Line connection to bellcrank for take-apart wing

[frank williams]

How do you connect the lines to the bellcrank on a take-apart wing?

[RandySmith]

How do you connect the lines to the bellcrank on a take-apart wing?

Frank  many do this with a clip, sorta the same as a homemade  line clip for HP handles, just short

you can slide a piece of flexible tubing over  the connection if you  Leary  of the stability 

Randy

[frank williams]

OK ..... that makes sense ..... tubing will keep from flopping back over itself ...
Thanks

[Dave_Trible]

Frank I'm yet to find anything that I trust or that I think might  not get caught inside when the line tension is off.  I figure I'm only going to take the thing all the way apart once or twice for air travel so I'm just rigging them as I would in a solid airplane.  When the need arises I'll cut them and rig new at the other destination.  Won't take long and I'll just need to tweak the handle neutral a bit.  Maybe I'll find something better but just not happy with anything I've seen.  Also my Delrin bellcranks are 3/16" thick which makes regular line connectors not workable- at least without a short attachment stub which goes back to getting caught inside....

Dave

[RandySmith]

the tubing will keep it straight and will not let it  catch on things or fold over, the clips are best homemade so you can make the bellcrank end large , or thick, while keeping the other end thin for the leadout hookup.

I have pictures somewhere,  i will try  to find and post them

Randy

[bill bischoff]

Couldn't you unbolt your adjustable leadout sliders and pull the leadouts through the wing? This would leave the leadouts securely and permanently attached.

[Phil Krankowski]

Make your LO's about a foot longer than needed and then the can stay attached in the box.

Phil

[Mike Haverly]

Here is how I do mine.  I tried other methods but went back to this on this year's model.  This is on my three year old Sultan with never a problem.  Of course it requires a Brett Buck style bellcrank.

[Paul Walker]

Mine looks like Mike Haverly's but I use a Windy type bellcrank and saw a slot in the ends for the eyelett to fit.  As Mike said, it works great and never a problem.

[Howard Rush]

I got some shoulder screws: http://www.mcmaster.com/#shoulder-screws/=yih241 .  They make a nice surface for the leadout eyelets to rotate on.

[frank williams]

Thanks guys ...... a big help ...

[Matt Colan]

in my thundergazer, I have two Hello Kitty clips with fuel tubing slid over them. Haven't had an issue and the plane is on its third year of service.

[Mike Haverly]

I got some shoulder screws: http://www.mcmaster.com/#shoulder-screws/=yih241 .  They make a nice surface for the leadout eyelets to rotate on.

The shoulder screws are nice.  The only reason I use regular 4-40 socket head screws is that I have them   It is important to make sure the unthreaded body of the bolt is long enough to make good contact.  Screw threads are like little knives if the were left to rotate inside of the phenolic attachments.  I always have to cut screws that are about 1" long to get the fit that I want.

[frank williams]

Matt
.... by Hello Kitty clips ... are we talking about something like this?

[Tim Wescott]

Matt
.... by Hello Kitty clips ... are we talking about something like this?

It's a long story.  Here's a pic (one of the other messages in that thread explains the name)  http://stunthanger.com/smf/index.php/topic,16851.msg212372.html#msg212372.

[Matt Colan]

Matt
.... by Hello Kitty clips ... are we talking about something like this?

Hi Frank,

The hello kitty clips are the ones that Randy sells, like Tim posted.

[Dave_Trible]

I got some shoulder screws: http://www.mcmaster.com/#shoulder-screws/=yih241 .  They make a nice surface for the leadout eyelets to rotate on.

Howard I like the shoulder bolt idea.  I thought about cobbling up something similar but was a little worried about the side thrust binding or wearing the crank bushing but these are low profile and I guess you could put one on  top and the other below the crank.  May do this on the next one.

Dave

[Tim Wescott]

Howard I like the shoulder bolt idea.  I thought about cobbling up something similar but was a little worried about the side thrust binding or wearing the crank bushing but these are low profile and I guess you could put one on  top and the other below the crank.  May do this on the next one.

If you have a ball joint on your bellcrank then you're already presenting a side load to it.  I just make my bellcranks with a good long journal (usually about 3/4" long) to keep it from tilting on the shaft -- that way the bellcrank itself may see some side load, but the bellcrank-and-bearing assembly will stay straight.  The bearing is glued (with epoxy) and screwed (with a 3/8-32 nut from a potentiometer) to a phenolic-plate bellcrank.  That makes sure that it won't tilt when it's being pushed and pulled upon.  Brett Buck does something similar, only using brass tubing.

[Dave_Trible]

If you have a ball joint on your bellcrank then you're already presenting a side load to it.  I just make my bellcranks with a good long journal (usually about 3/4" long) to keep it from tilting on the shaft -- that way the bellcrank itself may see some side load, but the bellcrank-and-bearing assembly will stay straight.  The bearing is glued (with epoxy) and screwed (with a 3/8-32 nut from a potentiometer) to a phenolic-plate bellcrank.  That makes sure that it won't tilt when it's being pushed and pulled upon.  Brett Buck does something similar, only using brass tubing.

Tim I've used my Delrin cranks since my kit making days and won't  change.  Never wore one out nor any of the other hundreds I made out there I ever knew about.  Don't believe in ball links either for a couple reasons.  Plain pushrod through a hole with a wheel collar-NEVER lets you down and allows a bit of play in the system which I prefer.  Ball links make the system too stiff which doesn't feel right to me out on the lines.  That's how I roll!

Dave

[Robert Zambelli]

Frank: Here is the method I devised to attach leadouts to a fuselage mounted bellcrank on a plane with a take-apart wing.
The leadouts, of course remain in the inboard wing.
The wing slides onto carbon fiber tubes in the fuselage.
With the wing about three inches from the fuselage, attach the leadouts to the bellcrank as shown in the photos.
Then simply slide the wing the rest of the way.
The plane, by the way, is a Charles Mackey Starlight.
Feel free to contact me with any questions.

    Bob Z.

[frank williams]

I made one of each type.

The wire clip ends attached to the leadout wire worked pretty well.  I used a copper Nico sleeve for the crimp.   I pull tested each individually to 60# +.  The 1/8 in phenolic bellcrank was ok till I put the ball bearing in the center.  There wasn't enough area left to support the load and it failed.  I need to make another with more meat in the center, maybe even out of 3/16" if I keep the bearing.

The aluminum sheet laminate passed a 60# pulltest.  I'll look into the shoulder bolts.

Thanks again all for your info.

 

[RandySmith]

I made one of each type.

The wire clip ends attached to the leadout wire worked pretty well.  I used a copper Nico sleeve for the crimp.   I pull tested each individually to 60# +.  The 1/8 in phenolic bellcrank was ok till I put the ball bearing in the center.  There wasn't enough area left to support the load and it failed.  I need to make another with more meat in the center, maybe even out of 3/16" if I keep the bearing.

The aluminum sheet laminate passed a 60# pulltest.  I'll look into the shoulder bolts.

Thanks again all for your info.

 

Hi Frank
ball bearings on the post are a bad idea, they do not move enough to build a film of lube, and vibration is very bad on them since they do noy move much at all. if anything needle bearings would be better, and bronze bushings are much better than any of the ball bearings

Randy

[Randy Cuberly]

I totally agree with Randy S. about ball bearings in relatively small oscillating applications.  The constant start, reverse, stop motions results in a lot of sliding of the balls instead of rolling and that results in rapid wear.  Unless the bearings are sealed, which increases friction and overcomes some of the advantage of ball bearings, contamination is potentially a problem.  Dirt, dust etc., can enter the bearing which again results in rapid wear.  Vibration can result in quick damage from fretting unless very close tolerances are used for clearances (Class 5) and that demands sealed bearings or the contamination problem is severe!  Also the price goes up a lot!

Except for the expense, carbon impregnated teflon bearings would seem to be ideal.  Torlon, a commercial bearing material consisting of the afore mentioned material has the property of actually decreasing in friction coefficient as load increases.  It also has very good vibration damping properties.
The stuff is very expensive however.  I have used it in Aerospace instrument applications and it performs as expected but the expense is probably prohibitive in small quantities.

In the end I agree with Randy S that a bronze bushing is probably the best and most practical solution.

I am very interested in your results because I'm considering building a take-apart for the first time.  60 years of flying CL and I've never built a take-apart...never seemed to have time to travel very far to contests 'till now.

Randy Cuberly

[frank williams]

This one has two sealed bearings at the ends of a 3/4 inch long tube to prevent wobble.  Both bearings are sealed.  The support rod is a piece of 1/4 inch titanium tube.  Smooth as glass.   I thought for sure I had the ultimate secret weapon.   

[Lauri Malila]

Hi.

For a simple dural sheet bellcrank, we jus solder piano wire clips to braided cable. About 1/2" overlap, bind with some copper wire and solder.
I only found a picture of outside end but inside wing it's pretty similar.
Of course, you must know how to solder steel and take the necessary precautions to avoid corrosion etc.

L

[Paul Walker]

This one has two sealed bearings at the ends of a 3/4 inch long tube to prevent wobble.  Both bearings are sealed.  The support rod is a piece of 1/4 inch titanium tube.  Smooth as glass.   I thought for sure I had the ultimate secret weapon.   

What went wrong with this one Frank?


After looking at your previous failure, it looks like the hole in the bellcrank was too big for the section width carrying the bending moment. The tension side was just too narrow, and the failure likely eminated from there. If you were to make that backside (of the hole) three times wider than it is now, it should do better. That's the strength issue, not the bearing wear issue!

[RandySmith]

This one has two sealed bearings at the ends of a 3/4 inch long tube to prevent wobble.  Both bearings are sealed.  The support rod is a piece of 1/4 inch titanium tube.  Smooth as glass.   I thought for sure I had the ultimate secret weapon.   

Hi Frank

I tried that in the late 70s and again 2 times in the 80s, I used sealed bearings, grease packed, the vibration beat them to death quickly
just FYI 

Randy

[SH Stunter]

Here is how I do mine.  I tried other methods but went back to this on this year's model.  This is on my three year old Sultan with never a problem.  Of course it requires a Brett Buck style bellcrank.

Great Idea/method.  A new column will be starting up in Stunt News and will be addressing and showing neat tricks and methods of building techniques.  With your permission, Can I plan to use this as a "how to" type idea? 

Also, all modelers and Stunt pilots can submit their ideas and building tricks to me as well.  (See Stunt News for more info on this.)

S-H modeler.

[Paul Walker]

Great Idea/method.  A new column will be starting up in Stunt News and will be addressing and showing neat tricks and methods of building techniques.  With your permission, Can I plan to use this as a "how to" type idea? 

Also, all modelers and Stunt pilots can submit their ideas and building tricks to me as well.  (See Stunt News for more info on this.)

S-H modeler.

Not as long as you hide behind your SH  modeler name.

What is wrong with using your real name?

[john e. holliday]

And I thought we were supposed to use our real name or the alias we are known by on the bulletin board.