The Aviation Historian — Issue 21 (October 2017)

Issue No 21 THE AVIATION HISTORIAN 15

AI.18 radar could be installed in the same space.
By increasing the diameter of the antenna from
24in (61cm) to 36in (91cm) and narrowing the
beam width, the radar’s range capability against
a Canberra-sized target would increase from 12
miles (22km) to 25 miles (46km). By changing the
radar from X-band to J-band the range would be
further increased, with the benefit of improved
jamming resistance — but this change would
take at least three years to develop.
As a quicker solution, a continuous-wave
(CW) variant of GEC’s AI.18 was considered
as an alternative and was in development with
government sponsorship. This variant would
also be countermeasure-resistant, but could be
further modified to provide illumination for
semi-active air-to-air missiles (AAMs) such as
Radar Red Top (a modified Red Top with a Matra
AD-26 X-band seeker) or Sparrow III.
The same systems used for air interception
could also be fitted with an S-band receiver to
home in on Soviet aircraft jamming the ground
radars used for early warning and fighter
control. English Electric noted that a second
crewmember dedicated to operating the system
increased the effective range of the radar and
improvements in range could be achieved by
increasing the size of the radar display.
English Electric’s proposal for a modified P.17A
interceptor variant, the P.22, was put forward
at a time when guns were being removed from
most interceptors, with Warton’s own Lightning
F.2 lacking the twin 30mm Aden cannon of
the earlier F.1. The twin-Rolls-Royce Medway-
powered P.22 was to carry all its ordnance

internally, mounted on a rotary bomb-bay

door, thus removing the drag that would have

plagued the F.155 interceptors, particularly

if Vickers’ 16ft (4·9m)-long Red Hebe missile

had been carried on wing pylons. Not that the

Lightning was free of draggy weapons, with

its two de Havilland Firestreaks or a Douglas

Genie/rocket pod combination on forward

fuselage-mounted “crates”.

The P.22 was to carry the new Blue JayMk

4 , soon be renamed Red Top, mounted on the

rotary bomb door. Owing to the 3ft (0·9m) span

of the missile’s main wings, the Red Tops were

staggered fore and aft to ease stowage within

the bay. To launch these weapons, the P.22’s

weapons bay door would rotate to expose the

weapons, which were then lowered on a trapeze

mechanism to increase clearance from the

aircraft. Interestingly, later in the development

of the collision-course Red Top, Sandys was in

favour of cancelling it and keeping the pursuit-

course Firestreak as the Lightning’s main

weapon pending the deployment of the Bristol

Bloodhound Mk 2 surface-to-air missile (SAM)

with CW radar guidance and improved ramjets.

So much for Sandys being a missile-lover.

It was this possibility — having no collision-

course weapon — that led to the Air Staff’s

interest in the Genie. The Douglas AIR-2 Genie

was a rocket with an American W25 nuclear

warhead, triggered by a basic time fuze set by

the pilot. It was intended to arm the Lightning

series, and Warton conducted a design

study under the designation P.23. This study

investigated the use and carriage of the Genie

Had interceptor development been allowed to continue, three of Had interceptor development been allowed to continue, three of

the front-runners would have been the Fairey Delta 3 with Red Hebe

missiles, and English Electric’s P.22 (with a rotary weapons bay)

and P.23 Lightning derivative (with a mixed weapons load).

Fairey Delta 3 with

Vickers Red Hebe

missiles

English Electric

P.22 with multi-store

rotary weapons bay

English Electric

P.23 with Douglas

AIR-2 Genie missile

on port fuselage

mount and rocket

pod on starboard

Artwork © 2017 CHRIS GIBSONArtwork © 2017 CHRIS GIBSON

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