george.mueller(at)aurora.
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 Posted: Thu Dec 28, 2006 9:09 am Post subject: Tips for New 701 Builders |
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I am coming to the end of airframe construction on my 701 and thought this would be a good time to summarize some of the things I have learned during the construction for the benefit of some of the newer builders on the list. When I started this project I had no aircraft building experience, so I came up the learning curve basically starting from zero.
1) Cutting aluminum: I tried a lot of things here. I tried a table saw with a metal cutting blade and would have pieces of aluminum shooting across my basement at 350 mph when the blade would catch the work. My table saw finally was destroyed cutting a piece of nylon (like what is used as a fairlead for the control cables) which caught between the blade and the edge of the hole the blade comes out of. Tough stuff. I spent a lot of time trying to use a router on aluminum, it never really worked for me. I never really mastered the snips. A dremel tool with a fiberglass cutting wheel works for some stuff, but for less than you might think. What really worked for me was a harbor freight metal cutting band saw. Cuts aluminum like butter. What also really works well is the OLFA knife. For example, when cutting out the slots for the slat mounts, drill two holes at each end of the slot, then lay a straight edge connecting the sides of the holes and pull the OLFA knife between them. After a couple of passes you have a groove and you can get rid of the straight edge. A few more passes and you will have a perfect cut. Another thing that I used for cutting big pieces like the fuselage skins was an air shears. So, band saw, olfa knife and air shears for cutting, in that order, and you might even be able to skip the air shears and just use the OLFA knife.
2) Finishing aluminum. I found a Delta belt and disc sander works well to do final shaping of parts. A scotchbrite wheel mounted on a grinder works well for deburring edges. A vixen file is also a valuable tool.
3) Riveting. I bought the pneumatic riveter from Zenith and hardly ever used it. I bought a cheaper riveter from Harbor Freight with the pointy snout and have done all my riveting with that. I never considered a hand riveter to be an option. Bite the bullet and buy a hand rivet squeezer for setting the traditional rivets in the trailing edges of the flying surfaces. You will also use this to set rivets for anchor nuts. For sure get an adjustable rivet spacer for laying out rivet lines. I use the #40 drill in the holes of the spacer to get a straight line. Some say this wears out the spacer, but the holes in my spacer are just now starting to get oversize so I have burned one $40 spacer for the project. I will buy a new one when I start the RV 8A (although I hear those kits are all predrilled). My rivet lines got straight once I figured out that I needed to use the spacer.
4) Deburring. The drill in the fingers is hard on the hand. Running a file over the holes is fast but doesn’t do a good enough job in my view. I like the swiveling hand deburring tool. I also tried the deburring bit in a cheap power screwdriver, that works, but for some reason ended up coming back to the hand deburring tool. Later in your project you will need to deburr holes where access to the back of the hole is limited. One thing that is really neat, go on Ebay and buy a used Codsgill burraway tool. This fits in your air drill and deburrs the front and back of the hole by just being inserted in the front of the hole.
5) Priming. I started out spraying zinc chromate from rattle cans, and I ended up using a paint brush to apply zinc chromate from a quart can to the inside of all the flying surfaces. I just found the brush easier to use. I cleaned with lacquer thinner, roughed it up with scotchbrite and cleaned again with lacquer thinner to prep. Use a respirator. On the inside of the fuselage I used SEM self etching primer to get a nicer looking grey finish and I sprayed this. Because of the self etching you can skip the scotchbrite step with SEM.
6) Bending aluminum. I bought a 40” bending brake from Harbor Freight ($100 on sale) and put a sheet of thin aluminum over the edge to get a 1/8” radius. My rule was if I screwed a part up I had to remake it from scratch, so I used this brake a lot. Dave Clay has a neat brake design on his website, if I was starting over I probably would build his.
7) The psychology of building. I became addicted to the building process so I never had any problem with motivation for the project. However, you will make mistakes that will make you sick. Some might become frustrated by the fact that their project is not perfect and become demotivated. You have to be accepting of the fact that you will make mistakes. However you cannot progress by ignoring mistakes, they need to be corrected. As I mentioned above, my rule was that if I screwed up a part I had to scratch build a new one. Some parts I made over numerous times. Often you will find that correcting mistakes will not be as difficult as it first seems. Just start reversing (drilling out rivets) what you have done until you have gone back far enough in the build sequence to correct the mistake, remake the needed parts and start over. If you reach an impasse you will find that the solution will often present itself after you sleep on it and come back later. Be mindful of the fact that you are learning a lot as you move through the process, and that is a real reward that happens well before the final payoff of flying your plane. The Zenith list, the RV list, EAA Sportair Workshops, Homebuilt Help videos and AC43.13-1B/2A Acceptable Methods, Techniques, and Practices were all very valuable sources of information for me to help with the building process.
 701 specific items. Being a newbie builder I didn’t want to stray far from the plans. However, I am going to drill out the rivets in the top skin of my horizontal stabilizer and replace the .040 forward mounts with the thicker .063 mounts before I do the final assembly. I also beefed up the seat belt anchor on the tunnel, and replaced the kit supplied seatbelts with a beefy 5 point harness. I added a Ballistic Recovery System. I used the Skyshops FWF kit, at the time it was better than Zeniths although they have recently improved theirs. But you get an airbox and cabin heat with Skyshops.
That is all I can think of right now. I hope this is helpful to some of the newer builders out there.
George in Milwaukee
701
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