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Building Tips and technical articles. => Building techniques => Topic started by: Richard Logston on April 17, 2014, 10:34:26 AM

Title: Bellcrank and leadouts
Post by: Richard Logston on April 17, 2014, 10:34:26 AM

I am finishing up a 38 Special profile version to be powered by a .40 OS max engine. Question, I have a 4 inch black plastic bellcrank ( actually looks like carbon). What would be the best way to attach the lead outs? Should I use a small tube for the wire to bear on or can I just thread the wire through the original size hole without it cutting into the bellcrank in service. I have been out of C/L since the middle sixties, but have built several c/l airplanes in the last three years. But have only flown two flights since getting back.

Title: Re: Bellcrank and leadouts
Post by: Bill Little on April 17, 2014, 10:43:21 AM

Hi Richard,

The tubing route is a great way of doing the lead outs, connecting them to the BC.  That is the way I do all of mine bigger than 1/2A.

BIG Bear
RNMM/AMM

Title: Re: Bellcrank and leadouts
Post by: Tim Wescott on April 17, 2014, 11:27:15 AM

Tubing.  Even if you have to open up the holes a bit.

I use 3/32" OD tubing from the hobby shop.  There are folks who have found smaller tubing, which would work better, but I don't know where to get it (McMaster-Carr?).

Here's how I did it on my last plane.  Everything worked well, except the part about forgetting to thread the control system through the wing first, and thus having to unwrap the ends, thread on the leadout guide, and rewrap.

http://stunthanger.com/smf/index.php?topic=27915.msg273968#msg273968 (http://stunthanger.com/smf/index.php?topic=27915.msg273968#msg273968)

Title: Re: Bellcrank and leadouts
Post by: Richard Logston on April 17, 2014, 03:02:03 PM

Thanks for your replies. Much help.

Title: Re: Bellcrank and leadouts
Post by: 55chevr on April 17, 2014, 04:54:02 PM

Yup,  McMaster Carr

Title: Re: Bellcrank and leadouts
Post by: Allan Perret on April 17, 2014, 06:08:12 PM

K&S has 1/16" tubing in brass, copper, or aluminum.  I use the copper, the ID is just big enough to use .027" lead outs.  Don't know if you can get .032" lead outs thru it, but the .027" still has breaking strength of 125#.

Title: Re: Bellcrank and leadouts
Post by: Don Hutchinson AMA5402 on April 17, 2014, 07:39:07 PM

I also use the K&S 1/16 brass tubing and 135# test cable. It mikes at about .030. I get it at a good fishing store in a small spool, normally used for salt water leader material. Just for fun, anybody know who K and S are??

Title: Re: Bellcrank and leadouts
Post by: Dick Pacini on April 17, 2014, 09:17:00 PM

http://www.ksmetals.com/

Title: Re: Bellcrank and leadouts
Post by: FLOYD CARTER on April 19, 2014, 09:50:31 AM

Most likely named for the owners... like Ken and Sam  (maybe?)

Title: Re: Bellcrank and leadouts
Post by: Don Hutchinson AMA5402 on April 19, 2014, 07:15:56 PM

Not even close, try again.

Title: Re: Bellcrank and leadouts
Post by: Don Hutchinson AMA5402 on April 21, 2014, 11:50:26 AM

A couple of guys from the Chicago area who were well known free flight modelers late 30's and 40's era. Wally Simmers of Gollywock and Jabberwock fame and Joe Konefes of Buzzard Bombshell fame. Ya gotta be an old old timer to know trivia like this!

Title: Re: Bellcrank and leadouts
Post by: Dennis Toth on May 20, 2014, 04:38:17 PM

Rich,
With the 38 Special as the leadouts are coming through the fuse be careful to bring the ends of the tubing into a tear drop shape and make the fuse holes large enough to have a little wiggle room around where the leadouts come through.

Best,       DennisT