Originally Posted by Lil Stinkpot
Remind me again, please: If a model is pitching up and down as it flies, like a mild case of dolphining, is it nose-heavy or is it balanced right on the edge, and is too sensitive? I'm reviewing the video from today's flight of the Radian, and it's making small bobbing motions, oscillating.
If it does this hands-off (that is, you're not moving the sticks), then it's probably nose-heavy. If so, you should be able to stabilize it by leading the pitch oscillation with opposite elevator (push as it's just starting to pitch up and pull as it's just starting to pitch down - you may need to adjust lead timing a bit). If it does this while you're flying it hands-on, it may be too much elevator throw, or CG too far back. Trim it for a nice glide speed with a smooth, gentle hand-toss, then try throwing it hard, straight
at the horizon or slightly down. Does it pitch up into a stall? Probably nose-heavy. If it pitches down, probably tail heavy. Adjust balance and elevator throw to taste.