The Prospector: A strange-looking, but unique aircraft

Discover the British 'E.P.9' Aircraft: Born from an Australian designer's mind, 'the Prospector' left an indelible mark in aviation. Explore its history, unique features, and the legacy of Edgar Wikner Percival.

Jamie Chalkley  |  08th August 2023
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    Jamie Chalkley
    Jamie Chalkley

    Jamie Chalkley literally grew up around Warbirds... and crop spraying! Quite the contrast! Not content...

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    British 'E.P.9' on runway

    Born from the mind of Australian designer Mr. Edgar Wikner Percival came a very British aircraft; the “E.P.9” (EP being the initials of the man himself!), or as known to those that flew them, we called them ‘the Prospector’. I say ‘we’ as it was the plane that introduced me to aviation. In fact, my very earliest memory of actually going flying was at the age of 3 or 4, climbing into the rear cabin (two bench seats, one behind the other) which at my stature of the time, about 3ft 4” felt, like the inside of a Jumbo Jet!

    I can’t remember exactly where it was. Certainly not from an airfield. I know I didn’t fly from an actual real life airfield until I was well into double figures. No, this would have been from a farm strip, maybe not even a strip, probably just a farm field. For this was the working horse and personal hack of my grandfather Jim Pearce. And it wasn’t just the size of the plane that was overpowering to my shortness and senses, it was the noise; the 295hp Lycoming engine, with its straight through pipes, absolutely roared like a Merlin as the throttle (or noise lever in this case) was advanced toward the firewall. 

    Yes, this was one strange looking bird, but it took off almost like a helicopter profile than that of a standard airplane departure, and with its full dropping trailing edge wing it could land on what felt like a postage stamp (well… maybe a 1 acre sized postage stamp). Given only 27 were ever built it’s not surprising most people aren’t too familiar with them, but it was quite the aircraft to behold! 

    A Wizard from Oz!

    From the flats of New South Wales, Edgar first laid eyes on an aircraft when one landed in a nearby farmers field. The year was 1911, so whilst this was still truly back in the dawn of aviation, it was most certainly also in the sunrise of the industry to come! The eager Edgar couldn’t contain his enthusiasm about the craft that came from the sky above and the pilot, a dentist no less, made sure the young Edgar’s smile was broad and bright as he offered him his first flight aloft. A year later at the ripe old age of 14, Edgar was designing and even flying a few of his own glider!

     Not many years later, The British Commonwealth extended its reach to pull in overseas pilots during the First World War and Edgar seized the opportunity to transfer from the Australian Military to the British Royal Flying Corps in February 1917. He is rumoured to have gone solo after less than an hour of training! He went on to fly air to ground strikes in the Nieuport and The Royal Aircraft Factory S.E.5. 

    Following the war, he returned to Australia for a stint of barnstorming and also set up his own charter business. During this time, he found great success in Air Racing and won the Melbourne to Brisbane event in 1921 and the Melbourne to Geelong race in 1923. He was clearly an adventurous aviator and the test pilot in him found opportunities to take part in all sorts of innovations including a catapult launch from a US battleship in a modified Sopwith Pup! 

    However, he seemingly missed the British skies and returned in 1929 as a British test pilot. He went on to start his own aviation company in the UK called the Percival Aircraft Company and specialised in racing design aircraft and found success with his ‘Percival Gull’ which was noted for both its speed and its range, and made headlines as the winner of the King’s Cup Air Race with an average speed of 142 mph. For that era of flying… that was fast! And it had some long distance legs on it too, for he went on to claim the badge for the first pilot to fly from Britain to Africa, and back, in one day! A number of world records in both time and distance were claimed in this model. His designs kept him busy enough to open several production facilities which as the Second World War came about found him also building some well known military aircraft under license, such as the de Havilland Mosquito (amongst others). 

    Around the world with a drawing board!

    Advancing a decade, the year being 1944, Edgar was over in the US to concentrate on engine design. After that, his mailing address moved further still as he headed down to New Zealand where he dabbled in some agricultural flying (Ag-Flying). But again, he must have missed the British Weather, as in 1954 back he came, this time to set up his last design and manufacturing company; ‘Edgar Percival Aircraft Limited’. And their first plane was called… the EP.9 

    Whilst from the drawing board of an Australian designer, the EP. 9 was definitely an all British aircraft. With the lines of a true workhorse and the performance to match, the EP.9 was a utility aircraft through and through and found a particular niche for itself in the agricultural sector. It’s first flight was back in the winter of 1955 and by 1958 multiple orders were placed for crop sprayer variants. The British Army also took two under evaluation as a potential Army aircraft. The majority were powered by a 6 cylinder Lycoming O-480, but some variants used instead an Armstrong Siddeley Cheetah engine; a seven cylinder radial developing 375 hp. A power increase from the 295 hp Lycoming. 

    Lowering the flaps AND ailerons for STOL performance 

    The STOL (Short Take-off and Landing) performance was very impressive. Particularly easy to demonstrate if operating on the lighter side of the weight envelope whereupon the aircraft accelerated quickly with the tail coming up promptly and due to the short forward sloping nose the forward visibility looking ahead was excellent, even with the tail down. The aircraft seemed (to me anyway) to come off the ground like a helicopter transitioning from the hover into forward flight, it was more hold it down than pull it off when it came to getting airborne. The stall speed was a staggeringly low 35 mph – the bird just wanted to fly! And thanks to the all dropping trailing edge (ailerons dropped down with the flaps) it gave incredible short field landing performance. However, it was important to be straight on finals before selecting that last stage of flap as with the ailerons also lowered (on both sides) there was reduced aileron deflection compared to when the flaps (and therefore ailerons) were raised. So a short field, steep, curving approach was something to be wary of.

     The strange, humped belly shape at the rear of the aircraft is thanks to the very versatile cargo door. From here you could load and install a one ton agricultural hopper, or load in three stretchers and flying doctor, or at least four parachutists, or some oil drums or at times – even some livestock! It really was a truly versatile aircraft! It could also fly with that cargo door on or off (such was the exit of the parachute jumper) or on several occasions I remember seeing the wing spray booms strapped to the underneath of the fuselage boom as a means of ferrying the spray gear from job to job, this avoided the drag and speed penalty of leaving them attached to the wings. 

    Felt like a jumbo… took off like a helicopter! 

    In total only 27 E.P.9’s were built and following a few changes in the hands of production, it was the Lancashire Aircraft Company that turned out the last few as the year 1960 approached. So whilst never a mass production aircraft it certainly was an interesting one, and for sure it’s designer Edgar Percival was a widely known and respected name in the aviation design and test pilot community. At the time of Edgar’s passing in 1984 he was a Fellow of the Royal Aeronautical Society, the Institute of Marine Engineers, the Institute of Mechanical Engineers and was a founding member of the Guild of Air Pilots and Navigators.

     The last one I flew was G-APWZ which was sold to New Zealand in the summer of 2002. To the best of my knowledge, this was not just the first EP.9 I flew in, but as a very young child, it was the first plane I ever flew in! I can still remember so clearly my grandfather being at the controls, him looking back over his shoulder at me and giving me a big thumbs up before we headed up into the great blue sky together. 

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