Issue No 22 THE AVIATION HISTORIAN 31
saw the addition of 1,600gal (7,275lit) of external
fuel, and in the reconnaissance role the normal
and overload weights were both increased by
100lb (45kg). This capability was made possible
by the choice of two of the most economical
engines then envisaged, namely the Rolls-Royce
RB.142R bypass turbojet (originally designed for
the de Havilland Trident as the Medway), each
giving 13,800lb-thrust dry and 22,500lb-thrust
with reheat, all in the smallest possible airframe.
A slightly less suitable alternative engine was the
Bristol Olympus 15R.
Other features that had contributed to the
aircraft’s small size were the carriage of a large
proportion of its fuel externally (in two 500gal/
2,273lit and two 300gal/1,364lit underwing
drop tanks), semi-recessed carriage of the
Red Beard nuclear weapon under the fuselage
and the reduction of electronic equipment to
the minimum that would ensure a successful
mission. The air-to-air refuelling tanker pack was
optional, a retractable probe having been placed
on the port side forward of the windscreen.
THE NUTS AND BOLTS
The P.1129’s wing design was chosen to cope
with the essentials of long-range, short-airfield
operation and high performance. This implied
a moderate span-loading and sweep angle for
economy at high subsonic speeds and a low
thickness/chord ratio for Mach 2 performance
(six per cent at the root, four per cent at the
tip). In addition, full-span leading-edge droop
and trailing-edge flaps with area suction were
required to augment the lift for take-off and
landing. The wing area and loading were a
necessary compromise between a value to best
satisfy the performance criteria (including the
loft-bombing manœuvre) and that desirable for
crew comfort and structural fatigue during high-
speed low-level operations.
It was considered that the chosen loading
of 90lb/ft² (440kg/m²) over the target should
provide tolerable conditions for the crew, but
it was acknowledged that there was a lack of
practical evidence on this aspect, and that an
active investigation would be embarked upon
using a two-seat Hawker Hunter. This would
include testing the effectiveness of such items as
spring-mounted seats as a means of eliminating
the resonant frequencies which were known to
be particularly distressing. The P.1129’s take-off
wing loading would be 101lb/ft² (493kg/m²).
The wing area was still large enough to give
good airfield performance without extremes in
lift aids, and to enable the loft-attack to be per-
formed without entering deeply into the wing-
buffet lift region. The low-position wing was
swept 42° at the leading edge and 36° at quarter
chord, and had 2° of anhedral and a saw-tooth in
the leading edge. The P.1129 also had a low swept
tailplane, a swept fin with a bullet fairing at the
rear base of the rudder, and a shallow underfin.
Studies on the structural fatigue aspects had
shown that, based on contemporary knowledge
of gust spectra, achieving a satisfactory lifespan
during flight at high speed and low altitude
would demand a very strong and efficient
structure, justifying load factors of at least those
normally associated with ground-attack fighters.The three-view general arrangement drawing of the The three-view general arrangement drawing of the
P.1129 as presented in Hawker’s January 1958 brochure. P.1129 as presented in Hawker’s January 1958 brochure.
At this stage the design incorporates the original semi-At this stage the design incorporates the original semi-
circular intakes with half-cones, and is seen here with a circular intakes with half-cones, and is seen here with a
semi-recessed Red Beard nuclear bomb in its weapons nuclear bomb in its weapons
bay. Note the optional wing tanks included on the plan bay. Note the optional wing tanks included on the plan
view, in which a cumulative total of some 1,600gal view, in which a cumulative total of some 1,600gal
(7,275lit) could be carried.
TAH ARCHIVETAH ARCHIVE