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  #21  
Old 09-30-2012, 10:19 AM
Mich48041 Mich48041 is offline
 
Join Date: Apr 2008
Location: Riley TWP MI
Posts: 3,070
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Scott is not wrong very often. I appreciate the very helpful advice that he has given over the years. He does not like criticism of Van's Aircraft. That is to be expected. Most of us have pride in the work that we do. Keep up the good work, Scott.
One thing that the service bulletin does not mention is lifting the RV-12 to take the weight off from the landing gear while tightening bolts. I think doing that is a good idea to minimize possible binding of the bolts. It is not hard to lift the aircraft using the sawhorse method. Push the tail down, put a sawhorse under the bulkhead near the steps, then lift the tail with a scissor jack under the tie-down eye-bolt.
Joe Gores
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  #22  
Old 09-30-2012, 12:15 PM
yankee-flyer yankee-flyer is offline
 
Join Date: Jun 2009
Location: Dayton, OH
Posts: 838
Default A lot more than 5%, Dick

Of those who have reported checking their outboard bolts, it look like over 80% have found them loose, ever after as little as 35 lours flying time. Now the percentage with buckled skins IS small, and I think is due to something else entirely.

Wayne 120241/143WM
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  #23  
Old 09-30-2012, 02:29 PM
Bob Kibby Bob Kibby is offline
 
Join Date: May 2008
Location: Arlington, Texas
Posts: 127
Default Jacking up the airplane to ascertain seating

Seems one must jack up the airplane to ascertain for sure seating or rivet interference of the 1202 plates. I think mine seated well during assembly but not absolutely sure.

. Any ideas?

Doug Dahl[/quote]

I would think you would want the weight on the gear to see that the the bolt head was seated to the saddle. With the weight off the gear I would think that the weight of the gear leg and wheel assembly would possibly pull down on the saddle and close any gap there was with the saddle. I found that my bolt heads were not seated with the weight on the gear. I have removed the small fuselage side skins so I could see the bolt heads but had trouble tellling whether they were seated or not. I took a photo with my iPhone and then downloaded it to Picasa 3 on my Desktop. By magnifying the bolt head to saddle area of the photo you can really see if there is a gap or not. I also sent the photo to Rian and he confirmed that I had a gap and pointed out the interference with the shop head of the bulkhead rivets. An interesting aside is that I thought I had found a sigificant problem when I noticed that I had a gap between the saddle and scuff plate at both ends of the saddle. Rian responded with the following:

"There should be a gap between the saddle and the scuff plate. This assures that the saddle is snug against and holding the gear leg."

Just goes to show that some gaps are "good" and some gaps are "bad". I believe that the reason the SB instructs us to "Use an even torquing sequence back and forth between each of the bolts" (fore and aft bolts- clarification by me) is that they don't want you to bottom out one side of the saddle on the scuff plate. My thoughts, Bob Kibby N712BK
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  #24  
Old 10-01-2012, 01:39 PM
HDDAHL HDDAHL is offline
 
Join Date: Feb 2007
Location: hilton head sc
Posts: 97
Wink

I complied with the SB today. Thanks to the suggestion (Kibby?) about removing the lower small side skins; that helped a great deal.

No cracks found; didn't expect any, no hard landings all on hard runways. Did have a little rivet interference and rounded off the u 1202's.

Took about three hours. did not jack the plane up.

Doug Dahl
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  #25  
Old 10-03-2012, 08:41 AM
DQC DQC is offline
 
Join Date: Nov 2011
Location: Payson, AZ
Posts: 7
Default 3 out of 4 loose, no cracks

Complied with SB. 3 out of 4 AN5-20A loose. No cracks. 1 of 2 AN6-24A bottomed out; added add'l washers & new nut. 90 hours TT
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  #26  
Old 10-03-2012, 11:33 AM
lewy lewy is offline
 
Join Date: Nov 2009
Location: Jackson Ohio
Posts: 139
Default Loose bolts

Hi, how many washers did you use?
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  #27  
Old 10-03-2012, 07:30 PM
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Tony_T Tony_T is offline
 
Join Date: Dec 2008
Location: Lacey, WA
Posts: 1,365
Default SB completed...

Completed the SB on my 12 today. I drilled off the two Cover Plates to get a good look at the hardware after 168 hours, and a lot of landings, all on hard surface.
As found, one of the U-1202 brackets did have a small rivet interference and gaps on each side did not look quite equal. The other U-1202 bracket looked square. There were a lot of threads showing beyond the nuts on the AN6-24A bolts. I believe these nuts were bottomed out on the bolts, but some clamping was taking place because there was an imprint of the washer in the powder coating on the bracket.

After taking off the nuts on the outboard AN5 bolts I found no cracks in the C-channel but it was apparent that the washers do not bear the full 360°, as was noted in previous posts:


I corrected the rivet interference by slightly grinding the U-1202 per the SB. I used the even torquing sequence and verified the U1202s were holding the gear leg evenly. I added an additional washer on each of the AN6-24A bolts per the SB.

One thing that I would like to see is a change from rivets to nutplates and screws holding on the F-1275G left and right Cover Plates. This might be something we could do individually, post AW inspection.

Tony
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Last edited by Tony_T : 10-03-2012 at 07:41 PM.
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  #28  
Old 10-03-2012, 08:54 PM
tim walter tim walter is offline
 
Join Date: Apr 2011
Location: san rafael
Posts: 110
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Quote:
Originally Posted by Tony_T View Post
Completed the SB on my 12 today. I drilled off the two Cover Plates to get a good look at the hardware after 168 hours, and a lot of landings, all on hard surface.
As found, one of the U-1202 brackets did have a small rivet interference and gaps on each side did not look quite equal. The other U-1202 bracket looked square. There were a lot of threads showing beyond the nuts on the AN6-24A bolts. I believe these nuts were bottomed out on the bolts, but some clamping was taking place because there was an imprint of the washer in the powder coating on the bracket.

After taking off the nuts on the outboard AN5 bolts I found no cracks in the C-channel but it was apparent that the washers do not bear the full 360?, as was noted in previous posts:


I corrected the rivet interference by slightly grinding the U-1202 per the SB. I used the even torquing sequence and verified the U1202s were holding the gear leg evenly. I added an additional washer on each of the AN6-24A bolts per the SB.

One thing that I would like to see is a change from rivets to nutplates and screws holding on the F-1275G left and right Cover Plates. This might be something we could do individually, post AW inspection.

Tony
Good idea Tony, I definitely think that would help inspections down there.

Also that's a very telling photo, you should definitely send that to Vans.
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  #29  
Old 10-03-2012, 09:51 PM
NASA515 NASA515 is offline
 
Join Date: Nov 2011
Location: Hansville, Washington
Posts: 536
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Quote:
Originally Posted by Tony_T View Post

I corrected the rivet interference by slightly grinding the U-1202 per the SB.

Tony
The problem does not seem to be - based on your picture- interference with rivets - it appears to be a "shoulder" or non-flush machined pocket that prevents the washer from bearing 100% on the web of the channel. What's needed is a radiused washer to even the difference in height (or grinding the pocket down to flush - ouch!)

Did you do this with the airplane on the gear? Or jacked (Remember - I have your sawhorse stands....)

Could you have done this in Friday Harbor? Just wondering. You know - "Before Further Flight"?

Bob Bogash
N737G
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  #30  
Old 10-03-2012, 10:47 PM
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Jetguy Jetguy is offline
 
Join Date: Aug 2008
Location: Texas, Fort Worth
Posts: 1,237
Question How about this!

After following this thread one thing I can see that I don't like is that little lip shown in Tonys picture and pointed out in other post. Maybe Vans could offer all RV12 owners a special machined washer with a set bend on the bottom of the washer but even across the top where the nut would rest on it so that when the nut is tighten it would put equal pressure 360 degrees around the surface at that location. I'm sure with all the special tools they have this wouldn't be to much of a problem to make. As a minimum change the machine process when making the spar for future RV12 so that it is flat at that location. Just my personal observation. I have checked my and found no cracks.
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RV12 N1212K
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