An icon of world record breaking history, the speedboat Bluebird, is about to return to the water... with a little help from TWI.
The hydroplane overturned and sank in Coniston Water in 1967 during a fatal attempt by pioneer Donald Campbell to raise the world water speed record above 300 miles an hour. Campbell's body and the buckled and corroded wreckage of Bluebird K7 were brought to the surface in March 2001.
TWI's contribution to the restoration lies in returning the hydroplane's main triangulated spaceframe chassis to its former glory under the supervision of PDS Engineering in Lancashire. 'The wreckage was extricated from mud and silt at the bottom of Coniston in remarkably good condition' recalls PDS's technical director Chris Woodcock. 'Some areas however were badly perforated and the nose was entirely broken off in the accident'.
'This is a renovation, not a rebuild' he insists. 'Wherever we can we've retained original material in keeping with recognised aircraft restoration techniques. In other words badly corroded areas are, in many cases, repaired using patches rather than cutting out and discarding original material'.
The 1954 built spaceframe was made from 2" square box grade T59 aviation specification material. Lack of availability of the original grade material for restoration work forced the adoption of its nearest metallurgical equivalent, T60. 'Since Bluebird's construction welding processes have become considerably more refined.' says Woodcock. 'Back in the 1950s it was welded using the oxy-acetylene gas process, but since then the Tungsten Inert Gas shielded arc welding process has been invented and developed'.
This was the process chosen by the man behind much of the welding, Colin Eileens TWI's Principal Welding Instructor. 'Today the compatible filler wire used conforms to EN1668 W 46 2 W4Mo' he says. Material preparation and cleanliness before welding have been fundamental to the success of re-uniting badly corroded and damaged areas. Balanced welding techniques were adopted to minimise distortion and reduce residual stresses in the restored frame to aminimum.'
The remainder of Bluebird, the engine and bodywork, is being restored in a second location in Tynemouth, Newcastle under the supervision of the project's instigator Bill Smith. The body was made from aluminium sheet and destructive electrolytic action between it and the chassis has occurred in several places. The Metropolitan Vickers 'Beryl' Turbo-Jet engine was largely magnesium and has acted throughout the vessel's time on the lake bed as a sacrificial anode.
Campbell set seven world water-speed records between 1955 and 1964 in the K7 Bluebird. The first was at Lake Ullswater on July 23, 1955, where he achieved 203 mph (325 km/h). The series of increases peaked in December 31, 1964 at Dumbleyung Lake, Western Australia when he reached 276.33 mph.