Construction was largely of spruce with plywood covering and light alloy components at strategic points. Wing sweep-back on the leading edge was just over 42° to facilitate low-speed research. Two diminutive engines (Turbomeca Palas) were buried in the upper fuselage with a NACA flush inlet on the top of the fuselage and toed-out exhausts located at the wing roots. Blackburn, who produced the Palas under licence, hoping to market these engines as a new product line, supplied the powerplants for the Sherpa programme.