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Author Topic: MFA Bolt On Gearboxes - noisy?  (Read 450 times)

Colin Bishop

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MFA Bolt On Gearboxes - noisy?
« on: April 30, 2021, 06:15:16 pm »

I'm considering using a couple of these motor/gearboxes for a a possible paddler project. There woudl be a 1:1 timing belt drive to each paddle. (the prototype had independent paddles)

https://www.componentshop.co.uk/motor-385-gearbox-ratio-11-1.html

Can anyone tell me if they are noisy in operation? The alternative option is to gear down using pulley drives only.

Any comments welcome.

Colin
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SteamboatPhil

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Re: MFA Bolt On Gearboxes - noisy?
« Reply #1 on: April 30, 2021, 06:30:39 pm »

Colin
I have one similar from Iain geared 100:1 and 1.5-3 V and it is a little noisy especially when I fixed it to a flat surface in the boat, I solved most of the problem by mounting it onto a 1/4 thick balsa base which sort of worked as an anti vibration mount (sort of ! )
Hope this helps
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TheLongBuild

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Re: MFA Bolt On Gearboxes - noisy?
« Reply #2 on: April 30, 2021, 06:43:30 pm »

Get a cheep rubber/foam mouse mat and mount it to that. But no idea about how noisy.

Seacommander

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Re: MFA Bolt On Gearboxes - noisy?
« Reply #3 on: April 30, 2021, 08:20:14 pm »


I have never used them in that manner, but have had them for other non boat projects and found them noisy to the point where they bugged me.
My father did a Reliant Tug 40 years ago , he still has it and still sails it. He used Monoperm's with the plastic Pile gear boxes,
They were dead quiet and he was able to get just the right gear ratio as well
If you could get some old stock units that would be a good way to go, Dad's original motors lasted about 30 years 
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Colin Bishop

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Re: MFA Bolt On Gearboxes - noisy?
« Reply #4 on: May 01, 2021, 04:13:38 pm »

Thanks for the info. Looks like a bit of sound insulation in the mounting is the best bet. Glynn Guest tells me that he used one of these and noise wasn't too bad.

Colin
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John W E

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Re: MFA Bolt On Gearboxes - noisy?
« Reply #5 on: May 01, 2021, 05:44:30 pm »

Hi there Colin


Just wondering - is this model that you are considering building limited to the size of drive pulley that is connected to the paddle wheels?   The reason being would it not be better off gearing down, using a large pulley on the drive shaft of the paddle wheels and a smaller one on the shaft of the motor?    therefore not requiring a gearbox on the end of the drive motor.


just a thought,.


I do have 2 of these gearboxes myself and I think it is personally what you consider noisy.   I dont think they are really that noisy - I have heard worse noise from misaligned motors.


John
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Colin Bishop

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Re: MFA Bolt On Gearboxes - noisy?
« Reply #6 on: May 01, 2021, 06:14:09 pm »

Hi John,

Thanks for your input.

I have considered that and trawled through the Paddleducks forum where there is quite a bit of practical info. The paddles probably need to rotate in the 150/300 RPM range while the 385 motor I'm looking at is around a nominal 10,000 RPM so ideally you want something like a 30:1 reduction which is a heck of a lot for a single pulley system so really the gearbox has to do most of the work with fine adjustment on the final drive. (and of course the battery voltage and speed control).

If I build the model I don't want it to be a major project so would like to use off the shelf components which is possible with the MFA 385 geared motors and MOTIONCO timing pulleys and belts.

The nearest MFA gearboxes are either 50:1 or 11:1, neither of which are directly suitable I think, but pulley sizes could either drop down the first or boost up the second without the need for big pulleys.

The hull will incorporate quite a bit of balsa with ply so will not act as a plastic 'boom box'. Hopefully OK as long as it doesn't frighten the ducks.

I do love these little problems...

Colin

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John W E

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Re: MFA Bolt On Gearboxes - noisy?
« Reply #7 on: May 01, 2021, 06:31:25 pm »


Hi there Colin - just a thought, when I built the Forceful paddle tug, I was advised that the paddle wheels should spin between 400 and 500 rpm.  I therefore bought the correct ratio pulleys and belt drive to get the standard 550 motor to give me the required rpm of the paddles on 6 volt.  When I actually finished the model and put it on the lake - I found it to be on the 'slow' side and easily affected by the wind.  So, naturally, I stepped up the voltage on the motors to 12 volt.  This gave me excessive speed of the model but also the paddles tended to 'whisk' the water similar to a food mixer - so this wasn't ideal.   To cut a long story short, I went to 7.2 volts and that seemed to give me a reasonable speed.   Here's a link to the website for como drills - no doubt you will have been on this site.   The only thing is with using these pulleys you would have to possibly make a bush up for the pulley that you fit to the spindle of the 385 series motor.

(website update Jun 18) 917D Accessories (mfacomodrills.com)


back again, Colin, modifying - just been on to Ebay to have a look because sometimes the lads who run the trucks  model cars use belt drives and I have come across these 2 little gear boxes, they look quite interesting.


The other thing is, have you thought about looking at Meccano stuff for to drive the paddles, as they do small plastic cogs and plastic chain too.


Small DC Motor with belt drive & gearbox with slip clutch 0856A - as pictured | eBay

John
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Colin Bishop

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Re: MFA Bolt On Gearboxes - noisy?
« Reply #8 on: May 01, 2021, 07:14:43 pm »

Hi John,

Thanks again for your comments.

I'm looking at the ps Bilsdale which is much smaller. 35 inches long and around 40% of the weight of Forceful.

Thanks for the link, I will have a look at it.

Colin
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mrzippy

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Re: MFA Bolt On Gearboxes - noisy?
« Reply #9 on: May 02, 2021, 09:49:04 am »

Hi Colin,

Posted this a while back and it may be of help - I use 'HPC Gears' at Chesterfield
for anything gears, pulleys and belts wise, parts are usually in stock and available from their massive warehouse site -
provided one understands the technicalities involved !

Recently replaced a slipping Meccano brass pulley and rubber band/belt two stage reduction drive on a 30" stern wheel steam launch,
with more substantial toothed belts and pulleys from HPC.

Lots of technical info on their website, most of it going straight over my head - I'm not an engineer,
therefore I took the model along and HPC's technical guy went into action with micrometers, vernier and calculator,
measuring shaft centres and pulley diameters etc.
He returned from the stores half an hour later with the exact components -
one pulley requiring minor drilling out to the correct shaft size, excellent service, but not cheap!
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John W E

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Re: MFA Bolt On Gearboxes - noisy?
« Reply #10 on: May 02, 2021, 10:11:42 am »

Hi there Colin,


Is this the paddle steamer you are contemplating building?  I was having a look on the web and, as far as I can see, there is only a small cabin area in the middle of the hull to which you could accommodate any driving pulleys.  So, somehow, you may have to take the drive from the main driveshafts of the paddles through a small drive  gear wheel and maybe a worm drive because of the clearance between the shaft and the deck of the model.    Obviously then go down the route you are thinking with the gearbox. 


John
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RST

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Re: MFA Bolt On Gearboxes - noisy?
« Reply #11 on: May 02, 2021, 10:20:28 am »

Possibly a throwaway idea but would a worm drive work?  That might simplify gearing down then using pulleys if a gearbox is required anyway?
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Colin Bishop

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Re: MFA Bolt On Gearboxes - noisy?
« Reply #12 on: May 02, 2021, 10:26:02 am »

Yes, that's the one John, it was originally published in MB December 1972 and I have that copy but I have also ordered the plans from Canada. There may be sufficient room in the deckhouse to accommodate a 'step up' from the 50:1 gearbox which would feature a small pulley at the paddlewheel shaft end but I'll have to wait until the plans arrive. The drawings in the magazine are 1/7 of the full size model so I can't really take accurate measurements off them.

As far as the motors are concerned it would proably be a case of fitting one forward and one aft. I wouldn't rule out connecting the cabin to the boiler case to make a bit more room if necessary as it wouldn't be very noticeable. I might also deepen the hull a bit.

When I've got the plans I can check what is and isn't possible.

RST, yes, worm drives are possible but I think they would be pretty noisy.

Colin

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John W E

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Re: MFA Bolt On Gearboxes - noisy?
« Reply #13 on: May 02, 2021, 11:01:16 am »

hi there


Colin, worm drives, if set up right, tend to be a lot quieter than conventional in line cog drives.  Also, you tend to get a lot more tork out of them.  It's just finding the correct gears to use.   I thought I had cracked it - but - when I looked at the home of the place its in Japan, a bit far for you to go to pick gearing up.   See if I can find the link again - no doubt when all of this virus stuff settles down, maybe a canny cruise just to pick some gearing up.   Good excuse :-)   Here pet, we are just off to Japan to pick some modelling gear up!


The gears are cheap but getting there a bit expensive.



KHK Gears - Gear Manufacturer

John
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RST

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Re: MFA Bolt On Gearboxes - noisy?
« Reply #14 on: May 02, 2021, 12:30:40 pm »

There's also a reasonable selection of geared motors at technobots to consider.  They have a few different makes.  I've only ever used the smaller MFA metal geared planetary motors before (still torquey!). Was quite quiet by itself.  I'm not sure a worm on a cog will be that bad. I read somewhere also a brass on a nylon gear is quieter than when both are the same. Never tested it myself.
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Colin Bishop

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Re: MFA Bolt On Gearboxes - noisy?
« Reply #15 on: May 02, 2021, 01:20:20 pm »

Don't overthink this guys! I don't want to get into model engineering. The MFA gearboxes have 6mm output shafts which match MXL pulleys and the paddle drive shaft will be 3mm which is also a standard MXL size.

I think the MFA geared motors, mounted on a sound absorbing base together with a timing belt final drive will do the job OK without sounding like a pneumatic drill. Just have to wait for the plans to establish what space is available and the relevant clearances.

Thanks all,

Colin
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