Categories: all aviation Building a Biplane bicycle gadgets misc motorcycle theater

Wed, 22 Mar 2017

Building a Biplane: Gathering Materials

I am finally making some forward progress on actually building a biplane, instead of merely thinking about it, and doing activities that prepare me for the eventual build.

The first thing to figure out about the build -- about what happens the first time I take a piece of wood or steel and try to turn it from raw wood or steel into an airplane part -- is where to start. The Marquart Charger has so very many parts.

So, I fell back on a couple of reasonably simple tests: 1. What can I do that will not be a huge committment (in case I hate it and realize it's a waste of time)? 2. What do I already have the skills to do?

The answer to #2 is simpler than #1, so I'll address that first: I know how to work with wood. Although I've had a class in welding, and I was reasonably happy with my progress there, I currently lack equipment to perform welding, and my skill level at the end of class was clearly... beginner. There's work needed before I want to honestly assemble any airplane parts with my welding skill. So, woodworking was a logical starting place.

The only parts of the plane that are made of wood are the wings. The wings are made of these parts, when viewed simplistically: wooden ribs, built up out of little sticks and epoxy; 12 foot long spars that cost hundreds of dollars each; and some steel cables, fittings, and welded parts. The ribs need to be built before the wings can be assembled, so ribs are a fairly obvious starting place.

The rib is built up of 1/4" spruce sticks known as capstrip. The general idea is, you build a jig to hold the various pieces in place by cutting out a piece of plywood or MDF, then screwing blocks or inserting pins, then you cut out a bunch of capstrip to the appropriate lengths, fit them into their locations, and glue the whole thing up with epoxy. Those little squares are made of 1/16" thick aircraft plywood (don't even ask how much aircraft plywood costs), and are also glued on, then stapled in place. Once it's all held together with staples, you can pull the rib out of the jig, flip it over, and glue down the plywood gussets to the other side, and start on another one. There's also the plywood nose-piece which needs to be prepared beforehand.

So, then my list of things I need to acquire before I start goes like this:

As you can imagine, not every store in town carries aircraft certified plywood. There's no market for it. So, that has to be ordered from a specialty supplier in Illinois. Ditto the 1/4" capstrip: specialty supplier. Fortunately, the epoxy and supplies are easy to find locally. The special stapler (a Senco SFT10XP-A/D) wasn't available locally that I could find, but was available online. Special staples from Senco are ridiculously priced (mostly because they come in quantities sufficient for building 100 airplanes), so cheap Chinese Ebay staples are on hand for a trial, and if I don't like them I can order the name-brand ones. The MDF I'll be using for a jig hasn't been acquired yet, but is easily available at any lumber yard for not very much money.

The fancy wood has been ordered, but I don't yet have a delivery date from the supplier.

Of course, I have a stumbling block: the garage isn't finished yet. I've been dragging my heels on getting out there and tackling the final steps, which are to clear it of everything and paint the floor, then to move all my workshop stuff into the space and build a work table for the plane.

There's also the unacknowledged missing tool: how to cut out the nose pieces? I can do it with the jigsaw I already have, but really a bandsaw is the right tool for the job. I don't want to put theater-quality parts into this plane, I want aircraft quality parts. So there may be a major-ish tool purchase on my path before I can really start.

Even with the impediments and stumbling blocks in front of me, it's pretty cool to be getting close to actually sawing wood on the first part of my very own biplane build!

Posted at 14:33 permanent link category: /charger

Categories: all aviation Building a Biplane bicycle gadgets misc motorcycle theater