|TURBO COMP AIR SEVEN -- FLIGHT REPORT by GEORGE PAPADATOS, AEROPLANE MAGAZINE|
The Comp Air exhibit tent was a very crowded place at "SUN 'N FUN". Two of the airplanes on display, the Turbo Comp Air Ten and Seven were at the epicenter of curiosity. On January 14, 1999 designer and builder Ron Lueck, an "all out power man" who believes that "you cannot have too much power", test flew the Comp Air Seven, a conventional taildragger, with a 650hp Walter Turbo Prop engine stuck in its nose. The results were nothing short of spectacular. After talking to Ron, a very laid-back individual, and taking a close look at the advertised performance figures, I decided to find out myself what this unusual combination of plane and engine would really do.
The Turbo Seven prototype has a long pointed nose with a wide short exhaust stack coming out of the right hand side of the cowling, a clue that this otherwise innocent looking large taildragger hides a secret. (Fig. 20)
Front entry for pilot and co-pilot was like getting in many a tailwheel airplane; it requires bending, pulling and twisting your body a bit. Alas, entry for rear passengers was a fitness test. Older relatives have to be physically lifted and carefully deposited inside the plane unless a stepladder is provided. The two front seats were nicely padded but the rest of the plane was bare; without upholstery and sound insulation.
While climbing in the co-pilot's seat the first thing I (Fig. 21) noticed was a huge lever in the middle of the center console which combines thrust and prop control. Pulling it all the way back puts the prop into a feather position; depressing a release button takes you to idle and reverse thrust. On the panel, Ron pointed out, two most critical instruments for the operation of the turbo: TOT (Turbine Temperature) and Torque Indicator.
When he fired up the Walter and the Avia three-blade prop started to turn, crowds gathered quickly in disbelief, but as someone said, "hearing is believing". That unmistakable turboprop sound was a definite promise of excitement ahead. Applying full power on take off could surprise anyone in this airplane. Acceleration is reminiscent of the Thunder Mustang; only smoother. We got airborne in less than 400ft climbing at more than 3000ft/min and doing 120mph. It felt as if the hand of giant picked up the plane and threw it skywards. A more civilized climb can be achieved at 2000ft/min and 175mph.
While leaving the pattern, we outperformed the "Lancair Columbia". Ron waived goodbye to its pilot several times as we went by. With a smile in his face he said to me "This guy used to pass me all the time; not anymore. Not since I put the Turbo in". I leveled above the cloud cover at almost 10000ft. Using 80lbs of the 127lbs available torque produced a staggering 220kts cruise at 63% of the power. Jet fuel consumption at that configuration is 34 gallons an hour; a reasonable amount if one considers that this is a seven-passenger airplane with a useful load of 1500lbs.
Controls were a bit on the heavy side, as expected from a plane of that size designed mainly for trips at altitude. Directional stability is excellent and the plane feels as if on rails when flown straight and level. Once in a turn the Comp Seven stays there in a very neutral mode. Slow level flight down to 80mph was very controllable and we stalled at 58mph.
Flying at slow airspeeds and a high angle of attack causes jet fuel to leak from the engine bringing a strong odor of into the cabin, a potential cause of discomfort for passengers. Applying power during an emergency go around is a delicate operation as the turbo reacts with a lag and full throttle application cannot produce the instant response of piston powered engines. The same holds true when making power adjustments on landing; the engine/prop response takes a couple of seconds, which, to some can be critical. A speed of 70mph can be easily maintained on final.
I was told that Ron would occasionally surprise his passengers by going into reverse thrust on final and parachuting the Seven down the runway. He did not try that with me. We went into idle and the plane floated down the runway to a gentle landing. It was only after touch down that reverse thrust was applied to slow the Seven down.
The Seven is a big, comfortable, all-composite construction airplane; easy to fly once accustomed to turbine engine management. It can take off in 300ft and land at 1000ft strip. The kit costs$40,000 US dollars and the Turbo engine package another
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