Chapter 13/23 – Static ports & Baffles

My first task this morning was to safety wire the last bolt on the alternator that secures it to the bracket arm.  However, when I tried to insert the 0.032″ safety wire it felt like it was snagging up on something.  I’ll note that when I was I tightening this bolt yesterday during its final torque, my 1/2″ wrench slipped off it a couple times… then slightly rounded, it was hard to get the wrench back on (I found out WHY today… read on!).

Well, I used the smallest drill bit I had, 0.040″ to clean out the hole, with very little resistance.  Probably just a burr I thought, so I pressed forward with my safety wire job.  After pulling the wire tight, it simply tore out the bolt head side and popped out of the channel.  Yup, the wire had pulled right through the seemingly soft bolt (equivalent to Grade 5 I found out).

Clearly I needed a new bolt.  As insurance in case I couldn’t find one locally, I finished up an order I had sitting on ACS for nearly 2 months now, of course adding a 5/16″ AN bolt with a hole in the head.  With the damaged bolt with me, I then went downtown to grab a Grade 8 fine 5/16″ bolt and try my luck at drilling a hole through the head to get this alternator installed!

It was at Lowe’s that I discovered that this was not in fact a 5/16″ bolt, but rather a M8-1.25 metric bolt.  Hornswaggled again!  Hmmm??  Well, they didn’t have any Grade 5 or 8 metric bolts, so I went to another local hardware store that carries just about everything.  There they had both 8.8 (~Grade 5) and 10.9 (~Grade 8) bolts, so I grabbed both.

Below is the original bolt sitting on the C-clamp, and the Grade 8 equivalent clamped up to have the head drilled to take safety wire.

I didn’t mess around with trying to go through a corner, but rather went straight through a wrench flat… Success!

I then installed the new bolt, got the alternator positioned and then torqued it to spec.  Once in, as you can see, I got this sucker safety-wired up.

Now to digress a bit from engine stuff.

A while back I was looking at some various airplanes at the airport, including a Long-EZ, and noticed the seeming lack of STATIC ports on Long-EZs… clearly because the plans simply has an aluminum tube in the side wall with 3 tiny holes drilled into it.  I had planned on using more traditional static ports but as I thought about it, I liked the look (or “non-look”) of nearly imperceptible static port(s).  To be clear, I’ll note that the plans only has a static port configured on the left side.

In a recent discussion with Marco, I circled back to the plans style static ports and asked his opinion on going with one side only or both sides more in line with a traditional light aircraft (or quite a few out there I should say).  He was of the opinion that for a plane that is IFR capable it should have 2 static ports, one each side.  I point out this discussion because beyond observing what other planes have, I’m going to admit that I don’t claim to know the in-depth dynamics of one vs two of these suckers.  And honestly I’m not going to take the time to do research, so Marco’s kung-fu wins out here by default and I’m cramming 2 of the original style static tubes in my bird… one each side.

Thus, I pulled up Chapter 13, cut two 6″ lengths of 3003-0 tubing (plans calls out 5052, but I didn’t have any on hand) and cleaned them up.

I then crimped the ends on one side, flattened the outboard side a bit (to make the tube more “D” shaped, with the flat side going against the inner skin of the outer wall.  I then bent the tubes as I thought they would need to be inside the avionics area [that changed in rather short order… ].

Now, many, many years ago I had marked the sidewalls with the plans position for the static ports.  I’ll note that I have the more traditional looking ones actually on hand and those things are just under 1″ around max on the exterior side, much less than that coming through the sidewall.  One thing I wasn’t expecting (unintended consequences) was having a clearance issue with my embedded rudder/brake cable conduit and the now longer height-wise static tube.

This caused me to have to move my static ports up about 1/2″ from the plans position. Deal breaker?  I highly doubt it.

I spent about 20 minutes each side drilling the starter hole, then digging out the foam and increasing the height of the hole so the static tube would sit flat against the inside surface of the outer sidewall skin.

Before I micro’d the static tubes into place, I used my shop light to shine through the new holes/slots to mark the outside of the nose to establish a “drill line” where the 3 holes will get drilled (which I’m pondering the number now that I have 2 static inputs).

I then whipped up some wet micro, as per plans, and poured it into the static tube holes before then reinserting the static tubes into the wet micro.  Since a good bit of both holes are below the exiting tube, I simply used a piece of tape to keep the micro from running out and the tubes in place.  Tomorrow I’ll add more micro and probably a small patch of BID across the extended oval-shaped hole.

Here’s the left side static port.

And the right side.  The tape and popsicle stick is to keep the static tube flat against the outer skin.

I then got to work on the right aft lower baffle bracket, what I’ve been referring to as the “Melvill” baffle bracket.  I gooped up the lower and forward edge, as well as around the large engine bolt, before bolting the bracket into place.  I then safety wired the bolts.

Again, another minor yet important task complete!

On the left side I actually kicked off the no-kidding baffling installation by riveting the lower aft baffle segment to the underlying bracket (pic below)… Now, beforehand I did goop up the front edge tabs that go against the inner baffles.  After the rivets were installed, and I then taped up the area around/over them to protect against the black goop (RTV).  I then finished gooping up the front edges and corners of the left aft lower baffle.

I waited well over an hour to let the goop set up and then carefully pulled the tape off the top.  Some of the goop had cured fully and was rubbery, while some of it underneath was still wet and would cause a mess requiring cleanup.  Overall I think it looks pretty darn good (note the inboard rivets).

Tomorrow I’ll get up underneath the baffle and goop up all the seams from the underside as well.  I also plan on getting the right aft lower baffle installed, and… who knows?  Maybe the topside baffles as well!

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