Van's Air Force
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Should I round these corners?
- Thread starter jlfernan
- Start date
Round the corners?
Jorge,
You'll likely get answers ranging from a) no rounding necessary to z) round and smooth EVERYTHING...
My opinion and what I did was smooth the edges with a small fine file, round the corners slightly with same file, and buff down the edges that contact the skins as it appears you have done. This way you have no points or sharp edges that would concentrate pressure against the skins.
Then again, I've been told that I'm overthinking this and making it waaaay to much work. Hey, it's my baby and I'm enjoying the build.
Enjoy yours and best of luck!
When I get the feeling that I'm stressing too much about such details, I remind myself of the guy who (reported here on VAF) asked Van's a question and was told something like "It's a truck! Build and go fly it!".
And whatever you do, don't ask about primer! <grin>
Dave
Kit #121, Emp, Fuse, Wings, and Finish kits done. Engine to come soon.
Jorge,
You'll likely get answers ranging from a) no rounding necessary to z) round and smooth EVERYTHING...
My opinion and what I did was smooth the edges with a small fine file, round the corners slightly with same file, and buff down the edges that contact the skins as it appears you have done. This way you have no points or sharp edges that would concentrate pressure against the skins.
Then again, I've been told that I'm overthinking this and making it waaaay to much work. Hey, it's my baby and I'm enjoying the build.
Enjoy yours and best of luck!
When I get the feeling that I'm stressing too much about such details, I remind myself of the guy who (reported here on VAF) asked Van's a question and was told something like "It's a truck! Build and go fly it!".
And whatever you do, don't ask about primer! <grin>
Dave
Kit #121, Emp, Fuse, Wings, and Finish kits done. Engine to come soon.
Looking at the photo, it appears that the edges have been hit with a 3M wheel, or something, that makes the edges thinner. It almost looks like a chisel edge, so to speak.
Or is it an optical illusion in the photo?
If the edges are thin, I don't think that's a good thing.
"Just barely rounded" is my criteria. You don't see many cracks originating at the edge. Corners, yes. Edges, no.
IMHO, more damage is done by over-doing the edge smoothing and deburring than is done by under-doing.
YMMV, and to each his own. My $2. (Forget the pennies!)
Or is it an optical illusion in the photo?
If the edges are thin, I don't think that's a good thing.
"Just barely rounded" is my criteria. You don't see many cracks originating at the edge. Corners, yes. Edges, no.
IMHO, more damage is done by over-doing the edge smoothing and deburring than is done by under-doing.
YMMV, and to each his own. My $2. (Forget the pennies!)
Like the title asks...these are on the main wing ribs.
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12vaitor
Well Known Member
+1 on Blue Roloc disk
It did not take me long to figure out the blue roloc disk was the fast way to round over aluminum corners and for general edge clean up of punch marks. I usually run a 3" in a 90 deg die grinder, followed by a 1" 3M 7A abrasive wheel in a straight die grinder. I use them so often they are dedicated tools with this setup. The 1" wheel is great for edge deburing and a lot easier to use than the 6" one in the bench grinder. Really works well for those wavy edge wing ribs and lightening holes. Buy a box full, you will need them all by the time you finish a -12.
John Salak
RV-12 #116
It did not take me long to figure out the blue roloc disk was the fast way to round over aluminum corners and for general edge clean up of punch marks. I usually run a 3" in a 90 deg die grinder, followed by a 1" 3M 7A abrasive wheel in a straight die grinder. I use them so often they are dedicated tools with this setup. The 1" wheel is great for edge deburing and a lot easier to use than the 6" one in the bench grinder. Really works well for those wavy edge wing ribs and lightening holes. Buy a box full, you will need them all by the time you finish a -12.
John Salak
RV-12 #116
PilotBrent
Well Known Member
Sand paper
I found using a small ScotchBrite wheel horizontally mounted on a drill press was the easiest way to quickly smooth out most of the ribs' edges. If its small enough you can insert into the lightening holes too. But for the corners, while a small file works, a small piece of sand paper is actually faster.
I found using a small ScotchBrite wheel horizontally mounted on a drill press was the easiest way to quickly smooth out most of the ribs' edges. If its small enough you can insert into the lightening holes too. But for the corners, while a small file works, a small piece of sand paper is actually faster.
David Paule
Well Known Member
It's worth rounding those corners generously to save weight. The excess material does little structurally and isn't needed. Of course, leave proper edge distance for the holes. Get in the habit of saving weight now and it'll pay off.
I've found that a snip with hand shears and a file work pretty well to do this, if the part is held in a vice with wood blocks in the jaws.
While you're at it, don't forget the inside areas at the bottoms of the slots. They should be cleaned up well, too, to avoid cracks.
Dave
I've found that a snip with hand shears and a file work pretty well to do this, if the part is held in a vice with wood blocks in the jaws.
While you're at it, don't forget the inside areas at the bottoms of the slots. They should be cleaned up well, too, to avoid cracks.
Dave
The Wizzard
Well Known Member
way to much effort
your at the point of overkill! Trust me, it should only take a couple of min. to clean up a rib. you have turned those pieces into chisels and thats not the point. just clean up the edges with a hand deburring tool and move on! Way too much thinking on those ribs. It dosn't have to take years to build this thing!
your at the point of overkill! Trust me, it should only take a couple of min. to clean up a rib. you have turned those pieces into chisels and thats not the point. just clean up the edges with a hand deburring tool and move on! Way too much thinking on those ribs. It dosn't have to take years to build this thing!
Rounded corners.
Rounded corners save a little bit of weight and reduce the chance of cracking. Rounded edges again reduce the risk of cracking and it is much easier for primer to adhere to a rounded surface.
Corners that have not been rounded save a bit of time but add to cracking risk.
Would I buy an aeroplane that had been built with un-rounded corners...... probably not. In my mind the builder has not done all he can to reduce the risk of stress cracks........ if ha has not done this simple thing what else has he failed to build properly? For me its one of the signs of excellent workmanship against good, bad or mediocre.
What I did was to snip the corner off at 45 degrees then round it with a file smoothing off the edges with some 1000 grit. Overkill? Probably but I dont worry about any cracking there.
Rounded corners save a little bit of weight and reduce the chance of cracking. Rounded edges again reduce the risk of cracking and it is much easier for primer to adhere to a rounded surface.
Corners that have not been rounded save a bit of time but add to cracking risk.
Would I buy an aeroplane that had been built with un-rounded corners...... probably not. In my mind the builder has not done all he can to reduce the risk of stress cracks........ if ha has not done this simple thing what else has he failed to build properly? For me its one of the signs of excellent workmanship against good, bad or mediocre.
What I did was to snip the corner off at 45 degrees then round it with a file smoothing off the edges with some 1000 grit. Overkill? Probably but I dont worry about any cracking there.
brad walton
Well Known Member
2 inch Scotchbrite
Plus 1 for the 2 inch Scotchbrite disc. It is fast, easy and does a great job. Smooth and round all corners and edges as per Van's manual that came with my plane. Section 5, "Construction Materials and Processes"
Plus 1 for the 2 inch Scotchbrite disc. It is fast, easy and does a great job. Smooth and round all corners and edges as per Van's manual that came with my plane. Section 5, "Construction Materials and Processes"
RetiredRacer
Well Known Member
David's got it!!!!
I'm with David Paule here. Build it light!
Heeeyy!!!! Isn't that what planes are supposed to be....LIGHT!!!!
Ok, maybe that's not everybody cup of tea, but really it doesn't take much more effort to nip them off and sand them round. I found once I started doing it it seemed just as quick to nip the corners off and sand them round as it did just to sand them round.
Now, can I ask you what type of primer are you going to use?.................
I'm with David Paule here. Build it light!
Heeeyy!!!! Isn't that what planes are supposed to be....LIGHT!!!!
Ok, maybe that's not everybody cup of tea, but really it doesn't take much more effort to nip them off and sand them round. I found once I started doing it it seemed just as quick to nip the corners off and sand them round as it did just to sand them round.
Now, can I ask you what type of primer are you going to use?.................
joedallas
Well Known Member
Edges or Corners ?
I think we are talking about two different things, section five is talking about rounding the edges. I think this thread is about rounding corners about the radius of a rivet hole( keeping the minimum distance from the edge) as indicated in post 12 is not required in my view.
It may save some weight and probably not affect the strength of the connection. however it is a lot of work to maybe save 1 pound total.
I deburr with a Scotchbrite wheel and use a small file to take the sharp edge off the corners.
I think we are talking about two different things, section five is talking about rounding the edges. I think this thread is about rounding corners about the radius of a rivet hole( keeping the minimum distance from the edge) as indicated in post 12 is not required in my view.
It may save some weight and probably not affect the strength of the connection. however it is a lot of work to maybe save 1 pound total.
I deburr with a Scotchbrite wheel and use a small file to take the sharp edge off the corners.
rv7boy
Forum Peruser
I was going to ask about the "scalloped" edges on the other part of the rib until I noticed this is an RV-12 part. I was beginning to think you got "carried away" deburring the ribs. Does Van's do that to save weight on the RV-12?
My RV-7 ribs don't look that way. Then again, my ribs are six years old, so maybe this is the way all ribs look now.
My RV-7 ribs don't look that way. Then again, my ribs are six years old, so maybe this is the way all ribs look now.
I think the scalloped edges on the RV-12 wing ribs are there to save weight, and they may also make fluting a little more efficient. However any weight saved by rounding the`outside' corners on the ribs is clearly miniscule when you do the maths, although as a principle saving weight makes sense. I did round these corners slightly with a file just because it seemed to be good `aircraftsmanship', but not to save weight or because I thought it was necessary for any structural reason. Rounding`inside' corners is a very different matter of course.
