Three Days, Twenty Six Parts, A Warbird Update

This fall and winter I am spending part of every other week apprenticing to my friend and  aircraft mechanic Scott Draper at S.D.Air Service in Rutland. I have hopes of earning my own A&P mechanics license (Airframe/Powerplant) and one of the ways to achieve that goal is to apprentice. I need to log 4000 hours of wrench turning time before Scott will sign me off to take the A&P exams. The timing works out well for me. This winter, with a recovering shoulder, I am not yet able to do the “heavy lifting” (logging, sawing, shoveling and firewood) jobs here on the farm. I can catch up on things I can do on the farm one week, then work on my airplane the other.

While in Rutland, I spend a good deal of the apprentice time working on my own warbird

Drilling holes in the plexiglass windshield

It’s a Taylorcraft L2M – a plane from World War II. Scott or Ray (another mechanic) will pull me off from my project when they need help with something, or are working on a system that I know nothing about, or on something that is just interesting.

The Taylorcraft has been my project on and off for a decade now. I’m doing a ground up restoration of this 68 year old airplane. I’ve taken it completely apart, inspected each piece, painted or repaired them, and I’m remanufacturing parts that were taken off when the warplane was civilianized in 1946. Figuring out what’s missing then building new parts makes the project take a lot longer; not having a lot of time down in Rutland doesn’t help.

Last week I had to manufacture 26 little clips. These clips hook over the butt rib, an aluminum wing rib that is attached to the fuselage and provides the attach points for the plexiglass that goes over the top of the airplane. The clips will attach to the butt rib and then the plexiglass screws on to the clip. These clips are also some of the parts that are no longer available to purchase and must be made. My starting point for designing them was a couple of original clips and the blueprint.

I started with a thin sheet of cold rolled steel purchased at a metal fabrication shop in

Bending the sheet steel around the angle iron jig

Rutland. They cut me three 1/2 inch x 48 inch strips. I then cut each of these strips to lengths of 3 inches. Next I had to bend these strips to their proper shapes. After some time spent brainstorming, I built a “jig” out of a piece of angle iron. Jigs are a tool that you fabricate that make it easy for multiple pieces come out the same; I make a lot of these tools in my airplane project. Using vice grips and pliers I could clamp the metal strip in the proper position, then bend it around the jig. There is quite a trial and error period here, but after about 20 of them, they started to look pretty good!

The jig I made for drilling holes in the clips

The next thing to puzzle out was the holes. Each clip has two holes, offset from the center, each a different size for the screws to go into. After more brainstorming, I built another jig to clamp in a vise on the drill pres. With the help of a match stick,  so the curve put into steel clips would not be changed during the drilling, and 3 different sized drill bit (4 if you count the one I bent during the trial and error phase), I had proper holes in all 26 clips.

Using a jeweler’s file, I filed the burrs from the freshly drilled holes, and pushed on “Tinnerman” nuts. Tinnerman Nuts look like clips themselves; they are thin U shaped clips with a hole in them that slide into the clips I made. The hole in the nut has small ears that grab onto the threads of a bolt as it is screwed in. I’ll attach the clips to the butt rib, and then the plexiglass will screw into them.

These are the different stages of the process from metal strip to final clip (original clip far left).

My clips are now almost done. I just need to dip them in zinc chromate primer to keep them from rusting and they will be ready for use.

So, 3 days to make these 26 little clips. I asked Scott “How can anyone rebuild an airplane at this rate”? He laughed and replied, “it’s because you’re putting it back to original condition, many people would just simply screw the plexiglass directly to the butt rib”.

Blue print, clips and tools

I enjoy the often slow and meticulous work of the rebuilding process. These weeks I spend in Rutland are a good mental break from thinking about what I can’t achieve around the farm because of my shoulder. Instead, I’m thinking about what is possible with patience, brainwork, and the watchful eye of a good tutor.

Mechanics Ray and Scott "hamming it up" over an airplane part...not one of mine.


6 responses to “Three Days, Twenty Six Parts, A Warbird Update

  1. Good luck on the refurbishing the L-2. Always wanted to do something like that, but never had the guts to start. The Beech was sold a year ago, and have only flown once since then. I need to stay home a lot, and lack of sleep take all of the spring out of my steps.
    Don Jones

  2. Will: Great update on your warbird. At least we know it has one great refurbished gas tank! Good luck with your mechancs license, and may that wonderful L-2 take to the sky soon. I have just installed a wind generator in my Pietenpol, as it has a battery, but no alt or gen. Trial next week.
    Best regards,
    John (Heather’s dad)

  3. Pingback: Warbird Update | Catamount Aviation & Under Orion Farm·

  4. Pingback: Lost Screw Holes, and Mill Bastard Files-War Bird Update December | The Flying Farmer·

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s