January 12, 2006

Here’s the Gretz pitot tube mount. It’s tied into the rib by a small piece of angle. Making the matching hole for this in the skin was fun with a file.

Here’s Dave doing the thankless task of deburring. Lot’s of holes to do Dave!

Our next task was to put a conduit run in each wing. This was quite tricky, as the skins are already on the inboard part of a QB wing. We adapted a 3/4" Rotabroach cutter by putting a bolt inthe end instead of the grub screw, and using a bunch of socket set extensions to get the length we needed to reach through the multitude of ribs. We just added more and more extensions, like boring a hole into the earth.

Rotabroach cutters are THE single best way to cut holes in sheet metal. They leave a really clean hole, and they go through quick!

Here’s the driving end.

This is somewhere along the length, close to the cutter end. The tape is there to prevent the whole thing coming to pieces as we pull it out. Didn’t want to lose any bits of extension in the wings and have to go fishing for them later.

Here’s how long it ended up! It’s probably about 3 1/2 feet.

And the holes it left behind. We put a #30 pilot hole in each rib to guide the Rotabroach properly. Putting the pilot holes in was also a lot of fun with drills.

Yet another shot of the holes we bored in the wing ribs.

While Dave was deburring skins, I set about the pitot plumbing. I bought these fittings a while ago now, in preparatin for this moment. Out pitot is heated, so we need to have a length of aluminium tubing to soak up some heat before going to plastic. Here, I got an AN fiting to 1/8" pipe, and a plastic 1/8" pipe to fit 1/4" OD tubing. Looks like it’ll work a treat.

Here’s the rest of the tube. Looks like it’s been mauled by a bear doesn’t it?! Well, the trouble is, you need to leave enough length to be able to connect the whole thing up through the pitot tube mount. Once it’s all connected, I’ll go through and sort it out so it’s neater and better restrained. Until we get the skin on and the pitot connected, there’s no real point in making this all look pretty.