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Building Tips and technical articles. => Building techniques => Topic started by: Paul Taylor on February 10, 2010, 08:27:55 PM

Title: How to secure the bellcrank rod??
Post by: Paul Taylor on February 10, 2010, 08:27:55 PM
OK, this is a first for me.
I got a Tom Morris bellcrank from CLC (thanks Jim!) I am attaching like Gary did on this plane.
After I put sheeting on top, I will put another little lite ply "button" size wood over the post.
I know I leave a little bit of the rod sticking out on the wing, so how do most finish off the top. Dab of JB weld?

This is going in a full fuse.
Title: Re: How to secure the bellcrank rod??
Post by: Wynn Robins on February 10, 2010, 08:35:32 PM
just leave it.....if you have installed it correctly with spacers inside the wing, it aint going anywhere! ....if not, JB weld or solder a washer on it.....

I would also put a ply brace a bit bigger then a "button" on there.
Title: Re: How to secure the bellcrank rod??
Post by: Paul Taylor on February 10, 2010, 08:45:52 PM
Yea, I don't see how it could come out. Did it like the instructions said. Fuel tubing, wheel collar, and a washer. But you never know.
And remember I like to add weight when I can. HB~> LL~
Title: Re: How to secure the bellcrank rod??
Post by: Ward Van Duzer on February 11, 2010, 08:30:42 AM
Rather than just a "button" on the post, I like to use a triangular piece of 1/8th ply top and bottom with the post going through the apex of the triangles and the opposite flat side up against the inside of the fuselage side. You now have your plywood support epoxied to the post, the centersection sheeting, and the fuselage side...

W.
Title: Re: How to secure the bellcrank rod??
Post by: Paul Taylor on February 11, 2010, 06:21:20 PM
Rather than just a "button" on the post, I like to use a triangular piece of 1/8th ply top and bottom with the post going through the apex of the triangles and the opposite flat side up against the inside of the fuselage side. You now have your plywood support epoxied to the post, the centersection sheeting, and the fuselage side...

W.

Huh?

Can you draw me a cartoon.
Title: Re: How to secure the bellcrank rod??
Post by: Bill Little on February 12, 2010, 09:06:51 AM
I totally agree with Ward!

Use a piece of ply wood that will go over the post AND connect to the inside of the fuselage on the top and bottom.  You will destroy the entire plane before the BC post pulls out!  ;D

I use a piece that is abut 1 1/2" wide where it hits the fuse side, and 1/2" wide where it goes over the rod. All gets epoxied to whatever it touches.

EDIT: Do this final support after you attach the wing to the fuselage.  Then lay a fillet of your choice all the way around the interior of the fuselage/wing joint.  Epoxy and microballons is good for that, it doesn't need to be more than an 1/8th to a 1/4 inch fillet.

Big Bear
Title: Re: How to secure the bellcrank rod??
Post by: Jim Pollock on February 12, 2010, 11:11:16 AM
Yup,

Ward and Bill are absolutely correct.  That would make the thing as indestructable as possilble.
15X Pull test, who me worry!  Nope!

Jim Pollock   H^^
Title: Re: How to secure the bellcrank rod??
Post by: Paul Taylor on February 12, 2010, 09:14:54 PM
Would some body cut into there plane and take me a picture? LL~


No wait... I think I might understand it...

Stay tuned.
Title: Re: How to secure the bellcrank rod??
Post by: Jim Pollock on March 04, 2010, 09:14:30 PM
Paul,

It shoulda came with a diagram?  Didn't it?  I don't think I forgot to pack a diagram.....

Jim Pollock, Hopefully not forgetful   n~
Title: Re: How to secure the bellcrank rod??
Post by: Paul Taylor on March 05, 2010, 07:08:01 AM
Hey Jim,
You did put the instructions in and it all fell together. Some one suggest "the apex of the triangles" on the post and so on. When someone uses 20 dollars words is throws me. LL~
Title: Re: How to secure the bellcrank rod??
Post by: Bill Little on March 23, 2010, 10:06:40 PM
Hi Paul,

A *little* late, but I remembered this:  I Dremel off the rods flush with the ply so they are not sticking out, then epoxy a small piece of ply over the rod ends.  That makes it doubly sure that it cannot move up or down.  A *touch* of weigh, but it's near the CG and I just like the *security*. ;D

Big Bear
Title: Re: How to secure the bellcrank rod??
Post by: Robert McHam on March 24, 2010, 12:39:55 AM
Hi Paul,

A *little* late, but I remembered this:  I Dremel off the rods flush with the ply so they are not sticking out, then epoxy a small piece of ply over the rod ends.  That makes it doubly sure that it cannot move up or down.  A *touch* of weigh, but it's near the CG and I just like the *security*. ;D

Big Bear
Bill, I like your idea for sure and weight is important but near the CG like this, I wouldn't worry either.

 I have a picture of a friend's bell crank with a simple Zbend.  Held up pretty good it seems. Have a look and judge for yourself. A picture is worth a thousand words!
Title: Re: How to secure the bellcrank rod??
Post by: Clint Ormosen on March 24, 2010, 08:06:22 PM

 I have a picture of a friend's bell crank with a simple Zbend.  Held up pretty good it seems. Have a look and judge for yourself. A picture is worth a thousand words!

ummm....... I don't think that's the rod he was talking about.
Title: Re: How to secure the bellcrank rod??
Post by: Ward Van Duzer on March 26, 2010, 02:40:52 PM
That looks like a PERFECT bellcrank! Made of Jello, I believe! Never use a perfect bellcrank on anything over an .010 airplane!


W.  :P
Title: Re: How to secure the bellcrank rod??
Post by: john e. holliday on April 02, 2010, 07:50:00 AM
Back when didn't know any better I used a lot of the Perfect Bellcranks.  Never any problem as the combat ships usually didn't last that long.  Also it loks like someone had a bad case of elevator flutter.   H^^
Title: Re: How to secure the bellcrank rod??
Post by: Bill Little on April 03, 2010, 05:57:53 PM
Bill, I like your idea for sure and weight is important but near the CG like this, I wouldn't worry either.

 I have a picture of a friend's bell crank with a simple Zbend.  Held up pretty good it seems. Have a look and judge for yourself. A picture is worth a thousand words!

Hi Robert,

The Z bend will hold fine, but look how much it hooged uot the BC!  The hole is twice as big as original.  A piece of brass tubing in the hole (and the cable holes, too).

Big Bear
Title: Re: How to secure the bellcrank rod??
Post by: Brett Buck on April 03, 2010, 08:22:36 PM
Also it loks like someone had a bad case of elevator flutter.   H^^

     I saw one pretty much exactly like that come out of an ARF Nobler - after about 4 flights!  That's why you have to replace it. The old Perfect bellcranks didn't have much of a problem with this, but the ARF copy is absolutely hopeless.

     Brett