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Author Topic: Prop Tube / Prop shaft length  (Read 1967 times)

Billyruffian

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Prop Tube / Prop shaft length
« on: April 13, 2010, 09:40:09 AM »

I have  an old mardon model kit to finish off that was given to me.  The proptube is fixed in place.  The prop shaft is threaded both ends either 2BA or 5mm - not checked yet.  But, with the prop and lock nut fixed, the shaft extends past the tube by the length of the thread plus 3/16", so with the coupling firmly screwed in place there is 3/16" of shaft between the end of the coupling and the end of the proptube.

Is this likely to cause a problem and should I be looking to replace the shaft with one slightly shorter?

Thanks
Cyril
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Colin Bishop

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Re: Prop Tube / Prop shaft length
« Reply #1 on: April 13, 2010, 09:45:53 AM »

I would just make up a spacer from a piece of brass tube with a diameter which fits snugly over the shaft. Too loose and it will rattle. Make it a bit longer than the gap you have so that the nuts at each end can be screwed up tight to lock the shaft and then eased off a little to give minimum play.

Colin
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Billyruffian

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Re: Prop Tube / Prop shaft length
« Reply #2 on: April 13, 2010, 09:52:13 AM »

Thanks Colin - have to get some spare nuts ans washers as there is only one on this thing - but simple solution thanks again.

Cyril
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DickyD

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Re: Prop Tube / Prop shaft length
« Reply #3 on: April 13, 2010, 01:07:22 PM »

You could always fit a locking collar to the shaft up against the tube.

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

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Re: Prop Tube / Prop shaft length
« Reply #4 on: April 14, 2010, 09:51:42 AM »

Sorry to ride on this posting since it's about tube too.

I just received my purchase of prop shaft with tube from UK (I am in Singapore). The tube does not come with a little tube that I see commonly in the boat models here. Do I really need this little refill tube or can I just fill up the tube with grease and run the prop without the refill tube?

I am putting these tubes in the Revell ETV Waker, so it's not going to be racing anytime.
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DickyD

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Re: Prop Tube / Prop shaft length
« Reply #5 on: April 14, 2010, 10:31:59 AM »

I take it you are talking about the oiler tube.

It is a convenience rather than a necessity as it makes it easy to lubricate the shaft.

If you havent got one then you need to withdraw the shaft, squirt a small amount of grease into the tube then put your finger over the opposite end of the tube and re insert the shaft.
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CGAux26

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Re: Prop Tube / Prop shaft length
« Reply #6 on: April 15, 2010, 02:52:35 AM »

In addition to the locking collar recommended by Dicky D (and me), I put a close-fitting nylon washer between the locking collar and both ends of the prop tube (aka shaft log).  This makes a better wearing surface on the ends of the shaft log, in forward and reverse.
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Cklasse

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Re: Prop Tube / Prop shaft length
« Reply #7 on: April 17, 2010, 05:01:20 PM »

One more question,

must 2 prop shafts be parallel to each other or can they slant outwards, something like a V.
I intend to use the gear housing from my electric shaver to drive 2 shafts with a single motor of the shaver. The problem is the distance between both output point of the gear housing is shorter than the distance of both shafts when parallel, hence the slight V layout.

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Martin [Admin]

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Re: Prop Tube / Prop shaft length
« Reply #8 on: April 17, 2010, 05:59:12 PM »


Shouldn't be a real problem as long as the V is as shallow as you can get it, after all many shafts are angled donwards.
Make sure the the angle is exactly equal both sides or you'll end up with differential steering.

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