Elev. Pull pull Question

[rickwallace45]

I've used this all-thread for four years on ailerons, elev, etc w/ no
problems. 

Don't remember the source, but someone specifically recommended the mild
steel in the all-thread in favor of the hardened (more brittle) steel of a
6-32 socket head screw -  and the idea was to have a horn that may flex a
bit without fatiguing and breaking, as harder, more rigid materials can. 

 

I can't quote metallurgy on this one - all I know is that the mild steel
all-thread into dowels set into square balsa blocks set into the control
surface has never shown any problems. 

 

Rick

 

-----Original Message-----
From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org] On
Behalf Of ronlock at comcast.net
Sent: Tuesday, November 30, 2004 11:36 AM
To: discussion at nsrca.org; discussion at nsrca.org
Cc: Karl G. Mueller
Subject: Re: Elev. Pull pull Question

 

Another option- buy 6-32 all thread at local hardware store.

Cut stud lengths as needed and thread into hard points with a bit of epoxy.

Ive been using them for years for elevator, aileron, & rudder.

 

Ron Lockhart

-------------- Original message -------------- 

Matt,

 

I have used # 6-32 socket cap screws for years now and never had a failure

with these. Buy a box of 100 about 2" long at your local industrial supply

for about $20-25, cut of the heads, put a couple of grooves in the non
threaded

part for the epoxy to hold and glue these into the hard point (1/2" dia
dowel) in 

your movable surface. Do no drill all the way through. Just up to the top
sheeting.

You can offset the hole in the hard point toward the hinge

line to adjust for proper distance for the hole in the plastic end, that
receives the

clevis, to line up over the hinge line. Socket cap screw are heat treated,
but not 

all the way. They still have a soft core and will bend under enough force,
but

not with the amount of force used to move the surfaces.

 

Karl G. Mueller
kgamueller at rogers.com

 

----- Original Message ----- 

From: Rcmaster199 at aol.com 

To: discussion at nsrca.org 

Sent: Tuesday, November 30, 2004 9:28 AM

Subject: Re: Elev. Pull pull Question

 

Keith, please note that 4-40's are known to snap off a control surface. It
has happened to me. The break is a straight forward fatigue fracture. If
6-32's are not useful to you, consider 5-40's. Personally, I do find 6-32s
do just fine in this application

 

MattK

 

In a message dated 11/30/2004 3:17:03 AM Eastern Standard Time,
tkeithb at comcast.net writes:

Cat's Meow? Maybe not, but darn close. The only thing that keeps them from
being the Cat's Meow in my book is the 6/32 threads which don't offer as
precision of adjustments as 4/40 or the MK horns. 

 

Lance's suggestion of offsetting the control arm at the servo is perfectly
valid also.

 

Keith Black

 

 

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