[WIP] "Fast Track" with RC Train Motors

[JamesJT]

I wanted to make something small and fast so I've been experimenting with RC train motors. This is the best so far.

http://www.youtube.com/watch?v=vbGRQ_OBg9w

I had to add weight to keep it from flipping over.

[Victor Imaginator]

It's somewhat crazy crawler fury... Are these motors so powerful?

[JamesJT]

I have found that RC train motors are great with direct drive and low weight but as soon as you add gears (friction) and more weight you are better off with L-motors.

I hope to develop this in to a ripsaw EV2 but I want to keep all the "fury".

[TheMindGarage]

That thing is insane! The way it turns on the spot reminds me of the time I took 2 EV3 Large motors and made a bi-wheel vehicle with custom 15cm wheels (made from tank treads) and 1:5 gearing up. The result was a vehicle that could do 15-20kmph when driving straight (if you can get it to go straight...) or turn on the spot at something between 200 and 400 RPM.

[syclone]

That thing is crazy!

If believing Sariel's tools, the train motor has 1250 RPM and the buggy motor has 1245 RPM on the faster output. They are faster than the buggy motors,but has half the torque( 0.9 train and 1.83 the buggy)

Edited July 26, 2016 by LXF

[suffocation]

Reminds me of any one of my cats chasing a mosquito.

[leinaud]

That thing is amazingly spastic!

[JamesJT]

I started V2, I'm going to try 4 motors off 1 LiPo. This project looks ready for a BuWizz.

lego 063 by James Tillson, on Flickr

I'm not building a scale model but I hope it will look something like this:

Ripsaw EV2 by James Tillson, on Flickr

Edited July 27, 2016 by JamesJT

[MaxSupercars]

2 additional motors should not bring extra notable performance. They add also unnecessary weight. You'll see... :)

Otherwise interesting use of train motors... ;)

Max

Edited July 27, 2016 by MaxSupercars

[JamesJT]

I know it won't go any faster as the gearing is the same but I was hoping to add more torque for climbing. I had to add the 73090 counter weight (53g according to bricklink) that I won't need with a longer wheelbase and each train motor is only 57g.

V1 was 370g, V2 will be about 430g but with twice as much torque.

What is the best way to ensure each motor has all the amps it needs? IR V1 with 2 motors per channel, IR V2 with 2 motors per channel or 2x V1 with one motor per channel?

[MaxSupercars]

The IR V2 with two motors per channel is probably the best solution. Of course 2x IR V2 - one for each motor is more better. V2 can get more current from LiPo but if one motor in channel stalls, it cut off the current flow.

Because I do not have IR V2, I use 2x IR V1 + 2 motors, one per motor and 1 LiPo.

Otherwise I use 1 SBrick for 2 motors and 1 Lipo.

Max

Edited July 27, 2016 by MaxSupercars

[JamesJT]

I had to scrap the suspension for now as the tracks kept falling off.

I tried all combinations and IR V2 with 2 motors per channel was by far the best. The thermal protection cuts in if I spin too long. It was no fun at all when I swapped the LiPo for AAA box.

http://www.youtube.com/watch?v=cFSxrScXnp4&feature=youtu.be

It is slower but easier to drive, I have lost the "fury" so V3 will be back to just 2 motors (was it that obvious Max?).

I think the key to making this work will be finding the perfect wheelbase, track and contact patch.

[MaxSupercars]

Insane fast vehicle. You force me to try the same with train motors. 2 should be enough for me :P

I have forgotten how fast they are. In fact they must be because of small diameter of train wheels. :)

And yes LiPo is LiPo... :)

Max

[2LegoOrNot2Lego...]

Excellent concept and indeed so fast...!!! Cool... ;-)

[JamesJT]

You force me to try the same with train motors.

I hope everybody has a go. This is fun!

V3 and its back to 2 motors. I extended the wheel base from V1 but it was only 2 wheel drive and would not turn properly on carpet.

FT 001 by James Tillson, on Flickr

It went much better when I saw an easy way to make it 4wd again.

http://www.youtube.com/watch?v=DDl7RROh8Ow

I think I prefer V2 as it was easier to control.