Hello to All,
I have been collecting diesel locomotives for a wile now , some older athearn non flywheel drive diesels ,some bachmann and others.lately have gone with Bachmann since there upgrades in paint and finish and there pulling power and traction and performance when maintained have done very well better than some that require a gear box tuning and a wire up type thing and throw the contact strips away . Why has Bachmann lost the flywheels in there standard diesel locomotives ???, There old plus series at least had em ,Would this be considered a down grade ?I had to mill the frames in the sd40 and the gp38 and now they sing like a kato . Thanks for all the work Bachmann. Wheres the new SPECTRUM diesels besides the old dash 8 and sd45???
With metal costs on the rise, I guess Bachmann decided this would be a way to cut costs. After all, many who buy standard-line Bachmann have no idea what flywheels even are, let alone the advantages of having them. Bachmann might justify this by saying that most new diesels have built-in DCC, so they could be programmed to glide to a stop (not that helps with smoother operation altogether, but it is something).
Timothy
The need for flywheels is greatly negated by DCC. And I am not a DCC guy. The need in DC locos can be greatly lessened by having better contact to the rails and multi pole skew wound motors.
Anyone who thinks flywheels make an engine coast to a stop more like the real thing has certainly had vastly different results than me. The old Key brass coasting drive was something else all together.
In fact, for a mainline engine that is going to spend minimal time at slow speed, a higher speed motor and more gear reduction may prove entirely adequate. Flywheels are hard on motor "bushings" (as most little motors do not incorporate real bearings).
Isn't the "real" advantage of a flywheel the ability to "coast" through brief losses of power due to dirty track, plastic frogs, etc?
dlm
Quote from: danmerkel on February 26, 2008, 04:44:01 PM
Isn't the "real" advantage of a flywheel the ability to "coast" through brief losses of power due to dirty track, plastic frogs, etc?
dlm
My thought also, the momentum built up by the flywheel will take most engines through the switches, eliminating the dead frog problem.
The idea of flywheels was to improve the intial momentum when starting. The other benefit was a more gradual coast down when the throttle was closed.. It was supposed to mimic what a real locomotive would act like and for the most part, they do. For some locomotives with tower gearheads, the effect is negated by the gears. When designed and implemented well, the flywheel drive system give realistic motion when starting and stopping. A secondary benefit is the ability to coast and not have jerky starts and stops.
Quote from: ALCO1000 on February 17, 2008, 07:57:14 PM
Wheres the new SPECTRUM diesels besides the old dash 8 and sd45???
I agree. You don't even see these diesels anymore...Anywhere!!!
what about the Sd40-2 and the sd50?
My earliest experience with flywheels was on old farm tractors that weren't very powerful. The flywheel helped on occasional small grades without having to downshift. They carried over to newer models, still called flywheels but help power to a lesser sense, as newer engines have more low end torgue rise.
I see no advantage of having flywheels in locomotives. My Bachmann GP35 will pull 30 cars at a scale speed of 98 mph, and coast realistically to a stop. All you need is a good steady hand on the throttle.
I had an early model Bachmann diesel that went so fast it flew off the curves at half throttle, but no power to pull anything. Newer motors have more torque and they are geared for a more realistic running speed and more power to pull cars.
Bob
Another factor this thread overlooked is the use of 5 pole motors vs. 3 pole motors. Early in the use of flywheels a lot of motors were 3 pole and the flywheels did help to smooth out the jerks at low speed. A 5 pole motor has better low speed torque and in combination with flywheels makes low speed operation very smooth.
Quote from: modlerbob on March 03, 2008, 12:31:37 AM
Another factor this thread overlooked is the use of 5 pole motors vs. 3 pole motors. Early in the use of flywheels a lot of motors were 3 pole and the flywheels did help to smooth out the jerks at low speed. A 5 pole motor has better low speed torque and in combination with flywheels makes low speed operation very smooth.
But, judging from this thread.....3 pole motors may be coming back.
http://www.bachmanntrains.com/home-usa/board/index.php/topic,4500.0.html (http://www.bachmanntrains.com/home-usa/board/index.php/topic,4500.0.html)
Sid
I don't think any of the high end or even medium priced locos will have 3 pole motors.
Quote from: modlerbob on March 03, 2008, 11:29:20 AM
I don't think any of the high end or even medium priced locos will have 3 pole motors.
Did you not read the thread.?
http://www.bachmanntrains.com/home-usa/board/index.php/topic,4500.0.html
The Bach Man himself confirms that the newest Spectrum 2-8-0 now has a three pole motor.
Bachmann isn't a high end manufacturer. I'm sorry Mr. Bachmann but thats the fact. None of the other manufacturers have announced a switch back to 3 pole motors
Sid;
What logic do you-or would any manufacturers in a highly competitive market-have in using a three-pole motor. Are you familiar with motor theory? I ask that not as a castigation, but out of curiosity, because there is a world of difference in a three V. five-pole motor. The more poles, the smoother the run, the better acceleration/deceleration rates, the less lead/lag relationship, etc.
In my experience with small motors here, I have found three-pole motors to be pretty inferior . That having been told, I would bet that no company in a discretionary niche market would be caught dead with less than an excellent product. Excellence is too easy to accomplish these days.
RIch
Quote from: r.cprmier on March 03, 2008, 03:33:04 PM
Sid;
What logic do you-or would any manufacturers in a highly competitive market-have in using a three-pole motor. Are you familiar with motor theory? I ask that not as a castigation, but out of curiosity, because there is a world of difference in a three V. five-pole motor. The more poles, the smoother the run, the better acceleration/deceleration rates, the less lead/lag relationship, etc.
In my experience with small motors here, I have found three-pole motors to be pretty inferior . That having been told, I would bet that no company in a discretionary niche market would be caught dead with less than an excellent product. Excellence is too easy to accomplish these days.
RIch
I was quite surprised when it was confirmed that Bachmann had switched from 5 pole to 3 pole motors for the 2-8-0.
Mr. B indicates in that thread that the rating was the same for the two motors.
Nothing was mentioned about the other Spectrum steam models so it may only be the 2-8-0, but then if it is a cost cutting measure.
I wonder if it is because of the DCC decoders now being installed in the newer Spectrum's
It is impossible for a 3 pole motor to have identical specs to a 5 pole motor. Just like in piston engines the more cylinders the smoother it runs. poles being equivalent to cylinders.
The flywheel can have multiple purpose. Momentum is obvious. A smaller motor with a flywheel may be more economical that a larger motor with out. In O-scale the flywheel may be equiped with an optical sensor that is coupled to an electronic speed control. Extreme slow speed realism is sought after in O-scale (2-scale mph)
Here are some pictures of an upgrade. Larger motors replaced with smaller motors with flywheels. Weaver E-8's with and Engineer on Board speed control upgrade.
E-8 A unit with standard can motors, no flywheels and an electronic forward reverse unit.
(http://www.mikedian.net/trains/Model%20Train%20Pics/Model%20Train%20Pictures/E-8%20upgrade/slides/IMG_2898.JPG)
Remove all.
(http://www.mikedian.net/trains/Model%20Train%20Pics/Model%20Train%20Pictures/E-8%20upgrade/slides/IMG_2900.JPG)
Put it all back together with much smaller motors. Note the reader tape and optical sensor on the front motor.
(http://www.mikedian.net/trains/Model%20Train%20Pics/Model%20Train%20Pictures/E-8%20upgrade/slides/IMG_2943.JPG)
(http://www.mikedian.net/trains/Model%20Train%20Pics/Model%20Train%20Pictures/E-8%20upgrade/slides/IMG_2944.JPG)
The new electronics greatly enhance automatic operation with on board speed control. The flywheel motors are a definite plus.
I have many locos (HO) that have flywheels and many that don't. The difference in performance is very great. If for some reason the track power is cut the locos without flywheels slam to a abrupt stop while those with flywheels (most of them at least) coast to a stop. When this happens on my layout (rarely) it's always on the back side and on a curve, the abrupt stop causing cars to derail.