection. The Alvis Leonides Major is a radial piston engine with a double bank of cylinders.

The Bristol Type 173 was intended for civilian passenger service and was extensively assessed by British European Airways. It was then developed into the Type 192 (later named the Belvedere) for the Royal Air Force.

The Adour turbojet is used in the SEPECAT Jaguar and the Hawker Siddeley (now BAE) Hawk.