The Fournier company in France, manufacturer of a range of sporting aircraft, was in receivership and its RF6B, an aerobatic two-seat club trainer with fabric covered steel-tube fuselage and wood-and fabric wing designed in the early 1970s, looked promising. Slingsby bought the last of the RF6B line, numbering 10 or so aircraft in various stages of completion, along with all manufacturing rights, and called it the T67A.

Those aircraft were leased out to various aero clubs in the United Kingdom and the clubs were asked for their full and frank comments. At the same time, the T67A was being re-engineered for production in fibreglass at Kirbymoorside, Yorkshire, but retaining the shape and all the RF6B’s good points, and incorporating suggestions filtering back from the aero clubs. The end result was the Slingsby Firefly, a range of aerobatic trainers of differing engine power in the one airframe.

The Slingsby T67 Firefly was the world’s first aerobatic GRP aircraft to receive full public transport certification, meeting both the British BCAR and American Aviation Administration FAR part 23 requirements.

First flown in May 1981, the base model is the T67B, with the 116 hp Lycoming engine. The T67C has the 160 hp Lycoming carburettor engine, still with fixed-pitch propeller, while the T67D is fuel-injected, 160 hp, and with constant-speed propeller, as well as having wing mounted 159 litre fuel tanks in place of the fuselage mounted 113 litre tank found in the B and C models. Next is the T67M (for military), still with the same engine as the D but with a few extra items of equipment that air forces can’t do without, and top of the line is the T67M200, with 200 hp fuel-injected Lycoming because the military doesn’t think of any aircraft in terms of less than 200 hp.

The most potent and best-balanced of them all is generally reckoned to be the 160 hp fuel-injected version, with full inverted everything, which will exceed all military specifications except horsepower. The M models come with inverted fuel and oil systems as standard equipment, while the lesser versions are all equipped with sump trays that retain a semblance of oil presssure under negative G, but of course run out of power upside down.
First flight of the T67M200 was made on 16 May 1985 and production examples are powered by a 200 hp (149 kW) Textron Lycoming AEIO-360-A1E engine. Customers for this version to 1990 include the Turkish Aviation Institute, King Air in Holland and the Royal Hong Kong Auxiliary Air Force. Production of the earlier T67B, C and D exceeded 90 aircraft.

From 1992 one-hundred and thirteen T-67 Firefly were operated in USAF service as T-3A Firefly (92-0625 to 0662, 93-0555 to 0596, and 94-0001 to 0033), wearing civil registrations, at Randolph Field TX.

T67B
Engine: Lycoming O-235, 116 hp
Prop: fixed-pitch
Fuel cap: fuselage mounted 113 lt

T67C
Engine: Lycoming O-320, 160 hp
Prop: fixed-pitch
Fuel cap: fuselage mounted 113 lt

T67D – Engine: Lycoming IO-320, 160 hp
Prop: constant-speed
Fuel cap: wing mounted 159 lt

T67M Firefly
Engine: 1 x Lycoming AEIO-320, 119 kW
Span: 10.6 m
Length: 7.3 m
Wing area: 12.6 sq.m
Empty wt: 650 kg
MTOW: 907 kg
Max speed: 256 kph
Initial ROC: 360 m / min
Ceiling: 4570 m
T/O run: 190 m
Ldg run: 230 m
Fuel internal: 160 lt
Range: 980 km

T67M-200
Lycoming IO-360-A1E, 200 hp

By November 1947, a powered version of the T-8 Tutor was undertaken, somewhat against his wishes, by Mr Fred Slingsby, and this, the T29 Motor Tutor, featured a new fuselage with a fixed, divided-axle type undercarriage and tailwheel married to the standard Tutor wings and tail unit. The first prototype G-AKJD was completed at Martin Hearn Ltd, Hooton Park. It first flew, as the T29A with a 25hp Scott Flying Squirrel engine, in December 1947 but this first prototype was underpowered.

The second prototype, the T29B G-AKEY which first flew in June 1948, was being built by Slingsby Sailplanes and had a 40hp Aeronca JAP two-cylinder, horizontally-opposed air-cooled engine; a single 9.5 Imp gallon fuel tank was installed. Completition was delayed to incorporate any modifications indicated by the flight tests.

It was intended that the Motor Tutor should be sold in kit form for assembly by Ultra-Light Aircraft Association groups but when, after protracted deliberations, the ARB at last granted the Motor Tutor a C of A it was not for training and, since this role had been the main reason for developing the type in the first place, further work on the Motor Tutor ceased and an initial order for six was cancelled.

Five or six other conversions are known:

G-AXMB
By C.W.Osborne used a Type 7 Kirby Cadet (single-seat T.31) BGA.805, probable ex-VM590. It was converted at Bedford with two 220cc Villiers motorvyvle engine mounted one on each wing strut and termed a Twin Cadet. It was converted to a Motor Cadet with a converted Triump T-100 in the nose later.

PFA.1312
T.West

PFA.1385 G-AYAN
P.J.Martin and D.R.Wilkinson converted T.31B BGA.1224 (ex-RAFGSA.223) at Twinwood Farm. Powered by a VW 1600cc as ‘Thermal Hopper’ c/n 003, it was first flown in 1971.

PFA.1573 G-AZSD
R.G.Boyton, Epsom, used an un-completed Slingsby-airframe, probably c/n 561, starting in 1972 as constructor’s number RGB.01/72.

PFA.1586
G.Milton

A Motor Cadet was resident at Bickmarsh, UK, built on T.31B RAFGSA.297, BGA.1346.

c/n 537 / ex-RA883, BGA.535
About 1957 R.Swinn converted T.7 Cadet into a Motor Cadet using a JAP J-99 engine at Sutton Park.