The blueprints of a prototype World War One fighter plane, which could be the earliest surviving work of a famous Dutch engineer, have been discovered in Bradford.

A total of 201 drawings and four sheets of notes, the work of Frederick Koolhoven, were found stashed in boxes and hidden in a partition wall by workmen in a former factory of Christopher Pratts in North Parade.

The plans show the design for the Armstrong Withworth FK10 quadraplane, two of which were built in Bradford by the Phoenix Dynamo company at Thornbury in 1917.

The planes, a fighter N511 and a bomber N512, never saw active service and the blueprints were thought to be lost for ever.

But microfilm copies of the hand-drawn prints have now been handed over to Harry van der Meer, curator of the Koolhoven Aeroplane Foundation in Holland.

He believes the plans are the earliest record of Koolhoven's work and could be used to recreate a life-size model of a quadraplane as an exhibit for a Koolhoven museum in Holland.

Kevin Cairns, documentation assistant at the Bradford Industrial Museum, which is looking after the originals, said: "As pieces of paper the plans are worthless but in terms of history they're priceless, a very important piece of this city's past. Harry was over the moon when we showed him the blueprints. He didn't realise just how much of the detail about the aeroplane's structure was available for the drawings.

"So much of the history of Koolhoven was destroyed in 1940 when the Germans bombed the main Koolhoven factory in Rotterdam."

During World War One Mr Koolhoven worked as a designer for the aircraft division of Newcastle company Armstrong Whitworth, which developed the FK10.

Bradford-based manufacturing company Phoenix Dynamo was asked to build two FK10s as part of the war effort and enlisted the help of Bradford cabinet makers Christopher Pratt & Sons to help with the wooden bodywork.

Mr Cairns said: "The blueprints laid in our vaults until 1994. We had nothing to work on but after a lot of detective work we managed to trace the history and made contact with the Rotterdam link last year."

e-mail: charles.heslett@bradford.

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