Archive for the ‘Fuel Tanks’ Category

Wing Photos

November 1, 2010

As promised, here are some photos of the recently finished sub assemblies on the wing.

Roll Servo Install

As I wrote in the previous post, safety wiring those two bolts that mount the servo to the bracket was a bear. We’ll see what the tech counsellor says about the quality soon 🙂 Other than that it’s a pretty straight ahead install.

Right fuel tank cover plate and sender install

I got both the tanks closed finally. They still need pressure testing, but I’ll wait till later. I hope I never have to take these things off again. The screws are pretty soft and the philips heads mangle easily.

Aileron control arms primed

I went back and primed the ends of the smaller aileron control arms per Van’s suggestion. One end of each will be exposed to the elements so it is prudent here.

Safe Air pitot mast install in left wing

Pretty straight ahead. I used the template to align the position then rough cut the hole using unibits and the Dremel. With sand drums on the Dremel and the mini files, I smoothed everything to final shape. Match drilled and countersunk the pitot mounting plate and we are all done. I’ll have to wait to rivet until riveting the skin and running the pitot lines.

Right wing control and servo arms

Here’s the business end of the servo arm where it mounts into the aileron control horn at mid span on the right wing.

I started to put the inspection plates back on and twisted the head off of one of the small screws. Argh! So not I’ll either “ez out” the screw or remove the nut plate and reinstall a new one. For now though I am just putting the wings in the corner. Now back to the fuse!!!


Wings Nearing Completion

October 27, 2010

There’s plenty of updates that I’ve been meaning to post to the log. Both bottom wing skins are prepped including the hole for the pitot mast on the left skin. I’ll wait till wiring and pitot lines are installed later to close out the wings. Both fuel tanks are closed. This took longer than I hoped but its done… I think. The Proseal mixture for the right tank baffle seems to be taking a long time to pass the “fingernail test.” I attribute some of that to the change in weather but I might have been off in the 10:1 mixture. I’ll check it in a month or two to see if it sets well. Also I installed the Dynon AP roll servo in the right wing. Safety-wiring the servo mount bolts was a pain with very little clearance. If I were to do it over I might mount the servo to the bracket and then the bracket to the spar. It didn’t help that its been well over 7 years since I safety-wired anything so I had to knock the dust off that part of the brain. I’ve temporarily hooked up all the control rods and the AP linkage. Both wings are sitting pretty back in the stands. The wing tips will be saved till final assembly. Now a night of clean up and reorganizing so I can get the aft fuse riveted. The goal will be to hit the center section hard heading into the holidays. Stay tuned for photos!


August 23, 2010

It was one of those days on the project today. I got the bottom skin drilled yesterday and prepped all the fuel tank stuff so I could proseal today. Everything went well up to the point of squeezing the rivets that hold the antirotation bracket in place. I ended up try to buck them but then things really went south. I messed up the shop head. So here I am about an hour into working with the sealant (you get about 90 to 120 minutes before it stiffens up—forever). I’ve got tank sealant on the bracket, the rivets, and both sides of the fuel pick up tube where it exits the cover plate. I drilled out the rivet but got shavings all over the sealant where the fuel pickup line exits the cover plate.

I now have two choices:

1. Use all the MEK I have and remove all the sealant on the various parts so I don’t have to remake them.

2. Charge ahead and figure out how to buck the rivets correctly and pick out all the metal shavings from the sealant in about 15 minutes.

The T-715 bracket is held on the cover plate with two rivets. I couldn't get a bar or a squeezer in behind the nut to make it work.

Discretion being the better part of valor, I chose the latter. I hate remaking perfectly good parts. So I scrubbed everything off and put the project away for the day so I can research the problem before making another mess out there.

Bottom Skin and Fuel Tank

August 17, 2010

Tonight I started drilling the bottom skin for the right wing. I am taking my time on this step to minimize any elongated holes. I am especially careful on the spar hole match drilling. Getting the holes to match up well on the spar was a bit challenging. After reading some similar stories online, I rigged up a stand with some shims stacked under a couple of of the leading edge ribs. This helped take some load off the ribs and spar interface and in turn helped the skin fit a tad better and avoid messing up the holes.

Also on deck tonight was opening up the fuel tank and getting an idea of how to close then out. It looks pretty straight forward— I just need to install the float unit, torque the fittings correctly, secure here and there and screw everything together. I need to research a little to make sure I am not missing anything. One area I am concerned about are the reports of nuisance leaks around fuel tank rivets. Some builders are suggesting this happening to the QB tanks because not enough sealant is being used in assembly. So I took a look around the inside of the tank and was happy to see plenty of sealant covering the flanges, shop heads and corners in the tank. I’ll look at a deeper compartment with a mirror tomorrow.

Not a great shot, but you can see the sealant is well used in the critical areas

Here's my quick solution to relieve stress on rib flanges that might cause bad fit for skin