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From: "Alister Yeoman" <
yeoman@voyager.co.nz>
To: "Murphy Rebel" <
murphy-rebel@dcsol.com>
Subject: Re: Bungee gear
Date: Wed, 4 Nov 1998 21:42:33 +1300
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Hi again,
Thanks for the info, I was speaking to Grant from Murphy today and he
backed up what you say, he said Darral reckons to run about 12lbs in the
tyres.
I'd come to that conclusion in the last few days and have tried it, it
certainly softens the ride and appears to take some of the loads away from
the fuse.
Panting of the skins is a term used over here to indicate flexing of the
skins in certain situations.
I do have the latter kit with the stronger floor area, the problem is not
in the twisting forces with braking etc. but with the dissipation of the
loads through the fuse resulting from the flexing of the spring gear ( ie
weight bearing loads)
The panting I am getting is just ahead of the front door post,down low just
above where the corner rap meets the side panel, it occurs when the
undercarriage is working. It is causing the 'smoking' of the rivets down
low on the front door post.
It is of some concern, and obviously a fix is required, stronger rivets in
the area concerned would probably do the job, but I do wonder if a doubler
over the area that is 'panting' may be the best long term option,
especially with all the off airfield work that I do.
Murphy have been beating around the bush in regard to a fix for the
problem, but they have said that the front corner raps have been increased
in thickness to 35thou. ( I wonder why!)
Yes, the aircraft has only done 35hrs to date, but I am using the way it
should be used!! It has to hold up thats why I built it!!
And yes, I had to re-torque the under carriage bolts fairly early on, as
they had loosened.
Also remember that if you are fitting an 0-320, or a heavier motor, to do
the floatfix bulletin promulgated by Murphy, I found out the hard way, all
the taxiing over rough ground caused the top of the firewall to flex
creating some cracking of the firewall around the top mounts on either
side, this happened within 20hrs!!!
This all sounds very dramatic, but it isn't really, I just look at these
problems as just part of the shake down period, we'll sort this out and be
off like a rocket!
It is the neatest aircraft to fly, and you can go to the greatest places.
The other day my son and I tossed some camping gear and a rifle in the back
and headed off for the mountains, an hour and twenty later we dropped into
the headwaters of the Wilkins river on to an old deer hunters strip (Alt.
2000ft, 280 metres long and two metres wide!). We were surrounded by 8000ft
peaks.
We had an evening hunt in the most beautiful country possible, slept under
the aircraft, up early and away for another hunt then back for a late
breakfast. Toss the gear in the plane and off home, all in under 24 hrs!
What a way to travel!!
The only problems I am getting with the aircraft is associated with the
rough and undulating terrain that I am operating off, in the air the
aircraft has been faultless, I have full confidence that these issues will
be worked through reasonably quickly.
Cheers
Alister Yeoman
----------
From: Bob Patterson <
bob.patterson@canrem.com>
To: Murphy Rebel <
murphy-rebel@dcsol.com>
Subject: Re: Bungee gear
Date: Wednesday, November 04, 1998 5:05 PM
I run the fat tires - 8.00 x 600. They aren't very heavy-duty, but
they ARE inexpensive !! :-)
Normal pressure is around 20 lb - but i have run them as low
as 10 lb. The only danger if they're too soft is that they TURN on the
wheel, and pull the valve stem out of the tube !! :-(
Very fancy method - add air, then put a foot on the tire & push
on top - look for a little flattening (1/2" bulge ??) at bottom, and a
little side to side wiggle. Seems to give nice landings that way ....
It's unusual to see problems with the spring with such low time
- how many hours on the Rebel ?? What's 'panting' of skins ????
You might want to re-torque the bolts that hold the spring
gear on - I've heard of several that loosened up in the first 50 hours -
and there were one or 2 that had sheared bolts.
Were the rivets that are smoking dipped in epoxy when installed
??
You <could> paint some epoxy on inside & out now ... might help.
I hate to say this, but "the EARLY" spring gear kits were a
little
weak in the floor area. Newer ones have several doublers with 'fingers'
that are supposed to spread the loads much better, preventing the waves
in the floor. It might be possible to add doublers inside or out, even
now. It would depend where the problem is. I'm sure the factory could
help, if you sent photos of the problem spots ... (Hope you can get
someone to scan photos of your Rebel for us - we're all curious !)
.....bobp
Apologies to those who've heard "the Early" too often !!
----------------------------orig.-----------------------------------------
At 07:16 PM 11/3/98 +1300, you wrote:
Hi Bob,
You state that the tyres are the primary shock absorbers, I am having
some
trouble with my spring gear in that the loads are transferring to the
fuse
and causing some panting of the skins and minor smoking of some rivets.
What tyre pressures are you running?
Cheers,
Alister Yeoman
yeoman@voyager.co.nz
----------
was
NOT a problem, as the penny washers keep everything in place, anyway.
There is a note from MAM advising the use of larger bolts - a GOOD
idea.
It is also a good idea to turn some Delrin spindles (lathe) to go
over the bolts - it increases the diameter of the bolt, gives the
bungee
an easier curve to slide around, and makes the bolt stronger. The
spindle
fills in between the tube & the penny washer, putting the bolt in
tension.
Ron Barber came up with a simple gadget for making the bulk
bungee
into single rings - this is MUCH easier than trying to stretch it on
in
one piece, as per manual !! Or you can buy made-up rings - part # 9044
This is a 9/16" dia. bungee ring with 4.4" diameter. Because this is
not as thick as the supplied bulk cord, you will need 3 rings front &
back on each side. (will try to get a sketch of the 'bungee jig')
Can't help much with the 'new' cable arrangement without
re-reading
it (IF i have it !!). The problem with the old one, i believe, was
that
it was a little too long, and could get doubled over & KINK - greatly
weakening the cable...
'one continuous loop' sounds like they want it to look like a
large o, with the top & bottom bolts going through the ends, while
it just bypasses the middle bolts. Can anyone else clarify this ??
Please
??
THe bushing set is BRASS, and NOT necessary IF the gear is set up
properly. The idea of the bungees is that they are ONLY to move to
prevent structural damage to the fuselage. The TIRES are the primary
shock absorbers - which is why i like the BIG 800x6's !
The problems start when people rig the bungees TOO SOFT, so
they move over every bump. This WILL cause wear, AND can cause serious
structural damage on a hard landing, because the gear travel limit
will
be exceeded, causing loads to pass directly to the fuse !
The safety cable system DOES work !! I sheared the bottom of
the
gear tube a few years ago, on No. 001 - it was worn, and only a SINGLE
thickness. Don't worry, this WILL NOT happen on ANY production Rebel -
they are ALL built much more strongly !! In any case, the cable saved
the day - it just took the load, & we taxied in lopsided !!
----------------------------orig.-------------------------------------
At 03:03 PM 11/2/98 -0800, you wrote:
bolts
new
way
risk of
directions or
for
to
you
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