YellowJacket RV9

YellowJacket RV9

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Hi all,
Being the type of person who goes crazy without a project to work on, and being tired of renting 172s, I bit the bullet and have started an RV-9A build. Have a few degrees in engineering, so I'm somewhat mechanically adept, but have no airplane or metal experience, but excited to learn. This leads me to question #1...

Am getting ready to fabricate the L and R HS brackets (ie, step #1) and have accurately transferred the pattern to the angle aluminum. I know that I want to do my rough cut a bit away from the final dimensions, but how much? How much can I expect the clean-up and finishing to take off the aluminum? I'll err on the side of caution and start slow, but if anybody could give me a rough guideline on how much metal to leave around the edges it may save me a little guesswork. Also, should I initially drill the 9 holes with a smaller pilot bit and then enlarge? Looking forward to the day that this type of thing seems like a stupid question to me as well!

This site has already been a great help to me, so thanks for that, and in advance. If any Tampa Bay area RV'ers want to trade some newbie instruction for grunt work and manual labor, let me know!

Chris
RV-9A #93132
Clearwater, FL
 
Chris nice to have you here! Cut just a hair more then your line 1/16 would be good. I am sure you looked through all the VAF links to RV9(A) websites but take a look again at Smitty's http://www.smittysrv.com/more_stuff.asp?ID=216&Section=3

I've also heard that if you waste those brackets it would be beneficial in the future. You have to screw up something let it be these brackets. :D
 
In real life, those brackets can be up to about 3/8" bigger and still work fine. There is nothing in the way once they are installed.
hsbracket.jpg
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That doesn't mean that any other items fabricated can be over sized. I just remember when I cut and fitted mine, I had to make them twice because I was determined to get them exactly right. After mounting the HS and VS, I can see if I was off, I could file the angle to get it perfect. I would error on making this larger and file when you assemble it. Maybe it will save you the hour or so I spent making new ones!

Have fun, it only gets better and you will learn so much. It is very rewarding.
 
Finishing parts

I do quite a bit woodworking and own a small
Makita belt sander. It is designed to put on a bench
90 deg. To the bench surface. It works very well in leu
of a dedicated table top belt sander. You need one or the
other for a quality, efficient build, as it cleans up the cuts, rounds corners and also cleans edges of stamped parts. Follow up with polishing edges with a 3m scotch bright wheel on a bench top grinder and your golden. I use a metal scribe to scratch a very fine, accurate cut line on the measure. A metal band saw blade or jig saw cut slightly outside the line ( leave the line in carpenters terms). Most of the time you only need to clean up the cut with the wheel.
That is if you made a straight cut.
 
Form follows function

And for the holes to not tear out, edge distance is most important. Drill the holes first, then define the edges. I recall one hole needs to be spot on for positioning, the others not so much (+ or - .020 ?) Same with the overall shape as long as edge distance is maintained.
As a carrear sheet metal guy, this is sound advise. Bend to fit, drill to match, trim for edge distance, whenever possible, in that order.
 
Another 2 cents

Hi Chris and welcome to the circus,

You mentioned not being familiar with metalwork. Forgive me if this is obvious, but please be aware that aluminum is a very efficient thermal conductor. It pays to be properly cautious when you're power sanding parts to final size. A dramatic heat rise can arrive at your fingers very suddenly! Many of the builders on this site can readily describe the crisp ringing sounds a part makes as it ricochets off of walls, floors, cars, etc., clearly heard even over the sound of their own agonized wail. I can too. I now prefer to wear leather gloves for that operation, and also keep a container of water at hand to dip cool the parts.

Enjoy the journey!
 
I learned that lesson very quickly just running the dremel tool over it! Gloves on from now on, and safety goggles as well.

Chris
 
In addition

I also use a 10" Ryobi miter box saw with a
Carbide blade. Cuts though alum. Like butter.
Nice square cuts on your angle stock. Especially
The 2" and 2 1/2". Cut and leave the line or at the line and polish.
 
YellowJacket RV9 said:
I learned that lesson very quickly just running the dremel tool over it! Gloves on from now on, and safety goggles as well.

Chris
Click to expand...

Gloves are great - sometimes. Remove gloves before using drill press or anything else that spins with significant power. Your finger WILL wrap around a drill bit if the glove gets caught.

Safety goggles/glasses are good always.
 
Several other 9's in Tampa Bay area

Kurt,

Oversized by the thickness of a sharpie fine point is a good guide the rough cut. File or belt sand to size.

Also sent you a PM
 
Hazard of glove use.

I tend to work bare handed with water close by because of this;
A.C. 43.13-1B para 4-54 b." Reheating at Temperatures Above
Boiling Water. Reheating of 2017 and
2024 alloys above 212 ?F tend to impair the
original heat treatment. Therefore, reheating
above 212 ?F, including the baking of primers,
is not acceptable without subsequent complete
and correct heat treatment."
If I can't hold it, it's to hot (ha ha).
 
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