On March 9th David Lockspeiser gave a
two-part talk to the Association covering Singapore air force Hunter
flight testing and the design and development of his own 'Boxer'
multi-purpose utility light aircraft. After starting his aviation
career with Miles and Armstrong Whitworth, David joined the RAF
becoming a Pilot Attack Instructor (PAI) and Instrument Rating Examiner
(IRE). On leaving the RAF he joined Hawker Aircraft Ltd at Dunsfold as
a production and development test pilot on Hunters, leaving the
Company, now HSA, in 1968. David has flown 100 types; 160 counting Mks.
Whilst at Hawkers in 1962 David had designed a scheme for mounting a
pair of AIM-9 Sidewinder air-to-air infrared homing missiles on the
Hunter gun pack in place of two of the four 30 mm Aden guns, the other
two being retained, with an extra 20 rounds. This installation was
lighter than the standard 4 Aden pack.
A mock-up was made at Dunsfold and the idea
was received favourably by the RAF but the MoD maintained that
the Hunter would be phased out of RAF service in four years! HSA were
unwilling to pursue the idea in case it damaged potential P.1127 sales
so this idea, to modernise the Hunter weapons fit, lapsed.
However, in 1976 David met Bill Weetman, recently back from Singapore
where he had been working on new armament installations for the
Singapore Ministry of Defence Hunters, including Sidewinders, but this
time underwing. Bill said they needed a test pilot and David jumped at
the chance. After a quick trip with the RAF on the Hunter TMk7 he moved
to Singapore in 1977 where the air force operated single-seat FGAMk74
Hunters in the fighter/ground attack role and FRMk74A/Bs in the fighter
reconnaissance role. For training there were TMk75/A two-seaters.
Lockheed Aircraft Services Singapore (LASS) had the contract to enhance
the weapon capability of the Hunter. This included the fitting a US
'triple ejector rack' (TER) under the Hunter fuselage for bombs up to
1000 lb, an additional pair of underwing pylons inboard of the drop
tanks for Sidewinders, a Ferranti Isis gun-sight, a Decca TANS
navigation system and three alternative reconnaissance packs, in lieu
of the gun pack, containing different camera and IR linescan arrays.
AIM-9 Sidewinders on LAU-7 launchers, LAU-10 Zuni rocket launchers,
1000 lb bombs, BL755 cluster weapons and US Mk82 500 lb streamlined
bombs were to be carried in various combinations, with and without drop
TERs would also be fitted to the outboard pylons for twin carriage of
rocket launchers, 500 lb bombs and BL755s. The heaviest combination to
be cleared was 6 BL755s plus 2 AIM-9s with 230 gal drop tanks, giving a
take-off weight of 27,400 lb. David wrote the flight test programmes to
clear these equipments and configurations, conducted all the test
flights and wrote all the reports and the Pilots' Notes.
LASS had no flight test experience at all. Their managing director even
asked why it was necessary to do all this flying; didn't David trust
their engineers?! There was no test instrumentation fitted so David
requested a voice recorder; LASS put it under the ejector seat, so
David bought a commercial mini tape recorder and got it fitted it in an
accessible position. King non-Milspec light aircraft instruments,
including an attitude indicator with a 60 degree bank limit, had also
been fitted by LASS. Clearly, these had to be changed so David had to
redesign the instrument panel.
Eventually the flying got under way over the South China Sea in high
humidity and 30 deg C temperatures, with a chase Hunter. The programme
was successful and the Singaporeans operated their Hunters until the
early 1990s. Eventually they were sold to private owners in Australia,
New Zealand and the USA.
The 'Boxer', or Land Development Aircraft (LDA) had its roots in the
idea of a Design Liaison Engineer at Dunsfold, David Carter, who
thought that an inexpensive utility and crop spraying aircraft should
be designed for use in the countries of the less developed world; an
"aerial Land Rover". David (L) believed that a large cg range would be
necessary for maximum flexibility of loading and this led him to the
tandem wing layout, as experimented with by George Miles with his M35
Libellula and twin engined M39B aircraft in the mid 1940s. Besides the
larger cg range the tandem wing offered safe stalling and excellent
To test his idea David made a number of tissue covered balsa models
with different wing layouts. He settled on a parallel flat sided,
rectangular cross section fuselage with a nose cockpit and low mounted
adjustable foreplane with flap. At the rear was a high mounted, strut
braced, wing, with outboard ailerons/elevators and inboard
flaps/elevators, with fins and rudders inset from the tips. Twin
undercarriage legs were fitted, fore and aft, the front wheels being
steerable through an Akerman steering geometry derived from the Lotus
7, so that the aircraft could be manoeuvred over a detachable payload
container to be winched up into the centre fuselage.
The parallel chord, constant section wing panels and foreplane were the
same, as were the control surfaces and flaps. The whole design
sacrificed visual and aerodynamic elegance for functional practicality.
It was designed for easy manufacture in the 'third world'. With the aid
of Roger Dabbs, who did the stressing and Type Record, John Quinn and
Alan Daffey, a 70% proof-of-concept aircraft was designed and then,
with the agreement of John Lidbury, built in a Nissen hut at Dunsfold
by David and George Smith from Dunsfold's Production Department.
The LDA 01 aircraft, registered G-AVOR was moved to BAC Wisley and made
its first flight, powered by an 85 hp Continental C85, on August 24th,
1971. David found that his creation was fine longitudinally but there
was no rudder feel, turn entry was difficult and low speed directional
stability was weak. Adding bungee and aerodynamic balances to the
rudders helped. Support from BAC included wind tunnel tests and
development to ensure that the foreplane stalled first. This also
showed that vortices from the foreplane disturbed the wing flow leading
to the fitting of wing fences. Wing tip mounted fins were also found to
be better and were to be a feature of the full scale aircraft.
Flight testing continued at Hurn where, when ballasted to forward and
aft cg positions, the wide range proved to be even better than
expected; four times greater than a conventional aircraft. The LDA 01
also proved to be highly manoeuvrable. In 1975, with a 160 hp Lycoming
engine installed, David took it to the Paris Air Show where, painted
half in camouflage and half in civil livery, its performance was
interrupted by a swarm of bees settling on the cockpit requiring the
attention of the airfield fire brigade! In 1976 the aircraft appeared
at the SBAC Show at Farnborough.
The full scale production aircraft was to have wing-tip fins and
rudders, a tricycle undercarriage and large, side loading doors.
However, this was not to be; the project was killed when the LDA
01 was destroyed when the Optica hangar at Old Sarum, housing the
aircraft, was attacked by an arsonist.
After a short film the vote of thanks was given by Roger Dabbs who said
that it was David's drive, enthusiasm, charm and character that led to
the successful design and flight testing of this unique aircraft. The
audience responded with hearty applause.