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Re: Trike Nose Leg Bungee Breaking.

Subject: Re: Trike Nose Leg Bungee Breaking.
From: Fred Fillinger <fillinger@ameritech.net>
Date: Mon, 30 Jul 2001 09:55:53
Bob, your original message didn't come thru to me, but I get it in
context.  I avoided overlapping by substituting 1/2" bungee.  Doing a
leverage and math problem, and testing the #'s pull per % of stretch,
came out enough loops to appear to do the job, so maybe the math
method wasn't dumb, as a check.

It's easier to pull the thinner supplied bungee toward it's design
limit, and perhaps the overlaps caused concentration of stretching at
some point due to friction.  It may have been stretching in service,
like maybe too loose total, locally at the limit (it's not supposed to
stretch in normal service).  How'd you determine 350# tension at the
nose wheel?  Lakeland said push down quickly and hard on the engine,
in a maneuver like a gymnast mounting the horse.  Not very scientific,
but else??  I scored only 9.2 :)

On topic, I doubled the diameter of the safety cable, using plastic
coated comm'l cable.  Yeah, I know, not aviation grade, but 4X the
area, as there has been breakage on hard landing I hear.  The plastic
I figure will help prevent chafing of the frame, causing rust in
places you cannot inspect so easy.  I also swaged on 2 ferrules for
extra safety.

Regards,
Fred F., A063

Bob Harrison wrote:

> Hi! Guys.
> Further to my message yesterday on this subject.
> We are not sure that in fact the safety strap/cable actually was the
> culprit.
> It just may be the frame being a monowheel strengthened frame with
> the additional support members (the aircraft being convertible) that
> overlaying members of bungee due to restricted space have severed the
> lower bungee members by pulling them into the "Vee" and crushing them.
> Never the less a close inspection would be well in order for trike
> owner/operators.


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