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Subject: 
Re: Pulling power of different train systems
Newsgroups: 
lugnet.trains
Date: 
Wed, 25 Nov 2009 09:06:05 GMT
Viewed: 
14721 times
  
In lugnet.trains, Ted Andes wrote:
   In lugnet.trains, Reinhard “Ben” Beneke wrote:
   Hello after a long time!

I played around somewhat with the different train systems. The result is displayed in this table:



And probably more interesting as a video: Pulling power of different train systems at YouTube


Only the step 4 is featured in the video.

Hope you enjoy + Leg Godt!




Hi Ted,

thanks for your feedback.

   Very interesting experiment with plenty of variables to consider. It has my mental wheels turning...

It would be interesting to see this done with a “pull type spring scale” to measure the force...

That would in fact have been favourable. My test rig suffered under the effects of friction in the 3 wheels, which lead the wire. I have tried to minimize this by using high diameters.

It would also be
   interesting to adjust the mass over the drive wheels to determine the impact on gaining traction for a specific system (given the coef. of static and dynamic friction)...

Definitely. I am convinced, that in the first line the friction coefficient is not depending (very much) on the weight. The different coefficients I measured are basically due to different ages and types of rubber / silicon material.

If you look at the table the probably most surprising numbers are those of the 10153 motor without weight in contrast to the extreme weak 10020 engine. The only explanation for this is the material of the “rubber” rings around the driving wheels.

As a sidenote I may mention the 7898 engine, which has highly surprised me! I had experiences with some 7898 type motors and those have been the lamest I have ever seen. LEGO had addressed this issue by choosing a softer stickier type of silicon. And they did this twice. First generation has been horrible. Next was not very sufficient. But this last version offers fun. The engine still CAN slip under overload, but pulling force is maximized. Well done LEGO!

   ...when I’ve met with design engineers at GE Locomotive in the past, they always said the more weight in their deisel engines the better for pulling power. I wonder how much that applies to the various LEGO systems?

This is definitely one of the keys to higher pulling power. In real life you have steel vs. steel. So your only chance for higher friction force is higher mass on top. (Or use sand and live with higher wear on rail and wheels).

In Lego you can use higher masses or better “rubber”-rings. Too much of mass will of course reduce the life span of your motor, which is not made for that.

Old trains 4.5V and 12V had ribbed rails for higher friction. That in combination with good rubber and high weight is the reason for their good results.

...
   Hmmm... That could be a great next experiment - to see how varying mass over driving wheels can maximize the pulling power of an LEGO system engine....

Once you reach a mass that the motor wheels do not spin through, you are at the theoretical limit.

Leg Godt!





Message has 2 Replies:
  Re: Pulling power of different train systems
 
(...) --snip-- (...) --snip-- (...) Great video, Ben :) I watched it all the way through which is a bit rare for me. An interesting test would be the new motor with the old ridged tracks (since they are compatible). You may get really high traction. (...) (14 years ago, 25-Nov-09, to lugnet.trains, FTX)
  Re: Pulling power of different train systems
 
(...) The quality of the rubber is definitely a critical factor for friction, but it is not the only factor. I've found with a normal 10020, one motor, pulling a few Santa Fe coaches, the wheels will spin excessively (especially if you have a slight (...) (14 years ago, 27-Nov-09, to lugnet.trains, FTX)

Message is in Reply To:
  Re: Pulling power of different train systems
 
(...) Very interesting experiment with plenty of variables to consider. It has my mental wheels turning... It would be interesting to see this done with a <https://www.schoolo...T530CAT536 "pull type spring scale"> to measure the force... It would (...) (14 years ago, 25-Nov-09, to lugnet.trains, FTX)

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