I scratch built Yellow Bird starting in January 03 and it first flew in April 03. I used RCM plans called Cloud 9er as a guide. I changed the fuselage construction to fit my needs and changed the tail shape to make it look neater. It has a 71" span and is 52" long. It weighs 8.5lbs. The engine is a Super Tigre G75 and drives a 13X6 Master airscrew scimitar propeller. The wing is the thing. This wing has a semisymmetrical airfoil in the straight leading and trailing edge area (58" of the span)and is built flat. The 6.5" of each tip blends to a flat bottom airfoil and is washed out (twisted) 3/8" at the tip. This almost completely eliminates tip stall. I wanted to try flaps so I went with split flaps. In theory they are drag or airbrake flaps and should not have much effect on trim. They have wells in the wings so they completely retract into the underside of the wing. The flaps are 3"X 6" each and made of 1/8" plywood.

I own 30 acres of pasture land so I use a push mower to make a runway about 50X300 on rough old pasture ground. I built Yellow Bird to practice takeoffs and landings. I use Du-Bro Fiberglass landing gear and 5" Sullivan wheels. I flew it the first year almost every day. I used a Tower 3000 6 channel radio system in it. That worked and it never crashed because of the radio but it is real glitchy. In March '04 I bought a JR 642 system. It works much better with no glitches at all. The JR computer makes it possible to mix the ailerons and flaps. I use the gear channel to operate the split flaps. The split flaps are real effective. In calm wind landing with the flaps down is like landing with a 5 mph head wind. The theory about the split flap not effecting the trim was wrong, it takes a lot of down elevator to maintain a normal glide. A normal takeoff with flaps up takes about 50' of ground run. With the flaps down the airplane will jump up in about 10' of ground run. After it lifts off it wants to climb straight up and takes nearly full down elevator to keep it from stalling out. Using the JR radio computer I use the flaperon mode. I first put the flap portion down about 10 degrees. That improved the glide. I was surprised that it trimmed the airplane nose down. Thats just the opposite of what I had expected. Then I adjusted for about 20 degrees down flap. That didn't help anything and there was almost no aileron control. I now just use the 10degrees down.Yellow Bird is a fairly high drag airplane but with the Super Tigre 75 it has plenty of power. It has a real good climb. I fly most of the time with the engine at about 1/2 throttle. The glide is a little steep but the flaperons really improve that. It can do most aerobatic maneuvers. It is really unstable inverted because of the washout in the wing tips.

Yellow Bird can do two consecutive snap rolls both inside and out side. It can spin both right side up and inverted and can reverse the spin rotation right side up. One cool maneuver is to snap it at the top of a loop. I haven't been able to fly it knife edge and when I try to slow roll it when it gets just past the wings vertical it flips to right side up. I can do both inside and out side barrel rolls with it. I like to do hammer head turns with it they are just beautiful. A few weeks after the first flight Mike was out with me and I said watch this. I pulled up on the vertical line, half rolled and then did a hammer head and half rolled on the vertical and pulled out almost exactly at the original altitude. "Wow". The aggravating part is as many times as I have tried to do it again, I have never been able to duplicate that maneuver. I have gotten braver and moved my maneuvers down to lower altitude from maybe 300' to more like 100'. I rarely get disoriented. In level flight, I rolled inverted pushed out to vertical and did a hammer head but I didn't get perfectly vertical and blew the hammer head, got disoriented, and recovered from the screaming dive with about 10' to spare. I fly Yellow Bird almost ever day I fly it in the wind and cross wind. Mike was with me one day when the Parsons airport weather was reporting 18 gusting to 24. The airport is 10 miles to the southwest. I was doing 0 length takeoffs and what I call bird landings. Hover the airplane at about a foot altitude and settle straight down. How about backwards fly bys, what fun. Last week, Diann was watching me and taking pictures. Here are some of the pictures...

Flaps Up --------------------------------------------------------- Flaps Down