Flywheels in small 4mm shunting locomotives

[DCB]

Not sure if suitable magnets are available but by placing magnets in the brass gear wheel and more in a collar fixed to the drive axle it should be possible to make the drive gear slip on the axle under sudden shock loadings.  Have to see what is on ebay.   Might even fit tiny diesel shunters.    Even better it could fit those locos where the prototype almost never slipped such as GW 42XX tanks  see doodle

[hayfield]

How does the electronic system work in my Beamo loco, as its by far better than my locos with flywheels, which are in turn better than locos without flywheels ?

[5050]

No, i am not trying to wind anyone up. I fitted the flywheel because lots of other people fit flywheels to small 4mm scale shunting locos and I thought I'd give it a try. It doesn't appear to have made any difference and that's why I started this topic, which seems to have gone off course into some kind of wonderland.

Eee, I bet you wish you'd never started this thread eh, Dave.  Perhaps someone (not me!) should start a new thread based on 'Hi-Tec Alternatives to Flywheels' - and then actually make something to prove it works!

 

In a small industrial steam shunting loco.

[Ruston]

Because in the case of DC electric motors, the diameter of the armature directly correlates with the RPM produced under load.

 

 

 

Considering I'm running a brass USRA 0-8-0 off a motor 2/3 that size (10mm diameter 15mm long cylindrical body), yeah, it's pretty big for what you need it to do. The problem is OO scale modellers are living in the dark ages thinking the carbon brushed, rubberized "fridge magnet", 3-pole electric motors in their RTR locomotives are the pinnacle of technology when somebody bothers to make them coreless or skew wound. In such a tiny shunter a motor for a large N scale diesel would work just fine.

 

I bought some Mabuchi electric motors with 6 poles and rare earth magnets that are about the same size as your shunter's motor, and they are monstrously powerful.

The diameter of the armature and the rpm under load has nothing to do with the speed of the locomotive.The motor is connected to the wheels via a gearbox and in the case of the loco in my photo, a 90:1 gearbox and not forgetting that the voltage is controlled. I think I've already mentioned it earlier in this topic but it can be run down to just 4rpm at the wheels, which is far slower than is ever going to be needed in use. I couldn't care less about the pinnacle of technology because that motor cost just ninety nine New Pence (including post & packing) and it does the job perfectly, without rare earth magnets, clutches, or any other pointless nonsense. I could spend a lot more on a motor that's 5mm shorter but for what? To re-arrange everything to fit in a flywheel with magnets in it that would have even less effect than the solid flywheel that's already there? I should coco...

 

Anyway, I've had enough of this, so I'm off back to the dark ages and I'll leave you to it.

[DCB]

My Wrenn Ring Field motor powered 42XX would run at around 24rpm at the motor on 60:1 gears without a fywheel which was entirely pointless.  However it destroyed itself due to too much torque which is why am plotting ways to use a big flywheel while not destroying the final drive, crankpins or coupling rods when something goes badly wrong

 

Latest weird idea two flats on the driving axle and two rod magnets through the drive gear collar instead of the grub screw on a Romford or H/D gear wheel. maybe 4 in a Romford,  2mm dia X 4mm or maybe smaller.  Magnet should be attracted to axle and pull onto flats, maybe enough to drive?  Not sure if a band needed to keep the magnets in or not.   Just need to wait till 20th April when my magnets are supposed to arrive from China.  15 magnets for 99p inc postage and packing.

 

 

Edited March 5, 2018 by DavidCBroad

[TheGunslinger]

"Ok smartass how would you fit your fancy claptrap in my tiny loco?"
"Uh, maybe use a smaller motor for starters? It's a bit overkill for shunting speed."
"Motor size has nothing to do with how fast the locomotive moves! Oh btw I put a 90:1 gear ratio on this thing."

K then. If you wanted an echo chamber of agreeing opinions you could just put that in the thread title.

 

 

...because that motor cost just ninety nine New Pence ... and it does the job perfectly

 
Then why are you here? FYI those fancy motors cost $2.50AUD each.

[TheGunslinger]

My Wrenn Ring Field motor powered 42XX would run at around 24rpm at the motor on 60:1 gears without a fywheel which was entirely pointless.  However it destroyed itself due to too much torque which is why am plotting ways to use a big flywheel while not destroying the final drive, crankpins or coupling rods when something goes badly wrong

 

Latest weird idea two flats on the driving axle and two rod magnets through the drive gear collar instead of the grub screw on a Romford or H/D gear wheel. maybe 4 in a Romford,  2mm dia X 4mm or maybe smaller.  Magnet should be attracted to axle and pull onto flats, maybe enough to drive?  Not sure if a band needed to keep the magnets in or not.   Just need to wait till 20th April when my magnets are supposed to arrive from China.  15 magnets for 99p inc postage and packing.

 

You could just make this assembly your giant flywheel. If it tries to torque the driveline too hard it slips, simple. You might actually be better off with a grub screw (perhaps with a rubber cap on the end that engages the drive shaft) since that will give you finer control of precisely what point the flywheel slips.

[Regularity]

I bought some Mabuchi electric motors with 6 poles and rare earth magnets that are about the same size as your shunter's motor, and they are monstrously powerful.

Can I ask again, where did you get these, or can you at least tell us more about them, so we can search for ourselves?

[TheGunslinger]

Can I ask again, where did you get these, or can you at least tell us more about them, so we can search for ourselves?

Oh sorry, I didn't see your previous post!

 

Mabuchi SF-266SA, there are several people selling them on Ebay. Mabuchi make a huge variety of consumer grade electric motors, and most of them are quite good, even their basic RF-300 motors are quite good and a cheap and easy replacement for Lima pancake motors (as opposed to tearing CD drives apart as some members on here are wont to do, you can just buy the motors guys!).

 

And a handy guide for decoding their part numbers:

https://www.mabuchi-motor.com/product/knowledge/classification/designations.html

 

 

[Regularity]

Ta. At 18mmx18mmx30mm long, they would be substantially larger than the 1420 in the example photo...

[DCB]

 

 

Mabuchi SF-266SA, there are several people selling them on Ebay. Mabuchi make a huge variety of consumer grade electric motors, and most of them are quite good, even their basic RF-300 motors are quite good and a cheap and easy replacement for Lima pancake motors (as opposed to tearing CD drives apart as some members on here are wont to do, you can just buy the motors guys!).

 

Ah but you have to buy Mabuchi RF-300s whereas you get free CD drives when your computer dies...

[TheGunslinger]

Ta. At 18mmx18mmx30mm long, they would be substantially larger than the 1420 in the example photo...

Substantially longer, but they'd be overkill for such a small shunter. They'll happily power a 5600 class and provide prototypical pulling power. It was more an example of the kind of power density in a similar volume that I can personally vouch for. I can't remember the exact specifications for the Mashima motors, but if I remember correctly they used carbon brushes and ceramic type magnets, which means there's still room for improvement on Mr Mashima's exacting standards.

[AndyID]

It's interesting that Mabuchi is still in business. I think I still have one of their slot car motors that I bought 50 years ago

 

I still have a few Sagami motors. They are excellent but they went out of business when Mr Sagami died.

 

(Top Tip for Ruston: If you want to control the content, try using a blog instead.)

[TheGunslinger]

Ah but you have to buy Mabuchi RF-300s whereas you get free CD drives when your computer dies...

If I recall correctly when I did a forum dive on possible motor swaps, it was found all CD tray motors weren't created equal and quite a few were inferior even to the model loco products

[AndyID]

My Wrenn Ring Field motor powered 42XX would run at around 24rpm at the motor on 60:1 gears without a fywheel which was entirely pointless.  However it destroyed itself due to too much torque which is why am plotting ways to use a big flywheel while not destroying the final drive, crankpins or coupling rods when something goes badly wrong

 

Latest weird idea two flats on the driving axle and two rod magnets through the drive gear collar instead of the grub screw on a Romford or H/D gear wheel. maybe 4 in a Romford,  2mm dia X 4mm or maybe smaller.  Magnet should be attracted to axle and pull onto flats, maybe enough to drive?  Not sure if a band needed to keep the magnets in or not.   Just need to wait till 20th April when my magnets are supposed to arrive from China.  15 magnets for 99p inc postage and packing.

 

I'm not entirely sure what you are trying to do here but if you want to make a flywheel that can slip a bit under a lot of torque you could embed magnets in the flywheel. They would be attracted to a steel/iron disk attached to the motor. Put some sort of friction material (paper?) between the flywheel and the steel disk and you have a clutch. The magnets produce a force to keep the plates compressing the paper but they take up a lot less room than some sort of spring.

[BWsTrains]

No, i am not trying to wind anyone up. I fitted the flywheel because lots of other people fit flywheels to small 4mm scale shunting locos and I thought I'd give it a try. It doesn't appear to have made any difference and that's why I started this topic, which seems to have gone off course into some kind of wonderland.

As it happens, anything but IMO.

 

The best learning and advances come from healthy open discourse. I've learned a lot here on matters somewhat tangential (as I work with DCC) and suggest that being open to alternative ideas is rather good for innovation and change in our hobby. Let it flow, something really interesting ahead might surprise you!

[TheGunslinger]

As it happens, anything but IMO.

 

The best learning and advances come from healthy open discourse. I've learned a lot here on matters somewhat tangential (as I work with DCC) and suggest that being open to alternative ideas is rather good for innovation and change in our hobby. Let it flow, something really interesting ahead might surprise you!

I mean, we've gone from spitballing separate clutch and torque limiter ideas to a potential design for a flywheel with its own clutch, which could then be up-geared on even a small 2:1 gearbox for some pretty impressive amounts of momentum, without destroying your driveline and valve gear if something comes to a dead stop...

[Jol Wilkinson]

I have just seen this topic and found the various contributions most interesting. The OP refers to providing momentum to overcome brief loss of pickup.

 

Many of the responses refer to providing various mechanical solutions, including the simplest of adding a flywheel. For low speed locos, these have the drawback that their effectiveness, as already pointed out, is relative to the square of their rotational speed and the effective mass, so greater higher rpm gives far better results than at very low speeds.

 

Only two of my of kit built locos have flywheels, partly as it isn't always easy to fit suitably large ones in to small Edwardian locos but also because I haven't found the results very apparent. I have found that ensuring the "drive train" is free from binding, has minimal friction,etc. and having effective and continual pickup works effectively. All locos are sprung or compensated, with wiper pick ups on all driven wheels as well as carrying or tender wheels on some.

 

As these are run on a layout that only sees occasional outings, at exhibitions, we always take care that the track is clean.

 

The ideal answer is to have the power supply on board, e.g. battery powered with r/c control. DCC with "stay alive" devices is a good solution but only really disguises a problem with loco to track contact, track or wheel cleanliness, effective pickups etc. Using insulated crossings (frogs) builds in a hindrance. Getting the basics right to provide continual electrical feed to the motor should be the first priority.

[Ruston]

"Ok smartass how would you fit your fancy claptrap in my tiny loco?"

"Uh, maybe use a smaller motor for starters? It's a bit overkill for shunting speed."

"Motor size has nothing to do with how fast the locomotive moves! Oh btw I put a 90:1 gear ratio on this thing."

 

K then. If you wanted an echo chamber of agreeing opinions you could just put that in the thread title.

 

 

 

Then why are you here? FYI those fancy motors cost $2.50AUD each.

You're rather passive-aggressive, aren't you? Don't be so childish; If I wanted an "echo chamber of agreeing opinions" I wouldn't have started the topic.

 

The opinions I wanted were regarding the benefits of flywheels in small 4mm scale shunting locomotives, not opinions on my choice of motors, gearboxes, and how the kit is laid out, simply because they don't suit your pie-in-the-sky ideas when you're asked how you would make them work in a small space.

 

In my opinion, your flyheel would not make my locomotive run any better than it already does but that's just my opinion. Order yourself a kit  of the Yorkhire DE2,from Judith Edge, build it with your choice of motor and gearbox, and with your flywheel, then come back and prove me wrong. Until you have something to show then it's all just hot air, isn't it?.

[AndyID]

Evening all,

 

I would like to know people's opinions on fitting a flywheel to 4mm scale small shunting locomotives. The reason I ask is I am building a kit for someone and he wanted to know if I could fit a flywheel. I said that I could but, in my own opinion, it would be a waste of time and money.

 

My reasoning for this is that, even though the loco is large by industrial standards, the maxiumum diameter of flywheel would not be over 14mm and so couldn't store enough energy to be worthwhile after the resistance of the 6-coupled chassis and geartrain is considered, not to mention the weight of a train being hauled. But mainly because the loco will use an 80:1 gearbox and any energy that does overcome the resistances at a time of losing electrical pickup isn't going to last long anough to turn the wheels far enough to make any difference in crossing bad pickup spots, such as point frogs. Of course the time when you would most need to overcome bad pickup points etc. is when you are actually shunting, i.e. at low speed and at that time the flywheel is surely completely useless.

 

Or am I missing the point? Is there some other advantage to a flywheel on a shunting loco because a lot of people seem to fit them and I guess they must know something that I don't.

 

But you made it quite clear that you were more interested in having others confirm your already entrenched opinion that "it would be a waste of time and money".

 

If you really want an objective answer perhaps you could run the test that I suggested?

[AndyID]

The ideal answer is to have the power supply on board, e.g. battery powered with r/c control. DCC with "stay alive" devices is a good solution but only really disguises a problem with loco to track contact, track or wheel cleanliness, effective pickups etc. Using insulated crossings (frogs) builds in a hindrance. Getting the basics right to provide continual electrical feed to the motor should be the first priority.

 

I think that's the best solution. At the risk of antagonizing proponents of DCC, the nice thing about battery power and RC control is it allows a gradual transition from DC to RC. I sprung for some Deltang RC equipment recently with the idea of putting it in a shunter. The battery might have to live in a shunter's truck or something, but it will be interesting to see how it performs.

[Regularity]

I think that's the best solution. At the risk of antagonizing proponents of DCC, the nice thing about battery power and RC control is it allows a gradual transition from DC to RC. I sprung for some Deltang RC equipment recently with the idea of putting it in a shunter. The battery might have to live in a shunter's truck or something, but it will be interesting to see how it performs.

See post 30 in this thread. All articles, videos, presentations etc on installing DCC stress the need to make sure the loco runs smoothly on DC first.

 

You should be able to get some battery power into the shutter, depending on the engine. As an aside, the LNWR was fond of attaching a vacuum brake fitted van to increase the breaking power of engines that were weak in this respect, so not only a wagon to pack full of batteries, but a way to disguise the connection between the two!

Edited March 6, 2018 by Regularity

[TheGunslinger]

I think that's the best solution. At the risk of antagonizing proponents of DCC, the nice thing about battery power and RC control is it allows a gradual transition from DC to RC. I sprung for some Deltang RC equipment recently with the idea of putting it in a shunter. The battery might have to live in a shunter's truck or something, but it will be interesting to see how it performs.

I'll never forget Bachmann running a truly tiny 44T switcher with BlueRail and as many super capacitors they could fit into the body, with a short 1' segment of powered track it regularly passed over to recharge the caps. That there seems like the future of model railroading, at least until we can further increase the energy density of conventional batteries.

[Ruston]

But you made it quite clear that you were more interested in having others confirm your already entrenched opinion that "it would be a waste of time and money".

 

If you really want an objective answer perhaps you could run the test that I suggested?

No, you may be reading that into my question but you're obviously disregarding my last sentence:

 

Or am I missing the point? Is there some other advantage to a flywheel on a shunting loco because a lot of people seem to fit them and I guess they must know something that I don't.

 

 

Going back to the test, Chaz also suggested that back on the first page. I would try it but  I have only 4 locomotives that are fitted with flywheels Two are RTR and I can see that the flywheels definitely have an effect but one is a main line diesel type, where the flywheel is almost as wide as the bodywork and where the flywheel probably weighs as much as some of some of my small shunting types do entirely. I would assume that, being a main line type, the gearing is a lot higher than the type of loco we're discussing anyway so that's not really relevant.

 

Another is a 009 loco by Minitrains. It also has a flywheel that can be seen to have an effect but I have no idea what the gearing is on that. The other two are kitbuilt and have flywheels that are stuck on using Loctite, so I can't run a fitted/unfitted comparison without a great deal of trouble and the distinct possibility of wrecking the motors. It is these very low-geared locos where I can't see any effect in being able to over-run when the power is knocked off, hence the original question.

 

As far as the original question goes there have been people giving the pros and cons, someone saying that a flywheel definitely works, based on nothing more that the fact that he's spent money on it!, people saying that in such small locos a flywheel can't have enough mass etc.and every opinion inbetween.

 

You and Chaz are absolutely right about a test but I can't perform the test and until someone does such a test on low-geared (I would suggest the typical gear ratios offered by High Level - 60:1, 80:1, 90:1 and 108:1) small locomotives then everything else is just theory and opinion.

 

On the other hand, it has been said that fitting a flywheel  isn't necessarily about observable overrun anyway and is about smoothing out the running of the motor, and that is something they know that I didn't, as asked in my original question. Another question could be how we do we test for smoother running but I guess that opens another can of worms...

Edited March 7, 2018 by Ruston

[cctransuk]

No, you may be reading that into my question but you're obviously disregarding my last sentence:

 

 

Going back to the test, Chaz also suggested that back on the first page. I would try it but  I have only 4 locomotives that are fitted with flywheels Two are RTR and I can see that the flywheels definitely have an effect but one is a main line diesel type, where the flywheel is almost as wide as the bodywork and where the flywheel probably weighs as much as some of some of my small shunting types do entirely. I would assume that, being a main line type, the gearing is a lot higher than the type of loco we're discussing anyway so that's not really relevant.

 

Another is a 009 loco by Minitrains. It also has a flywheel that can be seen to have an effect but I have no idea what the gearing is on that. The other two are kitbuilt and have flywheels that are stuck on using Loctite, so I can't run a fitted/unfitted comparison without a great deal of trouble and the distinct possibility of wrecking the motors. It is these very low-geared locos where I can't see any effect in being able to over-run when the power is knocked off, hence the original question.

 

As far as the original question goes there have been people giving the pros and cons, someone saying that a flywheel definitely works, based on nothing more that the fact that he's spent money on it!, people saying that in such small locos a flywheel can't have enough mass etc.and every opinion inbetween.

 

You and Chaz are absolutely right about a test but I can't perform the test and until someone does such a test on low-geared (I would suggest the typical gear ratios offered by High Level - 60:1, 80:1, 90:1 and 108:1) small locomotives then everything else is just theory and opinion.

 

On the other hand, it has been said that fitting a flywheel  isn't necessarily about observable overrun anyway and is about smoothing out the running of the motor, and that is something they know that I didn't, as asked in my original question. Another question could be how we do we test for smoother running but I guess that opens another can of worms...

 

The bottom line is that, if you believe that flywheels improve the running of your locos, fit 'em where you can.

 

If you're sceptical; build two identical locos and fit only one of them with a flywheel - then you'll KNOW if they work for you.

 

It's what suits you that matters - not what anyone else believes.

 

Regards,

John Isherwood.

Edited March 7, 2018 by cctransuk