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Feature 3 | AIRCRAFT CARRIERS
that the F-35B would recover using a
HIHAT provides
vertical landing remains in place, the
a clear, intuitive
UK Ministry of Defence has in parallel
and NVG-friendly
been funding research to refine and
indication of hover
de-risk the use of an SRVL manoeuvre.
height and relative
This involves a STOVL aircraft
ship movement to
executing a ‘running landing’ on the
the pilot in the side
carrier flight deck, using air speed to
hover position.
provide wing-borne lift to complement
engine thrust. The touchdown position
on an axial flight deck is similar to that
of a conventional carrier – about 150ft
(46m) from the stern – but no arrestor
gear is required as the aircraft uses
its brakes to stop within a distance of
300-400ft.
Compared to a standard vertical
landing, a SRVL recovery offers the
prospect of up to 2000lb (907kg) of
additional payload ‘bring back’ for the
F-35B. It would also reduce propulsion
system stress and extend engine life.
Viability
Work to date has established the
fundamental safety, operability and
operational benefit of the SRVL
technique, with QinetiQ’s Harrier T.4
Vectored-thrust Advanced Aircraft
Control (VAAC) testbed aircraft
embarking aboard the French aircraft
carrier Charles de Gaulle in mid-2007
to perform a series of SRVL recoveries.
Studies are continuing in order to refine
the concept of operations, mitigate
failure cases, and optimise the deck
lighting arrangement.
There is now an additional requirement
to augment the baseline VLA suite with
a landing aid appropriate to the SRVL
approach manoeuvre; clearly, with no Referenced Velocity Vector (SRVV) onto array (down to a safety height of about
arrestor equipment and a poor dynamic a VLA datum. 40ft above deck) to evaluate its ability to
flight control response at low speeds, the A trial of the concept was undertaken accurately indicate an SRVL glide scope
angle of approach and speed needs to be aboard the aircraft carrier HMS aimpoint to the SRVV.
accurate regardless of sea state. To this Illustrious in November 2008, with A second lighting array was rigged
end QinetiQ has undertaken research QinetiQ using the VAAC Harrier to fly on the carrier flight deck itself. This
into a new VLA concept, known as the approaches to a demonstration ‘Bedford was used for a parallel evaluation of the
‘Bedford array’, which takes inputs from array’ mounted on the ship. visual acuity of the lighting system on
inertial references to stabilise against For the purposes of the trial, the the deck.
deck motions (pitch and heave). lighting array was installed in the A total of 66 VAAC launches and
The ‘Bedford array’ takes inputs port catwalk adjacent to Illustrious’s recoveries were performed during the
from inertial references to stabilise flight deck. The VAAC Harrier did not ‘Bedford array’ trial (the number of actual
against pitch and heave. The software- actually perform SRVL recoveries to the approaches being considerably more).
controlled lighting pattern provides an ship owing to the limited dimensions of The trial, described as highly successful,
aim point for the recovering pilot, who the flight deck, but flew representative saw accurate approaches flown in
will position a helmet-displayed Ship SRVL approach profiles to the catwalk conditions up to Sea State 6. WT
28 Warship Technology January 2009
WT_Jan09_p26+27+28.indd 28 12/23/08 2:24:32 AM
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