;RF-6B: :Main Fournier production series with
Rolls-Royce-built
Continental O-200 engine (43 built) ;RF-6B/120: :RF-6B with
Lycoming O-235 engine, one built ;RF-6C: :Four-seat version of RF-6B built by Sportavia with
Lycoming O-320 engine, four built, developed into
Sportavia RS-180 ;T67A :Slingsby-built RF-6B/120 certified on 1 October 1981, O-235 118hp engine, wooden construction, 2 blade fixed prop, fuel in firewall tank, single piece canopy, ten built ;T67M Firefly :First flown on 5 December 1982 and certified on 2 August 1983, the T67M was developed from the T67A as a
glass-reinforced plastic aircraft for a role as a military trainer. The T67M has a fuel-injected Lycoming AEIO320-D1B and a two-blade Hoffman HO-V72L-V/180CB constant-speed propeller, single piece canopy, fuel in firewall tank. The fuel-injected engine with inverted fuel and oil systems allowed the aircraft to perform sustained negative-G (inverted) aerobatics, although inverted spins were never formally approved. A total of 32 T67Ms (including the later T67M MkII) were produced. ;T67B :First flown on 16 April 1981 and certified on 18 September 1984, the T67B was effectively the T67A made, like the T67M, in glassfibre reinforced plastic, but without the up-rated engine and propeller. O-235 118hp engine, 2 blade fixed prop, fuel in firewall tank, single piece canopy. A total of 14 T67Bs were produced. ;T67M MkII Firefly :Certified on 20 December 1985, AEIO-320 fuel injected 160hp engine, 2 blade constant speed prop, inverted fuel and oil systems. The T67M MkII replaced the single-piece canopy of the T67M with a two-piece design, and the single fuselage fuel tank with two, larger tanks in the wings. ;T67M200 Firefly :Certified on 19 June 1987, the T67M200 had a more powerful Lycoming AEIO360-A1E with a three-bladed Hoffman propeller, inverted fuel and oil systems. A total of 26 T67M-200s were produced. ;T67C Firefly :Certified on 15 December 1987, the T67C was the last of the "civilian" variants, based on the T67B with an uprated Lycoming O-320 engine, but without fuel injection and inverted-flight systems found on the T67M variants. Two blade constant speed prop. Two further sub-versions of the T67C copied the two-piece canopy (T67C-2) and wing tanks (T67C-3, sometimes known as the T67D) from the T67M MkII. A total of 28 T67Cs were produced across the three versions. ;T67M260 Firefly :Certified on 11 November 1993, the T67M260 added even more power with the six-cylinder Lycoming AEIO540-D4A5 engine, three blade constant speed prop. Unusually for side-by-side light aircraft, the T67M260 was built to be flown solo from the right-hand seat to allow student pilots to immediately get used to the left-hand throttle found in most military aircraft – earlier models of the T67M had a second throttle on the left-hand sidewall of the cabin. A total of 51 T67M-260s were produced. They were used to successfully train hundreds of RAF, RN, British Army, and foreign and Commonwealth pilots through Joint Elementary Flying Training School until late 2010. ;T67M260-T3A Firefly :Certified on 15 December 1993, the last military version of the T67 family was the T67M260-T3A, of which the entire production run of 114 was purchased by the United States Air Force, where it was known as the T-3A. The T-3A was basically the T67M260 with the addition of air conditioning. Although the US media claimed the aircraft was to blame after four aircraft were destroyed in accidents, no engine stoppages or vapour-lock problems with the fuel system were found during very thorough tests at Edwards AFB. All three instructors killed in the accidents came from the C-141, a large-transport aircraft. Their only prior aerobatic experience was in Air Force pilot training in the T-37 and T-38 jet trainers. This, combined with lower air density at the higher altitude of the Academy airfield and training areas, meant spin recovery was delayed and/or improper spin prevent/recovery techniques were used. Parachutes were not worn on the first fatal accident but were worn on the second and third fatal accidents. Both of these accidents were caused by low altitude spins. Following the three fatal accidents and an engine failure in the Academy landing pattern the fleet was grounded in 1997 and stored without maintenance until being destroyed in 2006. ;CT-111 Firefly :Designation by the Canadian Forces internally only as aircraft are registered as civilian aircraft ==Operators==