Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Anyway to Have Bachmann 2-10-0 Chuff in-Sync?

846 views
9 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    May, 2014
  • From: Berwyn, PA
  • 433 posts
Anyway to Have Bachmann 2-10-0 Chuff in-Sync?
Posted by Trainman440 on Sunday, September 16, 2018 10:59 PM

Hi, I have a Bachman 2-10-0, it has small diameter wheels. Most decoder's chuffs go out of sync as the speed increase/decreases. 

For ex, if you program the chuffs to be in-sync at speed step 10, it will be way out of sync by speedstep 30. Its because the speed curve is so drastically lower than the average engine, and the decoders arnt programmed for that.

Besides adding a chuff cam, is there anyway to help compensate for this?

My options are TCS wowsound, ESU Loksound, or Tsunami2. Does one of these have a feature that can adjust for this?

Thanks, 

Charles

---------------------------------------------------------------------------------------------------------------

Charles L.

Modeling the Santa Fe & Pennsylvania in HO!

Youtube Channel: https://www.youtube.com/channel/UCLb3FRqukolAtnD1khrb6lQ

  • Member since
    February, 2002
  • From: Reading, PA
  • 25,088 posts
Posted by rrinker on Monday, September 17, 2018 7:17 AM

 It's physically impossible to have the chuffs actually in sync with the piston movements without some sort of sensor. All of those decoders have settings to keep the proper number of chuffs, and even adjust the strngth of the chuff based on load on the loco. Usually when a steam loco is nearing its top speed, the chuffs sort of merge together and unless you are using a strobe to see just where the rods are, I can't see how you've even know in what part of the piston stroke the chuff is being emitted.

                                             --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    May, 2014
  • From: Berwyn, PA
  • 433 posts
Posted by Trainman440 on Monday, September 17, 2018 9:18 AM

Yea, at speed, but problem is theres such a huge difference, that even at speed step 30, you notice a difference, and that's pretty major. 

And it messes with me ._.

Charles

---------------------------------------------------------------------------------------------------------------

Charles L.

Modeling the Santa Fe & Pennsylvania in HO!

Youtube Channel: https://www.youtube.com/channel/UCLb3FRqukolAtnD1khrb6lQ

  • Member since
    February, 2002
  • From: Mpls/St.Paul
  • 10,786 posts
Posted by wjstix on Monday, September 17, 2018 10:11 PM

If your speed curve actually curves, there's nothing you can do. The chuffs are connected the the power going through the decoder - the more power, the faster the chuffs. On a straight-line speed curve (no speed curve) it will work fine.

Stix
  • Member since
    February, 2005
  • From: Vancouver Island, BC
  • 21,497 posts
Posted by selector on Wednesday, September 19, 2018 9:21 AM

I have managed to get my chuff rates across five or six different decoder types to synch pretty well.  I don't synch mine at speed step 10 because each drive is different and the driver diameter is different; speed step 10 will mean different speeds from locomotive-to-locomotive.  Also, cold drives act sluggish and require more voltage, and thus more BEMF.  As they warm under load, the drives' characteristics change enough that settings for nice synchronization of chuff rate at a given low speed step will be off by about a quarter revolution after ten minutes of running.  It's a fact of life with our toys.

I would recommend running your locomotives for a while, even if having to grit your teeth and suspend disbelief.  Then, at about 20 scale mph for THAT locomotive, whatever throttle setting it takes, do the CV programming for synch of chuff.  Record the number inside the box of the locomotive, and then live with some out-of-synch chuffing when the engine is first used.

  • Member since
    February, 2002
  • From: Mpls/St.Paul
  • 10,786 posts
Posted by wjstix on Thursday, September 20, 2018 9:10 AM

I've noticed too that since it takes more power for an engine to pull a train than it does to just run by itself at a given speed - that is, it takes a bit more power for a train to pull a 10 car train at 20 scale MPH than it does for the engine running light to to 20 scale MPH. To compensate for that, I synch up the chuffs with about a half-train's worth of cars (based on the length of train I expect the engine will normally be hauling). That way, the chuffs may be slightly off running light, and slightly off with a train, but overall it's always pretty close to correct.

Stix
  • Member since
    January, 2005
  • 536 posts
Posted by hdtvnut on Tuesday, December 04, 2018 6:02 AM

You may not want cam, but when I want an HO steamer to have the correct sync so it will look good when starting/moving slowly, I inspect to see if there's room for mounting a subminature reed switch on top of the frame next to a driver, and if there's room on the inside of the driver for epoxying very small, thin disk magnets.  Usually four, but for a few engines like the UP 4-12-2, six, or eight for articulateds.  Your loco may not have room.  Tsunami2's won't work for this, because they don't have sync inputs any more - too bad.  

BLI uses a magnet in the flywheel and a reed switch, but this requires a pulse scaler in the decoder, the ratio of which depends on 4, 6, or 8 chuffs/rev and the gearbox ratio.  They shipped their beautiful 4-12-2 with incorrect chuff sync because their scaler couldn't match their gear ratio for 6 chuffs/rev, so I took out the Paragon2, did the reed switch thing and put in a WOW.  Looks and sounds great. 

Never liked Paragon2/3's much anyway.  They're easily identified by a purposely mis-timed chuff, alright by itself, but the same idiosyncrasy in every type loco?  And corny long whistles.  Who designs this stuff? 

 

  • Member since
    November, 2005
  • From: Phoenix, AZ
  • 512 posts
Posted by woodone on Tuesday, December 04, 2018 6:53 AM

With the Tsunami2 decoders there is no cam wire to be used- the decoder counts the segments on the motor so when you set the chuff rate it will remain in sync with the motor RPMs.

  • Member since
    February, 2002
  • From: Reading, PA
  • 25,088 posts
Posted by rrinker on Friday, December 07, 2018 7:01 AM

 As do others with BEMF - but that only means you get the right NUMBER of chuffs no matter what speed. I stand by saying that the only possibly way to actually have them synchronized correctly with the rood motion is via a cam or some sort of sensor - even the sensor on the motor side is a bit iffy, as you'd also have to engage the gears with the rods in the proper orientation vs that sensor on the motor shaft, whereas a cam or other sensor of that type is on the actual wheel and it physically synchronized to the rob position.

 If it bothers anyone that much - in smaller scales probbaly not so much, but maybe in larger scales. It works close enough for me if there is approximately the right number of chuffs - once you are going too fast to see the rods clearly, does it really matter? And the position of the chuff in the stoke - well, that depends on the cutoff setting so it's not as jarring to have the chuff come at the beginning of a stroke or the middle. It's when you can clearly count each wheel revolution and only get 3, or maybe get 5 chuffs when there should be 4 that it gets noticeable that something is off.

                                   --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    January, 2003
  • From: Dover, DE
  • 1,297 posts
Posted by hminky on Friday, December 07, 2018 9:22 AM

Really hard to tell if there is a sync problem at speed under normal conditions.

Install at:

http://www.pacificcoastairlinerr.com/1905/decapod_sound/

 

Harold

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Users Online

There are no community member online

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!