Hello:
I also had the MOD 37 extra strengthening tubes added by the
factory a few years ago. I now wonder where to fit all the bungie
cords after having converted to TRIGEAR. Ian I cut the extra tubes
OUT again? I do like them, though, as they add extra strength to
the frame. Also, who knows if I convert back to MONO once the
Glider wings come in reach?
Your comments, please!
Christoph Both #223 Wolfville, Nova Scotia, Canada
Subject: RE: Trike Nose Leg Bungee Breaking.
Hi! Fred.
I just replied to you but somehow the computer cocked it up.
The Mod was 45 2nd October 1997. Mod 37 added the extra strengthening
members to the Mono frame and for trikes the mod.45 removed them and
supplied stronger bungee.
My Mod instructions say increase the length of bungee by 75% the distance
between the blue stipes relaxed is 12mm and stretched should be 21mm.
Now I know why my bungee failed I'm somewhat reticent that I've cut the
members out (actually left the lower 3" of the forward members in , also the
left the mono lift link stops in )
I'll advise you of developments . Has anyone spoke to Andy Draper yet over
there yet?
My nose leg failure was due to a wheel barrow event hitting the front of the
wheel bending the leg down up to 12" along the leg from the front.
Yes, when the 2" of slack on the safety strap is taken up the bungee is like
a bowstring, that's why the bump stop is cutting it .Lets face it if the
rear fulcrum of the leg moves down 2" then the bump stop welded to it at 90
deg must also move back 2"
Whilst I haven't drawn it I can see the fact without the bungee present.
To measure the shock load that begins to exercise the bungee with only my
wife present she used a long thick board with about a 4:1 lever placed
across a drum lifting up on the tail with a packing of foam to spread the
load , whilst I pulled down on the propeller and watched the digital balance
for the "break load".
I can't see the wings making a lot of difference being on the C of G but
mine were fitted anyway.
Regards
Bob H G-PTAG
-----Original Message-----
From: owner-europa@post.aviators.net
Sent: 03 August 2001 03:21
Subject: Re: Trike Nose Leg Bungee Breaking.
Bob Harrison wrote:
>
> Hi! Fred.
> Just browsing through one or two saved messages arrived back with this one
> and it occurs to me that you are still working on 350# as per PRE the "
> increased bungee size mod. My mod instructions uplift the break weight to
> 400lbs to 500lbs with engine fitted. This means a lever applied to uplift
> the tail to effect the test down on the nose wheel. When I said I pulled
> down on the prop. it must have been when the break weight was 350 lbs.
> Sorry to "rabbit " on about this but prefer to know you are on the safe
side
Do rabbit on, Bob, except saying that here that could alarm the
ladies!
I have don't have that mod. I was just about to post re how 1/2"
bungee, and hooks instead of knots, may solve your your crowding and
thus chafing problems. That'll take another loop, and I don't know
how neat it will be and still avoid overlaps. I may actually have
400#. It was stretched at 145%, and it didn't seem it should be
subjected to more (one catalog says 140%). I have her apart anyway to
take care of those pesky V's that pinch the cord, maybe flox something
in there to widen the V.
If you do corner Europa, let me us what you learn. I am more
confused. I don't see what's wrong with occasional bungee exercise in
abnormal landing/taxing situations, as long as it doesn't chafe. Some
are designed that way I thought. As it approaches the 2" to whack the
safety cable, it takes lots of force, seemed to me. 500# is a narrow
margin against Rob Houseman's computed 700# yield strength of the gear
leg, and the caster angle of the fork could narrow that, and bend the
leg down up front. Is that what happened to you? Maybe the leg could
indeed yield before the safety limit is reached, due to sharply
increasing bungee tension.
Lever on the tail? Does that mean measure the lever arm, weigh the
nose, do the math, and apply the difference? Is that accurate w/o a
gorilla sitting on top of the fuselage fulcrum point? Especially w/o
wings installed.
Regards,
Fred F., A063
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