The issue ended up being that the plane was too tail-heavy. As the saying goes, a nose-heavy plane won’t fly well, but a tail-heavy plane won’t fly at all.

I grabbed a rock off the road and stuffed it into the battery compartment, and used a dried leaf to hold it in place along with the battery, and somehow my caveman tactics worked. It flew very well even on a breezy evening, although using the V tail as a rudder didn’t go well. It caused too much adverse yaw and general weird flight characteristics, so I’m sticking to bank and yank.

Everyone please join me in congratulating Pilot Pebble on his first successful flight! (The damage was caused by the previous pilot)