Projects: Lotusaurus Wrecks

What are you doing, my guy? After having such a great time driving (and destroying) Red Lotus in the 2013 season of PPPRS, I thought it'd be great to expand my knowledge in design, construction, mechanics, and electrical engineering by building my own Power Racing Series car.

In PPPRS, one big aspect of the races is Moxie. Moxie is essentially "style points." The crowd awards Moxie points to drivers for zaniness, crazy crashes, and awesome passes. Ultimately, being the most entertaining car on the track is often more important than being the fastest. The Milwaukee Makerspace has always had a lot of trouble in obtaining moxie points, so I decided that Moxie would be a big factor in the design process for our new car. While browsing the internet for "cool movie Corvettes" I came across Frankenstein:

an intense car from the cult 1970's classic "Death Race 2000."  Kids might not recognize it, but it looks like a dinosaur, so we went with that. Original ideas for names included "TyrannoCar" and "RawrRawrRacecar," but then Pete P. came up with the winner, "Lotusaurus Wrecks."

The Build

Since the old Red Lotus Corvette body was in need of retirement, I found a cheap replacement Corvette body on clearance at Target.

Using the new body as well as the seat, handlebars, tires, and batteries from Red Lotus, I designed the new car's layout. I traced the body on cardboard and deduced where the front and rear axles needed to go based on the wheel divets of the body and the old, battered seat.

Sketching the layout

Designing the front axle and steering assembly. 

With this sketch, I was able to sketch out a steering assembly. The rack and pinion steering mechanism was designed and built by one of the MMS's prominent PPPRS team members, Tom Gr. While building the mechanism, Tom taught me how to use a mill and a lathe. 

Once the front axle was done, Mike (another MMS Racing Team member) welded it and a pair of bumpers to two steel bars to make a frame. The front part of the frame is just about complete. Tom Gr. designed motor mounts for the back axle which were custom lasercut out of 1/8" steel by a friend of the Makerspace.

Stripped body with the new frame and steering

The wiring was taken out of Red Lotus and underwent an overhaul for Lotusaurus Wrecks. I have trouble with understanding where electrons like to go, so please bear with me here.

I have no idea what I'm doing.

We added a fuse holder to fulfill new PPPRS sanctions as well as an emergency kill switch. The electrics contained variable voltage circuits so we could add silly things like car horns and LEDs. Two 500W Motors from a past Milwaukee Makerspace car were installed and connected to our custom-cast aluminum hubs via bike chains. A new motor controller for Lotusaurus Wrecks came from a forklift, but the MC just couldn't lower the amperage enough to fit the PPPRS power restriction rules: we couldn't match the 1440W limit at 36 volts, and we blew many, many fuses trying to get this to work. Another member of the Makerspace, Ed C., built a whole new motor controller from scratch to try and circumvent the problem. Here we are trading out MCs minutes before a race!

Photo by the marvelous Pete Prodoehl

After putting in a set of hydraulic brakes (one for each front wheel) and figuring out things like the seat and where the batteries needed to go, we needed to add some power wheel to our power wheels car. After treating the plastic body with sanding and black primer, I added several greens and yellows using cardboard and spray paint. I took apart the headlights and front grill so I could paint them bright red.

Then I put stickers and teeth all over it and raced around the alley behind the Makerspace for a good long time. Here's a picture of the final product:

For moxie, I made up a cute dinosaur onesie that I ran around in while I smashed cardboard buildings and rocked out to Blue Oyster Cult. 

Accomplishments

For the 2014 season Lotusaurus Wrecks competed in three sanctioned PPPRS races (Kansas City, Detroit, and Milwaukee Maker Faires) and finished 6th in the regular season (out of 35 cars). Lotusaurus wasn't the fastest car, but its durability and moxie made it quite the contender. As a top ten competitor, the Milwaukee Makerspace participated in the PPPRS Championship race at the New York World Maker Faire. 

Lotusaurus Wrecks has been featured in numerous articles, demonstrations, videos, and lectures. In the media, Lotusaurus Wrecks was in the Milwaukee Business Journal, the 2014 Milwaukee Maker Faire "Meet the Makers" blog, the New York World Maker Fair 2014 poster, and Tinker Nation's (a PPPRS sponsor) internet videos on PPPRS and the definition of Makerspaces (below). I demonstrated the car at a Girl Scouts mentoring camp as well as a symposium for gender equality in STEM careers. Finally, I gave a talk on my background and how I built Lotusaurus Wrecks for the Global Leaders Project, an international student exchange between MIT and the Singapore University of Technology and Design.

Thanks!

I would just like to say thank you to Tom Gr., Pete P., Ed C., Mike T., and the rest of the Milwaukee Makerspace Crew for teaching me all of the things and helping make Lotusaurus Wrecks the fiercest little dinosaur on the track. I miss you guys something fierce!