Skip to main content

Replies sorted oldest to newest

I have done at least three engines, where I added a flywheel. I bought some plastic rod about 1" in diameter. I sliced it and drilled out the center. After carefully adding it to the motor shaft, I simply ran the motor and filed the plastic to get it in balance. I don't have a lathe. Support the opposite end of the shaft while your driving the flywheel on.

After it filed smooth on the surface and both sides, I add the tach tape.

Last edited by Engineer-Joe

GRJ, I messed up the flywheel on my Williams Challenger. I drilled it out for a larger motor shaft that didn't work out. I put it back on the original motor with some heat shrink making up the difference. It's obviously not right. I filed it trying to get it back in balance. I added tach stripes to purposely keep it slow.

The flywheel has a U-joint attached directly with a square shaft protruding out of that. I wonder if any Lionel flywheel could replace it?

I'll have to get the exact measurements to check. I've now had this engine apart many times. The gearing is just too low. I shelfed this engine until I can figure out a way to change the gearing so that it's not having to work so hard to get to 50MPH or higher. Right now with the flywheel issue and the gearing, I have a glorified yard switching Challenger working hard at 20 MPH!

As pointed out in the other thread, you do not need a "thick" or heavy flywheel per se.  It could be a thin plastic disc with the black/white strips printed on the face of the disc (rather than on the edge).  From what I can tell, this is a $1400 MSRP engine so some DIY investment is warranted.

I hijacked what apparently is YOUR photo so as not to violate any rights. So we're on the same page, is this what we're talking about?

yvkLze2.thumb.jpg.6ec6bd63224a5e96d1a50141d883d135

And did you manually rotate the motor and count the number of rotations to get 1 revolution of the driver wheel (i.e., the gear-ratio)?  Have you found a downloadable MTH soundset for your engine...and do you know ITS gear ratio?  Is it important to be able to configure the PS electronics to generate scale-speed and to set the audio to 4-chuffs (or whatever this engine is) per revolution?

----

Here's an idea that may apply if for whatever reason you can't pull the gear from the motor shaft to slide on a "flywheel".

piko motor types

Using a motor drawing from a previous post, let's say you want to install a thin disc but can't pull the gear off the shaft.  I once had a similar situation wanting to put a tach sensor disc on the wheel axle of an O-gauge truck.  I did not have a wheel puller tool so ended up splitting the disc in half and gluing it back on the shaft.  In this case the disc had holes around the edge.  So this was using so-called "transmissive" IR vs. "reflective" IR as done with MTH striped flywheels.  The purpose of the flywheel is simply to provide multiple "pulses" as the motor spins.  Whether it's done by bouncing the IR beam off white/black stripes or by shining thru holes is irrelevant.  It's the same 3-wires to the PS2/3 tach sensor.  Again, you need to do some homework up front if it's important to maintain scale-MPH and/or calibrate to exact number of chuff sounds per driver-wheel rotation.  That is you may NOT want 24/24 white/black stripes on your flywheel or disc.

Attachments

Images (2)
  • yvkLze2.thumb.jpg.6ec6bd63224a5e96d1a50141d883d135
  • piko motor types
Last edited by stan2004
@stan2004 posted:

As pointed out in the other thread, you do not need a "thick" or heavy flywheel per se.  It could be a thin plastic disc with the black/white strips printed on the face of the disc (rather than on the edge).  From what I can tell, this is a $1400 MSRP engine so some DIY investment is warranted.

I hijacked what apparently is YOUR photo so as not to violate any rights. So we're on the same page, is this what we're talking about?

yvkLze2.thumb.jpg.6ec6bd63224a5e96d1a50141d883d135

And did you manually rotate the motor and count the number of rotations to get 1 revolution of the driver wheel (i.e., the gear-ratio)?  Have you found a downloadable MTH soundset for your engine...and do you know ITS gear ratio?  Is it important to be able to configure the PS electronics to generate scale-speed and to set the audio to 4-chuffs (or whatever this engine is) per revolution?

----

Here's an idea that may apply if for whatever reason you can't pull the gear from the motor shaft to slide on a "flywheel".

piko motor types

Using a motor drawing from a previous post, let's say you want to install a thin disc but can pull the gear.  I once had a similar situation wanting to put a tach sensor disc on the wheel axle of an O-gauge truck.  I did not have a wheel puller tool so ended up splitting the disc in half and gluing it back on the shaft.  In this case the disc had holes around the edge.  So this was using so-called "transmissive" IR vs. "reflective" IR as done with MTH striped flywheels.  The purpose of the flywheel is simply to provide multiple "pulses" as the motor spins.  Whether it's done by bouncing the IR beam off white/black stripes or by shining thru holes is irrelevant.  It's the same 3-wires to the PS2/3 tach sensor.  Again, you need to do some homework up front if it's important to maintain scale-MPH and/or calibrate to exact number of chuff sounds per driver-wheel rotation.  That is you may NOT want 24/24 white/black stripes on your flywheel or disc.

Its not my photo, its from a german train forum that another user on another forum found for me. This is the first part of my research, I know this will not be an easy stock type job and will take custom parts and planning  I have not purchased the engine yet due to if it cannot work with DCS install then I most likely will not purchase it.

The gentlemen on the german forum also did a somewhat similar modification but for magnet synced sound  

If putting the flywheel on the front truck of the engine instead of in the motor block, then it would be spinning much faster than the drivers.

If the flywheel is not 24/24 how do you adjust the software for that? Is there a minimum number of black and white sections?

Attachments

Images (2)
  • 0kOMlug
  • T4yoUld

You change the number of stripes on the flywheel to adjust the speed calibration.  The "standard" is 24 stripes, but you can run with far fewer if you have a lower gear ratio.  You can also run with fewer stripes for a higher gear ratio.  There probably is some finite limit to the maximum number of stripes, but I have never hit it.

FWIW, the DCS sensor is almost always on the motor flywheel, the exception that I've seen is a couple of STD gauge locomotives where they had it on it's own geared shaft.

T4yoUld

So that gentleman's approach appears to embed 4 cylindrical magnets around the edge of a plastic "O-ring".  This O-ring was cut in half and then fastened to the axle of the driver wheel.  Then he fabricated and mounted a small circuit board with a magnetic sensor (3-wires) which triggers every time a magnet passes by.  So that would generate 4 triggers per revolution of the driver wheel...and of course this matches your description of sound-triggering since presumably you want 4 "chuffs" per revolution (of the driver wheel).

The MTH PS electronics expects the tach pulses at a much faster rate.  The gear ratio of the motor RPM to the driver wheel RPM varies between engines.  It might be, say, 18-to-1.  It would be useful to inquire from that forum if he can manually turn the motor shaft and report the ratio.  Anyway, if there are 24 stripes on the MTH flywheel, then with a gear-ratio of 18, the tach sensor receives 24 x 18 = 432 triggers per revolution of the driver wheel! That's over 100 times; so it's the PS electronics which processes these triggers and in this case would initiate the chuff sound every 108 triggers (i.e., 432/4).

@yardtrain posted:


...

If the flywheel is not 24/24 how do you adjust the software for that? Is there a minimum number of black and white sections?

As GRJ notes, the standard flywheel is 24/24 stripes.  But the gear ratios of different engines varies.  The so-called soundset which you download into the engine memory contains the magic numbers on a per-engine basis.  The gear-ratio is in this soundset and tells the processor how many pulses of the tach correspond to one rev of the driver wheel.  This is how the processor knows when to generate a "chuff" sound.  There is an adjustment within DCS where you modify a command-control engine to generate a different number of chuff sounds per revolution.  This might assist in some situations and can be explored.

Separately, the processor uses the incoming tach pulses to control speed.  Previously, I asked how important it is for the engine to run at scale speed corresponding to the commanded speed.  The soundset also contains magic numbers that tell the processor the gauge of the engine so it knows how many tach pulses corresponds to a scale mile.  I believe the MTH engines all adhere to their so-called OneGauge which is 32:1.  As I recall, G gauge trains can vary widely I think down to maybe 20:1 or so.  So if you want commanded scale speed in sMPH to be scale speed, then you'll need to calibrate probably by changing the number of stripes.  This would be particularly important if you run MU consists since presumably you'd want multiple engines commanded to the same sMPH speed to indeed run at the same speed.  Otherwise, close-enough might be good enough if your consists always have only a single prime mover so to speak.

I know there have been efforts to decode the magic numbers in the MTH soundsets for the purposes of modifying them.  I don't know where that stands but seems there have been some OGR threads on this topic.

I can drone on - peeling additional layers of the onion depending on whether you are crying yet!

Last edited by stan2004

The closet to this engine that MTH has ever made is the BR44 in O scale. I am not sure what math I need to do from the audio file that someone mentioned. Is there a way to calculate the gear ratio of the sound file?

I assume you mean that you ca change the cuff rate in the DCS remote, I am not sure what the constraints of this is without checking again.

I am not crying yet, only determined to make this project happen.

Obviously because of how much faster the flywheel spins than the normal wheels means a lot needs to be adjusted from a typical DCS install. Also because I have not purchased this and there do not seem to be many inside photos of the gearboxes I cannot tell how much room there really is inside the gearboxes.

Last edited by yardtrain

There is always the synthesized method of generating the required pulses.  This would likely only work if the absolute exact scale MPH wasn't important, only the general operation of the speed control.

My idea is to pick a place on the drivetrain to generate pulses based on the speed, something like Stan's slotted wheel.

Using an inexpensive microprocessor board, you'd time the spacing of the pulses from the slotted wheel.  With that timing, you'd divide by your chosen ratio to simulate the DCS tach and output the tach pulses at the higher rate needed to simulate the motor tach.  At each sample, you recompute the wheel pulse timing and adjust the frequency of the output tach pulses.  With enough triggers per/rev from the slotted wheel, I think this might be a workable solution.  The only fly in the ointment I can see with this approach is it's possible there'd have to be special handling for the initial start of motion and when stopping.

Attachments

Images (1)
  • mceclip0

Add Reply

Post
The DCS Forum is sponsored by
OGR Publishing, Inc., 1310 Eastside Centre Ct, Suite 6, Mountain Home, AR 72653
330-757-3020

www.ogaugerr.com
×
×
×
×
Link copied to your clipboard.
×
×