Wed Nov 2 2011

Step mounting bolts and smoke oil line

My friend, Tom Thompson, was nice enough to send me these two AN3-26A bolts to use for my steps. He apparently had them from old North American surplus and made me a great deal on them (free!). Actually you can see the head is drilled, so technically they're AN3-H26A, but they're just fine for the steps.

A few minutes later, I had 'em installed and torque sealed. Would it be hard to believe that I sorted through my nuts to find two with the red fiber insert? I'm not too particular, am I?

After taking a lot of measurements and designing up a piece of tubing in SolidWorks, I made the first attempt for my smoke oil line. Somehow I managed to make the forward end an inch too short. Other than that it looks pretty good.

The aft end of the tube looks pretty good, too. Right now I'm planning to install a bulkhead fitting through the forward web of the spar and a snap bushing through the rear web of the spar. The elevation of the pass-through will match that of the two existing pass throughs so that I don't have interference with the control column.

It's a bit tricky trying to consider all the factors when placing these lines. Factors like:

  • Can the tube be flared before installation or does it need to be flared in place?
  • Is there room to get the flaring tool on the tubing if it needs to be flared in place?
  • Is there room for the B nuts?
  • Is there wrench access?
  • Is there at least one 90 degree turn between fittings (per AC43.13-1B)?
  • Is there enough support for the tubing along the run?
  • etc, etc...