Well, I can't find the relevant AN43 documentation, but Ron Wanttaja
says in Kitplane Construction that "Flight control pulleys are typically
AN210 or MS20220 models. Pulleys with a diameter of 2 inches or less
shouldn't be used to change the cable's direction more than 15 degrees."
(Page 211)
The Aircraft Spruce catalog sells pulleys. The AN210 pulleys intended
for use with 3/16" cable are available in 2" and 3.5" diameters. They
too say that the 2" and smaller cables "shall not be installed on
frequently used aircraft controls to bend the cable more than 15 degrees
---From a straight line." That leaves you with the largest AN210 pulley,
which is now called an MS24566-4B and is 3.5" in diameter.
They also have MS20220 pulleys. I can't determine the differences from
the MS24556 pulleys, but they are available for 3/16" cable in diameters
up to 5.5". You do need to pay attention to the allowable load limits on
these or any pulleys. See the chart in the catalog.
Aircraft Spruce does not list 3/16" 7x7 cable. 3/32" 7x7 has a breaking
strength of 920 pounds, while 3/32" 7x19 has a breaking strength of 1000
pounds. 3/16" 7x19 has a breaking strength of 4200 pounds, so the 7x7
probably breaks at about 3800 pounds. A 3.5" MS24556-4B pulley has an
allowable load limit of 1200 pounds - you do the trig to determine
whether the pulley or the cable gives out first at 40 degrees. I'm tired
:-)
You could also combine two pulleys to get the desired bend. A pair of
nice 2" pulleys would do you nicely.
dg
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Tony
Renshaw
Subject: Europa-List: Rudder Cable Max bend ability
<tonyrenshaw@optusnet.com.au>
Gidday,
I am wondering about the change of direction ability of the 7X7 3/16"
rudder cables. I would like to possibly change direction through 30-40
degrees at the one point, and therefore I think I need to know what the
cable can take. I haven't been able to find out sofar, so if anyone
knows
please tell.
Reg
Tony Renshaw
Sydney Australia
Classic 236 B.B. Taildragger (possibly convertible)
Tail, Wings, Ailerons, Flaps Complete and Connected
Lower Fuse in Jig, Tail Torque Tube installed
Mass Balance assembly installed and deflections sorted
Intended Engine: 912S CS prop (model undecided)
Instrumentation: Undecided
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