Karl Wingett-Smith remembers his time at Hawker from April 1960 to
I spent only a short time at Richmond Road compared with many members of the Hawker Association but, from the point of view of gaining experience, they were important.
Before joining the Installations Department (ID) to work on P.1127 cockpit air conditioning I had spent most of the previous decade with Handley Page (HP) at Cricklewood in northwest London. I worked there on design analysis of the fluid systems of what began as the HP80 prototypes and became the highly successful and long-lived Victor, the V bomber that never dropped a bomb in anger but made the Vulcan Falklands raids possible because of the vast quantities of fuel carried in the tanker conversions. Most of you will remember the late Harry Fraser-Mitchell, well, he and I were contemporaries at HP and quite good mates.
So, why did I move to Hawker Aircraft Ltd (HAL)? My home was then in Croydon and HP was 17 miles northward via places like Brixton, Victoria, Hyde Park, Marble Arch followed by about 5 miles of the Edgware Road with its 23 sets of traffic lights before turning off at Cricklewood Broadway for the final couple of hundred yards to the old WW1 Aerodrome site that was by then full of houses (just like Kingston was to become). Throughout the 1950s private car use grew astronomically and caused more and more congestion. My homeward travel time increased from less that one hour to more than two hours, and I’d had enough. Stupidly I’d thought that working for one aircraft maker would be the same as any other. I was wrong.
My time at Hawker was short, partly due to my relationship with the Head of Department, Dr Elias Gabbay, partly because during my time there I met the girl I later married and neither of us wanted to live in suburbia. Add to that the fact that the ID had a habit of ‘dealing with’ future bridegrooms light-heartedly in various ways that I wanted to avoid. (OK John Davey, you were always one of the ring leaders, so I didn’t let on!).
When I started at HAL my first tasks were to perform
mathematical analyses of the air conditioning system to establish that
it would be satisfactory. It had been sort of cobbled together with a
cold air unit from the two-seat Hunter, together with a new design of
primary heat exchanger and intercooler in series with air pulled
through it by engine intake suction when on the ground and at low
forward speeds with expectations of flow direction reversal in flight.
Dr Gabbay’s view was that it had worked on the Hunter so why not on the
I thought a little differently largely, I suppose, because HP had required me to do some quite extensive thinking about what could go wrong with Victor systems, how would we know and what could be done about it; a ‘what if’ process. I’d also prepared test and instrumentation schedules for ground and flight purposes and sorted through their results to produce reports. That also became part of the job in the ID.
At HP the elapsed time between release of a test request and getting the results back might be a year or thereabouts. At HAL, because there was a P.1127 cockpit in the Robin Hangar, it was a joy to do some sums in the morning, spend the afternoon testing with John (Davey) and sort through the numbers next morning; a great mixture and a joy to find out if we were right or wrong so quickly. But some aspects turned back on me!
A part of our testing showed that, due to the nature of V/STOL and transitions from forward flight to hover and back, there could be times when the inward and outward pressure differences that created heat exchanger cooling airflow could balance and so reduce that flow to zero, resulting in unacceptably hot air being delivered to the cockpit. The example established by the Hunter success was due to this changeover being instantaneous during the take-off run. The P.1127, with the virtually unlimited time that might be spent at this condition was a totally different kettle of fish. Also, Dr Gabbay didn’t want to believe my maths because I’d brought that know-how from my previous firm.
Anyway, John and I undertook a series of tests with reduced airflows and made that point. We also thought about a cure and working with the Project Office we found a possible relocation for the louvred exit for the cooling flow just to the rear of the sliding cockpit canopy. Our solution was effectively to turn that duct around and fit a pair of forward facing intakes. We made cardboard mock-ups and set about proving the point that it was possible.
Another problem we found on the test rig was in the flood/demist facility which was to deal with any loss of cabin pressure and/or canopy condensation by supplying a ‘modest’ amount of unconditioned engine bleed air as well as conditioned air to the cockpit distribution system. That consisted of alloy ducts with a series of drilled holes or slots that fed air directly onto all the transparencies and the pilot’s hands, feet and body. That installation used a Teddington Aircraft Controls electro-pneumatic butterfly valve that was 1.5 inch nominal diameter with flow limited by an orifice plate having a hole of roughly 5/16 inch dia. Firstly, we found that the valve was normally closed and would only ever be opened in an emergency. Great, but the damn thing seized up on us as it wasn’t ever moved. Remember, that was a standard valve that had worked well on other applications but the P.1127 was a shoe-string project, otherwise we might have come up with a lighter weight, special valve (as we did, later). That issue was readily overcome by simply writing an instruction that the valve should be opened and closed before every flight. Not only did it prove that it still worked but it rubbed off all the corrosion that had made it stick.
The next aspect of that installation was to assess the effects of ‘what if’ it is opened in fight. I can’t recall the exact numbers but the normal cockpit airflow was, I think, 30 lb of air per minute (was it 18 lb/min on single seat Hunters, 30 on 2-seat, or 12 and 18? Sorry, I’m going back 55 years or so.). My numbers showed that the addition of around 15 lb/min of air at engine bleed temperature could raise the delivery temperature of around 29 to 25 deg C by quite a bit, so John and I set up a simple test. The only operating controls for any part of the system were inside the test cockpit so we found a wooden box on which I sat while John set up the hot air supply and cooling fan. When it was all nicely stabilised and I, with shirt-sleeves rolled up, was comfortable on the box, I operated the flood/demist switch so the additional air came in. In an incredibly short time the 25 deg C became 230 deg, at which point I closed the valve. I certainly felt that my concerns were justified and went away to write a report to that effect and come up with some form of safety device.
At that time I certainly didn’t understand anything about the financial state of the project. I’d been used to working with backing of all new ideas coming readily from HP’s Resident Technical Officer (RTO). I learned much, much later just how important this was to ensuring that Britain retained a foremost position in aviation technology and manufacturing capability throughout the Cold War. An RTO held the strings of a modest purse and could sanction spend to evaluate possible ways of improving virtually any new military aircraft. After preliminary funding in this way the findings might result in another major project; P.1127 wasn’t funded in that way, money was tight.
Anway, I got the OK to come up with an idea; my
suggestion was that we should insert a thermal change-over sensor in
the main feed to the cockpit, set at 120 deg C, round about a safe
limit that would neither cook a fully dressed pilot much nor weaken the
alloy of the ducting. That switch was to operate in the temperature
control valve circuit and over-ride the pilot’s chosen setting to run
it to the fully cold setting. In that way the cold air unit would be
flat out to reduce the flood (bleed) air mix as much as possible. The
temperature control valve, incidentally, was of HAL design being a
rotating, ported sleeve in a ported body so that the mixture of hot and
cold air from the air conditioning pack could be varied. In its form at
that time it was driven by a Plessey electric actuator that took 30
seconds for full travel and was controlled by a pilot operated inching
switch. I recommended a faster actuator to improve the now
semi-automated response time. Plessey offered an interchangeable 15
The final part of my proposal was that the manually operated temperature control should be fully automated because I felt that it was a task that should not be added to the pilot’s workload when he was performing transitions. Again, Dr Gabbay was unhappy with my pessimism until he was to learn that I was right and that some of these things were not entirely pessimism run wild.
My brief experience of rapid temperature rise inside the cockpit led to some changes; we actually got a dummy pilot and a seat for it in the cockpit, and John and I were able to break into the control electrics and fit duplicate switchery outside on the instrumentation panel. Incidentally, all our instruments had to be read and the numbers written down by hand. John and I, working together, found that we could change settings, allow them to stabilise and record the results in 2 minutes. Not for us recorders and computers, we had slide rules. As far as the heat exchanger intakes were concerned, I don’t think I was believed – until a test on the rig resulted in softened transparencies that blew out under internal pressure! At that point our cardboard model received a bit more attention but, by that time I was married and had moved on.
In parallel with working on theory and practice with
the test rig, I also had the tasks of preparing ground test and flight
test schedules for the air conditioning system. These had to be drafted
and discussed with the company WID and ministry AID Inspection
Departments before being finalised and released. Having reached that
point my next job was to find or get made anything we would need to
perform these tests.
P.1127s were really simple machines, devised as the cheapest means of proving the feasibility of V/STOL using the Gordon Lewis and Ralph Hooper nozzles that made the Wibault fan concept actually workable. The airframe and systems were almost incidental to that requirement. Because of the relative positions of engine, cockpit and air conditioning equipment access could be difficult. Pre-flight ground tests required mainly pressure testing using compressed air with the pipework broken down in sections from engine bleed to cockpit entry in the rear bulkhead. Joints were split, blanks inserted and where required these would have AGS connectors for the separate air supply and pressure gauges. All tests were at Dunsfold, witnessed by WID and AID inspectors.
All of this work was undertaken shortly before the
first, tethered, hover in October 1961 when I spent around 30
continuous hours at Dunsfold. What I remember about that is that
Dunsfold called Kingston around mid-day on a Monday and my immediate
boss (the late John Apted) made the decision to drive down during our
lunch break so we could start work at Dunsfold shortly after 2 pm. We
worked through the day, grabbed a light meal in the canteen and
returned to join the night shift. During the night I managed an hour or
so’s rest on some boards on the hangar floor. I’m sorry to say that I
don’t know if John did the same or not, just sad that I didn’t even
think of asking. Then it was a canteen breakfast and back with the
dayshift (who thought we’d come back early!). We remained on the shop
floor until the lunch-time arrival of Stan Williams when we could leave
and return to Kingston. From there I drove home. At one point I woke up
to find myself driving down the wrong side of Acre Lane, Carshalton,
just a couple of miles from home.
There was a bitter pill to swallow afterwards because the entire air conditioning equipment was stripped out to reduce weight for the first hovers because the early engine was a bit down on thrust. I’ve always said that Bill Bedford in his plaster cast could have stood down and let the much thinner Hugh Merewether lift-off instead. No rudeness to either of these gentlemen intended, especially since neither can reply me!
There was one other part of the job that doesn’t
quite fit into either of the previous categories, that was some small
amount of work on the six aircraft as they were built in the
Experimental Shop at Kingston; that was pressure sealing the cockpits.
It was a simple task, really, just getting inside the cockpits and
plugging any leak paths with a silicone potting compound; at least,
that’s the theory. Firstly, at that time I weighed about 14 stone and
was near enough 6 ft tall – and had to get my head and one arm through
the pilot’s knee holes in the instrument panel to get sealant into the
nose. That required my back to the floor and legs up the rear bulkhead.
Why me? I then had some fair knowledge of the installation, I also had
a Private Pilot’s Licence that require me to have an annual medical
check for fitness – further, the cockpit had to be pressurised to find
the leaks. Yes, you listen for hissing and, with someone else outside,
feel for air movement with a wet finger. Of course, the cabin discharge
valves had to be rigged; otherwise they would remain open at ground
level. There were no real problems with that until I, inside the
cockpit concerned, and everyone around were aroused by a loud bang when
the canopy locks let go and I was suddenly decompressed. I don’t think
any damage resulted; the locks simply hadn’t been fully home and
luckily, they let go before full differential was reached. The men in
white coats say that I should be OK, given time…..my wife disagrees.
My reward for all this (apart from the overtime pay, that is) was to witness the first ever hovers from the grid at Dunsfold. I’m not 100% sure but the figure in the background of the photograph, behind the main wheel, could be me. I was certainly standing thereabouts, away from everyone else apart from the fireman. If it is me, I was wearing my motor cycle coat, bought in 1957 and still used in bad weather in 2018. If I become dissatisfied with it I shall complain to the makers, I still have the receipt.