Sat Sep 25 2010

Pilot / pax heat control linkage

After thinking about it some yesterday, I decided to thin down the pivot washers a little to take out some of the linkage slop. They were 0.062 thick, so I drilled a 3/8 hole in a piece of scrap 0.040 thick material and filed them down.

Only took a few minutes and they were each down to around 0.047 - 0.050.

Next, I started working on the locating the pivot point and stop plate. Here's my first attempt, but as you can see the hole would go right through one of the louvers.

To avoid that, the pivot point needed moved over and that meant notching out a corner of the baffle plate. I started by drilling a hole with a unibit. I drilled it a little large to allow clearance for the spacer washer (shown taped in place).

Sweet. Now at least the pivot isn't in the louver.

Rather than using a washer for a spacer, I decided to fabricate a little stop plate.

I also decided to make a new link...this one is joggled which will allow me to avoid a second spacer under the bellcrank.

Here's the new link. You can see that I also fabricated a new bellcrank as well (note the end hole in the bellcrank is only drilled 1/8 inch, not 3/8 as the previous version was).

The end of the bellcrank needed joggled up to allow for installation of the B Nut (Bugnut).

I also trimmed off the lower corner of the baffle so that when it's in the open position (actually shown in the closed position here), it doesn't cover much of the inboard-most passenger's louver.

Last item for the evening was to drill #12 hole in the bellcrank for the B Nut. I had seen these before, but couldn't remember what they were called. My friend, Tom, put me on the right track. With two thin washers on the bottom and one on the top, this is a nice snug fit. It still pivots easily, but doesn't wobble. Tomorrow I'll clean the primer off some of these parts, possibly prime some of the others, and rivet this puppy together.