Replies to This Discussion

Permalink Reply by Michael Herder on August 4, 2012 at 5:57pm

Damn near Ron.  Last year at Oshkosh, they taxied me for about a mile on bumpy grass.  I thought it a good idea to inspect everything under the cowl and found that I was hanging by a few rubber threads.  Al Beyers was kind enough to lend me (off of his own plane) a stop collar that would prevent me from having a prop strike if the bungee actually broke.  THe collar is about 2 1/2" and is a must in my opinion if you have one of the earlier kits that did not include a stop ring.  I departed oshkosh and made very very gentle landings until I got to Mexco missouri and replaced the bungee at the zenith factory!  They let me use their tools and helped where they could.

Here's the funny thing, 100 hrs later on the hobbs I found myself with a  similarly frayed bungee.  It is very obvious to me that this is not the result of the bungee being over stretched, rather a bit of rather sharp metal cutting in and prematurley wearing on the bungee.  THis time I really softened the edges, and even wrapped everything that is remotely sharp in a special tape.  I really think this time I wont have any further issues, but this will always be somethign  I monitor every time I open up the cowl.

On the older kits (mine is an HD) there was no stop ring and if the bungee pops you are majorly SOL and would certainly prop strike.  I also considered that if I did prop strike, I'd be in a really likely scenario for a flip and (extremely nose low) and due the prop (what was left of it ould likeley veer to the left quickly) McMaster carr sells what is called a Split collar shaft. it is 2.5" in diameter and will hopefullly never be used.

I bet you did like I did on that duct tape and bungee and made what I still refer to as the imaculate landing.  I touched down the softest I ever had when the heat was really on!

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Permalink Reply by Michael Herder on August 4, 2012 at 6:02pm

Here is what I used, I cant recall the exact one I bought, but you catch my drift.  You're lucky the rods had your back!

Real lucky in my opinion.

http://www.mcmaster.com/#shaft-collars/=ipht1b

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Permalink Reply by Mark Maltais on August 4, 2012 at 9:55pm

Hmmm....those Mcmaster collars seem a bit more safe than the skinny ring welded on my nose gear. Anyone know how well that little collar on my 750 would hold up?

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Permalink Reply by John Austin on August 6, 2012 at 6:29am

That little ring appears very securely welded on my nosegear - I suspect it would destroy the bearing block before deforming much. I would speculate that if there was a catastrophic failure, it would result in the bearing block splitting apart by stripping all the bolts out. That would take an awful lot of force ... my guess is that in that instance, the nosegear collapse would be the least of your problems!

Wasn't there a notice of some bungees being defective? Seems like there is a color-code to the threads on the surface of the bungee - I don't remember the details, but mine was not colored like the defective ones.

Perhaps someone who has lost a bungee with a ring welded on the nosegear can tell us if they had any further damage?

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Permalink Reply by Ron Lendon on August 6, 2012 at 6:59am

John, the little ring is not there. And that is the fault of the manufacturer, which is me. I left it off and over stretched the bungee is what it looks like. I'm stopping but the welding supply today and getting the 1/8 wire to form and install the ring at 95mm below the tee bar bolts heads just like the print said I should have.

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Permalink Reply by Bob Pustell on August 4, 2012 at 6:46pm

Once again, I find myself happy to be building a taildragger instead of a nose dragger..............  :)

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Permalink Reply by Ron Lendon on August 4, 2012 at 7:50pm

I was dragging my tail in today... Even through my flight bag way in the back to assist.

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Permalink Reply by Jim Palmer on August 24, 2012 at 5:05pm

Ron, Bob DePriest up in Hernando, MS had the same trouble with his bungee.

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Permalink Reply by JEFF COCHRAN on August 30, 2012 at 1:02pm

See this current discussion on the 750 forum. Appears to be bungee problem regardless of model.
http://www.zenith.aero/group/stolch750/forum/topics/nose-gear-bunge...

Jeff

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Permalink Reply by Phil Smith on August 31, 2012 at 4:52pm

Hi Folks,

I just went over 60 hours on my 701 and am reading all this about the bungee problem.

Believe me the next time I go out I"m gonna pull the lower cowl, set her on the tail and give it all a good look.

I remember reading about someone using a split collar bolted on the nose gear to limit travel. Has anyone determined a dimension that would be "right" from the bottom of the nylon bearing for the 701? I'm talking about providing enough travel and yet protect the prop from a ground strike if the bungee fails.???

 

From the looks of things I just don't want to trust it all to the "color of the threads" in different manufacturing batches.

 

Thanks

 

Phil Smith

CH-701 Buhl ID

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