Are flywheels worth it?

[tbdanny]

Hi all,

I'm in the process of re-motoring a West Side C-25.  I would like to fit a flywheel into this model, but doing so may interfere with the motor wires without serious re-engineering (by which I mean cutting another hole in the loco shell).  It's a NWSL 12mm flywheel with a 1.5mm shaft, and I want to know if it would be worth making additional modifications in order to fit this in?  The decoder I'm using is a TSU-750, if that's relevant.

Thanks in advance,

tbdanny

[Forty Niner]

I seriously doubt that a flywheel is going to improve much on a Sagami can motor, not only that 99.9% of these flywheels aren't balanced anyhow and that just causes undue stress on the motor bearings. Using DCC you'll be operating that motor under "pulse" power anyhow so for my money it would be a waste of time and effort. Also it really won't be big enough to have much of an effect..............save yourself the trouble and fine tune the mechanism, you're already 99% of the way there now with that NWSL motor.

Mark

[hminky]

Having run the same mechanism with and without flywheels, DCC and good electrical pickup do more for performance. The only thing flywheels do is add more weight.

Heresy, I know, but it is true. Manufacturers add them because they are an urban myth. I am sure there will be a gazillion posts to follow with no evidence how great they are.

Harold

[dehusman]

If you are using a BEMF decoder the decoder will fight the flywheel.

[Anonymous]

Flywheels can´t achieve, what a good motor and a gearbox can do for the performance of a loco.

Btw. Stonercreek RR is offereing a re-motoring kit for your loco. You´ll find it here

[Lee 1234]

A flywheel is mechanical momentum for the drive when it cannot pick up power from the track.  I'd try it without the flywheel.   If you have bad power pick up you will find out in a hurry.

[jeffrey-wimberly]

dehusman

If you are using a BEMF decoder the decoder will fight the flywheel.

Really? Funny I haven't noticed that with my two SDP40F's. One has an Athearn drive and the other has a Proto 2000 drive. They both have Digitrax decoders with BEMF enabled. Same goes with my two Atlas GP40's and my two Athearn GP38-2's. All the locos listed above have dual flywheels.

[DigitalGriffin]

Lee 1234

A flywheel is mechanical momentum for the drive when it cannot pick up power from the track.  I'd try it without the flywheel.   If you have bad power pick up you will find out in a hurry.

+1.  A flywheel adds something called Initial mass to the shaft.  It will resist slowing down or speeding up.  The advantage of which is if you have inconsistant electrical pickup, or a bad mechanism the flywheel will help compensate for that as it's rotational inertia carries it foward.  (More so for the former than the later)

The other benefit is it adds weight to your loco.  And that rarely hurts things.  :-)

I didn't know the stall current on canon motors was < .75 amps.  That's pretty good.

[DigitalGriffin]

jeffrey-wimberly

dehusman:

If you are using a BEMF decoder the decoder will fight the flywheel.

 

Really? Funny I haven't noticed that with my two SDP40F's. One has an Athearn drive and the other has a Proto 2000 drive. They both have Digitrax decoders with BEMF enabled. Same goes with my two Atlas GP40's and my two Athearn GP38-2's. All the locos listed above have dual flywheels.

Both true and false.  The BEMF can compensate for the additional load put on by the flywheels.  There's an adjustable "kick" amount parameter on most BEMF motors.  With flywheels it's a lil higher. 

[BRAKIE]

Got flywheels?

Yup..I won't have a locomotive that isn't flywheel equipped.

[hminky]

BRAKIE

Got flywheels?

Yup..I won't have a locomotive that isn't flywheel equipped.

That is why manufacturers keep putting them on locomotives. It is an urban myth. I have removed flywheels from locomotives out of necessity:

I had to remove the flywheel in an Athearn/Roundhouse 4-4-0 to put on an IHC 4-4-0 boiler. The locomotive ran the same without the flywheel. It ran even better when the suspect MRC dcc sound unit died and was replaced with a Soundtraxx Tsunami.

I have many locomotives without flywheels and they run as well as those with them.

All flywheels do is add weight.

Harold

[dstarr]

It's a judgment call.  Flywheels store momentum, enough to allow the locomotive to coast over a small dead spot in the trackwork.  If your trackwork is first class, and you clean your track, and you clean your locomotive wheels periodically, then a locomotive without flywheels works just fine.  A number of my locomotives lack flywheels and they run quite satisfactorily.   My trackwork and track maintainance standards are better than some, but not beyond the reach of any model railroad. 

   On the other hand, I like flywheels, and for a kit bashed locomotive I would certainly attempt to equip it with a flywheel.  You say motor wires are the difficulty?  Not sure if I understand, there is always room in the top of a diesel hood for wires.  Have you considered adding wire guides made from brass tubing and glued to the inside of the shell to keep the wires up out of the works?

 

[BRAKIE]

hminky

BRAKIE:

Got flywheels?

Yup..I won't have a locomotive that isn't flywheel equipped.

 

That is why manufacturers keep putting them on locomotives. It is an urban myth. I have removed flywheels from locomotives out of necessity:

I had to remove the flywheel in an Athearn/Roundhouse 4-4-0 to put on an IHC 4-4-0 boiler. The locomotive ran the same without the flywheel. It ran even better when the suspect MRC dcc sound unit died and was replaced with a Soundtraxx Tsunami.

I have many locomotives without flywheels and they run as well as those with them.

All flywheels do is add weight.

Harold

Harold,I recall how crappy none flywheel locomotives ran before flywheels and how smooth they ran after flywheels that's why I won't have a locomotive without a flywheel and that's no myth.

Clean track,dirty track,dead spot,rubber frog it doesn't really matter since the flywheel smooths everything out with momentum.

[hminky]

Locomotives just got better. It had nothing to do with flywheels. It is a myth.

Unless he adds more pickup his C-25 will run poorly. You need pickup on as many wheels as possible:

Visit:

http://www.pacificcoastairlinerr.com/1879/bachmann_4-4-0/wipers/

If adding extra pickups to a crap toyish HO Bachmann 1870's 4-4-0 makes it run like a dream, it is all about electrical pickup in the engine not flywheels.

Harold

[BRAKIE]

Harold,Sorry but,I will stand pat on flywheels and won't own a locomotive that isn't flywheel equipped.

From my experiences it was flywheels that smooth out locomotive's performance and that's no myth.

[Darth Santa Fe]

If the mechanism of any locomotive runs perfectly smooth and free, and has good electrical pickup, flywheels aren't necessary. When needed, I think they're more beneficial to DC users than DCC users. And they have to be large enough to have any effect, because a too small flywheel won't provide any noticable momentum.

I personally like using flywheels in my stuff.

[TomDiehl]

hminky

Having run the same mechanism with and without flywheels, DCC and good electrical pickup do more for performance. The only thing flywheels do is add more weight.

Heresy, I know, but it is true. Manufacturers add them because they are an urban myth. I am sure there will be a gazillion posts to follow with no evidence how great they are.

Harold

Urban myth? Hardly. A feature whose time has past, maybe. Perfect electrical pickup may remove the need for flywheels, but nothing is perfect and remains that way, according to Murphy.

[selector]

I posted in a similar discussion about a year ago now that I didn't really subscribe to the idea of flywheels, at least not in HO models.  I don't think they offer enough compensation for their engineering and installation costs. 

If they were twice as large as they usually are and spun up to 2000 rpm, sure, that would be useful to get engines over dirty bits or gaps and dead frogs in the #18 range.  But I feel they are too small, spun too slowly, and really rob the engine of what would be better weight if it its volume were filled with the equivalent volume in either tungsten or lead.

I believe that I have quite a few locos with flywheels, maybe all of them (?), and none are DC...they all have either a Tsunami, QSI variants, and LokSound.  I don't believe the tiny flywheels amount to a pinch of coon poo in the mix, and that is why my decoders either don't pay them any mind or they are as innocuous as I claim they are.

I must admit that I am not a mechanical engineer, and have undertaken no method to determine all this for myself.  All I can state is when my DCC/Sound engines encounter an electrical fault, they don't coast for four or five slowing inches as a properly weighted and spun-up flywheel would make it do.  Instead, they stop dead, quick.  So, I guess I'm saying I'm not seeing their value.

Crandell

[Hamltnblue]

The benefits of running with a flywheel are definitely not a myth. Also i'm sure if it was, virtually every designer wouldn't be adding them. On modern HO looc's the flywheel or combination of 2 is often heavier than the actual motor.  This prevents jerky movement when both accelerating and decelerating.  A quick google of electric motors and flywheel will give some insight .

[rrinker]

 Unless you have a motor with infinite poles, a flywheel DOES help. The better the motor, the less the help - turn a 3 pole motor by hand and you can clearly fel the cogging action, a 5 pole motor, not as much, and a 7 pole motor, barely. But it IS there. This is the same principle as the flywheel in your car motor, without the flywheel to smooth out the impulses from each piston it would be a very rough ride indeed.

 But high mass flywheels, or the whole idea of adding extra flywheels, is fairly pointless with DCC, or even a DC system that is more advanced than a rheostat and a direction switch. Feedback motor control works better with less inertia, and coasting action and slow acceleration can be simulated with electronic effects over a far greater range than you coudl ever do with a flywheel.

                                 --Randy

 

[jeffrey-wimberly]

I have a Proto 2000 PA1 with flywheels that can easily COAST three feet. Now that's quite some benefit.

[doctorwayne]

I don't see the point of flywheels in our models - their relatively tiny mass is a waste of space, even as weight. 

I bought an early Proto 0-8-0 switcher and even though it ran very smoothly with no current pick-up on the tender, I was very disappointed in its pulling power.  I was going to get rid of it, as it could handle only three cars on the in-town grade where it was expected to work.  In hope of finding some available room within the boiler in which to add some extra weight, I dis-assembled it, finding a puny flywheel and an over-sized circuit board for the headlight.  After removing both and replacing them with cast lead blocks, the loco's pulling abilities more than doubled.  I decided to keep the loco, and modified it to more closely resemble a favourite prototype.  I was able to add even more weight, too, making it an even more useful loco. 

I have no problems, even without tender pick-up, of stalling or stuttering, and I don't clean track or wheels.  I'm also running DC power.

A flywheel in a carbody-style loco may be large enough to offer some benefits - the old Model Power E-units were a good example of this, especially once the noise was removed from the drive train.  However, for folks using DCC, the useful flywheel is in the electronics - that little spinning nickel is just for show.

 

Wayne

[Alantrains]

If there was a model train Adam and Jamie, we could ask them to bust or verify this "Myth".

I suspect that flywheels improved older motor performance considerably. Once we got 5 & 7pole skew wound armatures, I suspect the flywheel makes only minor improvement. I prefer flywheel equipped locos as my track isn't perfect.

Hey Jeff W,

3 feet is a good coast, I remember some old Hornby engines that had a single thread worm gear and a large diameter motor that would coast a foot or two from full speed.

Remember that if your controller puts any sort of short across the track in the off position, it will act as a dynamic brake. ie the motor becomes a generator any you loose some of the bebefits of flywheels.

Cheers

Alan J

[jeffrey-wimberly]

Alantrains

Hey Jeff W,

3 feet is a good coast, I remember some old Hornby engines that had a single thread worm gear and a large diameter motor that would coast a foot or two from full speed.

If I run it up to full speed and cut the power it will coast almost nine feet. And it's very, very heavy.

[Alantrains]

That/s impressive!

[Alantrains]

You might need working brakes on it!

[Texas Zepher]

jeffrey-wimberly

 

dehusman:

 

If you are using a BEMF decoder the decoder will fight the flywheel.

 

Really? Funny I haven't noticed that with my two SDP40F's.

Yes, an electrical reality, but  I don't know how you would "notice" it.  IT would be eddies of electrical current getting shoved into the back end of the decoder.  Remember the motor becomes a generator when "coasting" under fly wheel power.  With DC it is a non-issue because the current has no where to go.

In the early days of command control our club was having a very high failure rate of decoders.   We traced it to the power getting generated by flywheel generators.  Removed the fly wheels and the decoders started lasting a lot longer (longer as in instead of a few months some are still working over a decade later).

For DC a good set of flywheels on a locomotive is a nearly essential thing.
For command control locomotive a really good "life saver" capacitor is the essential thing (like the Lenz gold decoders) fly wheels not necessary and technically not desirable.

I have bunches of DCC locomotives with flywheels, but that is only because I hate rebuilding the motor to gear linkage and just I don't have the time to do it.   For a DC only locomotive I can't imagine running without flywheels.   I don't see any myths or mysteries to solve.

[doctorwayne]

Texas Zepher

 

.....For DC a good set of flywheels on a locomotive is a nearly essential thing.
For command control locomotive a really good "life saver" capacitor is the essential thing (like the Lenz gold decoders) fly wheels not necessary and technically not desirable.

I have bunches of DCC locomotives with flywheels, but that is only because I hate rebuilding the motor to gear linkage and just I don't have the time to do it.   For a DC only locomotive I can't imagine running without flywheels.   I don't see any myths or mysteries to solve.

 

Care to elaborate on the DC aspect of this?   I run DC and, while I've had lots of flywheel equipped locos, the only one that seemed to benefit was the Model Power loco with the large diameter flywheels. Even then, the only time it was noticeable was when the power was cut.  Hood-type locos or steamers don't have room for much of a flywheel, at least diameter-wise, and I remove them in favour of adding additional weight.  Any decent DC throttle can simulate flywheel-like performance and I've never seen any need to coast over dirt or dead spots on the track - that's a pick-up issue that's readily addressed if it crops up.

 

Wayne

[Forty Niner]

I think the point is being missed here with all of the "posturing" about whether flywheels are useful or not. The original poster explained he has an HOn3 C-25 loco he's working with. Now this thing isn't much larger than an N Scale boiler so the flywheel will have to be very small to fit in the loco, we aren't talking about a Hobbytown E unit here. So how much of an affect would it really have, about as much as the size of the flywheel or almost none.

Secondly, and everyone seems to want to choose to ignore the obvious here, these things aren't balanced, again, very hard on motor bushings.

Third, flywheels were introduced back before todays high torque "can" motors such as the Sagami's, they worked great on the cheap motors they were designed for, open frame 3 or 5 pole motors. They worked well removing the "cogging" action of these motors, although again they still are not balanced.

With todays super smooth new motors and good gearboxes flywheels become a mute point except to make a crappy running engine "appear" to run smoothly. It still come down to having a good motor, a good gear box, and the entire mechanism being tuned for smooth operation.

All he really needs in that C-25 now is as much "weight" in that thing as he can get into it possibly including the tender to insure good power and good contact. He has the biggest part of the equation soved with the NWSL motor.

Again, if you have a crappy running engine a flywheel will help considerably, but that's more of a cover up than a solution. Sort of like the old joke of putting lipstick on a pig, but you still have a pig, that doesn't change.

Mark

[selector]

I don't understand your use of the word 'posturing', Mark.

In any event, you and others who talk about the problems with balancing and such reinforces my conviction that they don't add much to a locomotive's smoothness. If, as you say, they are badly balanced (and I wouldn't know), then spinning them up to a truly contributory rate would tear the drive-trains apart. That doesn't seem to be a big problem in the industry, certainly not in any locomotive that I run, some now onto 6 years. If they don't tear themselves apart, it means they turn relatively slowly. If they turn relatively slowly, they provide minimal assistance to a stalling engine. As Doc Wayne has agreed, the volume is better utilized with added weight. That added weight would contribute as much momentum to a stalling locomotive as a considerably lighter weight rotating four hundred times a minute.

Crandell