A major engine refurbishment of an aircraft is nearly completed.

The de Havilland Gipsy Major 1 petrol engine at the de Havilland Aircraft Museum at Salisbury Hall, London Colney, has been dismantled to learn how the engine actually worked.

Volunteers Peter Coard and Roderick Coleman have been checking torque settings of the bearings of the crankshaft which had been removed when the engine was dismantled.

Restoration of the four-cylinder engine, which has bronze cylinder heads, began at the museum four years ago.

When finished it will be fitted with a shortened propeller and join a number of other de Havilland petrol, jet and rocket engines on display in Salisbury Hall’s Halford Collection of DH power units.

The unit is believed to have been built by de Havilland at its Hatfield factory in the early 1940s for use as an instructional engine at its Aeronautical Technical Training School.

It is believed it was used countless times by the company apprentices learning how the engine actually worked and how to dismantle it.

The engine was displayed on the company’s stand at the Society of British Aircraft Companies (SBAC) Air Show at Farnborough, Hampshire, in 1947.

It is also believed the aircraft was on show at the Paris Air Show of 1948.