TopCap Pull-Pull Question
 

I took my TopCap out for its maiden yesterday. It LUVS the 50 SX by the way.

A fellow club member wanted to know if the pull-pull setup could be replaced with push rods.

He just bought the TopCap ARF and opened the box to view all the parts so now he can't return it.

He said the only plane he ever had a BAD flutter issue with was due to a pull-pull system so he is a bit gun shy.

I told him I didn't know and would ask you guys. Let me know what you guys think and I'll pass it on to him.

Rick

Re: TopCap Pull-Pull Question
 

If the pull pull caused flutter than it wasn't installed properly. The advantage of pull pull is that there is a constant pull on the surface at all times. If anything you'd have more chance of flutter with a rod than with pull pull because the rod can flex.

You can use rods but the pull pull is 10x better setup thats why Morris uses them...

TopCap Pull-Pull Question
 

Ditto what my buddy Wreck said and...

The metal rod would have to be very long. You would need to change the location of the servos so they are close to the fuselage. You would then need a bunch of supports for the wire all the way back to the control surface. The fuselage is sheeted and not all hardwood, so I have no idea where those supports could be mounted. Besides that, the pull pull tubes are already in the fuselage!

It's either going to flex or just bend if he uses a rod. It will be hard to get the throws needed for real 3D flying. There will also be more control slop with them rods, which is a big deal on these FunFly airplanes. It will also be heavier. The pull pull cables practically weigh nothing...A couple big metal rods really could add significant weight. The Top Cap ARF is not one of those "A little extra weight won't matter" type of airplanes...

So, tell your friend no. Tell him to get some help (from you!) and to get the pull-pull set up right. It's a little confusing the first time, but really easy once you get it figured out. Makes for a VERY secure linkage that just can't be beat...I don't think I'll ever go back to rods now.

TopCap Pull-Pull Question
 

David and Brian

Thanks guys.

When Kyle told me he had flutter with the pull-pull on another plane I asked what he thought caused it. He said he knew what it was ... one of the cables broke at high speed causing the elevator to flutter which then stripped the servo and caused a hard crash.

I will pass this info onto him and we will see what he wants to do. I think pull-pull works great.

Rick

TopCap Pull-Pull Question
 

If done correctly the cable should never break.

TopCap Pull-Pull Question
 

Wreck, i recently had a cable break on the bench. this was after about 100 flights on my knife. the break occurred right at the adjuster where it goes tru the hole. i noticed some play in elevator and decided to adjust cable. after adjusting tried it a few times and that is when it broke.
i think i may fly with them too tight but not sure...any other ideas?

TopCap Pull-Pull Question
 

OK, I guess I should have said it shouldn't break if done correctly. Like with all things after a period of time preventive maintenance should be done to ensure the cables are still in good shape. Everything in life can break over a period of time.

TopCap Pull-Pull Question
 

I think if you kink the cable (does that word work here?) and get a "bend" in it, that will make a weak spot in it... What were you using for cables anyway? All cables are not equal... ;)

I sure hope mine don't break...I guess I'll have control in at least one direction if they do? :rolleyes:

TopCap Pull-Pull Question
 

Yep, that's the pull-^%$#*! set-up. Very challenging.

TopCap Pull-Pull Question
 

Kevlar does break and is pretty fragile...

Coated Kevlar is 10x better, and steel cable is also great..

just make sure they stay snug and tight and watch for wear and tear and you will have no trouble with them

TopCap Pull-Pull Question
 

Yep, one advantage to pull-pull on a profile is that is keeps the side of the fuse clean (no control rods) so that the ailerons can snuggle right up to the fuse.

This gives you aileron control in the hover, which is nice if you don't want to torque roll!

I made a mistake on my last Su-Do-Khoi and put the control lines right through the holes of the servo arm, forgot to use the adjusters on that end. I fly the heck out of that plane, and I keep checking to see if the lines are starting to eat through the plastic servo arm, but so far so good.

TopCap Pull-Pull Question
 

I did the same thing on my TopCap. The instructions led me to believe thats the way it was supposed to be until I turned the page and saw the photo.

Thought about leaving it, but instead decided to do it right. Went to the hobby shop and bought 60 ft. of control line cable and brass tube for crimps. Cost me less than $10. Small price to pay for knowing it is done right.

Hope your's holds up ... could be nasty :)

Rick