Quick driveshaft question

[chunkymonkey28]

Hello,

I recently purchased an old hull from a friend. I'm currently restoring it and things are going smooth so far. However, it needs a driveshaft and I want to use a flex shaft. Here are specs

Boat length: 27"
motor: feigao 1755 kV L
battery: 7.2V
Stuffing tube is 3/16"

here is the driveshaft that will fit my stuffing tube (with teflon liner):
http://www.offshoreelectrics.com/proddetail.php?prod=oct-oc098L-24c

My question is, is a .098 driveshaft thick enough in my situation? Will it work ok with my setup. I appreciate the help.

[Diegoboy]

.098 is too small for a 27" boat
I believe a .130 w/ liner will fit, but let me check on that...

[Diegoboy]

Nope, .130 w/ liner will need a 1/4" tube. What is installed (3/16) will handle the .098 w/ liner.
Again the .098 is too small for the hull. I think he ran a .130 w/o a liner

[chunkymonkey28]

O.k. So can I run a .130 w/o a liner? What difference does having a liner make? Thank you!

[Diegoboy]

Some guys use the liner, some don't. The biggest issue is friction in the tube, w/o a liner, the tube material can get worn out faster by the friction from the flex cable. requiring replacement of the tube prematurely. On the other hand, w/o a liner gives you the benefit of a smaller diameter tube.

[Jeff Wohlt]

Most of the noses on Fuller/Octura FE struts are 3/16" You can run no teflon with 3/16" brass to the nose and run the 130 cable if you want. If not, you can leave the teflon exposed the last 2" and just put the teflon in the strut. We did that for years and how it was designed.

[longballlumber]

In the case of brass tubing and flex shaft (NO LINER), I have never see a stuffing tube that needed to be replaced simply because it was worn out from friction. If the boat is built correctly, setup correctly (shaft, motor, and strut alignment), and the cable properly lubricated the stuffing tube should last the life of the boat.

However, Jeff is correct. It seems that many of the FE struts are designed for use of a liner. What I have done in the past with Octura struts, I would remove the brass bullet and use brass tubing to telescope to the correct diameter to fit the strut.

[Diegoboy]

In the case of brass tubing and flex shaft (NO LINER), I have never see a stuffing tube that needed to be replaced simply because it was worn out from friction.

I haven't either, but that doesn't mean it can't happen.

[Jim Bob]

I raced nitro boats for twenty years, ran brass tubing without a teflon liner, and never had to replace a stuffing tube because of wear. If it is properly maintained and set-up correctly it should last the life of the boat.

[crrcboatz]

I have been in rc boating for 32+yrs, you can bank on it that you will not wear a stuffing box of brass only through. Never seen it or heard of it.

Rest easy on this one.
Curt

[chunkymonkey28]

Wait sorry but what's a strut?

[Jeff Wohlt]

If oyu have a 3/16" nose strut then run brass directly in to it around 1/4". As long as the prop shaft is not hitting it.

A strut is the part your prop shaft and stuffing tube go in that is hanging on your boat transom. Do you have a straight tube coming out of your boat and no strut? This is common for hydros set up the scale way.

[chunkymonkey28]

Maybe some pics will help. The boat is a submerged prop btw. There is just a single 3/16 tube that runs from the bottom of the boat to the inside

Back/bottom of boat

http://i41.tinypic.com/10qxyiq.jpg







Here's the inside. The back is on the right of the pic. You can see the brass tube where the driveshaft goes thru.
http://i43.tinypic.com/2wncsv5.jpg

[chunkymonkey28]

so yea, this boat doesn't have any struts

[chunkymonkey28]

Hey guys, so I've been looking around a bit, and it seems like a flex shaft may not be my best option. The original shaft in this boat was a 4mm diameter straight shaft. I'm also using 1/8" Octura plastic props. I found these shafts which seem to replicate my old shaft exactly, and for a submerged prop drive they might perform better than a flex wire setup.

http://www.offshoreelectrics.com/products.php?cat=106

U guys think this would be better? I know motor alignment is more critical with these but I don't mind.