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  #1  
Old 03-01-2015, 12:03 AM
Jackm Jackm is offline
 
Join Date: Feb 2012
Location: Prosser,WA
Posts: 272
Default Wing Jack warning!!!

This week we started our first annual on our RV10. We had inspected the wheels and brakes and decided to replace the tires and brake pads and service wheel bearings all in one shot after initial inspection. During the build we had the RV10 up on the stands numerous times with these wing jacks with no problems.....Well today we had a problem..... and it was my fear from the the moment we started using these a year ago. The airplane was just a inch off the tires...a loud snap and a crunch with no danger but it could been much worse as I was working on removing the cotter pin to remove the wheel retainer nut. I didn't think I was creating any movement to the airplane but who knows....I was a Dumb *** for not watching close. The reality is it happens fast and safety is a concern.
https://www.dropbox.com/s/edyondxkdi...46084.jpg?dl=0
I am not exactly sure what went wrong but a few thoughts so this doesn't happen to others if you are using the same system.
1. Do Not lift both sides up at same time, Block the tires on opposite side and nose to prevent the aircraft from moving the aircraft.
2. Do Not lock the homebuilt pipe cap to the stud bolt...oversize the hole and leave the nut above the pipe cap slightly loose to allow the cap to pivot as you lift and lower the aircraft...mine was tight.
3. Use Grade 8 bolts for the stud and keep cap as close to wing skin as possible.
https://www.dropbox.com/s/r95kdwqkhq...2_HDR.jpg?dl=0
The fix is somewhat simple with installing a stall warning inspection kit in the place of the hole.
This ruined my day but no one got hurt...hopefully this prevents any future incidents.
https://www.dropbox.com/s/wwp2b5tcrw...39083.jpg?dl=0
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  #2  
Old 03-01-2015, 03:42 AM
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rleffler rleffler is offline
 
Join Date: Jun 2006
Location: Delaware, OH (KDLZ)
Posts: 3,891
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Jack,

Sorry to hear about your misfortune.

I'm curious, what do you think would have happened if your bolt didn't shear?

I've got a custom milled solution that a friend made for me. It seems to cope with angles adequately.

I also don't push my luck when the aircraft is on the stands. Anything that I can do before jacking, like removing cotter pins, slightly loosening bolts/nuts, etc minimizes movement and potential accidents. For example, I'll back off the wheel nut a half a thread or so to elimate having to use extreme force while on the jacks.

I do agree that folks need to be careful when they got the aircraft jacked up and take appropriate safety cautions.

Here's a photo of my jack stand. It's an URL to mykitlog page. For some reason I can't get the URL for the photo with Safari this morning.

http://mykitlog.com/users/display_lo...=146253&row=20

Bob
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  #3  
Old 03-01-2015, 05:42 AM
BillL BillL is offline
 
Join Date: Sep 2007
Location: Central IL
Posts: 4,355
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Just looking gives one a sick feeling at first. Thank you for sharing your experience.

Jack, to the exact cause of failure - I am surmising from your post that the pipe cap fits pretty tight on top of the end of the cylinder, and that the angle of the pipe cap and rigid connection did not allow any pivoting - then when jacking the pipe cap was bending on the attachment bolt and broke the bolt?

Is this correct?

OK - Don't use a grade 8 bolt, use a grade 5. Grade 8 is more likely to break than bend, whereas the grade 5 will bend instead.
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  #4  
Old 03-01-2015, 05:57 AM
Vlad's Avatar
Vlad Vlad is offline
 
Join Date: Oct 2008
Location: NJ
Posts: 7,386
Default "Wing Jack" be your call sign

Quote:
Originally Posted by Jackm View Post

...

1. Do Not lift both sides up at same time, Block the tires on opposite side and nose to prevent the aircraft from moving the aircraft.

...


Thanks for reminder Jack sometimes I skip using my square wheels. Sorry to hear about the damage. The positive side is now you have a stall warning inspection plate. Did you put any doubler?


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  #5  
Old 03-01-2015, 07:24 AM
kkmarshall kkmarshall is offline
 
Join Date: Sep 2014
Location: Central Tx
Posts: 82
Default Wing jack

I know there are many methods & opinions but I jack one side at a time by using a 1ft 2by12 well padded under the main spar just inboard of the gear leg. Steady as a rock. I am not the builder but he gave me that advice & it works well. YMMV
Keith
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  #6  
Old 03-01-2015, 07:30 AM
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Walt Walt is offline
 
Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 4,716
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That really sucks
Jacking an aircraft is always a risky process and I hate that Van's does not incorporate provisions for jack pad mounts into the plans. If I ever built another RV I will make provisions for something like this where the pad is bolted to the aircraft and the weight is properly transfered to the spar (not sure the tie down was designed for this especially on the 10). I may even purchase a set to play with and see if they work on my 7A.



http://www.aircraftspruce.com/catalo...rt30M-C210.php
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Last edited by Walt : 03-01-2015 at 08:01 AM.
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  #7  
Old 03-01-2015, 08:00 AM
N427EF N427EF is offline
 
Join Date: Oct 2005
Posts: 1,510
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Walt, that would be an excellent idea .
I have never liked the wing tie down bolt as a jack point.
I use the same kind of jack but place it on the fuselage underneath the wing spar carry through.
A padded 6x6 one inch piece of plywood spreads the load and lifting on the inside requires much less lifting distance than using the mid wing tie down location.

A location to bolt on a pad would be great.
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  #8  
Old 03-01-2015, 08:12 AM
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larrynew larrynew is offline
 
Join Date: Oct 2007
Location: In New Braunfels, ist das Leben schön!
Posts: 772
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Timely thread. I'm leaving for HF in a few minutes to get a jack to make one for the airplane.

Here's a thought. Put a safety "box" between the wing and jack. Imagine a metal cigar box (no top) upside down with a hole in the bottom. The "tie down screw pipe cap thing" goes through the hole in the cigar box into the wing holding it tight against the wing. If the jack slips off the tiedown, it's captured by the box minimizing or eliminating damage. The box would also spread the load on the bottom of the wing like a boat jack.
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  #9  
Old 03-01-2015, 08:24 AM
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Walt Walt is offline
 
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Location: Dallas/Ft Worth, TX
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Whatever you use be sure that the jack/jack point can pivot freely as the angle changes. Most aircraft jacks use some type of ball/socket arrangement for this reason, and as Bill indicated above this is likely the cause of failure in this particular case.
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EXP Aircraft Services LLC
Specializing in RV Condition Inspections, Maintenance, Avionics Upgrades
Dynamic Prop Balancing, Pitot-Static Altmeter/Transponder Certification
FAA Certified Repair Station, AP/IA/FCC GROL, EAA Technical Counselor
Authorized Garmin G3X Dealer/Installer
RV7A built 2004, 1700+ hrs
Website: ExpAircraft.com, Email: walt@expaircraft.com, Cell: 972-746-5154
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  #10  
Old 03-01-2015, 08:33 AM
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DanH DanH is offline
 
Join Date: Oct 2005
Location: 08A
Posts: 7,728
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Jacking aside....

Pretty sure the skin is structural. When installing the new access plate, you'll need to be sure the rivet and screw arrangement is adequate. Vans would probably help you with that.
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