What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Shim Material on empennage?

alpinelakespilot2000

Well Known Member
Well, here's question 2 of the night...

I'm fabricating the two HS-904 shims from AS3-040 material as per the instructions on p. 6-1. I'm having trouble identifying the AS3-040 from which I should be manufacturing them. The best I've come up with so far is that in my "emp. small parts bag" I have two pieces of Al that are 1/2" x 4" and the thickness seems to be about .040 (although I don't have a caliper--probably need to get one--but it does fall between the thickness of the hs-ribs and the hs-spars). The shims are supposed to end up 1/2" wide. That said, when I look at the complete materials/parts list in the preview plans, they say that the HS-904 shims are constructed from material that is 5/8" wide (not 1/2" material I found in the small parts bag). I haven't found anything that is 5/8" wide.

Any suggestions on from where I manufacture these parts? I have the trim bundle, but there too, nothing is labeled identifying the type of aluminum or the thickness.

Any help? I'm starting to think that the hardest part of this project is going to be identifying parts!

Thanks.

Steve
 
shims

Those are the correct pieces. After you square up the stock, they'll measure near the 1/2". Yes, get a dial, not vernier, caliper. There is another piece of stock (.063 thick) included for use as the corner reinforcing doubler angle in the left elevator.

Steve
wings
 
It appears Steve and I are at the exact same stage! Before I shut it down for this evening, I too, was looking for the correct stock to make the shims out of?

I didn't dig deep enough to find the pieces you guys mention in the 'small parts bag'. I did find a sheet of .040 stock, about 5-6" x about 14". Are we sure we don't cut them out of that?

Thanks!
 
Gary...

Hi Gary--

It seems like you guys are just getting to questions I had a couple weeks ago (and have since, I think, figured them out)--but it does sound like we're close.

I just got done priming all the HS/VS parts (+plus the rudder skins and stiffeners) yesterday. Today I riveted the HS and VS spars together. Tomorrow, I'm going to start with the dreaded flush riveting of the skins on the HS. I too wonder how I'm going to get the bucking bars in there, but will plan to have the wife helping me!

The HS/VS spars + doublers went together OK. I had to drill out about 3 rivets that folded over a little, and the three lowermost holes on my HS attach brackets could not be riveted with my 3" yoke, so I had to use the gun on them (and left a couple "smiles" around those rivets on one of the brackets) but I think I ended up with a pretty solid 1st riveting job.

This is all going together pretty fast, but I did have to redo one HS attach bracket--needed a new piece, for which Van's only charged $2.50 (+$5.00 shipping/handling)--and I'm going to redo my rudder horn brace because I have only about 5/32 edge clearance wjhere it tucks up under the lower rib. (When you cut out the brace, make sure you leave the entire tooling/scribe mark holes there--if you cut from center-center you run the risk of cutting too much off and not leaving the edge distance needed.) That's a $9.00 part (+probably anohter $5 in shipping). Oh well.

Sound like about where you are?

Steve
 
Steve,

Just read your post, how did the priming session go? Did you do anything different, or just clean and spray? Is it adhering like you wanted?

Will
#91056 - Wings
 
Hi Will--

Priming went pretty good, but I learned alot the first time. It seems to be adhering pretty good--it only scratches if I drop it against something sharp, sometimes not even then. It was a nice 53 degrees outside so no problems there.

Working out of a full gallon of 615 and 616 is difficult. I have a little 7oz Harbor Freight sprayer (Dan Checkoway suggestion), but I found myself having to refill so much that I think next time I need to just mix up a substantial amount of primer first in a separate container, and then have it ready to pour into my sprayer as I need it. I think that would reduce the potential for me contaminating my big gallon of 615.

I'm not sure I'm happy with the spray gun--I never felt like I got a consistent spray pattern, and consequently probably put too much on in some places, but I'm a complete novice at spraying with a compressor, so it was probably just me.

Out of curiousity, did you prime the rivet holes on the steel hinge brackets after you matched drilled them. I didn't (forgot to) and now wish I would have--fortunately I'll be able to see/inspect them in the future so it shouldn't be an issue. Regardless, I do need to find a brush-on type of primer to do spot priming. Any suggestions there?

Thanks for the suggestions. I'll wait again to prime until I get the remainder of the empennage (rest of rudder and both elevators ready to go).

Steve
 
Steve,

I had the same experience using the small gun on my first priming session :mad: The next time, I used my fathers quart size gun and it worked much better.

As far as the hinge brackets go, I did not prime them after match drilling. I thought about it, but decided not to do it as the whole thing is already protected and the rivet holes, after being filled with rivets probably aren't very likely to corrode. I may paint some over the rivets later, but I doubt it. I haven't really seen any other builders making too big of a deal about it, so I am not too worried. Spot priming with a brush (which I confess I have not done yet, so take with a huge grain of salt) I plan to do with some mixed up Vari-prime. I don't see why I shouldn't be able to do with a brush what I know I can do with a spray gun.

As for your primer coverage, I was told by my EAA Tech inspector, that you are really looking for a coat that looks almost too thin. He said, you should almost be able to see the shine of the aluminum through the primer and you should definately be able to see the sharpie....without any distortion other than a slight color change. Most of my areas that I though were too thin, he said were just right and the others were a little heavy.

Will

#91056 - Wings
 
Last edited:
Back
Top