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  #11  
Old 11-10-2020, 08:50 AM
bsbarnes10 bsbarnes10 is offline
 
Join Date: Sep 2019
Location: Texas
Posts: 34
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Thanks to everyone for your ideas and responses. Unfortunately I'm worried all proposed mitigations (awl, rivet pusher, and reamer) have the same issue: burrs/cracks. Using the awl or rivet pusher are likely to create microtears and possible cracks in the future. I ended up ordering a reamer and I've found it does a much better job than a drill bit at NOT making burrs but there are still detectable ridges on some holes.

What I've decided to do is bite the bullet and final ream all the holes. This adds another step because I then have to disassemble and deburr. Not all holes can be deburred because of the order of construction but I'm more comfortable getting the holes I can access (which is most of them) versus reaming and then immediately installing the rivet with no deburring.

Am I being overly cautious? Probably. But I like the build process and although I do want to get a finished airplane, I also don't mind investing a little extra time now to avoid problems in the future. As always, YMMV.

Thanks again to everyone for the responses!
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  #12  
Old 11-10-2020, 07:37 PM
RFSchaller RFSchaller is offline
 
Join Date: Oct 2010
Location: Phoenix, AZ
Posts: 3,068
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Bruce,

Iíve built 4 homebuilts, three kits and one plans built. My first project I obsessed over every detail. What I learned is to relax and use common sense. There is no one rivet that will cause me to fall out of the sky. Spar pins and control cables and their ilk require perfection. Other stuff is less important. I used the suggestions mentioned here and have over 1000 hours on my airframe with no issues.

My engineering career started in the nuclear Navy where everything was rigorously controlled. When I moved to the nuclear industry it was a bit of an adjustment to start using my brain to determine what things affected safety and what didnít. There are only so many resources and they need to be focused on the important stuff.

Good luck with your build. It will be a great educational experience and give you a real feeling of achievement that first flight.

Rich
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  #13  
Old 11-11-2020, 02:31 PM
Wrench Wrench is offline
 
Join Date: Nov 2017
Location: Fleming Island, Fl
Posts: 2
Default Final size Matched Hole Kits

Hope I don't get " flamed " for this, my first post...

I'm a potential builder of one of the " final size, matched hole " kits but am concerned the kits as advertised below aren't the real world experience ?

I would not be concerned with a bit of minor reaming as long as it doesn't require taking everything back apart to debur. Is that realistic ?

Thanks !

" Vanís Aircraft has initiated the process of phasing in the production of final-size, matched-hole RV-10 parts. Until now, all parts for the RV-10 have been produced with slightly undersized holes, which the builder must up-size with a drill and then debur prior to assembly. We will be transitioning the RV-10 kit to final-sized holes, much like the RV-14 and RV-12iS kits. There is no increase in kit prices associated with this planned change.

We are excited to remove a portion of the initial work that builders need to perform on certain parts of the RV-10 airframe assembly with this change. Aircraft parts with final-size holes may be dimpled and then assembled right out of the box, after deburring the edges of each part as needed. This removes the need to first cleco the parts together, drill them to size in assembly, then disassemble and debur."
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  #14  
Old 11-11-2020, 05:33 PM
Mich48041 Mich48041 is offline
 
Join Date: Apr 2008
Location: Riley TWP MI
Posts: 3,182
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Bill, welcome to VansAirforce.
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RV-12 Flying
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  #15  
Old 11-11-2020, 08:02 PM
Charlie12 Charlie12 is offline
 
Join Date: Oct 2014
Location: Port Orange FL
Posts: 42
Default working holes in aluminum

At the risk of being more detailed than anyone actually wants to hear, I spent 45 years as a structural design engineer in the aircraft world, 30 years of it teaching aircraft design in college. My experience was that aluminum is sufficiently ductile that it is quite forgiving of minor hole irregularities when rivets are being installed. This is because rivets swell to fill the hole as they are set. Bolt hole size is a much more critical issue because tension in the bolt as the nut is torqued actually makes the bolt diameter shrink a miniscule amount. Few textbook discussions point out this distinction.

When I was working in Air Force flight testing, one heavily stressed structural modification actually had a written requirement for interference fit fasteners. Rivets had to be tight enough in the holes that the rivets would not go into the hole without being pressed in. The concept was that slight cold-working of the hole actually made the hole/sheet stronger. I felt comfortable that my gentle twisting of the awl into my rivet holes was doing that.
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Last edited by Charlie12 : 11-11-2020 at 08:03 PM. Reason: typo
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  #16  
Old 11-11-2020, 08:45 PM
rv9builder rv9builder is offline
 
Join Date: Jan 2005
Location: Irvine, CA
Posts: 914
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Quote:
Originally Posted by Wrench View Post
I would not be concerned with a bit of minor reaming as long as it doesn't require taking everything back apart to deburr. Is that realistic?
I hope so. I've used a reamer on many, many holes on my project, and usually only a few very small shavings were removed by the reamer. There were no obvious burrs after reaming, and rivets that wouldn't fit, even after trying to align the holes with an awl, easily slipped into place.
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  #17  
Old 11-13-2020, 05:53 AM
Wrench Wrench is offline
 
Join Date: Nov 2017
Location: Fleming Island, Fl
Posts: 2
Default Final size Matched Hole Kits

Appreciate the replies.

Ironically I tripped across a " you tube video " last evening wherein this issue was covered in detail. Search for " Plane Lady " and you'll find it. I found it very informative.

These kits are obviously well thought out and crafted by the folks at Vans...the completion rate is simply amazing.... as were the flight qualities in the one I recently flew in... That was a mistake

Thanks !
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  #18  
Old 11-13-2020, 09:23 AM
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rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,401
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A couple of comments regarding the fit of parts and a need to final drill when the expectation is that it shouldn't be required.

There are a bunch of factors that can have an influence on this. They have been mentioned before but they are worth repeating for those new to RV's.

- Hole size tolerance - Every part produced has to have a tolerance. In the context of holes, if they are punched at the small sized end of the tolerance, the rivet fit will be a bit tighter. This variation is usually influenced by the age and sharpness of the punch tool.

- Rivet diameter tolerance - there can be a tolerance induced variation in the rivet diameters from batch to another. Van's Aircraft has no control over this.

- Proper preparation of parts - Proper adjustment of flange angles and straightening via fluting is critical to having parts align properly. If fluting is done on parts to get them "pretty straight", they will go together, but not with the same level of ease as if it was done very accurately.

- Getting parts properly aligned - Even if the other 3 factors list above are not working against you, you can still get parts clecoed together that are just slightly mis-positioned enough to prevent clecos from being inserted. The difference between an easy slip fit of a rivet into a hole, vs wont go in at all is as little as 1 - 2 thousandths of an inch (.001 - .002) Clecos can't be relied on to assure that level of precision.

Tapered pins mad from dull #30 drill bits can be very helpful for this. Using them to help get proper alignment while clecoing can make the difference.
Just one single rivet, installed after reaming a hole because the rivet wouldn't go in, can be enough to lock in the slightly misaligned position and then require all holes in that are to be reamed. It is often helpful to get a bunch of rivets inserted in holes on an assembly, before setting any of them.

In the context of RV kits other than the RV-12, these factors are usually not relevant except for to a very limited degree because anywhere that flush rivets are installed, the dimpling process enlarges the holes a small amount making rivet fit much less critical.
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Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.

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RV-6A (aka "Junkyard Special ")

Last edited by rvbuilder2002 : 11-13-2020 at 09:27 AM.
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  #19  
Old 11-13-2020, 01:48 PM
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greghughespdx greghughespdx is offline
 
Join Date: Nov 2011
Location: Aurora, OR
Posts: 970
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One additional note: For matched-hole, final-sized parts (on RV-14, -12 and -10 where applicable) our tool tolerances are also tighter. In other words, we monitor and manage our punch tooling for the production of those parts to help ensure the holes remain within the final-sized hole measurement standards/tolerances. When the punch tools reach the point where they are no longer within tolerance for final sized holes, they can sometimes be used for other punch jobs where the tolerances are not as critical.
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Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.

Building RV-8A since Sept 2014
Dual AFS 5600, Avidyne IFD 440, Whirlwind 74RV, Superior XP IO-360
VAF build thread - Flickr photo album - Project Facebook page
Aurora, OR (EAA Chapter 105)

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  #20  
Old 11-13-2020, 08:53 PM
RFSchaller RFSchaller is offline
 
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Location: Phoenix, AZ
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To Ninerbikes comment: I fly both my 12 and my Cherokee 180 every week. I love the Cherokee (bought it in 1985), but honestly itís like wrestling a Mac truck compared to the light controls of the 12. The heavy solid feel of the Cherokee is great for single pilot IFR when stability is a definite advantage, but landing the 12 is so much easier with the crisp responsiveness of the 12 in the flare.
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