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[smiffy]

Hi Peeps,

I've got the smell of balsa in my nostrils and revved up for building. I've made lots of models and the like in the past so my building skills are reasonable but the only boat I've built was 24 years ago whilst wearing short trousers thanks to one of the guys on here I've now got the plans again to have a go at it again with my boy  - Sea Rider from the Model world TV programe in 1975 - 30inch flat bottom frigate - Thanks Dougal99

Before I loose myself completely in nostalgic waffle my questions are:

Prop Tube - the one I've got is simply a tube with a shaft/prop - there are no seals on the tube so whats to stop water creeping up the tube or do i just make sure the internal end is above the water line?

Motor linkage - my plan is to use a piece of rubber tubing to give me flexibility on the mounting - is this a sensible thing to do or should i use a some proper linkage?

Rudder - I shall use 2 linkages on it but was going to opt for wire as opposed to solid adjustable ones - am I asking for trouble? I've read some posts on here that strongly advise double solid adjustable but they seemed to be for high spec craft - my boat is really very simple and only for the boy to pootle about with on the duck pond. Little fingers cannot resist turning rudders so I'm concerned it would damage solid ones whereas the wire ones will flex?

Keel - I read somewhere that an experienced modeller had built one of these and put a keel on it for stability - so I'm not sure whether to put one on or not. I understand why I should use one but I want to keep things as simple as possible. My boy is only 7 and a keel would get in the way of his imagination .

I think thats it for now...................but I shall be back with more as the weekend progresses - I've got an urge to resurect a half built airboat but I'll save that for another post .

[chingdevil]

Welcome to the forum Smiffy

We tend not to scoff, because if you do not know you have to ask questions and there are plenty of people on here ready to give good advice, even to questions you think are really silly.

Prop tubes - the internal ends are rarely above the water line in a real boat so I would think most models are the same. You can lubricate the shaft before you put it together or build the prop shaft with an oiler in it. If you are not sure what that is, let us know and I can post a drawing.

Motor linkage - My personal opinion would be to use a proper motor coupling, you can get the motor and prop lined up ok and you have less chance of the coupling letting go if you get something around your prop, meaning you stand a chance of getting the model back to you.

Rudder - Again my personal choice is a for solid linkage either one or two rods, I feel you get a more positive control from them.


I do not know the model so I can not give any advice on the keel. I am sure there is someone on the forum who has built one or seen it to give advice on that

Have fun building and keep us informed on how it goes, remember the only daft question is the one you do not ask


Brian
Global Moderator

[smiffy]

Thanks Brian,

Never thought about the prop letting go if it gets fouled. Not sure what you mena about about an oiler - piccy would be appreciated.

Thanks 

[dougal99]

Smiffy,

With a simple prop shaft as you describe (or as I understand you) a shaft in a close fitting tube I would advise lubricating it before fitting the shaft in the tube, this should keep any water out. An oiler is essentially a small length of small diameter tube soldered at right angles to the motor end of the prop tube. A hole is drilled into the prop tube, this allows oil to be introduced into the prop tube without removing the shaft. For such a basic model and shaft assembly this may be a little too much. It really depends on how easy you think it will be to remove the prop shaft at a later date for servicing.

Rudder connection two arms - really good, one arm (even of wire) probably OK for this type of model.

Motor connector. Depends again on your prop shaft. I have a small frigate powered by two 30mm props on 2mm shafts. I use rubber connectors on those with no problem however, I wouldn't recommend them on anything bigger.

As for the keel, I would try the boat without it first (you can readily add a false keel later if necessary). My frigate, although a slightly more complex hull, performs OK without one.

HTH

Doug

PS Long grass is good for the wildlife 

[andyn]

My two penneth, hopefully of help...

For small propshafts I use Dow Corning number 7 Silicon Release Agent, it's expensive (not where I get it from though...), but is well worth it

Andy

[Mark47]

All good points so far

Always go for propper prop shaft connections. 

If the internal end of the prop shaft is not above water then when you reverse the boat you are almost guaranteed to get water in the hull, greasing or oiling them  are always a good idea.

Keels are on ships (real ones) to give a back bone to build on (and structural integrity). They are usually on models to give authenticity. If stability becomes a problem, your better with stabilisers fins or a combination of both.

Mark

[chingdevil]

Hi Smiffy

This is what a prop tube oiler would look like.

Brian

[DickyD]

Check this out for propshaft grease and oiler attachment.

http://www.cornwallmodelboats.co.uk/acatalog/prop_shaft_accessories.html.
.

[smiffy]

Thanks for the advice Peeps,

Decisions made, I shall go for greasing my tube ( ) and use a length of rubber tube for the coupling. I've put the prop tube in such a way that I can extract the shaft easily if I need modifications at a later date - (thanks for the advice Doug). I like the idea of the oiler but its a bit too smart for me at the moment (thanks for the piccy Brian)
I shall use 2 wires for the rudder links - i just know the boy won't be able to resist  so the wires should offer some protection for the servo.

As for the keel - we shall see what happens in the bath but I like the idea of stabilisers Mark 

Thanks a lot guys, I'll try and put a piccy up later.............

SMIFFY 

[DickyD]

Rubber tube is no good, go for the proper couplings.