Duratrax vehicle mod...

[OptimaMan]

Hey guys, I'm going to buy a Duratrax Pro and I'm going to mod this thing and keep a log of it. It's a very affordable vehicle at 99 bucks which include graphite parts, ball bearings, diff, and CVD's.

The most significant mod will be the drivetrain. I plan on getting 2 brushless outdrive motors and hook them up with 2 brushless controllers and have them direct drive with the swingshafts. NO diff, no tranny... no gear noise.. Just tire noise and ball bearing noise. Overall efficiency will be at least 80%!!!!!

This would be awesome because a brushless motor at 80-90% still loses 10-15% in drivetrain drag (5% loss per gear contact).

I need some advice and parts. First of all, a brushless motor with a kV of around 300-400 with power ratings of 150-300 watts.

Secondly, I need a way to mount the motors - does anybody have access to a CNC mill or any mill for that matter?

[tcolesen]

It may be hard to find outrunner motors with such a low kv. I looked on Ebay, and these are the lowest I could find:
http://cgi.ebay.com/Brushless-Outrunner-Motor-850KV_W0QQitemZ6017312448QQcategoryZ2563QQrdZ1QQcm dZViewItem
http://cgi.ebay.com/Outrunner-Brushless-Motor-TP-2410-12-Star-H-Torq_W0QQitemZ6016369931QQcategoryZ2563QQrdZ1QQcmd ZViewItem
http://cgi.ebay.com/1050rpm-v-Outrunner-Brushless-Motor-11-X-7-Props-X-3_W0QQitemZ6015497798QQcategoryZ2563QQrdZ1QQcmdZVi ewItem

If you contact Cold Fusion, he may be able to make something up for you.

This is definitely a good idea, but I can see some drawbacks. This setup will try to act like a locked diff, but to get diff action, the motors will need to be able to spin at different RPMs (perhaps a mixer could fix this). What would happen if one of the wheels stopped? You could damage a motor this way. A single gear reduction from each motor with a slipper clutch incorporated may be a good idea, just to save the motors.

In theory this will work, but for any real track driving there are some things that would need to be figured out.

[guver]

Use them to aid in steering, ie like increasing the power to the outside wheel.

[OptimaMan]

no, it will be TWO motors each going to it's own CVD and TWO controllers. Each motor will spin at different RPMs. My possible problem will be if one motor is slightly faster than the other... will drift to one side all the time.

[tcolesen]

OptimaMan, I don't know if you are still interested in doing this, but I just came across a slower, high power outrunner motor:
http://www.xushobby.com/servlet/Detail?no=109

[Mr. Constructor]

Hi Optimaman,

i might be helpful here too, just look at :

www.torcman.de

they do carry a wide choice on all those LRK Motors, and there are windings specialized to your needs possible !!
(I do use those motors in my Titanium Kanai 2 and my LRK Emaxx if ya might remember)

Good Luck

[Ventman]

One way to overcome the locked diff action that would occur is to put one-way bearings in each wheel, that way, the outside wheel can spin faster than the inside wheel in turns

[Mr. Constructor]

You´ll then have no brakes !!!
The reversing will not take the power to the wheels as the one way will spin free in this direction !!
So this is not possible, but how´s about trying the idea out on 2 smaller LRK in a 18th scale car ??? (the costs aren´t that high if it will not function then)

[___rollin___]

What if you use two motors and connect them to something to have them work in unison, like somehow have both motors facing eachother, one would operate in reverse. Then you wouldnt need to worry about the two motors being exact same rpm's. But are you planning to have the motors facing the tire they operate and just connect them to the cvd's? Wouldnt there be a ton of room for error there. Like the shaft is off .01 inch on one and is perect on the other. What if one tire weighs a few more grams, it will be turning then. I cant think of any way for this to work without some tiny error that will make this undriveable.
good luck though