I've been using a 2" or 3" Fox bellcrank for most things but I just took one of my slow rat wings apart and the hole for the push rod was punched out pretty big. Was thinking of going to a 3" nylon Brodak bellcrank but not sure if it can take the strain. What do you use?

MM

So your flying wires go through the lead out guide? What do you use for a lead out guide? I used flattened out brass tubing once. Flared the end polished it nice and smooth. Didn't take long the lines wore a groove in the brass that finally cut the down line. Never again, I think internal connections should be outlawed.

MM

Lately I have been making the line exit guide out of maple engine mount material.

chordwise

Not yet they're not. (yes, the pictures are two different wings)

Solld lines should not cut into any material.   At least that is my experience.   Now cable will be sort of like a saw blade, but I've never had one cut thru a lead out guide.

Not true, Doc. I can show you an aluminum wing tip guide where solids pass through and where they have eaten a slot just big enough to hang up the lines.

Bill

Why not try this method, it's popular in Australia.

The pic shows the general idea.

You wind solid 012" or 015" steel c/l line or similar into a tight coil on a piece of greased 3/32" Music wire or similar. Take it off and epoxy up the outside slightly, just enough to hold it together.

Drill out the wing tip to the OD of the above, The coil will expand slightly towards 1/8" or 9/32". A piece of engine bearer as shown above would work great to enable it to be fitted on "stunter" racer type wing tips

Insert the line guide but only epoxy it in at the very outside of the hole. This is so it can be replaced easily.

The cable ends can be soldered to a small piece of bent wire for the actual connection to the lines contained within a short length of fuel tubing, much like the ones on Russian F2D RTF Combat Models.

These can then be also replaced if necessary. The coil/cable pair rarely wear.

We're not allowed to solder our wires to the lead outs here in USA.

MM

I'm not suggesting that you should. What I'm suggesting is the system shown in the picture below. The cable is (low temperature) Silver soldered to a piece of Piano wire that's been tightly bound with fine soft wire. It's very strong and virtually indestructible. The method is almost universally used on F2D combat models.




Why not use blank Printed Circuit Board material for bellcranks? Also indestructible whether you etch off the copper or not.

 Not when the line's connected and the tubing is stretched over the whole connection.

OK I won't trouble you with any more ideas.