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Updated SB for Aileron Brackets

rocketman1988

rocketman1988

Well Known Member
For those who were interested in what Van's had to say about using Cherry Max rivets to complete this Service Bulletin, they have updated the SB to allow them.

Refer to page 11 of the bulletin for the revision...
 
rocketman1988 said:
For those who were interested in what Van's had to say about using Cherry Max rivets to complete this Service Bulletin, they have updated the SB to allow them.

Refer to page 11 of the bulletin for the revision...
Click to expand...

Thanks for the update!
 
Anyone that chooses to use Cherry rivets for some or all of the rivet locations should use caution.
The are strong rivets, but they are much less forgiving than solid AN470 rivets regarding installation errors. Hole condition is critical. If holes are enlarged at all, or out of square, oversize rivets should be used to allow for correcting the hole problem.
 
$5 endoscope from eBay

So my $5 endoscope from eBay showed up today. It does not focus very fast and the software for my droid would not take photos, but I could easily see all the rivets for the SB without any modifications. Best $5 I have spent on a tool for the plane. Plan on trying it out on the cylinders next.

John
 
Would be nice if Vans engineering staff approved the use of No 8 structural screws in place of rivets now they have allowed the use of "mixed hardware" ie Cherrymax rivets. Much less chance of a stuff up trying to rivet inside the wing.
Especially if only replacing a smoking rivet in an awkward spot.
 
RV6JOY said:
Would be nice if Vans engineering staff approved the use of No 8 structural screws in place of rivets now they have allowed the use of "mixed hardware" ie Cherrymax rivets. Much less chance of a stuff up trying to rivet inside the wing.
Especially if only replacing a smoking rivet in an awkward spot.
Click to expand...

This is not quite as simple of a change as you might think.

Standard rivets swell in diameter when they are installed.
Cherry rivets (Correctly sized and installed) swell very slightly when installed.
This produces a post installation tight fit .

#8 structural screws do not swell when installed. That would makes the hole fit for a screw the most critical.
 
Thanks for replying Scott. In the case of the aileron brackets, I would suggest that the load on the fasteners is almost entirely in tension which No 8 structural screws would do much better than AN4 rivets.
In the wings with smoking rivets it is only the top and bottom rivets that are smoking which suggests they are not up to the loads involved.
The chap who built this plane was no bunny when it came to driving rivets having built at least 13 complete RVs and parts of a lot more.
 
RV6JOY said:
In the wings with smoking rivets it is only the top and bottom rivets that are smoking which suggests they are not up to the loads involved.
The chap who built this plane was no bunny when it came to driving rivets having built at least 13 complete RVs and parts of a lot more.
Click to expand...

The S.B didn't address smoking rivets because there is no evidence of that issue.
If you know of someone that discovered that, it is a very isolated instance based on the information I have.
 
use of #8 structural screws...

I went to Vans and made that inquiry/case for #8 structural screws and got the traditional "anything outside the SB recommendations is at the builder/owners risk." I respect they need to be cautious in today's world. So, glad to hear Vans is expanding the fastener list, but like some have said, Cherrymax do not fill bad holes well at all and can "look good" at first. I have seen repairs in high load areas in certified aircraft with Cherrymax structural rivets loosen over time. Absolute double pain in the ... to replace and the hole gets bigger..... Some of this I suspect was a bad hole at the start, you know, those square ones! :) They can look great just after install, however, I think for areas of vibration and high/changing loads, like aileron brackets, they can fail over time if not done really really well. If I do make the mod (just recently closed up wings, darn!), it will be with #8 structural screws. Puts and takes the load where it needs to be, I will live with the extra couple of ounces.
 
edge distance?

The note on p 11 also allows up to AD5 (5/32") rivets to be used "if sufficient edge distance" exists. Measuring the parts in the RV-14 SB kit, the pre-drilled 1/8" hole centers all seem to be 1/4" from the edge. If required edge distance is 2 X shank diameter, does this mean that anything over AD4 is not allowed? What am I missing?
 
edge distance..

I use AC 43.13 -1B as my guide to what is or not allowed. Edge distance is 2 diameter of fastener (as you point out) from center of hole. So it can work, 0.157" rivet needs 0.314 from center of hole, bracket has 0.314", wow....no room for square holes....:)
 
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