The supercharged Rolls-Royce Kestrel, and its derivative, the Peregrine was a fairly standard design, with two cylinder banks arranged in a V form and with a displacement of 21 litres (1,300 cu in). The Vulture, in effect, was two Peregrines joined by a new crankcase turning a new crankshaft, producing an X engine configuration with a displacement of 42 litres (2,600 cu in). Although the Vulture used cylinders of the same bore and stroke of the Peregrine, the redesigned cylinder blocks had increased cylinder spacing to accommodate a longer crankshaft, necessary for extra main bearings and wider crankpins.[2][3]