Slingsby T-43 Skylark 3
The T41 Mk 2 was followed by the T43 Skylark 3 single seater, an enlarged and developed verison suitable for Open Class competition; this had the wing span increased by nearly 12ft to 59ft 8.25ft (18.19m) and the aspect ratio to 20.5, while the tail surfaces were enlarged, just as the Mk 2's tail unit had been larger than the Mk 1 's.
All the Mk3 variants had the same all-wood construction with plywood covering as the Mk 2, and a similar high-set laminar flow three-piece cantilever wing of spruce and plywood with air brakes in the upper and lower surfaces. The wing has a main spar and a light rear spar to carry the ply-covered ailerons, and is plywood-covered to the rear spar with a fabric-covered trailing edge. The wooden cantilever tail unit has a plywood-covered fin and tailplane and fabric-covered rudder and elevators. The landing gear is very similar to the Mk 2's, with a tail bumper as an alternative to the tailskid, and the monowheel can be replaced by jettisonable dolly wheels. The pilot sits under a one-piece blown canopy which hinges sideways to open, and he is provided with an adjustable seat and rudder pedals. The wingtips and front fuselage of fibreglass.
The prototype Mk 3 first flew in July 1955 and there were several sub-types; altogether 65 Mk 3s of all variants were built, and a Skylark 3B flown by the Argentine pilot Rudolfo Hossinger won the Open Class in the 1960 World Championships in Germany.
The Skylark 3A, of which seven were built, was the original Mk 3 variant with a length of 24ft 9in, and the Mk 3B had the cockpit moved forwards by 3in to compensate for the rearward movement of the cg caused by the larger tail; the elevator mass balances were also repositioned and the 3B's length was 25ft. Altogether 24 Mk 3Bs were built, and both 3As and 3Bs later had the all-up weight increased to 830lb by a retrospective modification.
The Mks 3C and 3D, two examples of each of which were built, were the same as the 3A and 3B respectively but had the wing spars strengthened to meet BCAR and ARB requirements.
The Skylark 3E was a 'one-off' experimental version (serial BGA 480) with outer wings of a different NACA 64-series section and reduced chord ailerons, but was otherwise the same as the Mk 3B; it was later converted back to this standard. The Mk 3F was the same as the 3B but had geared tabs added to the ailerons, a modified tailplane and elevator plan form of greater span, and an all-up weight of 830lb; 25 of this variant were built plus five more constructed from kits supplied by Slingsby.
Last variant was the Skylark 3G, which was the same as the 3F but with increased span ailerons of reduced chord with the geared tabs removed; four Mk 3Gs were built.
Wing span: 18.19m / 59.7ft
Wing area: 16.1sq.m /173.25sq.ft
Empty Weight: 272kg / 600lb
Payload: 104kg / 230lb
Gross Weight: 830lb / 376kg
Wing Load: 4.8lb/sq.ft / 23.36kg/sq.m
Aspect ratio: 20.5
Airfoil: NACA 63-3-620
No. of Seats: 1
L/DMax: 32 @ 79 kph / 43 kt / 49 mph
MinSink: 0.61 m/s / 2.0 fps / 1.18 kt
Span: 59 ft 8.25 in
Length: 25 ft 0 in
Height: 5 ft 9 in
Wing area: 173.3 sqft
Aspect ratio: 20.5
Empty weight: 547 1b
Max weight: 830 lb
Max speed: 134 mph
Min sinking speed: 1.84 ft/sec at 40 mph
Best glide ratio: 36:1 at 46 mph