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  #1  
Old 06-23-2021, 05:16 AM
keitht keitht is offline
 
Join Date: Jun 2016
Location: coupeville wa
Posts: 169
Default 7A Wing Attach Close Tolerance Bolts

Just put the wings on for the last time with the close tolerance bolts at the airport. The top row of bolts are no problem. The bottom row of bolts are a piece of engineering nobody could be proud of. There are major interference issues with the gear leg support weldments that prevent getting a wrench on the nut to do anything other than stop the nut turning. You have to insert the bolts with just a couple of threads through, get the nut started, tap the bolt in, turn the nut a quarter turn, tap the bolt and repeat until there are enough threads into the nut that the bolt can be drawn in by turning the bolt. I cooled the bolts down in the freezer overnight before inserting them in the spar fitting (with grease) but even so the bolt turning friction was significant so I donít have a good feel for what final torque I have on the bottom bolts. More of an issue for the AN4 size bolts. Having this poor quality of engineering in such a critical area just beggers belief. I am really surprised that there hasn't been more calls for Vans to fix the design in this area. This may get a pass grade from a FEA viewpoint but is totally unacceptable from an assembly and maintenance viewpoint.
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  #2  
Old 06-23-2021, 06:58 AM
Blake Blake is offline
 
Join Date: Oct 2018
Location: Raymond wa
Posts: 94
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Iím not looking forward to this. Iím not far behind on what you are doing. I just transported my fuselage to the airport on Monday and installed wings with temporary bolts. Going to try putting the close tolerance bolts into place tonight. Hope to maybe catch up with you one of these days since Iím not to far from you. Iím based at willapa harbor airport 2s9
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  #3  
Old 06-23-2021, 08:14 AM
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wcalvert wcalvert is offline
 
Join Date: Jan 2019
Location: Anacortes Wa
Posts: 299
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Keith

Just read your rant and feel your pain. My went on last week and there was the same issue, although I think the problem was my creation.

When the assembly of parts for the center section (F704D & F704E) are assembled, I used the small AN5 size close tolerance bolts for alignment. Looking back, that was a mistake since the long pole in the tent would eventually become the issue of getting the larger close tolerance bolts in place. Hard lesson learned and another example of an easy to add note that was omitted from the directions.

The best I could do with the issue was to use drill rod of the right size (7/16") with tapered ends in EVERY hole during assembly. Lube them up, tap them all way in, and tap them back out with the close tolerance bolt.

After torque, check the washers to make sure they don't spin. I plan to recheck the torque on those at the first condition inspection. But they are only working in shear, and the friction in the sandwich of parts only adds a little.

Down in Vernonia this week doing some flying, hoping for my first flight next week! Look forward to visiting with you soon.
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Bill (Wild) VA-165 '90-'93
Anacortes, Wa

First Flight 7/17/2021!!
- Been there, Donated 2021
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  #4  
Old 06-23-2021, 08:22 AM
DGlaeser DGlaeser is offline
 
Join Date: May 2005
Location: Rochester Hills, MI
Posts: 910
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The good news is that those bolts are for shear only, so torquing the nut is not a concern. The nut is just to keep the bolt from coming out 😎 There are numerous designs (sailplanes for example) that just use a washer and cotter pin to keep the bolt in place.
I have a modified open end wrench (ground down to be able to actually fit on the nut) that a few of us at my airport used to install those bolts. Not a fun job.
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RV-7A - Eggenfellner H6, GRT Sport ES, EIS4000, 300XL, SL30, TT Gemini, PMA6000, AK950L, GT320,
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  #5  
Old 06-23-2021, 10:40 AM
keitht keitht is offline
 
Join Date: Jun 2016
Location: coupeville wa
Posts: 169
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Quote:
Originally Posted by wcalvert View Post
Keith

Just read your rant and feel your pain. My went on last week and there was the same issue, although I think the problem was my creation.

When the assembly of parts for the center section (F704D & F704E) are assembled, I used the small AN5 size close tolerance bolts for alignment. Looking back, that was a mistake since the long pole in the tent would eventually become the issue of getting the larger close tolerance bolts in place. Hard lesson learned and another example of an easy to add note that was omitted from the directions.

The best I could do with the issue was to use drill rod of the right size (7/16") with tapered ends in EVERY hole during assembly. Lube them up, tap them all way in, and tap them back out with the close tolerance bolt.

After torque, check the washers to make sure they don't spin. I plan to recheck the torque on those at the first condition inspection. But they are only working in shear, and the friction in the sandwich of parts only adds a little.

Down in Vernonia this week doing some flying, hoping for my first flight next week! Look forward to visiting with you soon.
Bill,
Most of the problem for me was the gear leg weldment interference issue - should have built a taildragger like you are doing. I made up 3 shop bolts for the smaller dia bolts that had tapered ends but were long enough to get the taper all the way through. I put two in the top and one in the bottom inboard. Made up a tool (modified pry bar) to be able to remove the lower shop bolt by getting under the head and levering. The big bolts lined up well and freezing them down helped get them in without the need for muscle. Then the fun started with getting the nuts on. In the end I gave up trying to use a torque wrench on the lower bolts- just tightened until resistance increased and then ďfelt itĒ from there to get it nipped up and stop the washers turning. Not what I would prefer but donít see any other alternative.
I am really familiar with all the different methods used on sailplanes to attach wings and fuselage- mostly two much larger dia single pins in double shear to hold both wings and fuselage together in an easy to assemble and dis-assemble arrangement- nothing I have seen on sailplanes compares with the RV- 7A arrangement which is a major assembly challenge and likely to be impossible to dissassemble without damaging something.
Had two guys that had both built RV-6s helping me put the wings on - both were shaking their heads at the arrangement for the lower wing bolts on the RV-7A.
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  #6  
Old 06-23-2021, 11:27 AM
Ralph Inkster Ralph Inkster is offline
 
Join Date: Feb 2008
Location: Calgary, Alberta
Posts: 1,536
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I had a quantity of cheap wrenches I collected from yard/garage sales. I than cut, ground, or bent them to shape specifically for each nut around the gear weldment. Remember, you need a Left & Right version of each custom shaped wrench.
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  #7  
Old 06-23-2021, 12:49 PM
LarryMyers LarryMyers is offline
 
Join Date: May 2005
Posts: 6
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A rivet gun will make quick work of installing close tolerance bolts.
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  #8  
Old 06-23-2021, 02:09 PM
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wcalvert wcalvert is offline
 
Join Date: Jan 2019
Location: Anacortes Wa
Posts: 299
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Bummer ... well, good news is that it'll be done soon and I'm sure your wings will stay on just fine!

Of course, you say you should have built a taildragger ... now I'm trying to learn how to LAND a taildragger!!

Lots of new stuff in the GA world to wrap my head around. Feel like the FNG again!

Hang in there!
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Bill (Wild) VA-165 '90-'93
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First Flight 7/17/2021!!
- Been there, Donated 2021
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  #9  
Old 06-23-2021, 02:52 PM
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Raymo Raymo is offline
 
Join Date: Nov 2014
Location: Richmond Hill, GA (KLHW)
Posts: 2,340
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Quote:
Originally Posted by LarryMyers View Post
A rivet gun will make quick work of installing close tolerance bolts.
Not the ones he's having issues with. They have to go in slowly to allow the nut to be screwed on a few threads at a time. They then have to be torqued from the bolt head with run-on torque added.
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RV-7A - Slider - N495KL - First flt 27 Jan 17
O-360-A4M w/ AFP FM-150 FI, Dual PMags, Vetterman Trombone Exh, SkyTech starter, BandC Alt (PP failed after 226 hrs)
Catto 3 blade NLE, FlightLines Interior, James cowl, plenum & intake, Anti-Splat -14 seat mod and nose gear support
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Last edited by Raymo : 06-23-2021 at 02:55 PM.
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  #10  
Old 06-23-2021, 03:05 PM
VPYVO VPYVO is offline
 
Join Date: Sep 2011
Location: Melbourne Australia
Posts: 53
Default RV 14 much better

Was watching you Tube channel Flight Chops where he was putting the wings on his RV14.
WHAAAT?
The carry through spar goes outside the fuse and putting the bolts in looks soooo much easier.


Found this pic on a builders log.

https://www.myrv14.com/buildlog/2014...71600-033.html
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RV7 VH-RRA flying Sept 2017
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