U-Boot type VII/41, Assembly #1

[toppack]

I was going to order some more of the Robbe #1445 shaft-Couplers, since I don't have many more, but found out that Robbe no longer makes them. :mad:
I don't like the Dumas dog-bone couplers. (I call them Broken-Bone couplers)
Raboesch makes a pretty good, Small one, but it's too expensive, so I may have to start making my own couplings Now.
Man, It's Always Something! :mad:
I have thought of a simple design that may work, using nuts locked together on shaft with rubber fuel-line hose slipped over them. I'll need to test it, but I think it will work for low-torque motors, with small shafts and props.

[junglelord]

Not sure if this is the same thing, but could you not go neodymium

http://www.caswellplating.com/models/klikons.html

[Nuke Power]

This is how I did mine. The bras is to pieces of hollow square brass that can slip into each other. It makes drive coupling installation way easier due to the limited space inside and with the torque produced by the two 180 can motors its more then enough strength.

[toppack]

The main advantage of the Robbe 1445 couplers was that if the prop hits something and stops, the coupler would act like a clutch and not brake the coupler or prop, but had good gripping force during normal operation. None of the other couplers have that safety factor.

The Kli-Con magnetic couplers will not work for prop-shaft couplers but are good for servo-linkage-couplers.

[junglelord]

What size of motor in that beast?

A neodymium magnet of the proper size would handle the torque but may surpass the size requirements of the sub or the brass shaft....

The main advantage of the Robbe 1445 couplers was that if the prop hits something and stops, the coupler would act like a clutch and not brake the coupler or prop,

Neodymium should work well for that purpose.

[Nuke Power]

IMHO Your worriying about a non issue with the boat and trying to over complicate the thing. Your not going to break these little 1in brass props. The motors dont have enough torque to destroy the boat. The magnets would hold lateraly but would probably just spin around themselves.

[toppack]

I've never tried it but I certainly don't think magnets would work, unless you used Very Large magnets, which would be too much weight.

[toppack]

IMHO Your worriying about a non issue with the boat and trying to over complicate the thing. Your not going to break these little 1in brass props. The motors dont have enough torque to destroy the boat. The magnets would hold lateraly but would probably just spin around themselves.

I have personal experience with broken Dumas couplers and damaged prop because of a ridged coupler. So i like to have a slip clutch when possible.

[junglelord]

Thats exactly why neodymium is your answer...works perfect as a clutch.
:p

But come on, how could it not work for your model?
What size of motor you going to use?

[toppack]

Thats exactly why neodymium is your answer...works perfect as a clutch.
:p

But come on, how could it not work for your model?
What size of motor you going to use?

The motors will be what David puts into the 2.5" SD.
I'm not sure what he has in stock for them ???

[toppack]

About 10.mm size magnets may work if you also slipped silicone-rubber tubing over them, to keep them from spinning easily.
I may give your Idea a try, to see if it works. :) I have some magnets that size.

[Nuke Power]

do you have the SD yet. Is it instaled in the model?

[toppack]

Finding a good reliable, removable way of attaching the magnets to SD outout shafts will be the most difficult part of the assembly? I'll still need something with a set-screw type attachment, to go between SD and magnets?
Maybe I could epoxy the magnets inside brass Dumas-coupler end pieces?
And permanently attach magnets to shafts with soldered thinwall-brass-tubing, so the hose will slide tightly over it?
If this doesn't work, I'll send you a Bill for my time and Effort! :D

Not really, thanks for the suggestion.

Having this Forum as my 'Thinking Note-Pad' has been a great help!
Thanks Mike

[junglelord]

Would not just use the same plastic cleavice that the Merriman magnetic joiner encorporate?
But the end of the brass with glue and rubber cover would work.

[toppack]

do you have the SD yet. Is it instaled in the model?

No, I'm working Blind on this one. :D
This one was supposed to be shelved. I'm just trying stay busy while waiting for the T-class to get here. :rolleyes: