I had one of these. 11.75 pounds with a ST3000. Flew like it was on rails. Perfect aileron rolls with no wobbling around. I wasn't using any differential in my ailerons. Just flew it. It would do aileron rolls the length of the runway and it looked like you ran a string though the spiner and out the tail--then slapped the wingtip. It would snap clean and stop immediately when you let go of the sticks. No over-rotation in snaps or rolls. Inverted was almost hands free. All I had to do was put my finger on the elevator stick and it would fly level inverted.
I had to move both elevator servos up into the gas tank area and my rudder servo was pull/pull and mounted about 1" in front of the CG.
These planes are tail heavy as all get out. Keep as much weight up front as possible.
DO NOT put servos in the tail. You'll be sorry. You've been warned.
Gas on this airframe? NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
It's just not big enough. You need--absolute
bare minimum 1000 square inches for a gas engine.
Keep it light. That should be your biggest goal if you really want it to fly good. Light Light Light Light Light Light Light Light Light If you load it up with a gas engine--it's just gonna be a fat Cap like the other guys told you.
Fat Cap is no fun. Light Cap can reach out and bite you in the butt--but a Fat Cap will eat your lunch and spit you out laughing.
Put a 1.80 or 2.0 cubic inch motor on it. 2-stroke or 4-stroke -- thats personal preference you need to decide. I absolutely LOVED mine with a ST3000 turning a 20-6 prop around 7300RPM. That thing had all kinds of pull in the vertical lines.
Will it 3D? YOU BETCHA!!!!!!!! But, not if you hang a gas engine on the nose and make it weigh 13 pounds. Yeah, it'll hover all day long with a gas engine -- but there's more to good 3D than hovering. Do you want to do harriers with it? How'd you like to see it stop in it's tracks and pop straight up into a wall? Literally looks like you slammed it into a wall and it just stops right there. BAMM!!
Keep it light. And keep your hinge gaps a little big so you can get the absolute maximum deflection on the elevators and rudder. Then seal your hinge lines with covering or tape to prevent flutter. You HAVE to seal the hinge lines--because your going to need to leave a 1/16" gap in your hinges to make them deflect enough to get that tail under control. If you don't seal them hine lines--it won't live very long.
Most guys made the mistake of not enough control surface deflection and then claiming it would snap out in walls and harriers. Bull!! You just gotta get enough throw dialed in and fly it HARD. Dial in some expo and slam the crap out of it. This plane likes to be flown slow--but you have to really slam on it to make it 3D good. Thats why you have to keep it light and you have to not be chicken. Get those tail surfaces to max deflection and fly it like ya stole it.
It's a darn nice flying plane for such an old vintage. If I wasn't so hooked on gas ------- or if I ever had to scale down to that size again--------I'd pick one up and slap a Saito 2.20 on it. It's a nice plane and it will reward you if you just keep it light and power it really good.
Good luck. Hope my lop-sided opinion helps.
