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-   -   Section 38-22 Feeler Gauge Question (http://www.vansairforce.com/community/showthread.php?t=161638)

Stockmanreef 06-23-2018 07:35 PM

Section 38-22 Feeler Gauge Question
 
38-22 tells you to make a feeler gauge that is 2" by 6" by 0.040.

I have yet to find any suitable 0.040 gauge sheet metal in any of the kits. The only stuff close is the U-channel used to ensure that the the canopy does not twist. I guess I could cut that apart now that there is no real use for it, but it would be about 1" wide, which might be OK.

Or did I miss the 0.040 gauge metal in the kit?

Any thoughts about using 0.032 gauge instead of 0.040? If not, what kind of local shops sell sheet aluminum?

thanks

Bgill 06-27-2018 04:48 PM

Feeler gage
 
I waited to see if someone else would reply as I am not to that section yet..
I would suggest a standard automotive feeler gage set from a hardware or automotive shop. I have a large one that is roughly 4 x .5 that I use regularly. Often you can stack feelers together to get exact thicknesses. The other option would be to apply some tape to one side of the .032 shim to get it up to near .040.

daveyator 06-27-2018 06:18 PM

A useful fact. 040" is 1 milllimeter. Might help you find something to do the job.
Cheers,
DaveH

StressedOut 06-27-2018 06:51 PM

Quote:

Originally Posted by Stockmanreef (Post 1268885)
38-22 tells you to make a feeler gauge that is 2" by 6" by 0.040.

I have yet to find any suitable 0.040 gauge sheet metal in any of the kits. The only stuff close is the U-channel used to ensure that the the canopy does not twist. I guess I could cut that apart now that there is no real use for it, but it would be about 1" wide, which might be OK.

Or did I miss the 0.040 gauge metal in the kit?

Any thoughts about using 0.032 gauge instead of 0.040? If not, what kind of local shops sell sheet aluminum?

thanks

Ken,

For local shops I'd do a Google search. Almost any metal supply house will have sheet stock. Since it's just a feeler gauge the type of metal doesn't matter.

Aircraft spruce sells sheet metal too. A 2 ft. X 2 ft. X 0.040 in. sheet of 2024-T3 will cost you $15.76 + shipping.

Stockmanreef 06-27-2018 08:07 PM

I got a piece of 0.40" from a local shop for free. Apparently 0.032 gauge would work fine for this application, according to Van's. Just don't know why 0.040 gauge was specified in the plans, since it is very specific. Why not put in a range of thicknesses?

David Paule 06-27-2018 08:27 PM

Van's sells .040 in a variety of sizes. for example, AS3-040x2.75x8.969 for $3.25 is 2 3/4 x 8 31/32. Just a bit larger than called for. I don't know the RV-14 at all (I'm building an RV-3B) but going from your description, it ought to work. You might need to trim it.

Dave

smash 06-28-2018 01:07 AM

The feeler is useful for finding the gross area of the canopy that needs to be thinned, but I found that it was really only useful for the first approximation. The thickness of the feeler may make a difference if you are measuring on a very precise Solid Works computer model, but in real life .040 vs .032 isn't going to make much difference.

It is difficult to actually position the feeler and mark the area- even with one person on the inside and another on the outside looking in. If you end up with a marked area that varies significantly from the diagram shown in Fig. 2 on page 38-22 you might want to remeasure.

I only used the feeler to outline the area to start working. Once you find the general area that needs to be thinned it is easy to look through the plastic and see where the interference is. I probably went through 8 or 9 rounds of shaving and fitting before I was satisfied with the fit. Once I started shaving the canopy back in the demarked area, I set aside the feeler and and redrew the area just by looking through the canopy and observing where it was riding on the deck. As the canopy snugs, up the shape of the area changes. I took the approach of thinning a little at a time- it's pretty difficult to add material back if you go too far...

Stockmanreef 06-28-2018 06:22 AM

thanks for the replies.

Smash- I see that you went with the weights on the canopy instead of the ratchet strap. Did you try the ratchet strap at some point?

ken

smash 06-28-2018 08:48 AM

I did not use straps on the canopy. I got a decent fit using weights as shown in the manual- there wasn't any need to apply more force. Before fiberglassing I also used canopy clips (page 38-28 fig. 2) to pull down the canopy edge around some minor bulges.

rvbuilder2002 06-28-2018 11:14 AM

Quote:

Originally Posted by smash (Post 1269951)
I did not use straps on the canopy. I got a decent fit using weights as shown in the manual- there wasn't any need to apply more force. Before fiberglassing I also used canopy clips (page 38-28 fig. 2) to pull down the canopy edge around some minor bulges.

And the risk of using a ratchet strap is how do you know how much pressure you are actually applying?
Additionally, to get the desired fit, often times a bit of pressure in a localized area is all that is needed. The strap will apply pressure on much larger area.


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