Caution: Control System Stiffness

January 1986

We have previously warned builders to ensure absolute freedom from stiffness in the pitch control system. This is very important and must be corrected if it exists in your EZ. We never have particularly addressed lateral (roll) control system stiffness. While not quite as important as pitch, tight bearings in the aileron control system really spoils the nice flying qualities inherent in an EZ. Conscientious attention to detail here will pay dividends. Long-EZs and VariEzes have similar lateral control systems, the main difference being that the CS-132L belhorn in a Long-EZ is mounted inside the wing root, and the same part (CS-132) in VariEze hangs out in the breeze, inboard of the wing root, close to the bottom cowling. Both of these areas can be troublesome. In the Long-EZ, you must assure that the end of CS-132L cannot contact the bottom of the wing.

Even if you have to dish the skin locally, you cannot accept any rubbing here. In fact, it would be best to have at least 1/4" of clearance. The VariEze though, needs even more clearance between the lower end of CS-132 belhorn and the bottom cowling, because the cowling will tend to flex up in flight and could cause a rubbing interference, or even worse. For example, if your CS-132 belhorn just barely clears the bottom cowl while at rest on the ground, it is possible that in flight the cowl could move up enough to seriously interfere with lateral control of the aircraft! The answer is a streamlined blister on the bottom cowl which will give the required clearance and will stiffen the bottom cowl. Lubricate all bushings and bearings in the control system and do not fly until you have the control system working nice and free with no tight spots or stiffness anywhere within the full range of control stick movement.

Copyright 1999-2017 All Rights Reserved