Flight test: Percival Provost T1
PUBLISHED: 12:45 19 October 2018 | UPDATED: 12:45 19 October 2018
That's the Provost, the fine-handling 1950s RAF trainer cleverly configured to lead into fast jets | Words: Peter Turner - Photos: Peter March
In the late 1940s the Royal Air Force needed to replace its fleet of Percival Prentice and North American Harvard trainers with just one type: a single-engined basic trainer. As a result the Air Ministry issued Specification T.16/48, the requirement being for an all-metal, two-seat, piston-engined monoplane with conventional fixed undercarriage, with the handling and performance to replicate that of the contemporary jet fighters, notably the de Havilland Vampire.
Out of thirty proposals submitted, the Percival P.56, designed by Polish engineer Henry Millicer, and the Handley-Page H.P.R.2 were chosen for assessment.
An order for two of each of these types was placed on 13 January 1950, the prototype Percival P.56, WE522 making its first flight on 24 February. Both P.56 prototypes were powered by an Armstrong Siddeley Cheetah 18 engine. Percival also built a third prototype powered by the more powerful Alvis Leonides 25 engine which would be used on all production aircraft.
After rigorous comparative trials at Boscombe Down, the P.56 won the bid against the H.P.R.2, and on 29 May 1951 an order for 200 aircraft was placed. From this point on the P.56 was named the Provost.
Henry Millicer subsequently went to Australia where he designed the Victa Airtourer, another sturdy training aircraft in which I spent many hundreds of hours teaching. The family resemblance is certainly there, both in looks and the spritely handling.
In addition to replicating jet handling and performance, and to suit training missions, the cockpit seats were side-by-side. The feeling at the time was that the instructor could observe the student and better demonstrate flight procedures. Personally, I prefer tandem seating for instructing, à la Tucano.
It makes it easy to ‘cover’ the controls without giving the student the impression that he or she is not trusted! The very solid three-piece canopy was designed for good crashworthiness. Interestingly, to facilitate instrument flight conditions, extendable amber screens were fitted so that a student wearing blue-tinted goggles could not see out.
The instructor, not wearing them, could, however−a novel and effective feature. The cockpit was deliberately complex, exposing the student to an advanced environment and preparing them for their next leap into single-seat jets. With VHF radio fitted, not only cloud flying but instrument approaches and night flying could now readily be taught.
The Provost entered service with the RAF in 1953, the first batch being delivered to the Central Flying School’s Basic Training Squadron at RAF South Cerney, a lovely circular grass airfield near Cirencester. It had intensive flight trials in May and June of that year before instructor training started. Immediately it was evident that the Provost was more than capable for its role, being vastly superior to its predecessor, the Prentice, with twice the engine power.
After I flew the Cessna 170 (February 2018 Pilot) it was suggested I might like to do flight tests on its big brother, the 195, and the very different Percival Provost T1, G-MOOS. Unfortunately the C195 was ‘indisposed’ so it was the Provost next on a gloriously sunny day in April.
My old flying pal Barry was to fly the camera ship with Peter March and we all met up at AT Aviation’s facility at Dunkeswell.
I was immediately impressed by the Provost’s size. Having only seen the Shuttleworth example in flight before, it was much bigger than I imagined and certainly dwarfed the Chipmunk it was parked next to.
Andy Twemlow, AT’s founder and boss was busy wiping off oil streaks after a morning aerobatic sortie in ‘Oscar Sierra’ and we soon got chatting about the forthcoming test. Andy was to be my mentor, and there to keep me out of trouble.
While Andy continued his cleaning I did a walkround using a print-off from the Pilot’s Notes I had acquired. It was all very straightforward and standard.
By the time I arrived back at the pointed end Andy had the port engine cowling open and was topping up the massive six gallon oil tank. This beastie’s Leonides radial engine sure gobbles oil at an alarming rate, especially when being aerobatted.
It is worth pointing out here that, had the aircraft not been flown a little earlier, it would have been essential to pull the prop through four revolutions by hand to prevent the dreaded hydraulic lock which could cause serious damage.
Once Andy had finished we all sat down over a cuppa for a comprehensive briefing to ensure the three pilots and two photographers were all singing from the same hymn-sheet. That done, it was time to go.
In the cockpit
Climbing on to the wing, although not impossible, is rather a big stretch for a short-arse like me but was made easier by the use of a footstool and a grab handle on the fuselage. Once on the wing I donned the cumbersome parachute.
This consists of the parachute at the back and a cushion/dinghy pack which you sit on. Why put it on while standing on the wing, you may ask? Well, with it strapped on, any attempt to walk provides a good imitation of a duck waddling along and immediately shoots the wearer’s street cred down in flames.
Apart from that, climbing up on the wing could be rather dodgy! That said, getting into the deep cockpit is no problem. It is simply a matter of stepping onto the seat bucket then into the foot well and sliding down into place, the tailored bum pack fitting nicely into the bucket.
Once the rudder pedals and seat tracking have been adjusted the five-point harness can be secured. Although adjustable fore and aft the seats are fixed in height.
The cockpit can only be described as well lived in with knobs, switches, placards and instruments seemingly scattered at random, although in reality all came easily to hand in flight and, more importantly, worked. The two flight panels were bounded by white lines surrounding the six essential gauges for instrument flight training.
This arrangement was introduced by the RAF in 1937 and was to be dubbed the ‘six-pack’ (not to be confused with today’s understanding of the expression). What struck me about this arrangement is that it is not laid out in the basic ‘T’ as we know it today, with the airspeed indicator (ASI), artificial horizon(A/H), and altimeter across the top, and the turn and slip (T/S), directional gyro (DG), and vertical speed indicator (VSI) below.
This arrangement was not adopted until later, so I guess the Provost missed out on that; another little quirk. In the centre of the panel are a third altimeter and various engine instruments including the fuel gauge. To complete this period array the compass and VOR/ILS indicator sit atop the panel.
The flying controls are fairly conventional, although the stick is slightly different from normal. The lower column doesn’t move laterally, only fore and aft, with roll being achieved by the upper half which pivots laterally and controls the lower half in pitch.
The only other aircraft I’ve flown with this arrangement is the DH-come-Hawker 125 with its ram’s horns in place of the stick on the Provost. The benefit of this is that one’s legs do not get in the way of the lateral movement of the stick−vital in an aerobatic aeroplane. The rudders are individually adjustable via a knob on the lower outer side of each panel.
On the left wall are, as described in the notes, ‘the pupil’s controls’: the throttle and pitch levers (RPM), and elevator and rudder trim wheels. All of these are duplicated on the central pedestal for the instructor. Above that quadrant is the canopy hood winding handle. Forward of this are the pupil’s magneto switches and, aft, the pupil’s inertia harness release.
Going back to the central pedestal, from front to back are a variety of knobs, levers and switches which control cockpit heat, power settings, flap settings, battery master, aileron trim, idle cut-off, windscreen wipers and control locks.
On the left face of the pedestal is the fuel cock and on the right the elevator trim. The instructor’s mag switches are on the lower right panel next to the sidewall and, aft of that, a bunch of other switches ending with the instructor’s inertia harness release.
There are many more controls which I’ve left out for brevity except to say there is a modern VHF radio with a transmit button on each stick plus a VOR/ILS set. Without doubt this is a busy cockpit but, bearing in mind it was to train pilots eventually to fly single-seat Vampire jets, it is all quite necessary.
Once strapped in Andy welcomed me to the ‘Ugliest girl at the ball club’. Well she’s no beauty that’s for sure, more a purposeful worker. I bet she can dance though, I thought!
Following a cockpit briefing it was time to start up and release a few of those five hundred and fifty horses.
All was standard for a large radial, and after a few coughs the beastie burst into life and settled into a low rumble.
With 1,200rpm set we check the Ts and Ps and wait for the pneumatic pressure to build up to at least 220 lb to give us adequate brake and flap pressure. Shut-down checks on the Provost include lowering the flaps, so during the warm-up the lever is placed in the ‘up’ position. When the pressure is adequate they smartly raise themselves. With the park brake set we are ready to signal ‘chocks away’ and taxi out.
Taxi to takeoff
The brakes on the Provost need a delicate touch to keep the aeroplane running straight and to turn corners without swapping ends. With a narrow taxiway ahead Andy nudged us out onto Runway 17 then handed over to me.
Steering and braking is achieved by squeezing the lever on the stick and then applying the appropriate rudder. Too much pressure and you’re quickly looking back whence you came! The trick is to keep a couple of fingers between the trigger and the hand grip which prevents too much brake being applied.
In the event I found taxying no problem, soon getting used to the feel of the brakes, and we continued down Runway17 to hold short of R04, the duty runway, without too much embarrassment.
The pre-takeoff checks are pretty standard except, unlike many other types, the cockpit hood must be closed and locked to prevent unwanted airflow difficulties. Once airborne, however, the hood can be opened at speeds up to 180kt. With all set and our harnesses locked we lined up for departure. Like all radials the power needs to be applied smoothly; no hurried opening up as this can, if hastily applied, flood and stall the engine. Not just with radials but in any piston-engine aeroplane, I aim to take a minimum of three seconds from idle to full power.
The takeoff roll is standard taildragger with little tendency to swing. As the speed increases the stick is moved forward and the aeroplane flies off at about sixty knots in a slightly tail-down attitude. We accelerate to ninety knots for the climb, complete the after-takeoff checks and set the power to 2,900rpm and +2in Hg boost. Once all is settled the VSI shows a climb rate of around 1,000fpm. Very respectable and we’re not even using the max climb boost of +3.5.
Leaving the circuit to the north, we head to our rendezvous point over Upottery disused airfield and climb to 2,500ft for the air-to-air photos. Once in the cruise, power is adjusted to the economical/best range setting of 2,500rpm and zero boost, returning a comfortable 100 knots for the sortie.
At this setting we are burning 150 lb (94 lit) per hour which gives us a range of 240nm with a thirty-minute VFR reserve from the two wing tanks holding a total of 430 lb (270 lit). If range is not an issue, then the notes suggest a ‘more comfortable’ cruise speed of 120kt, returning a burn of 190 lb (120 lit) and giving a range of 220nm with reserves. As might be expected the all-round visibility from the cockpit is excellent.
I found the handling qualities of the Provost delightful. The controls are light, effective and nicely balanced. Due to the lightness of the controls the Pilot’s Notes caution that ‘care should be taken not to overstress the aircraft at high speeds’.
That said, it really is an easy and pleasant aeroplane to fly with good feedback. It proved ideal for the air-to-air photography, and indeed when we met up and slid into formation with the Cessna I found it easy keeping station and moving about for the camera. As we were quite heavy Andy kept a careful watch on the speed which, in the event, never got critical.
With the pics in the bag we broke away to try a few stalls which went by the book. Power off, flaps up, 65kt; flaps down, sixty; and in approach configuration, 55kt. All speeds were within acceptable limits and in each case there was a slight elevator buffet some five knots before departure, which entailed a moderate nose drop and little or no wing drop.
Recovery with power was very effective and quick. I would have liked to play more but, due to our heavy weight which made loops etc not advisable, Andy quite rightly suggested we return to base.
Rejoining directly downwind at 1,000ft QFE and 100kt, the checks were completed as per the book with the speed being reduced to ninety on base. With ‘land’ flap selected on final, this was reduced to 75kt. Handling throughout was once again easy and responsive.
For our ground cameraman Paul we carried out a touch-and-go, and flew a further circuit to touch down for a smooth three-pointer. Taxying in I have to admit I was wearing a huge grin! What a lovely classic British trainer it is. All this rare aeroplane needs now is a new custodian… and wouldn’t I just like to fly its successor, the Jet Provost.