Rudder Pedals and Elevator Brackets

I've been making small amounts of progress here and there. I'd been putting off the rudder pedal swingarms, because I wanted them offset to work with the offset seating. In order to generate more shoulder room, the pilot's seat will sit 3" forward of the pax seat. That doesn't sound like much, but it causes shoulders to overlap rather than push against, which makes things much more comfortable. My shop really isn't set up for metal work, so cutting, grinding, and jigging this 4130 has been a challenge.

This was my first jig attempt, and while I did get it to work well enough, it was a huge hassle. The second jig turned out a lot better, and was much easier to build.

These were sent off to be welded, and are now ready to be cleaned and painted. I'll be cleaning and painting the steel parts of the control sticks assembly at the same time.

While I was set up for it, I went ahead and cut my elevator pushrods to length. I have a 5/8" rod from my control sticks to a T lever, which transitions to cables, which run back to another T lever and a 3/8" rod to the elevator.

The pushrods are not yet connected to the rod ends in the picture, but that's not an oversight. I wanted to hook everything up before drilling holes and riveting, to make sure the length was right!

The main reason for my slow progress has been my own work in adjusting existing designs to fit my needs. Specifically the brackets/T-lever assemblies. It takes me a while to fabricate the metal bits, so I try to make absolutely certain that I don't have to re-make any parts due to unforeseen problems.  A few of my sketches are below, showing the bracket and T-lever setups.

This is a 4x scale drawing of my forward T-lever setup. From left to right: sintered bronze (SB) bushing, 3/4" aluminum spacer, aluminum T-lever, SB bushing inside the T-lever, 3/4" spacer, SB bushing. I have SB bushings on both ends, so that's what will contact the bracket, and I have a SB bushing through the actual lever itself to facilitate smooth rotation.

Next is a 1:1 drawing of the rear T-lever, which also incorporates an arm for counterbalancing the elevator. I will preempt this drawing by saying, I did not use this design. Rather, I adjusted it with spacers.

And here's a 4x drawing of the center of the assembly, or the pivot point:

From left to right: SB bushing, T-lever, 3/4" square tubing for counterbalance, 1/4" angle, SB bushing. The problem with this design is, the cables will rub the counterbalance arm when it pivots. As a result, I'll be adding a spacer between the T-lever and the 3/4" square tubing. 

This gives you a better view of the problem. The second and fourth "nut" from the top will have cables attached, and anytime the elevator isn't slightly up the counterbalance will intersect one of the cables. Adding an 1/8" spacer to the pivot point and the pushrod point should give me enough clearance.... or maybe 1/4". I'll be mocking this up *not* in the plane, to make sure I get it right, before I start drilling holes in the wrong spots. Anyway, I hope to have most of this finished after this weekend. 

Rudder Pedals (Part 1)

It's mid September, and I'm trying to use the rest of the warm weather to get as much fiberglass done as possible. However, it's raining and cold today, so I'm working on something the weather won't affect. I stole Mark Langford's design for rudder pedals. You can steal them too, by visiting his site.  These designs call for 4" aluminum angle stock, ⅛" thick. I was unable to find anything that large any thinner than ¼", so that's what I'm using. As a result, I had to slightly adjust the templates on the smaller piece of aluminum angle so the pedals would line up correctly. I printed the templates out on full-sheet labels, cut them and stuck them right on the aluminum.

My shop is set up for cabinetry, and I work with a lot of exotic woods on a semi-regular basis. Because of this, I didn't want to use my bandsaw to cut aluminum and risk getting aluminum shavings stuck in my expensive wood the next time I work with it. So I resorted to using a sawsall with a bimetal blade. I was able to rough out the shapes that way (along with some cheating with a drill press.)

From there, I used a sander to finish shaping the pedals and round the edges. I then drilled out a number of holes (as laid out in the drawing) to save weight.

I'll use the pedal swingarms to line up the pedals with the brackets, then attach the brackets and pedals with JB Weld. I may add grip tape if I feel it'll be beneficial. I have enough material to do two sets of pedals, but I haven't decided if I'll install them both or only the pilot's side. The passenger/"copilot" won't have brakes, so pedals would really be superfluous. Once I build my brake cylinder bracket, and have my seats installed, I'll attach the pedals to (and most likely relocate) the swingarms with PVC pipe and a screw (again a la Mark Langford).