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Commercial Nar Kart?


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Nick
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Commercial Nar Kart?

The 'Why didn't we think of that?" department presents this very clever micro gokart:

http://www.autoblog.com/2013/07/12/razor-crazy-cart-may-be-the-coolest-kid-size-drift-car-money-can/#continued

I am already trying to figure out to duplicate that drive system; perhaps a wheelchair motor with a 90 Deg. gearbox or a large brushless motor with a belt drive...

Post Sun Jul 14, 2013 11:01 am 
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Jaemus
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<Patrician|Away> what does your robot do, sam
<bovril> it collects data about the surrounding environment, then discards it and drives into walls

Post Sun Jul 14, 2013 11:26 am 
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Nick
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I was thinking more " shut up and start welding" Laughing.

Post Sun Jul 14, 2013 11:35 am 
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marto
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Probably because we aren't big enough companies to see through the litigation when some kid hurts himself on it and then it is apparently the manufacturers fault for making it go so fast.

Steve
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Post Sun Jul 14, 2013 6:04 pm 
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Nick
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I think it won't be on sale in Australia due to the small market and general lack of imagination. If you look at the Toys R Us American site, it has 8 pages of Razor products to the local site's 1 page Mad. If it can be sold in the 'Land of Litigation', it coul;d surely be sold here!

I just sketched up a front wheel assembly with dual 6" Colson wheels, and a Turnigy Rotomax brushless motor. With 5,300 W on tap (50cc equivalent) it should get up to the theoretical top speed of 24KMH pretty quickly. The whole thing fits in a 270mm diameter tube like on the Razor.

Post Sun Jul 14, 2013 6:47 pm 
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andrew



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we need to work out a way to import these in. Damn that looks like fun
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Post Sun Jul 14, 2013 7:36 pm 
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Nick
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You could get the US Toys R Us to ship it to a Trans-shipping company in the US and then get it sea freighted to here - would add another $100 or so.

Post Sun Jul 14, 2013 7:48 pm 
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Nick
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I did some measuring on the size the kart would need to be for someone my size; a 500 by 1000mm frame would be comfortable and with my legs folded up, the steering wheel would have to be around 580mm above the base plate to clear my knees.

That amount of height would allow many different motor & gearbox combinations to drive the front wheels; I have narrowed it down to three:

1) brushless outrunner with chain reduction
This sounds like the cheapest option, but it really isn't. After studying up on many EV forums, a un-sensored motor and R/C controller will not perform well in a vehicle that has sharp acceleration and deceleration.

Adding sensors and a better ESC from Kelly Controls would be a great solution, but that really increases the complexity and cost. This option will deliver the most power in the space available if a cheaper controller & sensored motor can be found.

2)Mag motor with a commercial gearbox
This is looking like a durable and cheaper option, given the plentiful supply of Mags and brushed controllers in the workshop. About half the power of the brushless option but I would only need to buy the gearbox, or possibly make a 3 stage chain reduction for even less money.

3)Dual wheelchair motors
This is the cheapest option of all Smile. Andrew very kindly gave me some chair motors and if they are mounted vertically with a short chain drive to the front wheel, I have everything except for the smaller mechanical parts. The chair motors will be slower than the other options but the chain drive ratio can be tweaked to improve that, as can a little overvolting.

Option 3 is the current winner and the next thing is to wire up the motors, the spare Sidewinder ESC and 30V worth of Lipos to see what RPM the chair motors are capable of.

Update: I have two working chair motors but they are rather slow - the tacho is playing up, so I can't get a reliable RPM reading.

Post Mon Jul 15, 2013 8:59 pm 
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andrew



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Sooooo got toys r us junk mail and there gonna have these for sale pre order or soon or something.

The crazy cart is bout 600 tho Sad
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Post Sat Nov 09, 2013 8:14 am 
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Nick
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That's very interesting - I would love to see the underneath of one to see how my design compares. <note to self: start welding the damn kart, OK?>

Post Sat Nov 09, 2013 4:47 pm 
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DumHed
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http://www.youtube.com/watch?v=sKOaF7esBFY
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Post Mon Nov 11, 2013 1:11 pm 
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Nick
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LMFAO! epically silly

Post Mon Nov 11, 2013 1:29 pm 
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kato



Joined: 11 Dec 2010
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Review, and how it's done. Pretty simple really, use an old scooter back end, and pivot the motor and wheel together vertically. The drift control isn't really a hand brake, it adjusts the rake of the rear casters from ~ 60 to vertical. The steering doesn't spin continuously, there is a discontinuity which would allow you to have your electronics and battery located not on the steering column. Niiice.

http://www.autoweek.com/article/20131202/carreviews/131129812

Post Tue Jan 14, 2014 9:00 am 
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kato



Joined: 11 Dec 2010
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Now in adult size. So much envy going on here.
http://youtu.be/FrGFjAlawmg

Post Thu Oct 16, 2014 10:58 pm 
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