[2.12.18] Ice Racing Electric Vehicles: ATTEMPTING MACH 0.1

Looking for a safe place to test your land vehicles? Have you tried ICE ?
Take a gander below for testing and tweaking of electric gokarts on ice, along with a build of a quite unique Ice Racing Skeleton Sled.

EBAY Ring Light
Printed Adapter Bit Downloads Conclusion Image Directory

The haistily thrown together motor controller

Electric Koolaid and Doomsled race about on the (semi)frozen tundra of massachussetts. Speed shown is datalogged from a GPS phone, so, its fairly accurate albiet not high update.  All around a blast.

Part 1: Retrofitting the 'Atomic Thing' for Ice Racing High Speed Duty.

So, just about everytime it gets cold enough for a nearby body of water to freeze, it also subsequently snows. This is a bit troublesome in a few ways. Like in ice skating or ice hockey, the fewer surface preturbations the better. While a small covering of snow is removeable, it fouls the top layer of ice and freezes into an intermediate ice-mush layer. This is fairly viscous and not that great for highspeed ice vehicles. The effect is visible far right, as  the vehicles penetrate through a top frozen layer into the semi-frozen mush, riding on an underside frozen layer. 
So as you can imagine it takes a rather particular type of weather conditions. Nominally, the temperature has to remain well below zero for a significant period of time without there being any snow-like percipitation. We finally found it, the weather reports lined up and lo, we had up to 11  inches of ice below our feet, time to put it to use with modified PWRS racing vehicles and custom high speed electric skeleton sleds.
Our encampment was right 
High speed electric PWRS vehicles you say? Atomic Thing (a V.W. Thing entry into 2014-2018 PWRS competitions) always had the stealthy feature of being intended for more speed than the event required. With an 8-speed shimano gearbox and a '7kw' motor, clearly there was some more headroom for speed. To fully utilize the motor, a 24S 10P cylindrical A123 module was assembled. This nets 84V fully charged at roughly 22AH. These packs were re-arranged from the 'a123 - hymotion' prius program. Initialy I had plotted that a lack of mass in the front would result in the vehicle having poor steering. Aside from the large battery pack and ice-skate wheels, the Atomic Thing was ready to go.
After some quick driving on ice, we realized that, a significant lack of traction was hindering preformance. We were very very efficient at spitting ice out of the back tires but alas the lack of rear mass resulted in a very shifty cart. To fix this, the battery module was 'haistily re-located' to the rear of the cart, with what can only be described as an oragami of ratchet straps.
We tried both ice-skate and studded wheels for the front and found that while the ice skates did provide better steering, it did have trouble over rough ice. As an alternative we tried studded solid tires to great effect. While the steering with studded tires was more of a slide, it was surprisingly less jarring.
Along with Atomic Thing, the Electric Koolaid Acid Test joined for Ice adventures
Electric Koolaid is the child of Frederick Moore and team  department of silly gokarts. The psychadelic outer shell is the artwork of the ever-excellent Audrey Horst. To prevent the shell from being shredded or soaked outside in the cold, it was opted to drive shell-less.

The great smooth, wet ice day was quite excellent. We had a great showing of miters-on-ice. Ice skates were brought out, kites were attached to lawn chairs and used as a mode of transportation and the weather held out quite well. The great Fred koolaid mobile was a great 'tow everyone back to home base' transport.
When I said 'kites and folding chairs being used as a form of transportation' I was quite serious. There was just enough wind to drag a person in a foldable camping chair at ~1-2 mph. Quite excellent indeed. The bottom of the chairs started with rough contact patches, but were buffed smooth by the end of the day. There was plenty of space to ice-sail about. 
Just for some reference here's what that chari looked like after a day of ice-kite action.

The great DOOM SLED awakens

So what is a DOOM SLED?
Credit for this wunder-contraption is due to the ever mighty Ciarian. He had this idea earlier in the year, a few mid holiday late evenings later the cad came together and the weldments were born.
One of the features was using mountainboard trucks for the front steering. If you recall earlier, I used a truck from a fairly beaten down mountainboard for the great Collapsable electric mountainboard project. The other truck now found a new home in doomsled. The truck was constrained by a cutout steel weldament and then bolted directly to the frame.  The frame itself consists of 1" square steel tube and pillow blocks for the rolling elements. A clever slot was included in the design to allow the motor to swap in / out.
Wait, what motor is that?
Convineninently, the motor was from a lab cleanout from the great IDC 2.00-boat class. The motor in particular is a Motenegy DC brush [ME909] monster. This is commonly used in some of the larger battlebots and large contraptions. Its even available on amazon [link]
Motor power is transfered to the wheel via a chain and keyed shaft. The shaft-to-wheel torque translates over two keyed hub adapters.
The steering took advantage of a rather stiff mountainboard truck. Two ice skates were removed from, well, ice skating shoes and attached to thick HDPE sheet stock. These were then attached to a hardened steel shaft that coupled to the mountainboard trucks. The hardened shaft took lateral loading off of the trucks, but still  allowed reasonable lean-to-turn motion.
Studded wheels?
Due to the low friction environment, we needed a fair amount of surface area to transfer motor force into the ground. The ever-excellent Fred found these solid, yet, forgiving tires and tried them out during the 2017 Power Wheels World Series on his cart, Electric Kool-aid acid test. They were mediocre on asphalt but did quite well with long self-tapping studs. Shown is the underside of the sled and the top-side polycarbonate shroud.
So how do you ride this thing?
There was some adjusting and positioning of re-used motorcycle / moped seats to find a reasonable lay-down position. Bolts were used to attach the seat, but due to its lact of internal structure, a large strap was used to ensure it remained constrained.
Version 1: The eve before testing.
It isnt a lot to look at but it came together remarably quickly. The seat was from i think jume's former longscooter, happily ratchet-strapped in place.
A chain guard made from some aluminum u-channel worked out swimmingly to keep the flying chain away from open fingers. Fron the top
The user interface may need a bit of twiddling, the right hand side is the throttle and the left hand side is the 'electric brake'. The electric brake had issues as nominally the amount of power disappation required to slow down the craft was fairly significant. It worked fairly well on the bench, but on a vehicle with alot of inertia removing that stored energy quickly was difficult through the chosen resistors. Incredibly undersized braking resistors shown right.

The haistily thrown together motor controller

Low Side Choppers

The haistily thrown together motor controller
Morning of our escape westward we ran a bench test of the controller and whole assembly. We were all excited about getting out there and scienceing

From the sponsors:

Version 1: Quick and dirty propulsion

Actually Using the vehicle


(There's other photos in the photo gallery)
Concluding Remarks:
From the sponsors:

If you have questions or comments, ask below or send over an email.
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Rensselaer Polytechnic Institute 
Electrical & Electrical Power