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Author Topic: Pulleys and drive belt  (Read 7859 times)

wjr63

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Pulleys and drive belt
« on: May 30, 2009, 11:47:54 PM »

I amgoing to be building two paddlewheeler boats. I want to drive the paddle with pulleys and the o ring drive. Does any onw know where I can get this. Thanks
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Proteus

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Proteus

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Re: Pulleys and drive belt
« Reply #2 on: May 31, 2009, 12:06:52 AM »

Also think about toothed belts, you do not need to put as much tension on them to get drive

Proteus
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kiwimodeller

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Re: Pulleys and drive belt
« Reply #3 on: May 31, 2009, 02:19:12 AM »

I would suggest you have a look at the Paddleducks paddle steamer website ( www.paddleducks.co.uk ) in the paddlewheels and drive systems section. I guess it depends on how big your paddler is but my experience on a large steam powered paddler was that neither O rings or toothed belts worked well. I have ended up with fine chain and have had no more problems in three years. You will also find by searching on the Paddleducks forum a lot of discussion on why you should use a solid drive axle linking both wheels together. Independent drive to each wheel is not necessary and in most circumstances is more difficult to operate than fixed drive to both wheels. Hope this helps, Ian.
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Seaspray

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Re: Pulleys and drive belt
« Reply #4 on: May 31, 2009, 06:47:08 AM »

Found HPC Gears to be very helpful.

If you phone them and ask to speak to the technical side, they'll work the sizes of pulleys and belts out for you.
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flashtwo

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Re: Pulleys and drive belt
« Reply #5 on: May 31, 2009, 08:10:17 AM »

Hi ian,

Mind you don't get steam oil (even a fine mist) on them, since, the ones I used on my test rig between the D10 engine and the generator became badly distorted and stretched and also the reinforcing wires came out.

I thought it was water that was causing the problem, but, having soaked one for several days it didn't make any difference, but the oil did.

I built a simple aluminium cover for tests and covered the belt with a cloth, when not being used, to stop any oil condensing on the belt - it did the trick.

IanG.
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bogstandard

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Re: Pulleys and drive belt
« Reply #6 on: May 31, 2009, 09:25:44 AM »

You are overlooking one slight problem when putting twin motors into a usually narrow hull of a paddler.

The length of the motors, plus gearboxes, plus room to fit the belts on, plus support for the individual shafts.




You will most probably have to go for the offset method as shown on the sketch.

This is the way I did my Glasgow hull, and that is a beamy hull for a paddler. I used toothed belts for the drive system, and as mentioned by others, they require less tension to be applied, whereas normal ring belts have to be kept in tension all the time, and put undue stresses on the inboard shafts. I suppose the hobby chain would do just as well, but I have never tried it.

It all depends on what you want the model to do. If just to sail around and nothing special, then a solid shaft is fine. If you want to turn on the spot and have super maneuverability (totally out of scale, but looks great on the water) then independent is the way to go. But really, you need to do it electronically with a rudder/motors mixer and independent matched speed controllers, trying to do it manually is a real pain, and you will end up sticking fingers where you don't want them to be.

Good luck on your quest.

John
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BarryM

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Re: Pulleys and drive belt
« Reply #7 on: May 31, 2009, 02:47:44 PM »

Whatever you do, don't go the chain and sprocket route. I did and found that it generated enough electrical interference to make the ship uncontrollable. Threw the lot out and put in toothed wheels and belts; problem solved.

I used twin motors arranged as per Bogstandard's layout, each with its own ESC (but without mixers) driving seperate shafts for my Director Class paddler.  Using my venerable Fleet TX I then have the option of single stick control of both motors with rudder for direction control or switch over to operate the shafts independently from L & R sticks and forget the rudder. In practice I usually use the latter without problems.

Good luck,

Barry M
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wjr63

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Re: Pulleys and drive belt
« Reply #8 on: June 15, 2009, 03:02:42 AM »

Thanks to you all for the suggestions. Barry how long of a chain did you have. What I am building is a 40.75 in sternwheeler. The plans look like I can have the elec motor pretty close to the wheel. Minimum amount of chain. Maybe 3 or 4 inches. I think for this boat and the way it will used ( just cruising around)  that the chain is the simplest way to go. Again thanks for the suggestions and advice. Wayne
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BarryM

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Re: Pulleys and drive belt
« Reply #9 on: June 15, 2009, 09:38:18 AM »

Wayne,

I was using 2 x 1" sprockets set about 5" apart on each paddle wheel.  I had suppressed and earthed everything conceivable, used a whip aerial from the Rx located remote from the motors and drive gear and stiill was getting massive interference whenever the motors were run. When I scrapped the chains/sprockets and replaced them with toothed belt and pulleys, I had a different boat - no interference whatsoever and I was also able to dump a lot of the additional suppression and just keep the basics.

By all means give the chain a try - who knows, you may get away with it - but be prepared to change it.

Let us know how you get on.

Barry M
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flashtwo

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Re: Pulleys and drive belt
« Reply #10 on: June 15, 2009, 09:49:59 AM »

Hi Wayne,

I suspect the chain is building up static electrictiy when it is moving. I had a similar thing with ejecting steam, believe it or not, which caused erratic movements with my control system.

I solved the problem by ensuring that the pipe the steam was ejecting from was earthed down with a wire to a common point at the negative of the boat's battery. It was very effective - no earth wire, interference - with earth wire, none.

I would advise fitting small lengths of copper braid (the solder wick from Maplins type of thing) as shaft "brushes" and wires from the bearing housings, and connect all back to the battery negative.

Ian.

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BarryM

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Re: Pulleys and drive belt
« Reply #11 on: June 15, 2009, 10:01:54 AM »

Hi Wayne,

I suspect the chain is building up static electrictiy when it is moving. I had a similar thing with ejecting steam, believe it or not, which caused erratic movements with my control system.

I solved the problem by ensuring that the pipe the steam was ejecting from was earthed down with a wire to a common point at the negative of the boat's battery. It was very effective - no earth wire, interference - with earth wire, none.

I would advise fitting small lengths of copper braid (the solder wick from Maplins type of thing) as shaft "brushes" and wires from the bearing housings, and connect all back to the battery negative.

Ian.


Ian,

Don't want to be negative (no pun intended) but I tried that also!  If chain and sprockets need so much extra supression, why go that route? Life's too short.

Cheers

Barry
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flashtwo

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Re: Pulleys and drive belt
« Reply #12 on: June 15, 2009, 10:05:31 AM »

Hi Barry,

Your message appeared as I was writing my reply - sorry.

The other interference that I had was from the ESCs driving the electric motors. With an oscilloscope, I could see the electrical spikes being generated by the ESCs were appearing on the metal chassis of the electric pumps. The electric motor windings weren't perfectly insulated and there was leakage to the chassis, which, electrically speaking, was "bouncing" up and down with the ESCs and taking other electrical items with it.

Again, taking an earth from the chassis back to the common negative of the battery cured the problem.

I know I don't have to tell you, but for other Mayhemers not familiar with the darker corners of the "black-art", the common negative was a single thick wire from the battery to an M4 bolt mounted in a wooden bulkhead to which all the earths and other negatives  were returned to - otherwise the battery terminal gets a bit crowded, as you might imagine.

Ian
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BarryM

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Re: Pulleys and drive belt
« Reply #13 on: June 15, 2009, 11:20:24 AM »

Ian,

Right enough; what sometimes initially appears to be a cavernous space can shrink enormously once all the gubbins are fitted in.  One point I've been reminded of is that metal-to-metal clevis connections for model aircraft control rods/cables are considered unwise because of the potential for generated interfence. Not nice at altitude!

I also earthed the negative to the prop shaft.

Cheers,

Barry M

PS. You're comment about escaping steam generating interference made me think. Is this likely to be a problem with steam whistles? I'm asking because I'm building my first steamer.
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flashtwo

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Re: Pulleys and drive belt
« Reply #14 on: June 15, 2009, 02:17:11 PM »

Hi Barry,

Not wishing to hijack the topic, I mentioned the steam electro-static effects in this thread:

http://www.modelboatmayhem.co.uk/forum/index.php?topic=17174.msg171539#msg171539

My computer control system, which was more susceptable to interference than ordinary kit,  is described in the Flash Steam thread:

http://www.modelboatmayhem.co.uk/forum/index.php?topic=15817.0

I would imagine that, with a steam whistle, you may not notice any electro-static induced glitches unless you were looking out for them.

good luck

Ian.


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barriew

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Re: Pulleys and drive belt
« Reply #15 on: June 15, 2009, 02:36:42 PM »

I've just been modifying the drive on my Lulonga sternwheeler. I am using plastic sprockets and metal chain drive. Not ideal but seems to work with no interference, but I am using 2.4Ghz O0  The problem I have found is that suitable geared motors have 6mm drive shafts, and the only reasonably priced sprockets I have found are for 3mm or less.

I would like to use toothed belts, but again I am not sure I can find suitable pulleys, one for a 6mm and one for a 3mm shaft. They also seem to be very expensive, although I did find this site http://www.motionco.co.uk/ last night and will investigate further when I've got this move out of the way ok2

Barrie
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BarryM

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Re: Pulleys and drive belt
« Reply #16 on: June 15, 2009, 03:03:45 PM »

Barrie,

Problem seems to arise when metal to metal sliding contact arises, i.e metal sprocket to metal chain. Your setup of plastic sprockets and metal chain would overcome that.

Ian,

Tanker explosions in the 70's were traced to static buildup on tank-washing guns which passed large quantities of hot/cold water.

Regards

Barry M
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barriew

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Re: Pulleys and drive belt
« Reply #17 on: June 15, 2009, 05:23:51 PM »

Barrie,

Problem seems to arise when metal to metal sliding contact arises, i.e metal sprocket to metal chain. Your setup of plastic sprockets and metal chain would overcome that.


Sorry - should have been clearer - Plastic sprocket on the motor, metal (Meccano) on the wheel shaft.

Barrie
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wjr63

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Re: Pulleys and drive belt
« Reply #18 on: June 24, 2009, 03:52:50 PM »

Thanks for all the suggestions and advice, after further research I came across the servo city site they have plastic sprockets and chain. The  next question now is sizes. I am building a 40.75 in sternwheeler. I will be using a 550 motor on 7.2 v Anybody out there got any suggestions.
Thanks
Wayne
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tobyker

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Re: Pulleys and drive belt
« Reply #19 on: June 24, 2009, 11:44:46 PM »

Check out technobots too - they sell some chain and sprockets - a fairly limited selection though.
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barriew

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Re: Pulleys and drive belt
« Reply #20 on: June 30, 2009, 01:25:38 PM »

Thanks for all the suggestions and advice, after further research I came across the servo city site they have plastic sprockets and chain. The  next question now is sizes. I am building a 40.75 in sternwheeler. I will be using a 550 motor on 7.2 v Anybody out there got any suggestions.
Thanks
Wayne

I usually go for about 120rpm as the speed of the paddles. Further help can be found on the Paddleducks web site - http://www.paddleducks.co.uk/smf/index.php

Barrie
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