The Revoplane 2 (or Revoplane II) is one of the world's oldest surviving helicopters, built in Austria c.1930. Designed by Raoul Hafner. In 1932 Hafner and his business partner, financed by millionaire Jack A. Coates, moved to Heston Airfield in Middlesex.
The R2's rotor head was modified and new blades fitted, but the power was inadequate, and the machine only managed to hover inches off the ground. However, it did serve as a rotor hub test bed.
In England, Hafner met Cierva of autogyro fame, and then focused his own efforts on gyroplanes, and the R2 was abandoned. In 1961 it was found in a crate at Weston-super-Mare, and was restored by Westland apprentices. It went on to be displayed at various museums, before reaching its present location, the Helicopter Museum at Weston-super-Mare.
Hafner went on to have a key role with the Bristol Aeroplane Co as their Chief helicopter designer.
See here for an article about Hafner's work, which incluses a rare photo of the R2 with its front wheels keeping off the grass.[1]