The ST2 is developed from the Speedtwin E2E Comet 1. The Speedtwin E2E Comet 1, originally named the Phillips ST1 Speedtwin, is a two-seat, twin engined aircraft designed in the UK to be capable of aerobatics and the only civil twin certified for intentional spinning. After a long development time, just two have been built. The ST1 was unlike the intended production machines, having modified Victa Airtourer wings, a welded steel tube fuselage, a wooden vertical tail and fixed, spatted landing gear from a DHC-1 Chipmunk. It was powered by a pair of 74.6 kW (100 hp) Continental O-200-A flat four engines. Seriously damaged in a taxying accident in the early 2000s, it probably did not fly again. Just before Phillips's death in 1997 a second prototype was begun, eventually making its first flight on 27 March 2007 powered by 104 kW (139 hp) Avia M 332 inverted four cylinder in-line engines as the ST2 pre-production aircraft. It was later fitted with 153 kW (205 hp) Titan/Lycoming IO-390 flat four engines. Speedtwin Developments had taken over the aircraft in 2000 and in 2012 announced the new name of Comet 1. E2E stands for "Engineered to excel". At this time future developments including a retracting undercarriage, armament and turbo-prop engines were planned; the original idea of offering kits for home building had been withdrawn. The Speedtwin ST2 is a low cantilever wing monoplane with wing mounted engines. Mounted with some dihedral, the wing is trapezoidal in plan, though there is little sweep on its leading edge. The trailing edges carry servo assisted ailerons and electrically driven plain flaps with a range of deflections between 0° and −40°. The vertical tail is straight tapered with a brief fuselage fillet; the rudder extends down to the keel via a small elevator cut-out. The horizontal tail, mounted on the upper fuselage, is also straight edged with slight sweep on its leading edge. Both rudder and elevators are aerodynamically balanced. g limits: +6/-3 The aircraft was damaged when a blade broke off the right propeller, striking the nose of the aircraft and the left propeller, necessitating a forced landing. The accident report can be viewed here. Only the two prototypes were built. Details below are for the ST2.
