Trimming is always a compromise, and it depends on what your objectives are. In 15 carrier where there is a speed limit, try to hit the speed limit. Hi speed points are more of a "sure thing", especially under less than ideal conditions. Try not to exceed the speed limit, though. If you consistently exceed the speed limit, move your leadout guide back.
Philosophy aside, if you are trying to trim for a good hang, first you need an aft CG. It's too far aft when the model is impossible to fly in high speed, OR whenever you are in a hang the model wants to go over 60 degrees or on its back. If the model is hard to fly fast but still won't hold a hang, try reducing your elevator movement.
Leadout position and tip weight work together. I think more tip weight is more beneficial than more line sweep. When you're flying level slow flight, tip weight gives you outboard roll for tension, with less yaw to slow down your high speed. Pull the nose up, and the tip weight gives you outboard yaw AND roll. If your plane won't stay out on the lines, you need more of something. If it bounces or bobbles all the time, you've got too much of something.
As previously mentioned, my 15s use 2 1/2 oz tip weight. The line guide is about 2" behind the CG, 14 1/2" from the fuselage. My airplanes are ballasted up to about 25 ounces empty weight. The Conquest 15 always hits the speed limit on 25% nitro. The MVVS only sometimes hits the speed limit, even on 50%. It may do better with a "pitchier" prop, but I haven't tried it with anything other than a 7x4.
First, make your airplane work reliably. Then try to make it fly slow. Then figure out the best balance between high speed and low speed for the best results. Good luck, and most of all have fun with it!
Topic: Speaking of trimming (Read 527 times)
