Experimenter is a magazine created by EAA for people who build airplanes. We will report on amateur-built aircraft as well as ultralights and other light aircraft.
Issue link: http://experimenter.epubxp.com/i/84816
Aerochia's First: The LT-1 "As a test pilot, you look at a new plane with an eye for what may present a problem. With this air- plane, all the things I thought might be problems weren't. There was plenty of rudder, plenty of aileron, plenty of elevator, and there wasn't any blanking or slop in the controls." So, Len felt confident before he left the ground. "When you're flying, it does just what you want it to do: Center the stick…boom!…the plane stops roll- ing. Good ailerons make for smiling pilots. This one makes me smile." Performance, as Measured So Far Len continued, "After we calibrated the airspeed indicator, we found that the stall came at 47 knots. When we called Greg Cole and asked him what he had predicted the stall speed to be, he said 47 knots. "With the stall strips, the airplane stalls straight ahead. The roll rate is about 120 degrees per second: crisp, but not twitchy." One of the modifications to the HKS engine that powers the LT-1 was to replace its twin carburetor setup with a single carb. Len thinks this interim modification is respon- sible for a reduction in horsepower from the rated 60 hp. (Andy Chia- vetta admits to a very quickly made air filter arrangement that he can't wait to improve.) Additionally, the airplane has not yet flown with its wheelpants. "Gear on this airplane is a huge portion of the drag." Still, Len said, "With the cruise prop, and no wheelpants, and probably down on power, it goes 129 knots." That's 148 mph. Oh, and the flight tests are being conducted in Thermal, Cali- fornia, in the summertime. Andy's design top speed of 150 mph seems pretty reasonable. Approach can be made as slow as 65 knots. Takeoff in this light air- plane is very quick, considering its small wing (60 square feet), lack of flaps, and modest power. Len said, "On the worst day, with the prop at steepest pitch, we use maybe 1,000 feet of runway." Flight Report Len noted that he felt "no strange vibrations. The throttle is smooth; it's easy to take off, easy to fly; smooth and responsive." So far, test flights have mapped the heart of the CG envelope. "One way to check when you're approaching the aft limit of stabil- ity," Len explained, "is when you do a standard turn, and then tighten it up, adding g's. You should always have positive stick forces. If the stick falls into your lap, you don't have enough horizontal tail. At the design aft CG, this airplane has enough." "When you're fl ying, it does just what you want it to do: Center the stick…boom!…the plane stops rolling." He liked the approach and touch- down, too. "The gear is in the right place. You can flare, touch down on the mains, and gently let the nose down. It tracks straight on the ground." Partially this comes as a result of just 60 nominal horses and a well-sized rudder. "There is very little P-factor. With the controls, you feel connected to the airplane. Ailerons and elevator have little or no free play, and there are no aerodynamic dead zones; when the control surface moves, the plane moves. There's a direct connection between the pilot's brain and the control surfaces. Controls are light but not twitchy; they have a good centering feel. The LT-1 has the immediate reaction of a high-performance aerobatic ma- chine, but the pitch and roll rates induced per inch of stick movement are less. With a flick of the wrist, aileron response is immediate, but you get 5 degrees angle of bank instead of 50." Len also said it's no effort to fly, including pulling it into and out of the hangar. "A test pilot likes a 20 NO. 2/OCTOBER 2012