Flexdrive stuffing tube- straight or s-bend?

[BHChieftain]

What's the best install plan for a new stuffing tube for a flexdrive? Straight shot from motor to the strut, or with an s-bend?

Thanks,
Chief

[sundog]

Neither would be my choice. A 'U' bend will allow it to straighten out at the strut. There's no need for the motor to be level (S bend) in a FE setup.

[Nitrosnifer]

The S bend is used in the JAE line of boats. I've always used a straight stuffing tube in all my riggers/scales. I built the JAE as per the instructions with quite a s bend. I thought it would drag but not so. The S bend follows the cables natural wiping and holds it in place actually creating lesser drag than with a straight or U bend. This was taken from the manual
Why an “S” shape?
Tests have proven that a tube with two
bends has less drag than a tube with one.
The reason is that two bends support the
flex cable better, reducing cable whip, and
drag.

[Nitrosnifer]

I guess you need to test it all out for your build/boat. I've seen scales running 3/16" cable and a "S"bend running hard where I've broken 1/4" cable in a similar boat without the "S" bend.

[sundog]

Yes, I have heard rumors of the virtues of the S bend, but have been skeptical myself. Like Nitro said it would be best (but a pain in the arse) to test each type in your boat to be sure.

[BHChieftain]

Thanks guys. The boat I have actually already has an s-bend, but I may need to rework the driveline, so if I do was wondering if I should keep that design.

Chief

[GP73]

What about deepvees? I need to reinstall the stuffing tube in my Pursuit, I could go straight or have a gentle U curve like the original stuffing tube.

The original stuffing tube got too hot and exploded after the flex shaft twisted. Initially I've fixed it with a smaller brass tube inside the remaining stuffing tube and used CA to glue them together, I was running a .187 cable without teflon and it worked well the first time, but the second time it was getting very hot again (200F).

Now I'm not sure anymore, should I try the s-bend?

Is it ok to cover the stuffing tube with a couple of layers of FG? Or should I just sand the bottom of the tube and use only epoxy?

[GP73]

Here is how it looks straight in, there is quite a bit of space under it, should I fill the space with epoxy or should it be laying flat on the bottom of the hull? :confused1: :help:

I'll be building another tube support, but I'm waiting for your expert opinions if I should go straight, u bend or s-bend since the support will have to match the tube. :smile:

5589555896

[driftah]

the gap should be filled with a piece of wood with a hole to match the stuffing tube imo.like a doughnut glassed or epoxied to the floor contour.to help stabilize the tube from vibrations and create rigidity in the driveline.

[GP73]

I hear you, I just built a small wood support, but your idea sounds much better. Now, how do you drill a U shaped hole in a block of wood? :biggrin:

But what about heat? Isn't that going to heat up the tube even more?

Picture of what I was going to use:

55936

I was going to lay some FG on the support and the tube.


the gap should be filled with a piece of wood with a hole to match the stuffing tube imo.like a doughnut glassed or epoxied to the floor contour.to help stabilize the tube from vibrations and create rigidity in the driveline.

[driftah]

bingo you got it bud glass or epoxy it down