Thought I might add my two bits worth here...
I used the standard Murphy tail wheel with the click-out for easy turning,
with a steel tail spring from Aircraft Spruce. It is part no. 06-14400 and
is for the Aeronca 7AC, 11AC. Cost was around $60 US. It was easily
adaptable with some drilling and adding a bushing in one of the existing
holes.
It works great, and I have never had a shimmy, or any other problem. I still
use the big delrin washer in front, and with full load and fuel the vertical
shaft of the tail wheel was nearly perpendicular to the ground.
-----Original Message-----
From:
murphy-rebel@dcsol.com [mailto:
murphy-rebel@dcsol.com]On Behalf Of
Bob Patterson
Sent: September 20, 2001 1:08 PM
To:
murphy-rebel@dcsol.com
Subject: Re: tailwheel castor (pivot angle)
*-------------------------------------------------------------------------*
The list archives are located at:
http://www.dcsol.com:81/public/default.htm
username: rebel password: builder
*-------------------------------------------------------------------------*
Hi Ken !
Without going out to measure, I'm fairly sure that the Delrin
spacer at the front of my spring <was> about 1" thick - with a curved
cut-out for the bottom of the fuse. Will check both Rebels - also will
have a look at the shaft angle. Have not had any operational problems,
like losing springs, with fiberglass springs. They can be shortened,
to change the angle, and to increase rigididty. I have had some occasional
shimmy, when I had the Maule tailwheel (they are prone to shimmy anyway !)
Since changing to the Scott 3200, there's only been a few brief
moments, at heavy loads, and I believe that shortening would eliminate
that.
One advantage is that the fiberglas will break if there is a
very large twisting side load - this would be better than a bent
fuselage ! The only disadvantage I've seen is that they do deteriorate
from UV exposure, over about 7 or 8 years outside - and even then,
it is a progressive thing, and very visible.
In looking at the trail angle of the vertical shaft, check it
when you have the weight of the wings, some fuel, and at least one
person aboard - the fiberglass spring will flex considerably, and
you may well have a correct angle.
......bobp
--------------------------------------orig.---------------------------------
--
At 09:07 AM 9/20/01 -0400, you wrote:
*-------------------------------------------------------------------------*
The list archives are located at:
http://www.dcsol.com:81/public/default.htm
username: rebel password: builder
*-------------------------------------------------------------------------*
Thank you Brian and Drew
A Delrin spacer almost an inch thick would have been required with some
more machinging of the TS-2 so I have started making a steel spring from
a Princess Auto 2 leaf trailer spring (cdn$14. on sale). It looks like
it will weigh about 4 lb which is a 2.7 lb increase. The stiffness
should theoretically be adjustable by varying the geometry of each leaf.
Although bigger drill bits keep shattering, it does seem to drill OK
with a 1/4" carbide concrete bit followed by hand filing. Didn't have
any luck bending it with a long 2x4, as per Bingelis, but I think he was
using thinner leaves. It does bend cold with the persuasion of a
hydraulic press though.
I haven't seen any info on the castor angle specifically related to the
Rebel, but I will aim for 1 or 2 degrees of trail as recommended by
Bingelis. Also I think my fibreglass tailskid may not have been supplied
by MAM so maybe nobody else even has a concern with the angle.
FWIW my TS-3 (1"x1" angle aluminum piece) that the stab struts fasten to
had an extrusion flaw that looked like a long crack along the bottom of
the V for about half the length of the piece. This is on a piece that
MAM supplied about 3 years ago. Most of the pits/scratch eventually
sanded out and a dye penetrant check (after sanding) confirmed there is
no crack, but it might be worth a look as it would be a bad place for a
crack to develop.
Ken
*-------------------------------------------------------------------------*
You have received this message because you have subscribed to the
murphy-rebel mailing list.
To unsubscribe from this list, send an e-mail to:
list-server@dcsol.com
with "unsubscribe murphy-rebel" in the body of the message.
For assistance contact
mike.davis@dcsol.com
*-------------------------------------------------------------------------*
*-------------------------------------------------------------------------*
You have received this message because you have subscribed to the
murphy-rebel mailing list.
To unsubscribe from this list, send an e-mail to:
list-server@dcsol.com
with "unsubscribe murphy-rebel" in the body of the message.
For assistance contact
mike.davis@dcsol.com
*-------------------------------------------------------------------------*
-----------------------------------------------------------------
List archives located at:
https://mail.dcsol.com/login
username "rebel" password "builder"
Unsubscribe:
rebel-builders-unsubscribe@dcsol.com
List administrator:
mike.davis@dcsol.com
-----------------------------------------------------------------