Short SB.1 / SB.4 Sherpa
The Short SB-1 experimental glider was constructed mainly of wood, and was used for research into the aero-isoclinic wing concept.
The particularity of this flying wing, designed by David Keith-Lucas, the arrow leading edge reaching 42 deg 22 min isoclinic developed from the theory of Major Hll, which had also been tested on a series of flying wings (Pterodactyl), built before the war by Westland. This demanded a flexible rather than stiff wing structure with the tips hinged to serve collectively as elevators and differentially as ailerons.
Following a serious incident occurred during a towed takeoff flight, it was found that this method was too dangerous. As Blackburn had acquired the license to manufacture small French Turbomeca engines, it was decided to redesign the system with two Blackburn-built Turbomeca Palas of 330-1b (150-kg) thrust, as the SB.4 Sherpa. The engines are placed side by side on the back of the fuselage in a compartment isolated from the rest of the cell by firewalls. The air inlet is located on the back.
The ejection of the burnt gases is done by two independent nozzles. It is slightly divergent. Compared with SB-1, the airfoil has been enhanced so as to allow a significant increase in the weight, primarily due to the increased presence of engines, their components and the fuel.
The SB.4 Sherpa first flew on 4 October 1953 from the airfield near Sydenham, piloted by Tom Brooke -Smith, chief pilot of Short.
Only one was produced.
The aircraft was recovered and partially restored (the wings are missing) by the Medway Aircraft Preservation Society Rochester, Maidstone Road.
It is now in possession of the Ulster Aviation Society. This association had recovered two Palas engines (Nos. 53 and 54), and considering a static display, based on the former Long Kesh in Northern Ireland.
Short SB.4 Sherpa
Engines: 2 x Blackburn Turbomecca Palas
Length: 9.70 m (31 ft 10 in.)
Wingspan: 11.58 m (38 ft)
Height: 2.77 m (9 ft 1.12 in.)
Wing area: 21.40 m² (230 ft ²)
Empty weight: 1400 kg (3,000 lb.)
Max speed: 275 km / h (150knts)
Cruise speed: 188 km / h (102 knts)
Service ceiling: 1500 m (5,000 ft.)
Endurance: 45-50 min