Popular Flying

March/April 2001

 

"Flying the WAM-CITEC ­Powered Europa"

"Test Pilot John Brownlow put the prototype Wilksch Airmotive diesel engine through its paces

	Full throttle, 2500 rpm	Gated Throttle, 2300 rpm
2000ft	132 KIAS	120 KIAS
5000ft	132 KIAS	120 KIAS

Six test flights have been completed in Europa G-WWWG powered by the WAM-CITEC prototype diesel engine and 64in diameter MT V7 VP propeller.

The engine was de-rated to 8Ohp for these early flights all of which enabled very valuable data to be gathered.

The tests were flown between January 2 and 9 in excellent test flying weather, almost unheard of in the U K at this time of year!

The aim was to assess endue handling, performance and reliability before more extensive flight tests with the second prototype engine installed in G-WWWG, planned to start about six weeks later.

Before each flight the engine started the first turn of the starter key. I almost wrote ignition key, but there are glow plugs for cold starts instead!

Reliability proved to be excellent. The engine ran faultlessly on every flight, but the oil and coolant temperatures needed careful management to keep within the conservative limits set for the first few test flights. The planned radiator and cowling changes should assist in this area.

The engineering briefing called for full power initial climb rate measurements, and level speed assessments at altitudes up to 5,000ft using full throttle and 2500 rpm, and at 2300 rpm with the throttle set with an artificial stop inserted on the throttle stem restricting power output to a repeatable 70 per cent.

Each level speed run was to be for a minimum of two minutes. The results were most encouraging, and the following data clearly shows that level indicated airspeed stays constant for given power settings as altitude increases to the maximum tested so far.

On all test flights engine performance was impressive. The climb rates matched other Europas at similar weights with 80 hp engines and VP propellers.

The maximum altitude reached was 6,300 ft. and there was still plenty of climb performance left.

For the first time when flying a home-built aircraft, the smoothness of power response and the low level of vibration reminded me of my long past jet fighter days.

And that nostalgic whiff of kerosene was there too as I started the engine. Well not quite kerosene, but agricultural diesel smells a bit like it!

 

Speed

It should be borne in mind that the speeds quoted are straight readings from the ASI, and in the Europa the AS fluctuates a bit. So they should be taken as reasonable ASI averages over the two-minute runs, and not accurately measured Rectified Airspeeds obtained with sophisticated instrumentation.

On completion of the first data­ gathering task, Mark Wilksch agreed to a fast fly-by so he could practice his video skills. By this time I had gained sufficient confidence in the engine to wind the Europa up to 155 knots for a low pass.

So 2300 rpm was selected on the propeller governor and the throttle used as required to achieve this speed in a shallow descent across the aerodrome.

As I had quickly come to expect the engine felt as smooth as a jet.

After taxiing in and closing down, the tank was dipped. The engine had used 13 litres of fuel for 55 minutes flying, from the start of the take off run to shut down and much of it at high power. A later flight gave a fuel consumption of 10 litres for 40 minutes flying.

So far as handling G-WWWG was concerned, there were no significant changes compared with other members of the breed I have flown.

As they are all amateur built, every Europa has its own little quirks! At full power in the climb, light pressure on the right rudder pedal kept the ball where all flying instructors want to see it, slap in the middle.

In the cruise G-WWWG flew straight with no tendency to fly one wing low, and with just a touch of right rudder needed to maintain balanced flight.

Increasing power, as expected gave nose up with yaw to the left, and on decreasing power the nose went down with yaw to the right, all absolutely conventional.

These early flights certainly left me with the firm impression that the WAM-­CITEC engine has a great future, and it is a pleasure to be involved with the engine development programme."