Developed from the F.1, the Vigilante F.2 had incredible performance thanks to the installation of a DeHavilland Stentor rocket engine in the rear of the weapons bay, nearly doubling the total available thrust. The attendant HTP oxidiser tank was housed immediately ahead of the motor ( two sizes of HTP tank were produced, the smaller of which allowed the forward third of the weapons bay to be retained for either a fuel tank or weapons ), with kerosene fuel being drawn from the aircrafts normal tankage
In operational service a typical load for the extreme range interception role would be a full size HTP tank internally, occupying the full length of the weapons bay, three underfuselage AIM-7 Sparrow or Skyflash missiles, fuel tanks on each of the inner four wing pylons, and AIM-9 Sidewinders on the outer two pylons. For shorter range missions two of the fuel tanks were often traded for an additional pair of Sparrows.
The rocket engine conferred the ability to gain altitude extremely rapidly, as with an aggregate thrust to weight ratio in excess of 0.8 even at maximum takeoff weight the aircraft could climb almost vertically straight off the runway - a spectacular manoeuvre which rapidly became a crowd favourite at airshows ! It also allowed the aircraft to operate at altitudes in excess of 80,000ft, even after the jet engines had flamed out due to insufficient oxygen, though due to the rarified air at these altitudes the aerodynamic control of the aircraft was considered sluggish. One mission profile demonstrated was essentially a ballistic trajectory which sent the aircraft to over 110,000ft. Whilst this allowed a distant target area to be reached very quickly the dangerous nature of the profile meant it was reserved for the direst emergencies only - most Vigilante pilots only ever carried it out in the simulator. Fortunately no aircrew needed to eject at these altitudes, as the odds of surviving were considered to be minimal.
The F.2 also had the distinction of being the only aircraft to successfully intercept an SR-71 Blackbird, a feat which it managed on a number of occasions during various joint US/UK exercises - the first time it happened the Blackbird crew were very surprised indeed to have an attacker coming in from above them !
Despite the risks entailed by the use of the rocket, competition amongst Vigilante crews to be assigned to an F.2 squadron was intense, thanks to it being a true 'rocket ship' in more sense than one.
Built from the Airfix kit, the rear fuselage Stentor rocket motor is from the Blue Steel missile supplied with the Airfix Vulcan, new pylons from the spares box ( not sure of their source ), nose from a Phantom, IRST pod from a Tornado.
The Stentor was a dual chamber motor - the large chamber produced 25,200lbs thrust and the smaller was throttleable between 1,000 and 6,200lbs thrust ( both figures at 45,000ft altitude- rocket thrust increases as atmospheric pressure decreases so thrust at higher altitude would be slightly greater ). Being a 'hot' HTP engine it burned kerosene in addition to the HTP, the fuel being ignited by the temperature of the HTP which had been decomposed by passing over a catalyst - 'cold' HTP engines just relied on the expansion of the decomposed HTP for thrust.