The Scrumpy Cup, as that first meeting was called, was very much a private affair at which the object was to shake down our new vehicles, learn what they were capable of, and lay the foundations of what would become the public series. There were many familiar faces from other parts of our community there, but this was the first time we had all come together as a group. We raced on a hard circuit, we raced on mixed soft and hard ground, we did time and manoeuvrability trials, and we raced at night. We had a nascent racing series, and arrangements were made behind the scenes to bring it to the then-upcoming Electromagnetic Field hacker camp at Eastnor in Herefordshire, where we unveiled it for the first time to our public.
On your marks
So just what is a Hacky Racer? There is a comprehensive rules document derived from the Power Racing rules on the Hacky Racers website but, in short, it’s a vehicle of less than 1500 mm length and 900 mm width, driven by one or more electric motors, and with a body derived from a toy or in the spirit of a toy. There are plenty of rules dealing with budgets and safety, and rather than restrict the choice of motor, the power is restricted by specifying maximum current for a given voltage by means of a particular fuse. Within that framework there is an astounding flexibility, and on our first grids there was definitely a wide variety of motor, battery, and chassis configurations.
We know exactly where this is going as you are reading this: you now want to build one yourself. Fortunately this is a very achievable aim, and there are a variety of suggestions to get you started. You need to think first about your chassis and running gear, then your motor and drive system and, once you have those, you should be able to attach whatever body you consider most appropriate.
The easiest way to solve your chassis problem is to use one off-the-shelf. One of the larger mobility scooters is a popular choice, but we’ve also seen small golf buggies and pedal go-karts pressed into service, and, when one of the originators of those hacker camp beer crates heard about the series, the iconic German Bobby Car child’s toy.
A Power Racing grid in Detroit, 2018
Credit Pete Prodoehl, CC-BY 3.0
Buying in
The advantage of using an off-the-shelf chassis is clear. You have wheels, suspension, and steering ready-made, and in some cases you can even use the same motors, batteries, and drive electronics. There are often some tasks to be performed in modifying the geometry of the vehicle, for example lowering the seat of a mobility scooter, but these are usually within the capabilities of a well-equipped workshop or hackspace. The motors however are another matter, because if a donor is already motorised, it is unlikely that it will have the gearing required to give it a competitive top speed. As an example, those competitors who used golf buggies found that, while they had the required power, they were significantly slower than others with custom motor configurations.
Building a chassis is a more challenging route, but lends the advantage of giving you complete control over your creation. A welded steel box section seems to be the preferred choice here, but one machine made clever use of welding together scrap bicycles. Beyond that, there is nothing to stop you using almost anything rigid enough as a chassis; with clever use of plywood or fibreglass, something truly unexpected could emerge. The self-build chassis maker must furnish their own running gear, but fortunately the world of quads and mini-motos has plenty of suitable suspension and other components.
power up
The motors and drive are a surprisingly straightforward part of the build, thanks to the Chinese motorised scooter and hoverboard industries. There is a ready supply of both motors and controllers that would have been undreamed-of only a few years ago, and what would once have been one of the most expensive components is now an extremely affordable off-the-shelf purchase.
The most popular choice appeared to be the 2 kW brushless electric scooter motors with chain drive, but as our German entrants showed us, the in-wheel hoverboard motors can also be extremely competitive. The batteries are an area in which the choice of a large lithium-polymer pack is not a difficult one to make. However, there are a significant number of safety rules associated with these batteries because they present a fire risk, so they must be contained within appropriate fireproof housings. The ubiquitous ammunition box is a feature of all racers for this purpose.
How your finished machine looks is completely in your hands, though. The previous paragraphs have made a few suggestions based upon what appeared at EMF and the Scrumpy Cup, but we know that this is a series that has a way to evolve. Think for a minute about Robot Wars and compare a heavyweight from 1998 with one from 2017: they are an entirely different class of competitor. The coming years will see an evolutionary process in the world of Hacky Racers as new ideas and new components arrive. It will get ever more fun and interesting and, due to the careful budget and power constraints, we hope it won’t lose its accessible edge. Get busy building your Hacky Racer now!
The Dustbin 7
Rory Mangles is somebody you may be familiar with through the Robot Wars Team Nuts, so you would expect that when he turned his attention to Hacky Racers it would result in something interesting. The chassis is a welded steel affair with what look like mobility buggy wheels and tyres, and it has the usual 2 kW Chinese scooter motor and controller, with LiPo batteries.
He’s done a beautiful job on the bodywork, with a vintage car feel provided by bodywork fashioned from a plastic waste bin, and the seat from a 1960s Triumph Herald. The car appears in more than one of the pictures we’ve chosen for this piece, and is definitely one to beat if you wish to become a serious contender.
The Ottercar and Ottermobile
Niklas Fauth and Jan Henrik are a pair of German hardware hackers who, among many other projects, have done a lot of work on reverse-engineering hoverboard motors. Theirs was the motorised beer crate that had British hacker camp attendees so envious in 2017. They heard about Hacky Racers only ten days before EMF Camp, and within three days had come up with a pair of machines that turned out to be extremely competitive.
The Bobby Car is an iconic German toy, a small but extremely robust child’s sit-on car. There is a downhill racing scene for these machines in Germany, so they are track-proven, and what Jan has done with the Ottercar is attach their trademark hoverboard motors in place of the original wheels.
The result is a very compact and extremely quick vehicle. To meet the Hacky Racer rules it has an external steel framework to provide some bumpers, but there is no actual reason for it to be there, beyond that rule.
Meanwhile, Niklas has taken a Kettler pedal trike, lengthened it, and replaced all three wheels with hoverboard ones. Both machines are fast and competitive, and have taken a completely diferent tack from their British counterparts. We hope that Hacky Racers will spread to other European countries, and the diversity this will spawn will make for a far more interesting grid than we’d see if only Brits were involved.
Trikemare before Christmas
The Trikemare from Alex Shakespeare is a scratch-built three-wheeler with an unusual design in the form of a tricycle with the single wheel at the rear. It has the same 2 kW scooter motor as four-wheelers such as Rule Zero, with a chain drive to a mini-moto rear wheel. At the front it has go-kart stub axles and steering. The motor is mounted using laser-cut plywood brackets which failed at the Scrumpy Cup but which proved reliable in their revised version fielded at EMF Camp. The result is a powerful, manoeuverable, and extremely competitive vehicle.
