Control Systems

Materials used to build airplanes seem to have contradictory qualities. Take control cable. It has to be flexible and strong. A length of 1/8-inch diameter, 7x19 galvanized cable has a breaking strength of 2,000 pounds-that’s enough to sustain the weight of a fully loaded Piper Cub, with a pretty good margin left over

In previous articles, I have discussed most of the hardware items needed to build your airplane. The last article in the April issue detailed rivets and their installation, aircraft screws, turnlock fasteners, and small miscellaneous hardware pieces.

The obvious question comes to mind. Why balance control surfaces? Do they really need to be balanced?

Very few homebuilders know or understand what the term "rig" ("rigging") has to do with airplanes.

A less than discriminating pilot may not know or notice that his airplane is out of trim... however severe that condition might be.

Sitting in the "office" of a P-51 once, I concluded that I would have a throttle lever that worked as smoothly some day. No doubt I could not even afford the gas to fly it, let alone fly the P-51, but I figured I could build a throttle control that felt as good. I decided I could custom build my own and make it look like it belonged in my little KR "office."

All pilots know how aircraft control systems work, and how to operate them.

FIRST, LET ME set the record straight on one thing in the matter of push-pull control systems vs. cable control systems. Some very authoritative books and manuals state in absolute terms that the main disadvantage of using cables for control linkages is that their tension must be adjusted frequently due to stretching and temperature changes.

FROM THE EARLY days of aviation up to the present aircraft builders have been, quite effectively, transmitting control inputs from the cockpit to the control surfaces with control cables.

THE ASSUMPTION IS reasonable. Flutter in ordinary flap-type control surfaces can be prevented, at least in the speed ranges most homebuilts operate, by using properly distributed mass ballast to obtain a 100% balanced condition.