Wings

Fuel Tanks 33 (2.5 hrs)

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Today it was time to start repairing the leaking tank. I started with the dreaded task of removing the processed access plate. I’ve read some posts that say this is a gargantuan task. A few have said its easy, but details on it being easy were sparse.

I started by removing the screws. If you look closely you’ll notice a dab of valve grinding compound on the tip of the philips head screw driver. I was skeptical at first too, but this works wonders in stoping your philips screw driver from caming out of the screw. In fact, it works so well that torqued and prosealed screws were a breeze to take out!   

Now I messed around for a bit before I discovered the secret to removing the access plate. I was trying several different tools, heat gun, MEK… no luck. Then I read a post which said use a plastic putty knife (I have something similar) perfectly perpendicular to the access panel and a hammer (I recommend a dead blow). BOOM! The plate was off in no time. If you subtract the time that I fussed about with other methods, this took less than 10 minutes to do. There is no reason to use a cork seal after figuring out how easy this is!

After a little MEK and scotchbrite action, the plate is ready to be put back on. This bay doesn’t technically have a leak, but one leak is close enough to the rib in the next bay that I’m going to seal in here anyways. 

Next I measured where to cut the access plate holes. I was originally thinking to do all four, but decided to do the two I needed and then go from there.   

Like last time i used my leading edge jig and the drill press rotated 180 degrees with a fly cutter to make the holes.     

Well look at this. I did affix at least one cable to the vent line. Maybe thats why I marked this task as complete. We’ll never know…  

Here are the two holes. I went with 4 inch holes. I went a bit bigger last time. but 4 inches is perfect. After looking at the wire, I’m convinced I can proseal all of the wire with only these two access holes.

I inspected each area to see if I could determine where it is leaking. If you look really closely in this photo you can see a gap. Its tiny, but its there. 

Wings 39 (4.0 hrs)

This entry was posted in Wings Wings - Structure on by

A couple of projects for today’s shop session. My buddy Jimmy gave me his motorcycle lift which I plan to use to support the center of the fuselage. Yes, its probably overkill. This thing will be supported with weight in it at only 3 points, but until that time I want as little risk to the structure as possible. This will allow me to support the middle easily at any orientation. I began by doing a full test of the rotisserie and rotating the fuselage completely upside down.

Next I measured the highest and lowest points.    

With the measurements in hand, I made a makeshift support. I will readdress later. Likely with a highly specialized milk crate. 

I also stopped at Lowe’s and picked up to extension bit holders for drilling out the middle two ribs under the wing walk doublers.     

The snap bushings supplied by Van’s are from Heyco and have an inner diameter of 0.27″. The tubing for the pitot and that AOA tube are 0.25″. I didn’t like the extra play so I ordered Heyco snap bushings (SB 432-243) with 0.24″ ID. I was worried they’d be too small, but it turns out they are an absolutely perfect fit.   

Next I ran the pitot & AOA tubing. Mike Bullock had needed to order some additional tubing for his AOA home-brew so I jumped on the order and ordered 100 feet of the green tubing. The blue tubing is left over from Mike. In the end, I”ll be able to sell all my extra tubing on VAF and save a bunch over using SafeAir1.   

The next problem I faced was determining how to route the lines around the bell crank. I came up with two options. The first option, shown below, routes the tubes around the outside of the bell crank. The one thing I don’t like is how severe the angle is on the green line (shown with arrow). Yes, it will probably be fine for 2000 hours, but I can do better.     

The second option was to route the lines under the bell crank as shown here.  

What I wasn’t sure of though, was how far down the bell crank will go. On the plans, using Van’s AOA, it stipulates leaving 5/8 of an inch. That being the case this should work. But again, I don’t like should. I did a lot of messing about here including mounting the aileron and playing with the position of everything.

That was as far as I got today. When I want to put my wings back into their corner, I realized that the ailerons will hit the rudder. I’ll have to flip the horizontal stab.    

Squire enjoyed sunbathing. It was a gorgeous day at the airport.   

Multiple Sessions (12.0 hrs)

This entry was posted in Fuel Tanks Fuselage Plans Wings Wings - Structure on by

This post encompasses several projects over three sessions in the hangar. First up I needed to figure out a way to mount the tail of the fuselage to my rotisserie stand. The axis of rotation is offset from the center of the tail. There are a couple of options for how to mount. I decided to make a padded cradle for the tail. I wrapped a cotton towel around the tail with duct tape. Then I clamped some 2x4s around very tightly to get accurate measurements. A short while later I produced this: 

I didn’t take a good picture of the front mount in my previous session, so here is that. 

And here is the final product for the tail mount. You can see how the center of rotation is offset and how I padded the tail in the cradle. The entire stand is sturdy, but it still makes me nervous. Especially while in the rotated position, its hard to tell how much of a torquing moment may be applied to the engine mount connections or any part of the frame. To protect against any mishaps I will continue to use the adjustable saw horses underneath. Additionally, I have a friend who is giving me an adjustable motorcycle stand. I am going to use that to create a center support that can be adjusted for any position near the center of gravity.

  

Here is the Hangar 51 mascot showing off his handywork.

That’s not a blue bow. Its poop bags. Keeping it classy.   

Next up, it was time to attach and torque the non-leaking tank to the wing. The screws get between 12 and 15 inch pounds of torque. I used torque seal to mark the bolts that were attached to the z-brackets.     

A trick I learned a little while ago that is seriously awesome; use a small dab of valve grinding compound on the tip of a your philips head screwdriver to avoid “caming” out of the screw head. Works wonderfully.   

I borrowed Mike Bullock’s screw driver click type torque wrench thing-a-majig. Works well.

I double checked that it work with my inch-pound bicycle torque wrench and a philips socket.

  

Squire enjoyed sunbathing. It was a gorgeous Sunday. 

I also drilled the second line that will hold either the AOA line or the pitot line. I still have two ribs remaining. The two interior ribs to the wing walk doubler are rather difficult to get at. I stopped at Lowe’s on the way home and hopefully I have a solution.    

My final project for the weekend was to complete the wing access panels. First I mounted the skins on the wings and match drilled. Then I deburred and dimpled.  Then I used a technique that I only just learned. Instead of using standard AN426AD3-3.5 rivets which require dimpling both the skin and the nut plate I used NAS1097 Oops rivets with the reduced sized machine heads. These only require a small countersink that you can do with your demurring tool in a few extra passes. Not only is it much quicker, but I think it results in a cleaner and more properly aligned product. There is no reduction in strength either. The nut plates bear the load… the rivets just hold the nut plates in place to prevent rotation.

You can see the results here:

And the final products.