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  #1  
Old 01-29-2017, 09:05 PM
goldbar goldbar is offline
 
Join Date: Apr 2010
Location: slc, UT
Posts: 26
Default Tip up blues.

My first attempt posting images, wish me luck.
I have been wrestling with this far too long, wish there were a tipup near by that I could just go look at from time to time, no such luck. Several questions, all related to getting the tip up canopy fit dialed in.
This is how the forward top skin F-771 and F-702 skin match, looks right I think.
[IMG][/IMG]


the next image is as I try to tip-up the canopy (use your imagination) and this is as far as she goes.
[IMG][/IMG]


so I know trimming will be in order down the road, but I'm nervous this should somehow be cleared up before moving on ? and if so, how?

Two more images showing the side fit of the F-702 skin, is this where bending the canopy frame a wee bit here and there to get the fit (that changes with each new piece of the whole added) correct to match the side of the fuselage?
towards the aft of the f-702 perhaps an 3/16ths.
[IMG][/IMG]

and towards the front of the F-702 about the same-ish.
[IMG][/IMG]



so these are my first image postings, I read all that I could till interest waned, so hoping these work.

Cheers.
kelly

Last edited by goldbar : 01-29-2017 at 11:01 PM. Reason: images not showing up.
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  #2  
Old 01-29-2017, 11:48 PM
wjb's Avatar
wjb wjb is offline
 
Join Date: Nov 2012
Location: Half Moon Bay, CA
Posts: 632
Default

Hi Kelly,

I've just run this gauntlet and know your pain. Note my signature line ;-)

Quote:
Originally Posted by goldbar View Post
My first attempt posting images, wish me luck.
I have been wrestling with this far too long, wish there were a tipup near by that I could just go look at from time to time, no such luck. Several questions, all related to getting the tip up canopy fit dialed in.

This is how the forward top skin F-771 and F-702 skin match, looks right I think.
http://s754.photobucket.com/user/sal...tml?sort=3&o=3
This looks reasonable; maybe a bit of a gap at the bottom edge near the fuse.

Quote:
Originally Posted by goldbar View Post
the next image is as I try to tip-up the canopy (use your imagination) and this is as far as she goes.
http://s754.photobucket.com/user/sal...tml?sort=3&o=2

so I know trimming will be in order down the road, but I'm nervous this should somehow be cleared up before moving on ? and if so, how?
This is a common problem and is usually fixed by trimming the 702 skin. Because the hinge point is below the skin surface, the 702 skin moves forward and up initially, so the gap closes and your canopy is stuck.

Another problem I found on my build was that my initial riveting of the frame halves, the position of WD-716 was a bit low, causing the 702 to bend and pull back a bit from the gap. This compounds the problem above because as the canopy lifts, the skin straightens and lengthens, requiring an even wider gap between 771 and 702.

Here's a quick drawing (worth 1000 words):



I would definitely check to see if you have this depressed WD-716 effect; you'll want to correct that (shims will work if the depression is not too big), otherwise the skin/skin gap will be larger than you would probably like. The rest of the gap is due to the location of the tipper pivots, but there's not much we can do about this when built to plans.

Quote:
Originally Posted by goldbar View Post
Two more images showing the side fit of the F-702 skin, is this where bending the canopy frame a wee bit here and there to get the fit (that changes with each new piece of the whole added) correct to match the side of the fuselage?
towards the aft of the f-702 perhaps an 3/16ths.
http://s754.photobucket.com/user/sal...tml?sort=3&o=1
I had to work at bending the frame to get the skirts to line up with the fuse. As you know, every rivet changes the shape of the thing, and in the end I was probably 1/16" off to the inside. I tried to shim (which would have worked) but the gap wouldn't have been perfect, so I decided to glass it like so many others before me. Now, the fit is like a glove.

Quote:
Originally Posted by goldbar View Post
and towards the front of the F-702 about the same-ish.
http://s754.photobucket.com/user/sal...tml?sort=3&o=0
This looks like 702 is a bit proud of the fuse. Mine still has a bit of this too. the pre-punched holes in the skin and WD-716 frame seem to set this distance, as does the location of the center point of the frame with respect to F771/F768A. (you can imagine, if you push down on the center of the frame, the left and right bottom edges will bow out as the frame rotates around the pivot points.) I would have liked the flexibility to NOT have the frame pre-drilled, so I could set the width better in the front.

It's a slow and sometimes frustrating process. Read and re-read all other posts here on VAF on this subject and go slow. I know if I build another canopy, it will come out quite a bit better because of all the gotchas that you didn't know a week or a month ago when you did some op.

Keep at it.

Oh, and you'll absolutely want to make a set of canopy stops, similar to Bruce's below. My canopy shifted 3/32 ~ 1/8 of an inch forward (when closed) when the struts went on.

http://www.europa.com/~swayze/RV-7A/.../20120225.html
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Bill Bencze
N430WB (reserved) RV-7 #74152, tip-up -- Learning Zen by working on the canopy.
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Defeating gravity one rivet at a time
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Last edited by wjb : 01-30-2017 at 07:32 AM.
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  #3  
Old 01-30-2017, 06:49 AM
BillL BillL is offline
 
Join Date: Sep 2007
Location: Central IL
Posts: 3,660
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Quote:
Originally Posted by wjb View Post
Hi Kelly,

I've just run this gauntlet and know your pain. Note my signature line ;-)



This looks reasonable; maybe a bit of a gap at the bottom edge near the fuse.



This is a common problem and is usually fixed by trimming the 702 skin. Because the hinge point is below the skin surface, the 702 skin moves forward and up initially, so the gap closes and your canopy is stuck.

Another problem I found on my build was that my initial riveting of the frame halves, the position of WD-716 was a bit low, causing the 702 to bend and pull back a bit from the gap. This compounds the problem above because as you lift, the skin straightens and lengthens, requiring an even wider gap between 771 and 702.

Here's a quick drawing (worth 1000 words):



I would definitely check to see if you have this depressed WD-716 effect; you'll want to correct that (shims will work if the depression is not too big), otherwise the skin/skin gap will be larger than you would probably like. The rest of the gap is due to the location of the tipper pivots, but there's not much we can do about this when built to plans.



I had to work at bending the frame to get the skirts to line up with the fuse. As you know, every rivet changes the shape of the thing, and in the end I was probably 1/16" off to the inside. I tried to shim (which would have worked) but the gap wouldn't have been perfect, so I decided to glass it like so many others before me. Now, the fit is like a glove.



This looks like 702 is a bit proud of the fuse. Mine still has a bit of this too. the pre-punched holes in the skin and WD-716 frame seem to set this distance, as does the location of the center point of the frame with respect to F771/F768A. (you can imagine, if you push down on the center of the frame, the left and right bottom edges will bow out as the frame rotates around the pivot points.) I would have liked the flexibility to NOT have the frame pre-drilled, so I could set the width better in the front.

It's a slow and sometimes frustrating process. Read and re-read all other posts here on VAF on this subject and go slow. I know if I build another canopy, it will come out quite a bit better because of all the gotchas that you didn't know a week or a month ago when you did some op.

Keep at it.

Oh, and you'll absolutely want to make a set of canopy stops, similar to Bruce's below. My canopy shifted 3/32 ~ 1/8 of an inch forward when the struts went on.

http://www.europa.com/~swayze/RV-7A/.../20120225.html
Now is the time to get that center splice correct so the picture above is corrected. You should adjust so there is NO deflection of that 702 skin when closed. This is the first thing to get right on this frame. jut put a straight edge across the skins and look for the gap. Do what ever you have to do to get that right before moving on. Replace the splice, or bend it - - what ever, but get it right.

Canopy stops: I installed them - made no difference. Once the front skin is riveted on, installation of the struts will not change the gap more than a couple of thousands. Although YMMV, mine did not move with strut installation.

I just a short time ago I riveted the front skin on mine, everything was perfect with clecos. Then after riveting it was - NOT. Just me, but I would suggest finishing the canopy after you have that skin riveted if at all possible. I think the radius was/is altered in the riveting process. I believe the rivet set bent the tabs on the sub panel radial to the skin curve and altered the absolute diameter of that area. The first side was perfect, the second radius was reduced and a stagger mismatch of the skins in appeared. Wings/scoops are the normal description of these. I have nothing but theory as avoiding them. Doing the 771 first will leave many options for getting that right in the end.

In the process, use all the clecos in the forward skin. I used cleo clamps on the longeron to get it to fit. Use spacers on the canopy frame to ensure the sides are parallel to the longeron. Use the same spacers when attaching the side rails. This ensures the 771/702 gap at the fuse does not change. Bend the frame as needed until perfect for forward gaps and stagger between 702/771 and along the fuse side skin. Make the rails fit that. (Tricky)
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Last edited by BillL : 01-30-2017 at 06:51 AM.
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  #4  
Old 01-30-2017, 08:23 AM
goldbar goldbar is offline
 
Join Date: Apr 2010
Location: slc, UT
Posts: 26
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Bill and Bill,
Cannot go to my garage right now but thank you both for very informative replies. I need to chew on this a bit. The canopy frame splice plate is riveted, I need to check that gap with a straight edge, but it seems I cannot move on unless that is opening now, as it won't miraculously operate once the canopy is further along/completed. And as the alignment changes each time they are assembled or disassembled, or riveted, ugh.
Thank you,
I'll get back to this in a day or so.
kelly
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  #5  
Old 01-30-2017, 09:02 AM
RV Jerry RV Jerry is offline
 
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Location: Chino, CA
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I would suggest you install canopy struts asap as they will usually change the fittings
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  #6  
Old 01-30-2017, 09:05 AM
RV Jerry RV Jerry is offline
 
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Fat fingers should read FIT on last word
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  #7  
Old 01-30-2017, 09:25 AM
Rupester Rupester is offline
 
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Location: Mahomet, Illinois
Posts: 2,127
Default another tip for temporary fitting

McMaster-Carr sells some cheap, all-aluminum, 3/32 pop rivets ... in boxes of 100 to 250. They're great as temporary holders during construction. They pull things up tighter than clecos and don't get in the way of canopy frame opening/closing during the fitting process. They come out with just barely a touch of a #30 or #40 drill. I found them hugely helpful, as they gave me a good idea what things would look like after final riveting.
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  #8  
Old 01-30-2017, 11:11 AM
BillL BillL is offline
 
Join Date: Sep 2007
Location: Central IL
Posts: 3,660
Default Canopy stops a necessity? Is there data?

Quote:
Originally Posted by RV Jerry View Post
I would suggest you install canopy struts asap as they will usually change the fittings
Jerry, I left off the struts until all was riveted. Canopy installed. I installed the complete canopy, measured the gaps then, without moving anything, climbed inside and installed the struts. There was no movement, no measurable change in the gaps. I measured the compression force on each strut, it was around 22.5# each.

I have heard a lot about the necessity of canopy stops, and I installed them, but wonder if this conclusion was reached before (or after) all was riveted?
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  #9  
Old 01-30-2017, 11:29 AM
Bavafa Bavafa is offline
 
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Quote:
Originally Posted by BillL View Post
Jerry, I left off the struts until all was riveted. Canopy installed. I installed the complete canopy, measured the gaps then, without moving anything, climbed inside and installed the struts. There was no movement, no measurable change in the gaps. I measured the compression force on each strut, it was around 22.5# each.

I have heard a lot about the necessity of canopy stops, and I installed them, but wonder if this conclusion was reached before (or after) all was riveted?
I second the call for the installation of the canopy struts. It had a huge effect on mine. It is very frustrating that the setup changes each time you put take it off and put it back on. Also using the pop rivet or some thing that can hold things together very tightly is a great suggestion as well. It is amazing how much things change each time.
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  #10  
Old 01-30-2017, 12:04 PM
BillL BillL is offline
 
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Location: Central IL
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Quote:
Originally Posted by Bavafa View Post
I second the call for the installation of the canopy struts. It had a huge effect on mine. It is very frustrating that the setup changes each time you put take it off and put it back on. Also using the pop rivet or some thing that can hold things together very tightly is a great suggestion as well. It is amazing how much things change each time.
This is totally opposite my experience. The struts should NOT be installed until the canopy is complete with the plexi fastened and epoxied. The front skin f771 should be completely riveted.

Then, my strut installation resulted in NO dimension change. Not forward gap, not side stagger, nothing.

So - again why, specifically, are the canopy stops needed?
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Last edited by BillL : 01-30-2017 at 01:56 PM.
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