Large Scale Central

Quest for smoke

Modeling Motive Power
#1

New thread for my smoke unit experiments, since it’s not really about the Hudson any more. A couple of additional videos to share:

  1. Train-Li smoke unit running at 15 V on the heater, synchronized with a Phoenix P8. In this one, I’m manually increasing the pulse frequency to simulate acceleration.

  2. This video demonstrates the MOSFET regenerative fan braking. I’m alternating between braking and freewheeling. In video #1, above, the fan braking is active.

Triggering is being generated by a bench function generator at 10% duty cycle.

The circuit driving the fan looks basically like this:

#2

I’m a smoke fan so I like it!!!

Richard

#3

Yup. They are a darn sight better then anything that came with my Bachmann or LGB products.

#4

Eric

What other smoke units are you going to try ???

#5

None, if I can get this one to work satisfactorily. It is the least expensive by a good margin. It’s more about the control then about the smoke unit itself, I have learned.

#6

This one looks interesting

#7

Eric Reuter said:

None, if I can get this one to work satisfactorily. It is the least expensive by a good margin. It’s more about the control then about the smoke unit itself, I have learned.

I have a smoke unit from a model tank that is driven by a piston rather than a fan. It’s works quite well but is loud. Would be really cool if you could make working pistons and run small hoses to the smoke generator! Inspired by Dave Bodnar’s ECLSTS Seminar, I’ve got some vape parts coming for my own experiments.

#8

Aristo / Polk even has a patent on a piston type smoke unit, and of course there were pistons in their first Pacific. Also the USAT 0-6-0 has a piston pump in the smoke unit.

Experience has been that the mechanism is noisy and does not last long. In trains the piston is normally used to delineate the chuffs, although some of the bigger piston ones are just to make more smoke with more pressure/air movement.

Never seen anything that has more volume than the Harbor Models unit:

https://www.youtube.com/watch?v=ub9p_45Jr-Q

(forgot how to embed video again)

#9

I checked with Harbor Models a while back, and they do not recommend pulsing. They said it would void the warranty. I think the fan is probably too large anyway.

#10

Pay no attention to the man behind the curtain … (https://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-wink.gif)

#11

Sean I am thinking of getting that KM1 unit which eric is welcome to experiment with when I get it.

#12

I would like to see how he does !

#13

Eric, I think the key is not to just run the heater at constant voltage, but to modulate that too. I know HM is coming from, maybe you have seen another member post his experiments, used a second battery for the HM unit, but pulsed it.

That heating element cannot run full tilt if the fan is not moving enough air on average… it will indeed melt down, and I’ve seen the pictures.

The Zimo units have been set up with 3 different voltages for the heater if I remember right, besides pulsing the fan. This is probably the minimum level of sophistication you need to make a bulletproof setup.

Notice the MTH units are mainly metal (and also the USAT and TAS)… I think this keeps them from self destructing when supplied with a constant voltage to the heater.

I’ll be playing with the Zimo settings soon. For my QSI, I have run the heater voltage a bit lower than max so it will survive sitting still or going slow for a while. I’ve got some other ideas/tricks up my sleeve for the settings of both decoders.

Greg

#14

I think that’s probably true. If I don’t get satisfaction from the Super Chuffer (which only modulates the fan), I will likely just move to a DCC decoder and AirWire Convrtr instead of the G3.

#15

Tyco had the puffing smoke on their Chattanooga Choo Choo. It used a lever that was pushed by a cam on one of the axles, and the lever moved a piston. My cousin had one, and it never puffed as good as the one in the TV commercial.

#16

Greg, a zimo decoder uses CV 137, 138, 139 for the heater control, but you need to make sure CV 50 is 0 for no voltage reduction, or set CV 114 to ignore voltage reduction on the function key used to activate the Zimo output or you get strange voltage output to the heater. Same goes for programming servos.

#17

Eric Reuter said:

I think that’s probably true. If I don’t get satisfaction from the Super Chuffer (which only modulates the fan), I will likely just move to a DCC decoder and AirWire Convrtr instead of the G3.

I just removed a G3 from a Shay and installed a WOW501. Noticed it has two connections for smoke. One for the smoke unit and the other for the fan. It has a CAM input also but do not know if that can be used with the fan.

Do not have a smoke unit to try it.

The sound is awesome.

#18

I’m working with one of my engineers to make a small, inexpensive controller.

First thing it will do is braking like Eric’s idea.

The next thing is to turn the heater power off if you have not “chuffed” in a certain amount of time.

Doing this should let you relatively safely run the heater at pretty full voltage and not melt down if you stop, that’s one of the dangers.

If you have this gadget, then you can basically make puffing smoke safely with any pulse input, reed switch or output from a decoder.

The next idea is to modulate it a bit, and have an idle setting, etc. After that, perhaps a diesel notcher.

Trying to do this simply and cheaply, but I do want it for my QSI units, which do not control the heater voltage.

Greg

#19

that sounds great Greg keep us informed of your progress I’d be interested in a handful for my QSI equipped stuff

#20

I’ll bet you are one of the first beta testers… (https://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-laughing.gif)

Greg