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?

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.

IMG_20110720_131346.jpgIMG_20110720_131322.jpg

[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?

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

Picture of what I was going to use:

IMG_20110720_230814.jpg

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