Monday, March 24, 2014

Other Uses for Welding Rods

Well, they are useful for welding too ; ) 

Not much time to blog these days with time running out to get the plane in the air and in the trailer for the Mojave Fly-in, but the list is getting shorter...

New Control System

The reason for revising the control column was to lower the seat so that I could wear a helmet. Along the way I discovered a few things. 

I had always blamed my plane's pitch sensitivity on the airfoil shaped tail and the gap seals. 

The control column was partially completed when I got the project but fit so I did not question it. Since there were a bunch things that were different than the plans so I started measuring things trying to figure out why they were built differently. I did not want to build something that did not fit. Most of what was different looked like solutions to mistakes that would have caused clearance issues.

The plans call for the control stick to be 9.375" from the pivot point to the top. Mine measured just over 12". I can't blame that on the previous builder since I built the stick. What I did wrong was put a teak wood grip on it that increased its length by 3 inches. Duh. The mechanical advantage was increased from about 3 to about 3.82. No wonder it had almost no resistance to stick movements during landing.

The reworked stick will be adjustable from 7-10 inches. It allows both tuning the stick force and removal of the upper part of the stick for maintenance.

The new system is almost finished. I revised it to fix some issues with the original design, mainly the rear idler. The way it was designed caused the elevator push/pull tube to seesaw within the control column. By redesigning it, the tube now runs flat, resolving a number of clearance issues.



The redesign also allowed me to move the control stick 3" aft, allowing me to rest my arm on my leg while flying. 


Still need to weld on the aileron control horn and finish a few details. I'll be happy to be sanding again...







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