Large Scale Central

Bachmann large scale Mallet VIDEO, from the B'mann site

General Discussion
#61

Dave,
Bachmann seem to have had a directional shift in its anticipated consumer base. Prior the intervention of inexperienced modellors and Thomas fans, the Bachmann forum was a decent place to visit and B’mann manufactured decent equipment. Fast forward to current day and we have a manufacturer that seems to cater for the less experienced modellor who wants something ‘whizzbang’ out of the box and runs like a jackrabbit at top speed. Slow speed reliability is not a criteria these days for the modern consumer.

    I can see a new forum being launched where a certain person is the moderator and you guessed it,  you have to be approved to enrol plus not say anything nasty or untoward.  You will also have the right to delete others member's responses to your topics that you do not like.  This idea has been tried before and obviously works really well (?).
#62

This is quite amazing, but only moderately amusing, how much can be written without doing the most elementary calculation… Assuming the top speed of the K-27 to be 41mph the wheels need to turn 345rpm. With 1:14.5 gear ratio, the motor shaft needs to turn 5000rpm (5002.5 to be precise). This is quite realistic for many simple electric motors near their nominal voltage, but I do not know what is the actual value for the 9000 series Pittman motor employed on the Bachmann’s K-27. Could anyone please verify this and tell me what is the rpm value at 18V for this particular motor?? Answering this will instantly solve the entire debate (if we all agree that the real K-27 top speed is 41mph of course). Best wishes from Tokyo, Zubi

#63
Stan Ames said:
With small layouts prototype speeds often do not look very good but as the length of the run increases, operating like the prototype becomes very reasonable and looks quite good.
Stan, I'll let others with more technical knowledge than myself debate the points you've made regarding the gearing of the K. However, I must respectfully disagree with the comment about prototypically slow speeds on small layouts. Obviously this is a matter which is very much subject to personal preference. But IMHO small layouts are where slower speeds are needed most.

A train running at full bore around a small layout covers the route in the least amount of time, emphasizing the limitations of the layout. By going slower, at more prototypical speeds, the lap time is drawn out and layout seems at least a bit more substantial.

#64

6150 @ 19V
They can handle a 26% overvoltage.

What driver diameter you using?

#65
Curmudgeon said:
6150 @ 19V They can handle a 26% overvoltage.

What driver diameter you using?


Curmee, thanks!!
Drivers on K-27s are 40". I think there were no exceptions or driver replacement in service, is that correct? (here is one reference: http://www.ghostdepot.com/rg/rolling%20stock/locomotive/narrow_gauge.htm K-28 had 44" and they were nicknamed sports models for their ‘excessive’ speeds;-) which were possibly still below 35mph… but must have been higher than normal operating speeds on the K-27 otherwise the nickname for K-28s would never have been coined!)
Well, 6150rpm is 23% higher than the required 5000rpm This means that the K-27 should reach speeds over 40mph at 15.4Volt if we assume that the motor rpm is a linear function of voltage (a pretty realistic assumption)
In order to restrain the motor and limit the speed with this gearing, one has to restrain the voltage electronically, which would not be required if the gearing had higher ratio, say 1:29.
Just for the sake of calculation, this example 1:29 ratio would provide the K-27 with the ability to ride at 25.12mph at 19volt which seems a quite realistic speed considering the voltage range commonly used in large scales is up to 24V. Assuming that we can use the 9000 Pittman motor with voltage up to 24V, the maximum speed at 24V (again using the linearity assumption) would be 31.85mph which is probably consistent with what prototype was able to achieve in normal operating conditions (for one example, Mr Horovitz suggests the top speeds for the K-27 in the range 25-30mph http://sidestreetbannerworks.com/railways/K-27/K-27.html )
All the above is what the elementary calculations tell (making use of Curmee’s 9000 motor spec.), anyone can draw their conclusions as they please. Best wishes from Tokyo, Zubi

#66

ZS,

The rpm is 6151 @ 19.1 volts no load speed. Peak torque stall 41.3 inch lbs of torque (a horse).
The full range of motor voltages is 12.0, 19.1, 24.0, and 30.3, your choice.

To my reckoning this is the strongest motor in the 9000 series class. It is for all intents and purposes the motor spec’d by Bachmann to Pittman to supply. These numbers are drawn from an option sheet in the Pittman catalog.
They are the same specs I supplied to Dave Goodson for Bachmann. They are the same specs given from the Pittman motor number. This motor I recommended. It is the best motor for largescale models of the No1. gauge(G1MRA), and of large size.

This is the motor in the Bachmann K-27. The Mallet may be using an 8000 series motor, as stanley suggests, but I would suspect of the same specs I use in requesting motors from Pittman (the same motor I have been using for 16 years) If Bachmann asked, Pittman would supply.

Barry - BBT

#67

Barry, thanks!! Strictly speaking we should be taking into evaluation rpm under nominal load. This is a very nonlinear characteristic which strongly depends on the type of the motor so I cannot guess anything here, except that if the motor is really strong, the normal operating speed will likely remain fairly close to no load rpm (and the current will increase linearly with load - in the case of a weak motor, the rpm will sink and the current take will surge) Best, Zubi

#68

Zubi, thanks for the expenditure of one of your torpedoes into the SS Ames.

Down by the stern.

#69

ZS,

My 8000 series Pittman motor has a no load speed of 10,158 rpm. I am certain none of my installed motors ever attain that rpm. geared out the axle rpm would be 339.73 rpm.

A very reliable motor, the only motor failures I have had concern short circuits, which were pretty severe. Most short circuits burn up the pick up wires, which then isolate the motor. Six motors in 16 years. The population numbers are proprietary.

Barry - BBT

#70

Barry, this corresponds with 3% rpm drop due to gear, axle(s), (rods?, etc.) friction, which is pretty minimal and to be expected. Still, your 8000 motor rpm is quite high and with 40" drivers your locomotive will travel 40.37mph at this rpm. Depending on your prototype, you may want to restrict the voltage range using some electronics. Best wishes, Zubi

#71

ZS,

As it turns out there is a self limiting action which precludes running at max voltage/rpm: running off of the next curve…then you have to pick up your loco, tender and any cars you were pulling. Look sheepish and steal back to a point where you can hopefully recover your dignity and composure and run again, a bit more sensibly.

Barry - BBT

#72

Barry, I see!! That is an external live neural net controller, sometimes referred to as operator’s brain… As long as it is switched on, things should work without any problems! Best, Zubi

#73

Geeeeeeeeeeeeeeeeeez! I don’t know about most of you but my head is hurting, from all this techno babble, and I thought you just took em out of the box and ran em!!! Whood a Thunk It??? LOL The Regalhttp://

(www.lscdata.com/users/blueregal/_forumfiles/vulturemainpic.jpg)

#74

The interesting part none of you caught was the foliage.
It is now December.
The railroad is in Keenedysylvania.
Look at the foliage and tell me when you think the video was shot.

I see all sorts of things in that video that are of interest to me.

But, that trackwork.
See the neat little ski-jump coming out of the tunnel onto the trestle?

And, talk about rough turnouts.

Some of those curves, boy, the cars get to wobbling a bit.

I see they dragged the caboose prototype out for the shoot.

I did like the way they high lighted the head lights.

After all these years of wimpy yellow or BRIGHT BLUE, I wonder if they really are correct in color and intensity?

This is commenting specifically on the information released by Bochman in the video.

#75

Hi All
Just to clear up a couple of points on the Mallet.

Ive just watched the video which came with the Mallet (Little River variant) and it says the following:

  1. The Mallet was filmed running on Stan Ames garden layout

  2. Stan Ames is listed as a Technical Advisor to this locomotive

Hope that helps

Graham

#76
Fred Mills said:
I'm really having fun watching this thread develop.......I'm looking forward to a REAL, in depth review of the articulated tank engine........vidio tales from never-never land, never tell the complete story.......so this thread should make for some good bed time reading right through until next Spring, when I can get back to operating a railroad again.

Thank you all. I hope you keep up the tales from the deep and dark secrets of gear boxes and bird rejected worms…

Bruce; your comments were well thought out, and nicely worded…I look forward to more of your thoughts on this subject.


Meanwhile, from over the pond - 'tis well-known and oft spoken of that wet crows fly faster at midnight.

But you didn’t hear that from me, okay?

tac

#77
Graham Ash said:
Hi All Just to clear up a couple of points on the Mallet.

Ive just watched the video which came with the Mallet (Little River variant) and it says the following:

  1. The Mallet was filmed running on Stan Ames garden layout

  2. Stan Ames is listed as a Technical Advisor to this locomotive

Hope that helps

Graham


So … you have one of them, then? When was it delivered? Where did you get it?

Do you have any first impressions about the engine itself?

Matthew (OV)

#78

No - I have two of them , they were delivered this morning at 0830.
I got both of them from the same supplier
I think my first impressions are that they are superb locos, they look absolutely great.
I have had both fitted with DCC /Eloksound decoders
Im a bit busy with work etc at the moment, in fact Im off to work in 45 minutes
I may have time to see how they run on Sunday - so Im looking forward to that.

#79
Graham Ash said:
Hi All Just to clear up a couple of points on the Mallet.

Ive just watched the video which came with the Mallet (Little River variant) and it says the following:

  1. The Mallet was filmed running on Stan Ames garden layout

  2. Stan Ames is listed as a Technical Advisor to this locomotive

Hope that helps

Graham


A heartfelt thank you for me, and my guess would be for all of us.

Now that that’s cleared up, hopefully there will be very little ducking and covering from here on out. From now on, when we ask a technical question about this locomotive, and are told to inquire of “Bachmann Industries” we now know who that means … the same man to whom Bachmann Industries addresses such questions, Mr. Stanley Ames.

I believe that may be the first breath of fresh air this corner of the stable has seen in some time.

Richard C.

PS. For futher clarification, would someone explain the difference between an advisor and a consultant? Does not one consult with an advisor for counsel or advice, and does not an advisor consult with, and give counsel to those advised?

#80

This is fine…a DCC operated machine…of course it runs fine…that’s what Stanley and Company want you to play with it on…DCC. Rightly so; B’mann is in the DCC business and hopes to convert everyone in that direction As H. Riley clearly stated a couple of years ago to me in Durango; “It’s the only way to go, and all model railroad locos will be DCC in the future”.

Now, after this bit of basicly “Out-of-the-box” testing; when are we to hear of a real, full report after a gutting, and seeking expedition into the real guts of this
articulated tank engine ?
I’m hoping that the report will finally show great progress by B’mann, into finally producing a fine locomotive, without any major problems.