Red Powered Glider - The first plane I built after time away for university studies. This plane was cut from EPS foam with a hot wire, and covered with white paper.
Features:
Original FoamFlyer design, no plans exist
T-tail with servos in the tail
Bolt-on wing
Removable canopy with magnet attachment
Pod-mounted motor in pushing configuration
Hardwood landing skid
Polyhedral wing
Painted with Krylon H2O "Red Sea"
Bottom of wing has yellow stripes for visibility
Specifications:
Wing Span: 72 in (183 cm)
Wing Area: 660 in2 (42.6 dm2)
Airfoil: 12% Clark-Y
Wing Loading: 10.9 oz/ft2 (33 g/dm2)
Fuselage Length: 72 in (183 cm)
Controls: Elevator, Rudder, Throttle
Servos: Hitec HS-81MG (two)
Receiver: Castle Creations Microstamp 4-channel
ESC: Castle Creations Phoenix 40 Brushless
Battery: Emax 3S2250 Lipo
Motor: Nippy Black 2510/114 Brushless
Propeller: APC 10x6 (pushing)
All-Up Weight: 50.0 oz (1417 g)
Construction time took about 8 weeks, off and on. The paper covering adds tremendous strength to the foam structure with little weight gain. The wing saddle section of the fuselage is very strong, as it is also covered with paper on the inside.
During construction small cables were inserted through the fuselage to allow the servo cables to be pulled through the inside of the fuselage. During painting and before servo installation, the guide cables fell out. It was difficult to get the cables back through the channels cut into the tail section. New channels were cut, so the only part of the plane where you can see the servo cables are at the tail.
When the plane was finished, it was discovered the nose was too short / the tail was too heavy. Even with the motor mounted near the center of gravity and the large battery as far forward in the fuselage it could go, it required 20.9 oz of lead counterweight in the nose to achieve the proper CG. This of course was rediculous, resulting in a total aircraft weight of 63 oz. Then I decided to cut the nose off just forward of the wing's leading edge and insert a 16 in long fuselage extension. This extension was constructed to match the fuselage cross section and was covered with paper and painted to match the rest of the plane. The net result was an increase in weight of 1.2 oz due to the nose extension, but a reduction in counterweight of 14.1 oz, for a total weight change of the entire plane from 63 oz down to a more reasonable 50 oz. Wing loading reduced from 13.8 oz/ft2 down to 10.9 oz/ft2. It still has lead counterweight, but much less than before.
First flight was on the morning of Saturday, July 25 2009 at a small grassy park in Tehachapi California. With the help of SlopeShredder, we prepared the airplane for flight under clear skies and no wind. It was then discovered that the battery would not reach the ESC due to the nose extension, so I had to run home (about 2 miles) to get an extension cable. Upon return we checked all the controls and were ready to fly it. Slopeshredder suggested a glide test, but I felt it was unnecessary.
We set the plane on the grass aimed South along the length of the field. I slowly advanced the throttle. SlopeShredder thought I was going to do some taxi tests, but prior experience with this motor told me it could pobably take off by skidding on the grass. The plane lifted off and climbed well, and cruised well at full throttle. There were some small trim differences in the elevator between full power and unpowered glide, this was because the motor thrustline is above the fuselage centerline.
Several flights were made by both myself and SlopeShredder. Landings were challenging because the plane gets into ground effect and floats. The plane would benefit from some flaps. The battery got a little warm as there was inadequate cooling inside the fuselage. Overall a fun project and good flying plane.
