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Author Topic: Shaft to motor coupling alignment  (Read 5070 times)

thelegos

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Shaft to motor coupling alignment
« on: October 18, 2011, 05:32:45 pm »

With every boat I've built I've taken much time and trouble to make sure everything in the drive line is as closely aligned as possible but my current project, the restoration of a Veron Thames Police launch has me wanting to do what has previously been unthinkable - deliberately create misalignment for what are basically cosmetic reasons.

The first picture shows the 'straight' installation, the motor sits high into the cabin area.

The second picture shows the problem, this is the cover I've made to go over the motor. My kids call it the 'dog kennel'  {-) I see what they mean, it's too big and not in keeping with the original boats which had a very neat low level 'box'.

In order to make it more acceptable I need to install the motor as shown in the third picture but this means installing the coupling as shown.
I realise this will probably use more power but will it cause any major problems, electrical or vibration.

Your thoughts would be much appreciated

Roger :-))






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nemesis

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Re: Shaft to motor coupling alignment
« Reply #1 on: October 18, 2011, 06:18:24 pm »

Hello, I, too do not like to have the shafts out of line, but if it has to be I would use a double coupling. Nemesis.
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Pirate

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Re: Shaft to motor coupling alignment
« Reply #2 on: October 18, 2011, 06:21:18 pm »

Before restoration, where was the motor/shaft and prop in relation to now? What prevents you from lowerin the motor?
Pirate
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ACTion

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Re: Shaft to motor coupling alignment
« Reply #3 on: October 18, 2011, 06:25:40 pm »

Whatever you do to that drive-line will not solve the trouble you're going to have with that  motor - see the paragraph here under "Bad 540 Motor" http://www.modelboatmayhem.co.uk/Common/Electrics/How%20Fast.htm#Fast%20motors
I'd take it out and think about a different type of motor altogether, maybe with the substitution of that long prop shaft for one which will enable you to fit the motor much further back and thus much lower.
Dave M
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The long Build

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Re: Shaft to motor coupling alignment
« Reply #4 on: October 18, 2011, 06:54:37 pm »

I can,t see a problem with the universal joint set up , the angle that it is at is well within the joints rotation without binding so should cause no issues in my opinion. 
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Circlip

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Re: Shaft to motor coupling alignment
« Reply #5 on: October 18, 2011, 07:13:03 pm »

Taint going to bind, but will run at a higher current drain. Despite u/j's, drives should always be in line if possible.  O0

   Regards   Ian.
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thelegos

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Re: Shaft to motor coupling alignment
« Reply #6 on: October 18, 2011, 11:00:04 pm »

Hi all,
Many thanks for your replies, first of all I've checked the motor as Dave M suggested and it's destined for the bin! I usually run Graupner 600's of varying voltage but this had the internal fan and I felt it might help in the absence of water cooling.

The shaft is as fitted all those years ago when she was first built, it is a bit long but this is tight and I've tried to remove one from a balsa boat before and the wood gives before the glue so I'm leaving well alone if possible.

A double coupling with the motor flat could work, it would move it forward but since the batteries are at the rear it could help weight distribution. I'll measure up and check that one out. A speed 600 will be shorter although I'm concerned about cooling now {:-{

Plenty to keep me going there, it was going to be a 'quick and dirty rebuild' but like all the others that start that way stuff comes up that need to be sorted - perhaps that's why I enjoy it so much :}

Roger
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mickyrubble

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Re: Shaft to motor coupling alignment
« Reply #7 on: October 18, 2011, 11:07:28 pm »

Hi,
why not cut the shaft down and cut out a rebate into the deck. O0 O0 O0 O0
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thelegos

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Re: Shaft to motor coupling alignment
« Reply #8 on: October 18, 2011, 11:16:47 pm »

Now that's a very interesting suggestion mickyrubble and not something that crossed my mind at all !!

Tomorrow some serious measuring must be done - I'll be planning this in my sleep now !

Roger
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treeboa

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Re: Shaft to motor coupling alignment
« Reply #9 on: October 18, 2011, 11:20:22 pm »

no way you can fit a coil around the can and add a water pickup and discharge pipe ??, that will sort your cooling
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thelegos

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Re: Shaft to motor coupling alignment
« Reply #10 on: October 18, 2011, 11:31:19 pm »

I've avoided the cooling because of the limited space between prop and rudder and getting pipes to the motor on these old box-style veron boats. The more I look at it the more wrong the shaft length, position and probably the angle are  {:-{

I will build an enclosure round the shaft which will also carry the motor cables, I guess if I make it a little larger that's where the water pipes can go as well. I had the same problem on a Veron Marlin I've just finished and ended up fitting a false floor!

More things to dream about !

Roger
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tobyker

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Re: Shaft to motor coupling alignment
« Reply #11 on: October 18, 2011, 11:39:27 pm »

I've always wondered why in model boats we so often use a proper cardan joint which means everythig has to be perfectly aligned down the plan centre line. Couldn't you save a lot of trouble by using a pin and disc drive, or even a pair of pins on the motor shaft and a crossbar on the prop shaft. I know there would be some sliding friction losses, but I should not have thought they would amount to much, and anyway they would be far less than those caused by a mis-aligned UJ.
 
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thelegos

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Re: Shaft to motor coupling alignment
« Reply #12 on: October 19, 2011, 07:36:26 am »

Hi tobyker, I'm inclined to agree. I looked at this little assortment yesterday to see if they would do the trick!
I think if the small chrome ball/pin and slot arrangement in the centre were bigger I'd have tried it as it is very forgiving.

Roger


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