I persuaded the newbie neighbor to get a Super Cub. Checked it out on maiden 2 days ago: had a wicked left turn, even with full right trim. Two pairs of hemostats and tweaking the rudder pushrod adjuster fixed that problem.
Yesterday: after 2 successful flights landed the plane on asphalt -- decent landing -- a little rough as it came in on a 2-wheel landing .. and as it did so it snapped the prop in half
. First time I've had that problem with Flyzone UM equipment. Also bent the prop shaft at the same time. Straightened the shaft and replaced the prop.
This morning: flew fine for 3-4 flights. Gave the dad a lesson, also his 13-year old son, and also his 12-year old daughter. Everybody happy.
Tonight: took the plane up and handed it to the dad, who flew it fine for a turn around the field.
Then all of a sudden, while the plane was above and fairly close in, it went into full throttle
climbing rapidly and drifting away (even tho there was no wind -- absolute calm.) I took control of the Tx --- couldn't do a thing with it. So I turned off the transmitter. Plane kept climbing. That means the Rx was locked in full throttle
-- and not the Tx. Turned the Tx back on -- still no control. The plane kept drifting away .. and finally landed in a high tree maybe 300 feet away.
Have never had this happen to me in four years of flying UM planes: first with the PZ Cessna, then the early Vapor, then many scratchbuilt foamy WW1 bipes, then the Flyzone Playmate, then many more scratchbuilts with those 'guts', then the Flyzone AlbatrosDV, then many more scratchbuilts with those 'guts', then testing flying this new Super Cub UM -- no trouble. Now this. Not a good way to introduce newbies to UM flying.