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01-03-2013, 03:11 PM
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Join Date: Oct 2005
Location: 08A
Posts: 9,500
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Quote:
Originally Posted by N427EF
Safety wire is installed to keep the pushrod from rotating
For whatever reason on the RV10 only.
It has no bearing on the safety of the nut and bolt.
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Apparently because of the long shank on the GMM-4M-675 rod end. If both jam nuts got loose the pushrod could rotate onto the long shank and run off the short shank on the other end.
http://www.myrv10.com/Plans/RV10_Plans_sec39-pg03.html
__________________
Dan Horton
RV-8 SS
Barrett IO-390
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01-03-2013, 03:24 PM
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Join Date: Dec 2005
Posts: 976
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Is there any way the safety wire could be mis-installed, or move/slip, and alter the working of the joint such that the bolt did turn / rachet one way, and "wind off" the nut?
There's something about that drawing and the safety wire that just doesn't look ideal to me, when combined with the theory of a nyloc being safe due no possible rotation of the bolt...
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01-03-2013, 03:33 PM
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Join Date: Nov 2006
Location: Boise, ID
Posts: 1,095
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Quote:
Originally Posted by N427EF
Safety wire is installed to keep the pushrod from rotating
For whatever reason on the RV10 only.
It has no bearing on the safety of the nut and bolt.
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Thanks, Ernst...I do believe there was an accident in the past few years where the end bearing pulled out of the pushrod. It was on an -8 doing acro, and the pilot had time to transmit that he lost elevator control.
My question was about the possibility of adding safety wire to the rod-ends so if they did detach, for whatever reason, that you would still have safety wire making the (albeit, loose) connection. That may still give you some control, I would think.
Is my thinking out of line on the need for this? I know it doesn't happen often, but I would think the loads pulling on the eye bolt would be pretty strong in many cases (high speed, large deflection, for example).
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Sonny W
Boise, Idaho
RV-7A Flying!
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01-03-2013, 03:35 PM
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Join Date: Jun 2006
Location: SoCal
Posts: 174
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RV-10 accident
Sonny- the safety wire is not around the bolt, it is secured under the bolt to assure the pushrod does not twist from it's installed length.
There are over 400 flying RV-10s, no has ever had this problem with the properly torqued bolt.
Pascal
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01-03-2013, 04:12 PM
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Join Date: Dec 2007
Location: Fredericksburg, TX
Posts: 662
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Do we know where (what altitude) the failure occurred? Was the aircraft flown for a period of time with trim only? Inquiring minds want to know.
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Jim Averett
RV-8
TS36 - Silver Wings
Fredericksburg, TX
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01-03-2013, 04:18 PM
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Super Moderator
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Join Date: May 2005
Location: Locust Grove, GA
Posts: 2,626
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Yes, I have seen this nut loose on a few inspections, including two very recent ones in the last month. I find it amazing that the final inspection ALL builders should perform is to go over the entire control system from beginning to end in all axis, insure each lock nut is tight, the jam nuts are tights, and the castle nuts have cotter pins in them and then MARK them with torque seal. It gives peace of mind to everyone. Once I find a loose jamnut or locknut on the airplanes I inspect, and there is no visible torque seal, I no longer trust the rest of the airplane.
It also pays many dividends for future inspections. One quick glance can confirm the security of the device.
Vic
__________________
 Vic Syracuse
Built RV-4, RV-6, 2-RV-10's, RV-7A, RV-8, Prescott Pusher, Kitfox Model II, Kitfox Speedster, Kitfox 7 Super Sport, Just Superstol, DAR, A&P/IA, EAA Tech Counselor/Flight Advisor, CFII-ASMEL/ASES
Kitplanes "Unairworthy" monthly feature
EAA Sport Aviation "Checkpoints" column
EAA Homebuilt Council Chair/member EAA BOD
Author "Pre-Buy Guide for Amateur-Built Aircraft"
www.Baselegaviation.com
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01-03-2013, 05:43 PM
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Join Date: Jun 2005
Posts: 3,275
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When I did the first flight for a 7A that I did not build, I took the time to examine every flight critical connection end to end. I looked to ensure that bolts and nuts were on, rivets installed to hold those VA-111 thingies, critical engine controls and hoses were on and secured, etc.
It took a while but it was my life on the line.
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01-03-2013, 06:27 PM
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Join Date: Jan 2005
Location: Marion IA
Posts: 1,095
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what safety wire on jam nuts?
Quote:
Originally Posted by Mike S
True, but if you look at the drawings, there is a jam nut, and it is safety wired.
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Hi Mike - I looked at my plans (-9A) and there is no safety wire on any of the jam nuts on any of the 7 pushrods that I can see. Also can't find it in the builders manual. Is it a -10 thing, did Vans add it after my kit, or did I just miss it and will someday have an interesting inspection?
__________________
Dave Gribble VAF #232
Building RV-9A N149DG (slider, IO-320, IFR)
Restored and Flying Beech Super III N3698Q
Marion IA
Struggling with fiberglass
There is no sport equal to that which aviators enjoy while being carried through the air on great white wings." Wilbur Wright, 1905
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01-03-2013, 06:33 PM
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Super Moderator
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Join Date: May 2005
Location: Locust Grove, GA
Posts: 2,626
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only on the 10
I'm pretty certain only the 10 has the forward rod end saftied, as it is much longer than any of the others due to clearance in that area.
Vic
__________________
 Vic Syracuse
Built RV-4, RV-6, 2-RV-10's, RV-7A, RV-8, Prescott Pusher, Kitfox Model II, Kitfox Speedster, Kitfox 7 Super Sport, Just Superstol, DAR, A&P/IA, EAA Tech Counselor/Flight Advisor, CFII-ASMEL/ASES
Kitplanes "Unairworthy" monthly feature
EAA Sport Aviation "Checkpoints" column
EAA Homebuilt Council Chair/member EAA BOD
Author "Pre-Buy Guide for Amateur-Built Aircraft"
www.Baselegaviation.com
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01-03-2013, 07:13 PM
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Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
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Quote:
Originally Posted by vic syracuse
I'm pretty certain only the 10 has the forward rod end saftied, as it is much longer than any of the others due to clearance in that area.
Vic
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Vic is correct.
Keep in mind, these are all different airplanes.
Even though they are all called RV's, it doesn't mean everything about them is the same. (in fact when comparing an RV-9 and RV-10 flight control systems, there is probably more things different than there is the same)
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