The Whirlwind 10 was a modified licence version of the American Sikorsky S55. A different control system with the fixed and rotating star I have mentioned earlier. It had hydraulic assistance at IIRC 1,200 psi which cancelled out the feedback from the main rotor completely. The fuselage was on two levels with the pilot’s seat elevated above the main cabin which was a clear box-like structure. It was designed to carry Grunts around in minimal, if any at all, comfort. To get into the cockpit though a large window one had to climb up the side of the aeroplane and sit there, master of all he surveyed. In front of him instead of a mighty radial engine of previous models he had a Gnome gas turbine, a licence built version of the GE T58 which although capable of producing 1,000 horsepower was restricted to about 750 hp so the transmission could cope. The cockpit instruments were electric; real Artificial Horizons and G4 compasses. On the consol an HP cock and a Speed Select Lever. This, through a computer, selected the rotor speed and held it without the pilot having to control the engine with a throttle. Beside was a large plunger. Should the computer fail then pulling this disconnected it from the engine throttle actuator and control of the engine was then in the pilot’s hands by means of a twist grip on the collective. There was no cam, it was raw throttle.
A press of the starter button and the engine whined into life, no clutches, it had a free turbine. At the rotor speed increases then the hydraulics, driven by the gearbox, come on line and with that one can feel that there is almost no resistance on the cyclic stick, the hydraulics have overcome all the rotating forces. Once everything is up and running a few checks to make sure the secondary hydraulics take over if the primaries are switched off and we are ready to go.
We lift into the hover. Left pedal to counteract the torque as the rotor goes the American way. It sits there in the hover, effortlessly. There is no feedback, hardly any feel, a slight movement of the palm controls any meandering that it dreams up. One learns to rest ones wrist on their knee and use it as a datum for the current manoeuvre. A totally different flight profile requires only inches of repositioning. Spot turns require more effort from the legs because the tail rotor is still a manual version. Compared to the Sycamore it was like stepping into a different world! Ground Resonance, with three Main blades, two Tail blades and four undercarriage legs was virtually unknown.
The normal exercises before the solo stage. EOLs were far simpler. Pull the Speed Select Lever and the engine backed off to Flight Idle; autorotate, a comparatively smooth flare and easy touchdown, anything between 0 and 15 knots. I was beginning to like this; there was a bond developing between me and the aircraft. Three trips, two and a half hours and I was off on my own.
On my third solo flight I was returning from Chetwynd, out relief landing ground at 500 ft. to return to the Tern Hill circuit. A glow on the panel; it was the Engine Fire Warning Light! Before I had time to check the Ts & Ps smoke started rising through the footwell which confirmed that there was a fire. Whirlwinds are made of magnesium and burn pretty well so there was no spare time. Down with the lever, HP cock and fuel pumps off, hit the fire button and Mayday.
There then arises the problem of where to land it and I was downwind. I turned in autorotation into wind and went for a small field that had dragged itself through the woods to place itself in front of me. My flare worked out fine and I landed with about five knots on. We were at the Brakes On phase in Standards so I skidded safely to a halt. To my relief there was no conflagration around me so I vaulted down to the ground.
It’s very lonely when you suddenly arrive in the middle of nowhere with, or without, a sick aeroplane. A quick inspection of the engine compartment, lots of steam and crackling noises but no fire anymore. A commotion from the sky as a Sycamore found me and landed alongside. They checked that everything was OK and then there was a protracted period whilst they found a way where they could get out of the field again.
Forty five minutes; FORTY FIVE MINUTES and a Whirlwind arrived with the guard who were going to look after the aircraft overnight. I was flown back and as it was late I was told to go home and sort the paperwork out tomorrow.
The problem wasn’t a fire as such; it was a split in the annular combustion chamber. The next afternoon I went in the back of a Whirlwind with an instructor to my aircraft. They had finished the engine change so we did the check runs and then I flew it back to Tern Hill.
Not only was it an advanced helicopter course but it was also the OCU because there were four squadrons of Whirlwinds in the Far East, another two SAR squadrons in the UK plus several small flights scattered around the world from Hong Kong to British Guiana. To this end we were trained in the whole spectrum of trooping, underslung loads and at the end we went to RAF Valley for the Mountain Flying and SAR element.
Mountains are beautiful to look at but they can hide a brooding evil when you fly amongst them. The natural movement of air around produces varying air flows that may bear no relation to the general wind around you. One is taught to look at a valley or ridge and visualise how it is going to affect you. For example the wind blowing over a ridge will have a marked upward flow on the upwind side but a rapidly descending airflow in the lee. Ignoring this and carrying out a normal approach path to the top of the ridge can lead you into the down flow and if strong enough it will exceed the helicopters rate of climb so you will fall short. Knowing the score one does a far steeper approach to stay in the updrafting air. One learns to read the possible severe turbulence that can be set up in the lee of mountains. Ignorance of these conditions can lead to disaster; for example BA911 which was torn apart by the turbulence around Mt. Fuji.
https://www.flightglobal.com/FlightP...20-%201067.PDF
Whilst I was at Valley Ian Smith declared UDI. I had been there three months previously on my Domcol leave so I knew it was boiling up. A sudden closing of a short friendship with two RRAF trainees doing a Hunter course as they were dispatched back to Salisbury.
On with the immersion suits and on to sea winching. You were now being assessed not only by your instructor but hairy old experienced winch operators and winchmen; a far more terrifying prospect. Hovering over land is fairly straightforward, it’s little more than flying a hot formation on a blade of grass but over the sea the surface keeps moving and the dinghy or whatever isn’t. There are loads of individual ways to maintain a 15 ft. hover over the sea; sometimes just telling the aircraft to keep still works as well as any. They were quite pleased with me and the suggestion that I would be suited for an SAR squadron was mooted.
Another part of the course was the mysteries of the Decca Navigation System, a hyperbolic system using low frequency phase comparison. There were three; red, green and purple indicators that were checked against a master. You Decca map had similar coloured lines printed on it and working out what colour and number lane you were on enabled one to get a cross cut with two with the third as confirmation. On the coaming was mounted a roller map with a pen which by a combination of the receiver rolling the map back and forth and shuffling the pen from side to side indicated where you were. The map itself was distorted as the curved line of a normal map had to be straightened out for the benefit of the mechanics. You could do a Decca instrument approach on the airfield down to 50 ft and within ten yards of the cross which was the aiming point.
When we returned to Tern Hill our postings were awaiting us. Good bye, thoughts of SAR, hello North Borneo with one year unaccompanied to boot. Just the job when you have been recently married. It was a foretaste of what was to come as I was about to lead the nomadic life of a military and then a civil helicopter pilot.
Other planning also fell apart. After my Final Handling test I was earmarked to return to Tern Hill for instructor training after my year in Borneo. That was scuppered because Confrontation ended early and the whole squadron came back to the UK in one piece. By then I had far more interesting plans than to join the training mill.
In January 1966 I arrived in Labuan to start a totally different form of flying that I had ever considered doing when I signed the dotted line in Salisbury six years earlier.
That's all for now.