Saturday, February 26, 2022

Time: 4h

• Worked on wiring diagram. Playing with tool called WireViz. I created the wiring diagram for the Trig TT-22 Transponder, TN-72 GPS Source and TC-20 Control Head.
• Spent 45 minutes or so figuring out the heim join for the aileron push rod to aileron connection. They don't make a heim joint that meets the requirements. The fittings on the aileron need to have a joggle put in them to accept a wider heim join, per Mark.
• Attached front of the 4 side stringers
• Began working on how rear windows will mount
• Put joggles in the aileron mount per Mark so the alieron push rod heim join will attach properly

Notes

• Determine proper heim join for the aileron push rod. The ones that came with the kit are the right thread but the heim join is too wide.
  • The right width of the heim join is 5/16" (0.312", 7.9mm). The thread should be 1/4" 28. The width of the only heim join in the kit with 1/4" 28 thread is 7/16" (0.4345"). The kit did come with hiem joins that has a width of 5/16" but they are 10-32 thread. For Aurora Bearings they make an MM3 that is the right width but it is 10-32 thread. MM-4 is 1/4" 28 thread but 0.375" wide. I can not find a 5/16" width with a 1/4" 28 thread.
  • Contacted Mark for help.
  • Mark said the proper heim joint does not exist. On the aileron fitting you need to put a slight joggle in both brackets to accept the larger heim joint.

Photo Stream

A proper fitting heim joint

This heim joint, though, is 1032 not 1/4 28 as needed by the push tube. The proper heim joint does not exist, thus the aileron bracket needs to have a joggle in both sides to move it from 0.312" to 0.375" width.

The most narrow 1/4 28 heim joint

Need to modify the bracket to accept.

Drilling out the temporary rivets to allow access to mount 4 front/side stringers

Modified rivet gun

Building a Zenith previously, we went through a few hand rivet guns even though the majority of the work was done with an air rivet gun. This one has served me well, even after grinding a lot of it away to fit in tight spots such as this one. Bought from my local Ace Hardware, a Stanley.

Ground in multiple places

The head is ground on three sides to fit close to other objects. The frame being ground is a new one for the Bearhawk to allow me to rivet closer to a tube.

We're not pulling big, heavy steel rivets, just small stuff.

Bevel in

I was thinking this would be nicer on the fabric. Bob's original design was for the bevel to be out, facing the fabric.

Test fitting one of the rear windows

Trying to decide to put the bevel in or out.

Working on expanding the control horn on the aileron

The heim joint is too wide. Mark said at the factory now they are creating two joggles in the countrol horn on both sides to expand it to fit the wider heim join. I need to do that on my kit.

One bend made, now to bend it back in further out to make it 90 degrees again.