Monthly Archives: April 2015


Multiple Sessions (12.0 hrs)

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.   


Fuselage Rotisserie 2 (4.0 hrs)

I accomplished two tasks today. First I completed the movable stand for the plans and drawings. I was sick of taping up the schematics everywhere and this setup lets me reference any drawing I want at any time.  

Its a basic tripod. I used a spare bit of angle and two c-clamps to hold the drawings in place. A simple hinge and a chain holds the third leg in place. Beautiful? No. Effective? Yes.   

Then it was time to set about connecting the firewall to the front engine stand. I drilled out the engine mount bolts a few sizes smaller than the eventual engine mounts will require and attached the engine mount. I carefully maneuvered and measure the fuselage position several times.     

Here is the end result. It might look trival, but I’m being super careful about this and as precise as I can be. I don’t want any damage to my precious fuselage!  


Fuel Tanks 32 (2.0 hrs)

Okay, first thing is first. I’ve been slacking on keeping up with my posts, and tonight I find myself several posts behind. I’m tired, so they are likely to be sparse on the details. Hopefully I’ll update them more thoroughly this week.

In other news of my slacking, I’ve not been doing a good job taking pictures during my recent sessions. I blame this on using my phone to play music in the hangar.

In this session I set out to leak test my two tanks. Mike Rollison lent me the manometer shown below. The leak test kit is courtesy of Mike Bullock. Man, KDMW is great for pilfering and borrowing tools for free!

The setup is simple. Connect the manometer to the fuel intake and close everything else up. Then pump air into the tank via the stem valve connected at the fuel drain. I used 4 inches as recommend by Van’s.        

Well, wouldn’t you know it. The first tank leaks in two spots along the baffle. This is the tank that I replaced the baffle during the z-bracket disaster of 2014. IMG_7748.JPG

Thankfully, the second tank was rock solid. I left the hangar with 3.5 inches of water, and when I returned half an hour later…

There was more than 4.5 inches! The temperature was going up rather steadily with the mid-day sun. Its clear this tank has no leaks.