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/113663
T h e E xc e p t i o n a ll y Ec l e c t i c Ellip s e Designer Dean Wilson (lef) with builder Scott Christiansen and his Ellipse. It's one of four kits ever made. Tree are still fying, but S/N 2 was never completed. engine baffling was a precise fit for the Ellipse's downdraft cooling and front oil cooler. Weight and Balance When the Ellipse was just about ready to fly, Scott felt he needed some additional information. "I called Dean because I wanted to get some ideas about flight testing and handling characteristics," Scott said. "He was helpful with that, and I was able to jog his memory about some weight and balance issues. He did say the Ellipse had an extremely long envelope from forward to aft CG; that with the fuel basically on the CG of the aircraft, and the front seats near the CG, only the rear seat and baggage loading were issues when you have more people in the aircraft. It turned out that the weight and balance was perfect the first time it was put on the scales; with one pilot and minimum fuel it was near the forward edge of the CG. As you put more people, baggage, and fuel into the airplane, the CG moves aft toward the rearward CG range. Dean designed a very good airplane." Flying the Ellipse One of the first things Scott did was taxi testing, mildly accelerating down the runway on the main gear and gently moving the stick fore and aft in small increments. "It would literally just rock on the landing gear," he 24 Vol.2 No.3 / March 201 3 recalled, "so pitch control was very effective. Add just a little bit of back pressure, and it flies off the ground at 65 mph, easily climbing at 75 to 85 mph with a 1,500 to 2,000 fpm climb rate, depending upon how slow I want to get it, with flaps of course." Those flaps are extremely effective, each being 12 feet long with a fairly wide chord. Scott has found "that half-flaps seem to be the ideal position for both takeoff and landing. This airplane is similar to a Piper Pacer with long glider wings; the airfoil changes shape from a laminar flow to a slight camber for about the last six feet of the wing. The wingtip ailerons are small but really effective; I can fly at very low speeds and still have full aileron control. Dean used this same wing design for his crop duster Eagle, which was one of the best ag aircraft out there as far as handling and load carrying." Scott did have a surprise on the very first flight when he discovered that he had to hold heavy right rudder—but he quickly determined that it was because the ailerons and flaps needed rigging. Despite that, he immediately liked the way it handled. "After retracting flaps, the Ellipse accelerates above 100 mph quite easily and has a cruise climb of 110 or 115 mph indicated, while maintaining a climb of 500 to 1,000 fpm," Scott said. "I did the flight testing at 75 percent power because I was breaking in the engine; so it was always 2400 rpm at around 24 inches of manifold pressure."