VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.

  #1  
Old 11-13-2014, 06:26 AM
Kahuna's Avatar
Kahuna Kahuna is offline
 
Join Date: Dec 2004
Location: Gold Hill, NC25
Posts: 2,419
Default Nose Gear Bolt Failure. Argh!

This past weekend one of our teammates, our only nose dragger left on the team, had a nose gear bolt failure resulting in a prop strike. I had seen this before on VAF, but had never seen one myself.
Fortunately he was not moving, or barely moving at the time, pulling out from a run-up, holding a brake to turn to square up on the taxiway. As soon as the plane started to rotate, the bolt failed, the gear leg rotated, and she nosed down and caught a few inches of the prop. We are very thankful for composite props, a little luck, and some heads up wingman that were around him at the time. A couple of weeks earlier, he had the tail down, nose gear up, greasing the nose wheel bearing, and had no play in the gear. Its also checked at condition. This hidden bolt, probably doesn't give much warning before failure. Had it failed in another phase of flight other than barely moving, it could have been much much worse for him and the plane. I think he has ~1500 hours or more on the plane. Probably worth considering a periodic change of this important bolt. Or stick it in your tool bag of reasons to own a tail dragger Thought Id share a couple of pictures.



__________________
Kahuna
6A, S8 ,
Gold Hill, NC25
Reply With Quote
  #2  
Old 11-13-2014, 08:19 AM
BillL BillL is offline
 
Join Date: Sep 2007
Location: Central IL
Posts: 6,322
Default Interesting

Thanks for sharing the essential information.

One thought is to check the torque on that bolt at inspection. Literally click the wrench on it at near the specified torque. This should ( no data here) reveal a weak shaft without adding any additional loads. It seems this is similar to a couple of 6's we have seen here with similar failures. If there is loss of torque, then it should be removed and replaced, as the crack could allow enough stretching to lose torque but still be intact enough to accept full torque. I have seen that on occasion, rare, but real.

I don't know if it allows a practical torque check, but every 100 hrs or annual should do it as a fatigue failure would take a while to progress. It would not hurt for all nose bolts to be checked now (next inspection trigger) for this condition. We could use some more good reports.

Glad it failed in nearly the most benign way. Pulling from the hangar would have been the absolute "best" way to fail.
__________________
Bill

RV-7

Last edited by BillL : 11-13-2014 at 08:21 AM.
Reply With Quote
  #3  
Old 11-13-2014, 08:34 AM
BCP Boys's Avatar
BCP Boys BCP Boys is offline
 
Join Date: Oct 2011
Location: Kennesaw, Ga
Posts: 881
Default

Mike, thanks for the report. Tell "Leggs" sorry to hear that happened to him. So glad that he is alright and the plane had minimal damage. As you said it could have been much worse. Thank the good lord for minimal damage . . . expensive but fixable.
__________________
Amir
----------
RV-7 - Regretfully Sold
RV-10 - Sold

Supporting VAF since the first visit
Reply With Quote
  #4  
Old 11-13-2014, 08:38 AM
bret's Avatar
bret bret is offline
 
Join Date: Feb 2010
Location: Gardnerville Nv.
Posts: 2,828
Default

Ouch! I wonder if the taper pin would be stronger, and not allow any movement?
__________________
7A Slider, EFII Angle 360, CS, SJ.
Reply With Quote
  #5  
Old 11-13-2014, 10:23 AM
tomhanaway tomhanaway is offline
 
Join Date: Aug 2006
Posts: 329
Default

Since I'm about to put the legs on my rv8a, this thread is major for me.
Separate from checking torque, is this a metal fatigue issue?

Does a bolt made of higher strength make sense?
Are they available?
I've read the threads about a tapered pin, would this address the issue?

Thanks,
Tom H.
__________________
Tom Hanaway
Moved to Murphy, NC
RV-10/N518TP-sold
repeat offending-8A N116TP-Now Flying
based in Copperhill, TN 1A3
Reply With Quote
  #6  
Old 11-13-2014, 10:36 AM
flyboy1963's Avatar
flyboy1963 flyboy1963 is offline
 
Join Date: Oct 2008
Location: Lake Country, B.C. Canada
Posts: 2,434
Default magical torque wrench?

This sounds like a good check of integrity, but can you show me the torque wrench for this application? I can hardly get an open end wrench on mine!
In the armchair engineering dept.....would some kind of additional key or pin keep the shaft in alignment even after the bolt shears?
In theory, the leg could still 'fall out', but in most cases, staying in alignment, and the static load would keep the leg in the socket.
__________________
Perry Y.
RV-9a - SOLD!....
Lake Country, BC
Reply With Quote
  #7  
Old 11-13-2014, 10:40 AM
RV6_flyer's Avatar
RV6_flyer RV6_flyer is offline
 
Join Date: Jan 2005
Location: NC25
Posts: 3,763
Default

This is not the first nose gear bolt to break. We had one a couple of years ago at the Capital City Air Show on one of the show formation aircraft (RV-6A). The nose gear bolt broke without the engine running while moving the aircraft if I remember correctly. It was fixed in less than an hour. The aircraft did fly in the air show after the fix. Since the engine was not running, the prop did come in contact with the ground.

IMHO, the hole size is critical. It must be just the right size else you have some play in the connection and the bolt will eventually shear.

I had the single AN3 (3/16") bolt shear years ago in my Aviation Products tail wheel mount to the tail wheel spring. I eventually replaced it with a Tapper Pin and have not had any issue since. The Tapper Pin was a change that the RV Guys flying out of Livermore Kalifornia came up and I borrowed the idea.
__________________
Gary A. Sobek
NC25 RV-6
Flying
3,400+ hours
Where is N157GS
Building RV-8 S/N: 80012

To most people, the sky is the limit.
To those who love aviation, the sky is home.
Reply With Quote
  #8  
Old 11-13-2014, 10:59 AM
Mike S's Avatar
Mike S Mike S is offline
Senior Curmudgeon
 
Join Date: Sep 2005
Location: Dayton Airpark, NV A34
Posts: 16,108
Default Lesson to be learned possibly??

Hmmmmmm I wonder if there is any connection with this http://www.vansairforce.com/communit...d.php?t=119353

Kahuna, what is the hole in the side of the lower cowling?? Damage from the prop??
__________________
Mike Starkey
VAF 909

Rv-10, N210LM.

Flying as of 12/4/2010

Phase 1 done, 2/4/2011

Sold after 240+ wonderful hours of flight.

"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."

Last edited by Mike S : 11-13-2014 at 11:02 AM.
Reply With Quote
  #9  
Old 11-13-2014, 11:09 AM
Bavafa Bavafa is offline
 
Join Date: Oct 2007
Location: Sacramento, CA
Posts: 3,639
Default

I am glad the damage is not any more than it is and all are safe.

I believe it was last summer that some one?s bolt had sheered and as a cautionary measure, I pulled mine to inspect and replaced it with another close tolerance bolt. The original bolt did not, or at least I could not, detect any sign of stress (close to head) that would break.
__________________
Mehrdad
N825SM RV7A - IO360M1B - SOLD
N825MS RV14A - IO390 - SOLD
N258SM RV14A - IO390EXP119 - in progress
Dues paid
Reply With Quote
  #10  
Old 11-13-2014, 11:13 AM
pa38112 pa38112 is offline
 
Join Date: Mar 2008
Location: Clarksboro, NJ
Posts: 1,004
Default

Does anyone have this bolt size handy? I am going to order some and just change it out every condition inspection. This issue got my attention last time it came up. Now I have seen enough that I feel I need to take preventative action.
__________________
http://aprs.fi/N153MC
2004 RV6A Flying
2002 RV6A Flying
1978 PA38-112
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 02:13 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.