Chapter 16 - Section 2

Fabrication of Pitch and Roll Parts


Tubing Parts

I was having a tough time cutting the steel tubing with my band saw, hand saw, as well as the jig saw - I spent at least a good 1 1/2 hours with little success. Then I remembered I have a $20 electric grinder I got from Lowe's several years ago which has a cut off blade as well. I was pleasantly surprised that it can whack off the steel tubing (to rough dimension) in  about 15 seconds. See how the sparks flew (left) and I was dressed for battle as well (i.e. eye protection, heavy gloves and sleeve protection). After a couple parts were cut and allowed to cool, I ground them down to precise dimension with the bench belt sander. Worked great! I did not cut all the tubing at once because some of the parts we are using differ from plan (e.g. FMN10), I decided to cut them as I need them. 


[Hindsight] I was reminded by a couple of people including myself (later on) that a pipe cutter can do a better job. I dug up the one in my garage that I bought for a bathroom project many years ago and tried a couple of cuts. It makes a much better cut than my grinder/cutter - BUT I have to admit, I like the grinder/cutter approach better. It makes its cut in seconds and the follow up sanding (with bench belt sander) is effortless. The outcome is still precise and clean. Maybe I need to take a tube cutting class to improve my technique...not.   


Installing the FMN10 Torque Tube Bearings

The bolts for the FMN10 are the AN4 (1/4") instead of the AN3 (3/16") in diameter. I followed Wayne Hicks' approach in  mounting the bearings to CS109 and CS118 respectively. I had to open up the center holes just a bit to make sure they are flush. I like this mounting method better because it gives me a bit more room between the CS109 block and the side stick. I also found a nylon washer (in place of the plan AN960-1016 washers)  that fits snugly between the torque tubes and the FMN10 plastic body and it made the interface smooth as silk... There is a drawback though - if the FMN10 plastic body ever pops out of its metal housing, these nylon washers will be too small to keep them in place. Fortunately, these nylon washers have the same thickness as the metal washers, therefore, changing it out will be simple. Soooo, I need to give it some serious thinking... 


I did not like the first of the two torque tubes I made because the hole I drilled for the control stick was crooked (not perpendicular to the torque tube). Consequently, when I push/pull on the control stick (forward/backward), it swivels crooked. So I spent a couple hours and made a new one. It turned out much better - part of the learning curve.


[Hindsight] I invested on a V-block from Aircraft Spruce (~$12) to help drilling vertical holes through the torque tubes. It's well worth the money. I also pick up a neat trick for drilling a straight hole down the center of a cylindrical part without using a V-block.