Tuesday, August 18th, 2009

AS W20 Tri-Jet

On Saturday morning 15th August, I had the opportunity to experience for the first time the AS W20 “Tri-jet”. With full fuel and the glider DI’d, Allen towed KYA to the threshold of Rny 02. While conditions were not ideal, with a north-westerly breeze – and a slight cross-wind, we prepared for take-off. Each engine was started in order, the wing walker removed and the throttle wound up to 100%. A quick check to see that each engine was producing max thrust and we were away.

The rudder is noticeably very effective very early, so steering is not an issue. Flaps were set to the first stage of reflex to get the flaps working in combination with the ailerons for good control to keep the wings level. At around 40 Kts, I reset the Flaps to zero, resulting in the glider becoming airborne. The glider accelerated to 50 Kts – still with no inclination to climb – similarly to 60 Kts – 70 Kts – and we were away, with the vario full-scaled at 10 kts. The air was fairly turbulent due to the effect of the wind, which was considerably stronger than on the ground. I climbed to around 500 Ft before turning left to fly downwind, endeavouring to maintain a steady speed to allow the Collibri to record the various parameters. I had a play with airspeed and climb rate – up to 90 Kts with no apparent improvement, then progressively back to 60 Kts in 10 Kts increments, which saw the climb rate progressively reduce. It was apparent the ram air effect had a considerable effect on engine performance. Now approaching 2500 Ft, I executed a number of steep skidding turns, with no effect on the engines, before shutting down number 1 and 3 engines. As the engine exhaust temperature reduced towards 80 degrees, these engines were retracted. I then had a play with Number 2 engine, changing the throttle setting down and back up, some steep turns in both directions, slipping and skidding turns before I shutdown this engine, having climbed to a little over 2700 Ft.

The engine noise is by no means uncomfortable in the cockpit – most of the noise disappears behind. With ear plugs, I could comfortably hear the radio above the engine and airflow noise, without having to have the volume wound up. The effectiveness of the rudder once the engine power is increased resulted in some over-correction initially. Ergonomically, Allen has the engine controls well laid out – I had no trouble reaching or adjusting the various items. The engine display is easy to read and select, and the few engine controls (which are necessary to adjust) set up to be very intuitive. With the engines shut down, the 20 was the same as it always was, extremely nice to fly, even in the turbulence.

After a flight lasting a total of 26 minutes, I landed back on Runway 02, well satisfied with my first flight in the AS W20 “Tri-jet”. Now looking forward to some more flights in the “20.

 

John Hudson.

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