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  #1  
Old 12-21-2015, 12:15 PM
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AX-O AX-O is offline
 
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Location: SoCal
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Default What happen to this cotter pin?

I went flying again yesterday and during my preflight I found this. It was not there before the previous flight. no signs of hitting anything. Any ideas on what could had caused this? I was thinking a rope but I have not been around any ropes. BTW, that is a DJM 4 inch wheel. Love it.





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  #2  
Old 12-21-2015, 12:25 PM
jrs14855 jrs14855 is offline
 
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Location: Lake Havasu City AZ
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Default Pin

That's why I don't like cotter pins in exposed locations such as that. I much prefer the best quality all metal lock nuts. I modified my tailwheel so that I have a much smaller bolt and nut "countersunk" into the tubular axle. It only took me a few hours on a lathe with a couple of custom tools. I'm quite sure I gained at least .0001 knots speed.
I'd offer to post a picture but its a top secret design.
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  #3  
Old 12-21-2015, 12:55 PM
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DanH DanH is offline
 
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Obvious problem Axel. Happens to me all the time. Your new airplane is so fast that the shockwave from the leading edge of the tire bends the key.


Quote:
Originally Posted by jrs14855 View Post
That's why I don't like cotter pins in exposed locations such as that. I much prefer the best quality all metal lock nuts.
+1. Just installed that tailwheel last week....new bolt, high quality metal locknut. Added some spacers on the outside to mate with my towbar. Probably lost 0.0001 knots

But hey, if that fix don't suit 'ya, turn the bolt 180 degrees so the cotter pin ears blow back in the breeze.
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  #4  
Old 12-21-2015, 01:39 PM
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rvbuilder2002 rvbuilder2002 is offline
 
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Default

I have seen tall grass cause this.

It is the reason that I use the alternate method of finishing cotter pins when installed in an exposed location (rudder cable ends, etc.)

Alt method is was detailed in a recent Sport Aviation article.

Or might it have been damaged by a tow bar?
Someone catching their shoe on it?
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  #5  
Old 12-21-2015, 01:47 PM
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Will give that a look Dan.
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The information that I post is just that; information and my own personal experiences. You need to weigh out the pros and cons and make up your own mind/decisions. The pictures posted may not show the final stage or configuration. Build at your own risk. Further more, these are my opinions and not those of my employer.
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  #6  
Old 12-21-2015, 01:54 PM
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AX-O AX-O is offline
 
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Quote:
Originally Posted by rvbuilder2002 View Post
I have seen tall grass cause this.

It is the reason that I use the alternate method of finishing cotter pins when installed in an exposed location (rudder cable ends, etc.)

Alt method is was detailed in a recent Sport Aviation article.

Or might it have been damaged by a tow bar?
Someone catching their shoe on it?
No tow bar. Will look up the article. Thanks
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RV-4 fastback thread and Pics
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The information that I post is just that; information and my own personal experiences. You need to weigh out the pros and cons and make up your own mind/decisions. The pictures posted may not show the final stage or configuration. Build at your own risk. Further more, these are my opinions and not those of my employer.
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  #7  
Old 12-21-2015, 02:28 PM
crabandy crabandy is offline
 
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I ended up using a double wrap of .040 safety wire, seemed to snag on less stuff.
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  #8  
Old 12-21-2015, 02:39 PM
alpinelakespilot2000 alpinelakespilot2000 is offline
 
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Is there any reason not to use a locknut here in lieu of the castle nut/ cotter pin? My towbar doesn't like the cotter pin.
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  #9  
Old 12-21-2015, 03:04 PM
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Toobuilder Toobuilder is offline
 
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The only reason to use a cotter pin there is if there is not a solid spacer between the bearings. The nut then is used to adjust the tension so you dont preload the bearings. If it's solid, use a lock nut and smoke it down.
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  #10  
Old 12-21-2015, 06:58 PM
laz laz is offline
 
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When you install the Cotter pin next time turn it 90 deg . Bend the ends around the outside of the nut a tuck them into the slots either side of the slot in the nut where the pin exits . This method is often used inside places where you can get scraped or cut. You may need a slightly longer cotter pin to make the bend into the slots.

Without the sharp tag ends exposed they are not likely to catch anything.

There was a article in sport aviation recently, showing just how to do it.
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