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Building Tips and technical articles. => Building techniques => Topic started by: Dan Labine on December 02, 2006, 05:46:09 AM

Title: Bellcrank Leadout hookup
Post by: Dan Labine on December 02, 2006, 05:46:09 AM

What is the preferred way to attach the leadouts to a bellcrank? I have seen posts that say it should be bushed with brass tubing but how is this done? Thanks.

Dan

Title: Re: Bellcrank Leadout hookup
Post by: Clancy Arnold on December 02, 2006, 07:55:48 AM

Obtain brass tubing slightly larger inside than the leadout cable.  Drill out the Bellcrank holes to accept the brass tubing.  Cut the brass tubing in to lengths about three times  the thickness of the Bellcrank. Insert a piece of tubing and swage (flare) it over slightly and then turn the bellcrank over and swage the other end of the tubing.  Do the second leadout hole.   The ideal is to have the tubing secure in the bellcrank but free to turn.

Many twist drill bits are tapered on the noncutting end and make good swaging dies.  If you anneal the tubing first it will swage easier.

Clancy

Title: Re: Bellcrank Leadout hookup
Post by: Bill Little on December 02, 2006, 10:16:25 AM

With the nylon/circuit board/CF material bellcranks, the Lead Out wire is passed through a piece of 1/16th" brass tubing, about 2 1/2" long  which is then run through the BC and bent in a "C".  After wrapping the ends of the LO's, the brass tube rides in the BC.  Don't know if that is a clear explanation................

Title: Re: Bellcrank Leadout hookup
Post by: Leester on December 02, 2006, 04:48:03 PM

Maybe someone with a digital camera could do a step by step and put in the StuntHangar useful tips section. If I had a D.C. I'd do it. But I don't.

Title: Re: Bellcrank Leadout hookup
Post by: Jim Thomerson on December 03, 2006, 06:36:00 AM

On smaller airplanes, up to 15 size, with nylon bellcranks, I have used the Teflon tubing for thick CA glue instead of brass, with good results.

Title: Re: Bellcrank Leadout hookup
Post by: Harry Rice on December 03, 2006, 11:08:52 AM

Apologies for sounding dim but is the idea to stop:

a) The bellcrank wearing
b) The leadouts wearing
or:
C) make a smoother action (i.e. better bearing)?

The reason I ask is I have access to 4" square plates 1/8" thick made from 50% Glass reinforced partially aromatic nylon which has the same tensile strength as cast aluminium alloys, and being a type of nylon is inherently a self-lubricating bearing material. Just wondering...

Cheers

Harry

Title: Re: Bellcrank Leadout hookup
Post by: RC Storick on December 03, 2006, 11:16:13 AM

Here are some photos on how to bush a bell crank. Click this link to see more tips.
http://www.stunthanger.com/tips.htm

Title: Re: Bellcrank Leadout hookup
Post by: Clancy Arnold on December 03, 2006, 03:43:43 PM

Harry,
The answer to your question is all three.  I would wonder about not bushing a glass reinforced nylon material, the nylon would not be a problem but the glass can wear the steel lines.

Title: Re: Bellcrank Leadout hookup
Post by: Russell Shaffer on December 03, 2006, 07:02:49 PM

What is the big nylon bolt for?

Title: Re: Bellcrank Leadout hookup
Post by: RC Storick on December 03, 2006, 07:12:14 PM

I have no idea. I only use 1/8 music wire for a pivot

Title: Re: Bellcrank Leadout hookup
Post by: minnesotamodeler on December 04, 2006, 03:36:55 PM

Hey, it's your bolt...What's it laying there for?

--Ray

Title: Re: Bellcrank Leadout hookup
Post by: Bob Johnson on December 06, 2006, 09:04:12 AM

Actually, it's my bolt. It will be the pivot on the .15 size Ki-84 stunter I'm building. It passes through an aluminum tube in the bellcrank (look close at photos) and the 1/16in. ply mounts top and bottom in the wing. Very light and more than adequate for a .15 powered plane, and I believe even up to a    .35 would not be a problem. I seem to recall doing a photo tutorial on bushing the bellcrank leadouts and posting it on SSW. If not, I could do so here if so desired. Let me know. Hope this helps.

Bob