Members anticipated an interesting and entertaining afternoon when
retired Dunsfold Chief Test Pilot, Heinz Frick, came to Kingston again,
this time to talk about his invention: Skyhook. They were not to be
In 1981 with Sea Harrier production coming to a close Heinz recognised that new ideas were needed to keep the project alive so he looked at ways to make the Sea Harrier cheaper and more combat effective. If equipment not actually needed for combat could be eliminated there would be large weight savings. Removing the undercarriage and its systems would save 1,300 lb which could be converted to extra fuel and/or weapons. However, this would require a new way of operating from ships.
Contemporary aircraft carriers were huge and expensive to procure and operate. USS Nimitz had a crew of 5,000! Even the UK Invincible class carriers displace 20,000 tons. Harriers had operated from much smaller ships but there had been difficulties, especially in bad weather, as only tyre-to-deck friction kept the aircraft on board. Rearming crews on deck had difficulties for similar reasons.
Heinz reasoned that sets of weapons could be moved to the aircraft in the required relative positions on trestles and, crucially, that the Harrier could be retrieved directly from the hover.
He found that the technologies needed were available so sought
opinions in the Company. Test pilot Taylor Scott, a RN ex F-4 pilot,
predictably thought it was a bad idea. John Fozard initially dismissed
the idea but did listen to Heinz’s arguments and agreed that relevant
Kingston engineers should see Heinz’s presentation; if the majority
agreed that the concept was feasible then Foz would give the go-ahead.
In essence the Harrier would hover alongside the
ship, a crane would pluck it from the air and lower it onto a cradle
where it would be refuelled and rearmed. The crane would then pick up
the aircraft, swing it overboard and release it into the hover to
transition away. The go-ahead was given with Diggy Motram coordinating.
Retrieval of the Harrier from the hover was the
basic requirement for the concept to work. Heinz believed that the
aircraft could be hovered accurately enough to keep the potential crane
hook-up point within a 10 foot cube. Engineers disagreed so Foz said
“Prove it!”. A hover sight was needed and a simple fixed device using
parallax from the pilots viewpoint was knocked up from bits of board.
This would tell the pilot when he was the right distance from the crane
and correctly positioned fore-and-aft and up-and- down.
Heinz arranged to borrow from the Fire Brigade a
Simon Snorkel hydraulic turntable with an elevating platform to which
the parallax sight was attached. At Dunsfold Heinz flew an FRS51 at a
height of 50 ft for an initial assessment and confirmed that hovering
inside the 10 foot cube 30 ft laterally from the sight was indeed
straightforward. Later more thorough trials using Company demonstrator
G-VTOL (now at the Brooklands Museum still bearing the Skyhook logo)
proved that a positioning accuracy of +/- 2 ft was achieved over
periods of tens of seconds, that aircraft relative velocity within the
contact window was less than 1 ft/sec and that the 30 ft distance could
be reduced to 25 ft. No autostabilisation was used and conditions were
gusty with wind speeds up to 25 kn well off the aircraft axis. Three
pilots took part.
Dowty-Boulton Paul were recruited to devise the ship-borne crane system applying their existing control technologies. The crane head, containing an inertial platform, was stabilised on earth axes when in position to retrieve the aircraft. As the crane moved the aircraft to its pre-armed trestle on board so the crane head became ship stabilised. Crane actuation was hydraulic with a triplex electronic control system. At the head of the crane was the docking unit consisting of four legs with stabilising pads, in the centre of which was an extending jack with a receptacle at its tip for receiving and locking on to a small pick-up probe on the top of the Harrier fuselage above its centre of gravity.
With the aircraft hovering in the capture zone beneath the crane
head the extending jack was lowered to lock onto the aircraft pick-up
probe. The jack was then retracted pulling the aircraft up tight
against the stabilising pads. The Pegasus would then be shut down and
the aircraft swung aboard the ship. The launch procedure was
essentially the reverse of the capture. Launch and recovery would be
possible in sea state 6 conditions ensuring world-wide availability of
99% of time at sea for a 4,000 ton ship.
With the system thus defined a brochure was prepared
and a presentation was given to the Ministry of Defence by John Fozard,
Heinz and Diggy. Amongst the audience were two admirals and two
captains, none of whom were really interested. When the vulnerability
of aircraft carriers versus smaller ships was raised the Navy objected.
Clearly the MoD had not been enthused!
Vosper-Thorneycroft (V-T) proposed a short, broad
ship of large capacity with a 16,000 mile range running on cheap
diesel, equipped with two Skyhooks and housing five aircraft. Still the
Navy was not interested. V-T also proposed a mini escort carrier with
eight Sea Harriers, two Skyhooks and a Ski Jump, which would of course
need the undercarriage but would allow heavier loads to be launched and
increased flexibility of operation. Again, no interest from the Navy.
Schemes to utilise container ships and river barges with packaged
systems also failed to find favour with the Navy.
An application to conventional carriers was conceived where Skyhooks could launch and recover aircraft from the open sides of hangar decks whilst the main deck was left clear for other operations. Guess what the RN reaction was.
At the time the USSR had M 1.3 swing-wing Tupolev
Backfire bombers armed with 180 mile range Kitchen stand-off missiles.
To protect a task force from attack would need continual fighter combat
air patrols (CAP) which are very wasteful of the finite fuel supplies
in the carrier. Small, economical, picket ships away from the task
force carrying a pair of Sea Harriers on stand-by, and a Skyhook, could
do the job effectively and economically. No interest.
How about using Skyhook equipped oil rigs to defend
the UK from incoming hostile bombers? No thanks.
Anti-submarine applications? You must be joking!
The list of advantages bestowed by Skyhook is long;
for instance: fully mobile base, long range fighter capability,
increased productivity, rapid conversion of merchant vessels, low cost
organic air power world-wide, Harrier capability maximised, large
return for minimum outlay, and non-aviation applications too e.g.
Skydrant to pick up oil from rigs. Referring specifically to Harrier
and carriers: capability of operation from smaller ships, launch and
recovery ship motion limits greatly increased with operation possible
in hostile weather conditions, launch and recovery easier and safer for
ship and pilot (hovering is easier than a VL), improved vertical
performance due to lack of ground effects and exhaust ingestion,
improved and relaxed engine handling and life due to reduced thermal
shock, less fuel used for takeoff and landing, reduced ship manpower,
reduced turn-round times, safer operations below deck, ideal for future
PCB (plenum chamber burning) applications, heavy undercarriage optional.
Development would be low risk and low cost because
no new technology was required, high value components were available
off the shelf, the majority of development would be carried out on
land, little development flying was required and only minor
modifications were needed by Harrier family aircraft. In spite of all
these advantages and benefits and a demonstration at the Farnborough
SBAC show of the ease of launch and recovery, the idea sank without
trace when British Aerospace declined to invest Company funds.
To end his fascinating talk, which contained facts
not generally known, Heinz showed a video including the Dunsfold flight
trials demonstrating to his rapt audience that the basic requirements
for launch and recovery were well satisfied.