I know all of us have built planes that initially were less than what we had hoped. Major or minor trim problems that wouldn't go away or that would take some sort of major rework to fix. I've suffered with planes for an entire season or ultimately splatted into to pavement because of one trim problem or another that I either couldn't manage to fix correctly or couldn't figure out or just because I didn't want to cut into a a plane.
Last weekend I flew a plane of my own design that I had been fighting since it was completed last fall. While I was fairly happy with it right from the start, it had a couple of trim issues that drove me nuts. One was pretty obvious. I simply designed the outboard flap too big. It generated too much lift and took a ton of tip weight to get the thing to turn levelly. That caused other problems (including some hinge and tracking problems). Truth was, I knew what I needed to do. I just didn't want to do it. The plane also suffered from a rather intense but brief "wiggle" on hard, outside control at 45 degrees and really poor tracking in level flight. Not so much a hunt as a certain jerkiness. Had no idea what was causing this. To top it off, it seemed impossible to get it to consistently turn and come out of a corner flat.
Anyway, after the season last year (and two disappointing contest appearances), I bit the bullet and cut the outboard flap off and built a new one that was still larger than the inboard, but by a substantially smaller margin. I also found out that when I put the landing gear into the plane, I managed to get pin the forward leadout behind it. The gear has a long torque arm (a trick I learned from Windy) that goes through the gear block and terminates in a hardwood block just under the covering on the top of the wing. As a result, I managed to get the forward leadout behind the gear leg causing some drag under tension. This certainly accounted for the hunting/jerking problem in level flight. Hard to be precise when the controls are dragging like that. I also found a rather large slow CA glop that much have dribbled down and pooled right on top of the elevator control horn. I found this, weirdly enough, using a dentist mirror and looking inside the control adjustment hatch. Had a fun time getting rid of that. The last problem was a little more straight forward. I had built the plane with just a touch too much down elevator. Just lenghtening the pushrod fixed the corner exit issues, thought the darned fairings don't line up perfectly now. Sigh... Always something.
Anyway, the point is, after all this nonsense and hunting down what seemed to be endless problems, I finally got to fly the plane last weekend at the Portland, Oregon contest. And surprise, surprise. The thing flies pretty well now. Still has a bit of that wiggle on hard outside corners at the top of the squares and horizontal eights, though it seem substantially reduced at this point. May need to think about some modification to the rudder to help attend to this, but so far, it's not enough to be too annoying and staying away from hitting the controls too hard at the top of the maneuver seems to largely eliminate this.
So, don't give up on that new plane if it's not all you had hoped. As long as it's of reasonable weight and built decently straight, other problems can be tracked down and fixed. Eventually. I'm really starting to like this plane now.
Topic: Making it work ... Eventually (Read 1432 times)