A PAIR of 'petrolhead' aviation enthusiasts have embarked on an ambitious mission to restore four wartime aeroplane engines to ground running condition for displays around the country.

Neighbours Patrick Smart and Peter Irving, of Topcliffe, Thirsk, have already fully restored one engine – one of only handful of known working Bristol Hercules in the world – and another is nearing completion.

They hope a further two engines will be completed within the next couple of years, provided the required parts are located following a world-wide trawl of aircraft museums and private collections.

Mr Smart, who owns Land Rover specialists Maddison 4x4 in Thirsk, said: "We are a pair of petrolheads, really. The reason I took the restoration on is my dad was a former pilot officer in the war flying with 158 and 640 Squadrons.

"He always praised the Bristol Hercules engines, as he said ‘they always got us home’.

“The aim is to get all four engines running together. What a sound that will be, we’ll almost have a full bomber.”

Mr Smart estimates the project to date has cost around £25,000, but says a restored engine in working condition can cost between £25,000 and £45,000.

Pilot Mr Irving is also passionate about the project, having first taken to the skies at the age of 16 and later joining the RAF to fly fast jets, culminating in the Tornado F3.

After leaving the RAF he became became a Virgin Atlantic Airways captain flying the Airbus A340-600.

Mr Irving said: “I am a true petrolhead and a very keen machinist and just admire the skill of the engineers who produced such works of art like the Bristol Hercules.”

The Bristol Hercules is a 14-cylinder two-row radial aircraft engine designed by Sir Roy Fedden and produced by the Bristol Engine Company from 1939.

It was the first of the company’s single sleeve valve designs to see widespread use, powering many aircraft in the Second World War.

Mr Smart and Mr Irving are now being supported in their quest to get the engines up and running by Morris Lubricants, a Shrewsbury-based oil blenders and marketers, which is providing classic oil for the engines in return for having two stainless steel fuel tanks wrapped with their brand logo.

Enthusiasts will be able to see the one restored Bristol Hercules engine running at a series of events this year including the Vintage Gathering in Northallerton on June 4 and the Croft Nostalgia Weekend on August 5 and 6.