Flight Impressions- CAC Winjeel

This trainer was a product of the Commonwealth Aircraft Corporation, formed in 1936 to establish an independent Australian aircraft industry. During the war the company licence built 200 Mustangs and 755 Wirraways (fundamentally improved Harvards with a geared, three-bladed and therefore quieter, prop). They also made the Wackett primary trainer and 250 belligerently barrel-shaped Boomerang fighters. In 1948, when recovering from the war, the government issued a specification for a basic trainer to replace the ageing Tiger Moths, Wacketts and Wirraways. In reply, CAC designed this robust and simple, fixed undercarriage, tailwheel machine with aluminium clad tubular steel fuselage, stressed skin wings and fabric-covered flying controls. Their chosen powerplant was Pratt & Whitney’s ‘baby’ radial, the nine cylinder, 450 horsepower (335kW), R-985-AN-2 Wasp Junior. (Plans to use CAC’s own 450hp (336kW) Cicada engine were dropped when it proved uneconomical).

Showing remarkable common sense, CAC sought advice from established RAAF instructors while, to expedite certification and service acceptance, test flying was undertaken jointly with the pilots of the Aircraft Research and Development Unit. Following the instructors’ advice, another sound cost-saving measure involved incorporating a third, rear, right-side seat, so that a second student could absorb lessons being learned by the pupil pilot. What better name could be chosen for the aircraft destined to train future RAAF pilots than “Winjeel” – the aboriginal word for “young eagle”?

The first of two prototypes was rolled out of CAC’s Fisherman’s Bend factory on Australia Day, January 26, 1951, to make its maiden flight in the hands of chief test pilot, John Miles, on February 3. An initial reluctance of the machine to spin properly was eventually solved after some experimentation by making the fin taller, moving it forward and enlarging the rudder. After further delays to development by governmental vacillation, 62 Winjeels were ordered, production taking place between February 1955 and August 1957, the last aircraft being delivered in February 1958.

For twenty years the Winjeel served, not only as the main primary trainer for the ADF but also as a communication aircraft, for searching for rocket debris after Woomera test launches and as a forward air control (FAC) trainer for directing ground attack operations. When, in 1975, the type began to be replaced in its instructional role by the New Zealand built AESL CT-4 Airtrainer, a few remaining Winjeels were used as hacks, a half dozen examples became instructional airframes at Wagga, NSW for apprentice engineer training and four FAC machines remained at Williamtown, still in service today though due to be retired at year end.

A number of the sold off surplus machines have found their way into the hands of nostalgic civilian owners to be used for recreational flying and air display work. One such is Don’s and brother John’s VH-WIU, Shabby Blue One, which now lives at the homebuilders’ and vintage enthusiasts’ own Serpentine airfield just south of Perth. Don Williamson was one of the many Australians to travel to the far side of the world to assist the British war effort. This bright young flying enthusiast joined up, aged 18, in 1941. After indoctrination and primary flying training on Tiger Moths and Wirraways he graduated as a 19 year old sergeant pilot, to be shipped to England in early 1943. After continuation training at Brighton and Bournemouth only three of his course of 157 pilots was selected for fighters, and he was the only one of these three to see operational service.

Initially slated for Spitfire BVs, he left Liverpool for Burma with a group of similarly qualified pilots. But plans were modified en route and they were offloaded at Cairo where, after an initial ten hours refamiliarisation on Harvards, they converted to Kittyhawk Mk 1s for subsequent operations in North Africa and Italy. Don’s career progressed through the improved Kittyhawk IV to the P-51 Mustang (which he flew on operations after a brief two hour familiarisation) until he was shot down by flak during a low level sortie north of Venice. Quickly dropping his dying machine onto a convenient beach, he scrambled out and distanced himself from the scene as smartly as possible. Undaunted, he then walked back through the enemy forces to the allied lines, living mainly on a diet of hand-caught frogs in the meanwhile.

Now 69 and retired, as he approached the end of his career the nostalgic Don hankered after an ex-military aircraft of his own to remind him of the more exciting types he had known in the past, so he searched for something with character but within the budget of his limited savings and pension. He finally found a Winjeel housed in the open at Cairns. This aircraft, VH-WIU, formerly an FAC machine, turned out to be a composite of A85-420 (the twentieth production example) and A85-461 (the penultimate airframe) rebuilt at Bankstown in 1971. It was owned by an ex-Vietnam veteran American heli-mustering pilot who, although highly experienced on helicopters, had less than 100 hours fixed-wing time so Don wondered how he coped with the big wayward machine.

After concluding the purchase, Don went to Cairns to pick it up with ex-TAA 727 flight engineer friend Pat Harrington. In four days the pair flew it from there all the way across the country to arrive at Serpentine in September 1985. Here it was adorned with the name Shabby Blue One, Don’s wartime callsign. ‘Shabby’ was No 3 Squadron RAAF (part of 239 wing Desert Air Force) and Blue Section flew top cover. Don was of course section leader.

The Winjeel is a big machine, its nose-high stance and long stroke undercarriage putting the cockpit way above the ground. When it has been sitting in the uninterrupted sun of a typical West Australian 35 degree summer’s day, its dark matt camouflaged airframe gets pretty hot so the traverse up the wing walkway and over the cockpit sill was made with caution for fear of scorched fingers. A canvas-lined handhold on each fuselage side assists, and the sturdy bright green rollover cage makes a useful climbing frame for lowering oneself into the commodious cockpit.

Once your backside has acclimatised to the extreme temperature, both front seats are comfortable, with standard military four-point harnesses and adjustment only for height. However, each top-hinged rudder pedal can be adjusted, like a Harvard’s, by pushing a side bar outwards with the edge of your shoe and allowing the pedal to move aft under spring pressure into one of a half dozen holes – being sure to check afterwards that they are symmetrical. As with most military trainers, there are two sets of primary engine controls, one on a central quadrant for the right seat instructor, and a second group set high on the left forward sidewall (with the sole friction knobs) for the pupil or solo pilot. More unusually, there are also dual elevator and rudder trim wheels, one group below the left throttle quadrant, with a second, aft pedestal instructor’s set which I later had to be dissuaded from using in flight.

Flying instruments are laid out in the standard six format, with a surprisingly big fuel pressure gauge on their right and tiny rpm and manifold pressure gauges above the central quadrant. Radios are in the middle and most secondary engine dials on the right hand panel, with circuit breakers below. With no flywheel, booster coil or priming pump to operate, starting is simpler than on many other R-985 installations; you just inject four squirts with the Ki-Gas primer by your left knee, check mixture cutoff and prop pitch fine, set the throttle a half inch open and press the powerful electric starter. After the Hamilton Standard prop’s two shiny blades have turned through a couple of revolutions the engine begins to fire and the mixture can go to auto rich, but you change nothing else. You hurry a Pratt & Whitney radial at your peril! The oil pressure rises quickly but the revs are much slower to build up to the low 800rpm idle, taking nearly half a minute before they have stopped increasing and settled down to a gentle loping rumble.

Even in Perth’s heat it took a while for the cylinder head temperatures to stabilise and all the contents of the big oil tank to warm through. While waiting we secured our harnesses and checked the systems. These combine the best of Australian, American and British experience, with hydraulic disc brakes, pneumatic flaps and manual carburettor heat (to the left of the central throttle quadrant). There are no adjustable cowling gills or oil cooler shutters, but this simplicity is made up for by a most unusual parking brake system. Although having a standard-looking locking plunger, it works in the abnormal sense that you stop the aeroplane with the foot pedals but, rather than then simply pulling out the knob, you have to completely take your feet off the brakes first. Failure to do this in precisely the correct order results in an extended plunger but no brakes!

Just like a Mustang’s or T-6’s, the tailwheel is normally linked to the rudder, allowing nine degrees of steering either side – adequate for all but the tightest turns. Moving the control column forward of neutral disengages this lock, freeing the wheel to swivel through 360 degrees. Taxying with the stick held well back, I found the steering reasonably light and without significant delay for normal taxiway manoeuvring. Tighter turns need anticipation. Pushing the stick forward to the instrument panel unlocks the tailwheel, while simultaneous application of full rudder, a dab on one spongy and not too effective brake and a prod of power get it going around the corner. With the turn established, just before you are pointing in the right direction, you bring the stick right aft again and apply full opposite rudder (and perhaps a touch of brake) to stop the turn and return the tailwheel to normal steering. Taxying is perforce made at a prudently low speed; I suspect if the heavy tail started to swing it would not be easy to stop.

The only remarkable item before takeoff check is to twist on half right rudder trim. The slow-travelling pneumatic flaps have four simply remembered positions: up, takeoff (twelve degrees), landing and emergency. Their single small, fuselage side lever is just below your left wrist but, however hard you search, you will find no gauge. To confirm their position you have to twist in your seat, peer over your shoulder and actually look at them.

The phrase ‘Greenhouse effect’ takes on an entirely new meaning under the utterly cloudless, ozone-depleted, sun-dominated West Australian sky, so the canopy is not closed until the last possible moment before takeoff. Its locking lever is below one’s left elbow, and has to be pulled out and pushed hard down. Two small side windows can be slid rearwards for a welcome draught at low speeds after lifting their slightly awkward catches on the top canopy frame.

Carefully lining up precisely on the centreline, I pulled the stick right back, centralised the tailwheel and rolled a foot forward to be sure it was locked. Looking through the rather ugly, curiously flat-paned windscreen, I noticed that, because we sat higher and could more easily see over the shorter, more sloping nose, the view was better than from either the Harvard or similar British Provost. Picking a distant aiming point on the horizon I gradually advanced the long, high-set throttle (taking care not to scrape my knuckles on the canopy surround) to Don’s economical takeoff power of thirty inches map (full power is 36ins). Holding the stick fully aft, as we started to move I kept straight with small steering corrections. Don had warned me not to lift the tail before 40kt (74kmh) or the rudder would not hold the swing, saying the brakes were “about as much use as a puff of hot air.” I eased the stick forward to lift the tail and improve the already good view, stepping quickly on the right rudder to kill an impending swing as it rose. Balancing her carefully on the main wheels, out of the corner of my eye I watched the speed quickly increase to 60kt (110kmh), when a gentle pull eased her into the air. Checking forward to fly level at ten feet, I waited until the ASI read 80kt (150kmh), then retracted the flaps (without trim change) and at 85kt (158kmh) raised the nose to establish the climb, carefully reducing rpm to 2000 (after a slight lag) and noticing a VSI reading around 1000fpm.

Levelling off, once speed had increased to 115kt (213kmh) I reduced power to Don’s recommended economical 24 inches and 1800rpm (the RAAF used 26 inches and 2000) and selected auto lean on the mixture control. Don reckons on a consumption of 78.5 litres (17.5imp gallons) per hour, giving three hours safe endurance with a 45 minute reserve from the 305 litre (67imp gallon) useable capacity for a 400nm (740km) still air range. The fuel gauge is accurate down to 70 litres (15 gallons), when it starts to fluctuate erratically and the book says “land!” Unfortunately the fuselage tank cannot be dipped to check this gauge because of a convoluted filler neck.

The forty-year-old Winjeel may be a big, heavy and fairly complex aircraft for a basic trainer, but it flies like a smaller machine, with crisp military style handling and a fast point and shoot roll rate. Don likens its feel to the Miles Master or its predecessor, the Wirraway, while I found it generally similar in character to both the shorter-winged Provost and the Harvard although slightly less agile than the former and, having lower power, flying rather more slowly than either. Although designed for them, the machine’s Permit to Fly prohibits aerobatics, but Don believes it does them “like a dream”, looping at 160kt (296kmh) and rolling at 150kt (278kmh). He also hears that, although it will spin with normal control inputs, it does so better with out-spin aileron. Accepting the limitation, out over the Indian Ocean coast he demonstrated a few exuberant wingovers, and I wondered if his mind was drawn back to that other beach, in Italy, so long ago. Diving towards the shore we could clearly see marine life on the ocean’s bottom, through the clear water. Pulling up over the thin, deserted ribbon of white sand we were glad there was nobody to disturb with our prop howl on this quiet post-holiday Tuesday lunchtime.

The Winjeel’s stall speed is a very reasonable 50kt (93kmh) regardless of flap setting. To Don’s delight its behaviour is representative of the classic fighters, signalled by slight buffet and wing rocking five knots (9kmh) before the break, but defined by a smart wing drop rather than the nose falling away, especially with flap down or if not absolutely in balance. Stalling is even more exciting in a steep turn or with lots of power applied, when it flicks enthusiastically.

Back at Serpentine, Don slightly wistfully pointed out that visibility is good enough to make a wartime curved approach unnecessary, so we made an ordinary square circuit, flying downwind at 95kt (176kmh) with twenty inches and 1800rpm. Turning base I throttled back to seventeen inches, took the first stage flap and let speed bleed off to the best glide of 85kt (158kmh), finally selecting pitch to fully fine and gently descending. Establishing a cautiously long final, I lowered landing flap and stabilised the speed at 70kt (130kmh), planning on a final reduction to 65kt (120kmh) with throttle closure crossing the fence.

Bearing in mind his Winjeel’s 3.5 metre track and Serpentine’s narrow nine metre runway (less than the aeroplane’s span and bordered by a five cm drop to the virgin sand), Don recommends forgetting the idea of a traditional three-point touchdown. In this attitude the rudder is blanked by the wing’s downwash to become only marginally effective, so he advocates making the landing a tail-down wheeler. Although hard work, the touchdown should be made tail-up if the wind is at all gusty (as it so often is after lunch when the daily sea breeze penetrates this far inland).

The Winjeel has lots of inertia so, under Don’s tuition, I got the power back promptly and flared carefully, holding off briefly to touch tail low, quickly checking the back pressure to hold her on the ground. The undercarriage is rather stiff, so if the touchdown is too hard she can skip, but this is all predictable. Moving the stick progressively forward till she slowed, I then lowered the tail while there was still some travel remaining, quickly jumping the tendency to swing as it dropped, doing some fast pedalling and using all my skill to keep this wayward handful on the straight and narrow. Once the tailwheel was safely on the tarmac I promptly pulled the column smartly aft for effective steering.

Approaching the taxiway I was suddenly aware of the hot cockpit and prickling sweat at my sides so, as we slowed to a walking pace, I reached my left hand upwards to the top canopy rail for the little side window’s lock to direct a welcome draught into my face. Although more effective, two-handed opening of the canopy at above taxi speed can be hazardous, although it is possible to stay straight by continuing to stare fixedly ahead, holding the stick in the crook of your right elbow and fumbling for the locking lever with your left fist. The fact that one would contemplate this potentially hazardous procedure at all attests to the tremendous power of the searing WA summer sun.

A prompt mid-runway turn off was followed by a smart taxi back to the threshold and a half dozen further circuits, each one becoming easier as my confidence in this challenging but predictable warbird grew with each landing. Eventually the increasingly favourable sun to yard arm ratio and a developing thirst (combined with the reducing fuel quantity) persuaded us to quit our fun.

The talkative and light-hearted Don’s apparently casual approach to flying belies his truly sensible and disciplined nature. Although well known locally for his sense of humour, witty interjections and carefree clowning around, his pre-flight briefing was one of the most comprehensive I have experienced, and his whole approach to our sortie was one of military thoroughness. At the SAAA’s WA chapter annual get together he was justly presented with a special award for a year of ‘utterly safe and professional flying’ – although the presenter, local chairman Arthur Winstanley, had to add that the casual onlooker “might not expect such airborne self-discipline if you met him on the ground”. Long may these two elderly warriors fly together – that wise and lively old eagle, Don, in his ‘Young Eagle’, the Winjeel Shabby Blue One.