| Start by checking the position of the fuel tank valve. Move
the indicator to both (or to the correct tank). Double-check that the fuel tanks are full.
This is extremely important, because turbine engines use up fuel at a high rate. Before
you start the engine, apply the parking brake and stand on the brakes, because when those
huge props start rotating, you can really feel the power, and you don't want the plane to
roll out until you're ready to go. To prevent surges, be sure all power switches and
navaids are off and the circuit breakers are in. Check all the controls to be sure they're
free and not binding, because this is your last chance to ensure there'll be full movement
of all the control surfaces. Takeoff is the same as with any high-performance taildragger, but with just a few more checks to make before you start the takeoff roll. Place the flaps down 10 to 15 degrees, recheck the fuel quantity and valve position, and make sure the fuel boost pump is on. Then, as with any aircraft with a constant-speed prop, cycle the prop once or twice with the power lever in the idle position. Check one more time to make sure the power lever is in the run position. Set the power to 30 percent and slowly move the prop lever to the aft position so you can check that the rpm are decreasing gradually. Now move the prop lever to the full-forward high-rpm position. We were eager to see how this second-generation Comp Air 7 Turbine aircraft would perform with its newly IRAN'd Walter 601D engine and overhauled Avia Hamilton prop. I wanted to see how this Millennium engine, sporting about 725 shp, would compare to that of the original 600-hp engine. When all systems were go, the pilot |
brought the power up to 30 percent torque and released the
brakes. Then, as the plane started to roll, he increased the power lever for smooth and
continuous acceleration. When the engine was up to full takeoff power, he checked the
engine temperatures and made sure the torque limits weren't exceeded. By the time he'd
done that (maybe four seconds), the plane was already off the ground. We used about 100
feet – maybe less – for our takeoff roll. We maintained best rate of climb (Vy), which was 110 mph with the two people aboard that day. Now came the fun of flying in a superpowered aircraft. Maintaining a 4000-fpm climb, we were already about 1000 feet above pattern altitude-even before we'd reached the end of the runway! Once the climb rate was established, the pilot reduced the prop lever to anywhere from 1900 to 1950 rpm for cruise climb, and then he checked the pattern again for traffic. With so much power, he knew we'd be joining the traffic within seconds. Because the Comp Air 7 Turbine was so much more powerful than the 182 camera plane with Editorial Director Bill Fedorko aboard, pilot John Cook (Cook's Diemech firm had overhauled the engine in this plane) had to throttle way back to stay in formation with it, but because both planes had a wide range of comfortable, tight-formation airspeeds, that wasn't a problem. When Fedorko finished the photo mission, he signaled, then headed back to the barn. Now it was MY turn to fly and see what this new, improved turbine aircraft could really do. I'd made a note of the recommended power settings for various cruise conditions so I could see how close |
the book figures were to reality (which in homebuilts
sometimes differs significantly). Because our plane had a five-blade prop, I held the rpm
between 1700 to 1850. I then reduced the torque and made sure the ITT didn't exceed 690
degrees. Once I had the right power setup, I could increase the tension on the knobs on
the power quadrant to prevent creeping. In medium cruise I checked out the controls by
doing steep 360-degree turns in one direction, then in the other. These maneuvers are
quite a test of the airplane's controls, because you have to use all the controls to keep
the altitude steady, and the ailerons and rudder are used to maintain a well-coordinated
bank without skidding or slipping. I had to use some rudder, but it wasn't a problem. In
spite of the fact that there was such a huge engine in a relatively small plane, the
aircraft handled beautifully. The first thing I noticed, in addition to the increased performance, was the quietness and lack of any perceivable vibration (compared to those qualities in the Comp Air 7 Turbine I flew last year). The cabin had been completely upholstered, and it had a smooth-running engine and a newly balanced five-blade prop. These factors made for an enjoyable and quiet ride. This was an entirely different experience from a reciprocating-engine airplane. Next, at 5000 feet I reduced power and tried my hand at slow-flying to see if it would stall. I held the stick back until my arms finally got tired, then I decided the big bird just wasn't going to stall without a lot more work. I noticed we were bouncing along at about 45 mph, and the plane was still flying. I had to use a great deal of rudder to hold the wings level, because the ailerons had given up several miles per hour before. |
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