12V for Robbe U-47

[preveze]

Robbe U-47 is my first sub kit.I had no marine modelling and building experience and there are some some faults on my kit.I filled the shafts with gress and rpm decreased considerabally.Sub seems too slow for me so I decided to power it with two serial connected 6V4AH batterries totalling 12V.I did not test it but can the stock motors handle this power?I changed the wiring with thicker wires and replaced the speed control with a switch.

[Guest]

Right. If you run the

Right. If you run the stock motors at 12 volts there is a good chance the motors will overheat and hence have a short life span.

The supplied motors (Speed 500) should have more than adequate power to submerge the boat at 6 volts.

In fact they tend to be a little juicy, so a lot of folk have replaced the stock motors with Speed 400's reduced with a toothed belt drive. These are sold ready to fit by one of the sub vendors, I think it's 'Ships and things', but I could be mistaken.

What grease are you using in the shafts?

Packing the shafts fully with grease will load the motor considerably.

I'm not that familiar with the Robbe kit, but I'm sure the shafts must have some sort of rubber seal/stuffing box to prevent water ingress.

If not consider uprading the shafts, Subtech do a good range of sealing devices.

Also use a good quality electronic speed control with your sub. A switch is bad way of controlling a model sub, crude and too many nasty things can happen to a switch which could easily result in the loss of your boat (i.e. it gets stuck on).

Cheers

Andy

[preveze]

I used Shell water resistant

I used Shell water resistant gress.Friction in the sahts is terrible Can you suggest me a heavy duty speed control that can handle 12V and hi amps that I can use in my further projects?

[Guest]

The controllers I use can

The controllers I use can be found at this site-

http://www.modelcontrollers.co.uk

Up to 27 volt working- they work great on 12 volts.

I see no reason to use anything else.

Keenly priced too!

Silicone based grease is best for your shafts.

Cheers

Andy



Edited By Sub culture on 1070564474

[safrole]

I converted to shaft seals

I converted to shaft seals with some 11mm seals from www.subconcepts.com. Here is the page showing the process.

--Jason

http://www.3rdgendecals.com/submarine.htm

[boatbuilder1]

shaft grease I have always

shaft grease I have always used prathers cable grease it is 100% manmade silicone grease blue in color and doesn't thin or melt with temps up to 500 degrees
I inject the tube before gluing in the boat and then insert shaft and and catch the excess grease as the shaft fills the cavity so none is lost this stuff is nice and you get a 1/2 pint for around 6 bucks one can lasts me thru at least a dozen boats

don't use this to stop leaks on flat surfaces though it just promotes the leak even faster



Edited By boatbuilder1 on 1070513738

[mit]

Having over 20 years in

[color=#000000]Having over 20 years in RC airplanes and Helis and the last 5 in electrics I can say this]