I second what David said. I have a 73 inch Cap and while entering a high alpha manuver the thing would tip to the left all the time even with spoileron. After scratching my head and walking around in circles I decided to check the differential of the elevators. I found this tip on a pattern website and I made the gauges. Really easy to make and makes it easy to check differential throughout the whole range of elevator travel.

An Idiot Proof Elevator Differential Gauge

If you have split elevators a very simple way to test for elevator differential is to get two stadard clothes pegs and epoxy in two straight piece of piano wire (as in the diagram). Clip the cloths pegs to your elevator's at an angle so the ends of the wire are almost crossed, then move your elevator up and down. If the wires stay the same vertical distance throughout the movement, you have perfect elevator movment! but if the wires change their distance apart you need to (if you have a computer radio) mix in some opposite aileron to couteract the elevator differential. I found this out after two years of flying a pattern plane that when ever you did loops you had to hold in right aileron.

Guy McCaldin (design John Payne)
Australia email: [email protected]