Hi ,

Back again 

I'm going to use the kit stock push rod wire on my latest project .
What I'd like to know ,is how to solder the "keepers" (washers) without damaging the nylon bellcrank ?
What do the rest of you use for a soldering tool (iron , gun or micro torch) ?

As always ...

Thanks

While it's possible to solder the washer when using a nylon B/C, it's not an easy thing to do. My solution is to use fine sandpaper to get everything nice and bright, and grind a thin slot 1/3 of the way through the wire about 1.8" above the B/C. Then I put on a plain brass washer and then crimp another brass washer into the slot. Then a careful application of JB Weld makes everything pretty darn solid and secure.

Rob: I use either one of these, the gun puts out some serious heat instantly.

Hi Curt,

I agree that the end of the pushrod needs to have a "flat" filed/ground on it where the set screw engages.  I believe that the way Tom Morris and Tom Dixon do it is fairly safe.  I would definitely J.B. Weld the collar and set screw in place. 

Wouldn't this function as well?

Bill <><

Rob,

Your concerns are well founded.   Soldering on push rods can damage plastic bell cranks and horns.   I prefer to use wheel collars and JB Weld epoxy.   In the attached photo, even though I did not have any plastic to be concerned with, my preference is still for the wheel collar and JB Weld.

A couple of details:   I like to file/grind a GROOVE for the set screw, so that in the very remote chance that it comes loose, it will not be able to slide down the wire.  Also, put RED Loctite on the collar set screw.   To maximize adherence of the JB Weld, degrease all surfaces that will be epoxied, and also roughen all surfaces with coarse sandpaper to provide a better surface for the epoxy to grip.

Take your time and do a through job here, as the control system is one place when no failures are allowed.

The plane in the photo happens to be a 40 size Time Machine, and the flap horn, with bushing, is from Tom Morris.

Cheers.

Warren Wagner

Hi Curt,

I agree that the end of the pushrod needs to have a "flat" filed/ground on it where the set screw engages.  I believe that the way Tom Morris and Tom Dixon do it is fairly safe.  I would definitely J.B. Weld the collar and set screw in place. 

Wouldn't this function as well?

Bill <><

Hi Bill.

Not really.

Loctite is designed to hold threaded fasteners in place.  JB is not.  Epoxy depends almost entirely on a mechanical bond to a surface.  If it is shiny and smooth (read wheel collar and piano wire) then it is just a matter of time before it will release.

I'll almost guarantee that if you epoxy a set screww in place with jb, I can unscrew it when cured.

Now, if one is careful, you can apply the epoxy in such a way that it WILL mechanically lock things in place, but by then, you've added the extra weight of the epoxy basicaaly for no reason--Loctite is the proper adhesive.

Nothing more is required.

Curt

Thanks for the info, Randy!  I had not heard of the J.B. Weld cracking, but I can understand that it would.

Bill <><

I use a piece of the thick paper label that comes with a package of bolts.  Just cut a hole in it and slip it over the end of the push rod. Have everything nice and clean. Add a little flux, drop the washer on, and solder away.  I've also added a twist of copper wire above the washer to give more solder hold.  I use a gun, not a torch.  Never had a problem damaging the bellcrank. 

Hey Wareen: Is taht the Tom Dixon Time Machine ? If so how about some more pics. Even if it isn't more pics are in order Please.

Leester,

Yes, that is the Tom Dixon "Time Machine".   It's design is influenced by the "Pattern Master", but several design changes have been made to shorten the *time* necessary to build a stunter.   It was a fun build, with the "Kept Foam Wing", which builds extremely fast.   The flying characteristics are superb!

It's still going strong, so if the GB Weld has cracked and fallen off, the wheel collars are still doing their job.

Cheers.

Warren Wagner