When I started my local race group a few years ago, there was a long discussion over what our class specifications would be. Each enthusiast had different ideas about what we should race, and it was suggested that perhaps we not define any specifications at all. After all, most pilots simply wanted to race whatever they had already built. This is great for informal flight days, but has some strong drawbacks when it comes to organized competition. More importantly, defining classes actually keep a group running smoothly and help maintain its membership.

What’s a Spec?

A class specification (often referred to simply as the “spec”) is a set of minimum and/or maximum attributes that a competitor must meet in order to qualify to race. This might include weight, power, materials, size… anything that can be used to define a group. Classes might be lenient or restrictive in what they allow and are generally written to achieve a specific experience that’s distinctive from other classes. Each participant in a group will need to be familiar with its spec. Your local group might use MultiGP’s specs, or could create its own.

Our local group settled on two classes for full-size quads: an “open” class and a “spec” class. The “open” class allows a fairly wide range of equipment, while the “spec” class is much more tightly defined.

Why Have a Spec at all?

Class specifications are needed to create a fair environment, and set a stage for different kinds of racing.

Set Expectations

Consistent expectations provide for safety and efficiency during an event. For safety, the spec might dictate a maximum weight; a maximum VTx power can help keep video channels clear and prevent dropout-related crashes. A spec lays out what’s fair so disputes can be minimized—you can prevent pilots showing up with hexes, tricopters, airplanes, or gas engines, if you don’t want them. The spec should be clear on what’s allowed and intended.

Level the Field

precision racing

Matching performance across a class makes every piloting decision count. You can’t buy your way to the podium with more powerful parts.

A spec almost always caps performance in a given class. In auto racing, it’s common for a spec to limit maximum horsepower, minimum weight, and the type of tires allowed. These prevent someone from producing a car with a significant advantage over the others. Performance regulation transfers importance from part selection and technical setup to the skill of the person behind the controls. Getting reasonably close to a performance cap can usually be done fairly inexpensively. As you approach the cap, it becomes more difficult—and more expensive—to find an advantage. Pouring in more money into a build offers only a small benefit over a much less expensive machine. Some teams will do this anyway to get as much advantage as they can, but those with fewer resources won’t be greatly left behind.

To achieve this effect, though, a spec has to be appropriately defined. Wide open specs that don’t restrict performance will turn into an arms race to build the most powerful machine. If that’s allowed to happen, the spec has failed to provide a competitive environment for racers and favors those with more money to spend. In less competitive sport there can be a place for an “open” class where pilots are allowed to bring whatever they already have—but most classes should be regulated to keep competition fair.

Our “open” class is basically the same as MultiGP’s existing 4S class. There are a few limitations for safety reasons, but for the most part anyone is welcome to come and fly. (MultiGP’s regulations don’t limit performance.) Our “spec” class caps motor size, cell count, prop blades, and prop pitch. These tighter restrictions keep all of the quads evenly matched. Casual racers can bring whatever they own and enjoy racing in the “open” class, but serious racers have a highly competitive class available. The approach has proven popular with our group, which has both types of members.

Provide a Unique Experience

Class specifications segment performance, but they should also provide different kinds of experiences. If race classes simply offer the same experience at different speeds, it’s a missed opportunity. Classes, in conjunction with race regulations, can create a diverse range of racing experiences to suit the tastes and styles of many different pilots.

  • Powerful machines provide lots of raw speed
  • Quads set up for maximum agility test pilot reflexes and skill in cornering
  • Efficient quads allow endurance racing
  • Slower craft enable close proximity racing and more frequent photo-finishes
  • Micro-class races are more approachable for beginners and can be held indoors
  • Open classes allow an easy entry point for beginners or casual racers

Each pilot might be drawn to a different kind of race experience—the amount of available power is just one small piece.

Our “open” class is set up in short sprints, while our “spec” class has more laps and requires more endurance. The “open” class uses a fairly simple layout, while our “spec” class course designs are more challenging. Each of these changes further differentiates the casual/competitive experience that we’re aiming for.

What Else Can a Good Spec Do?

fpv race gates

When different groups agree on a spec, visiting and racing in new locations becomes much easier. Set up your quad at home, and you’ll be competitive everywhere.

Universal Adoption

Our community should aim for a great set of specs that people understand and get behind so that it will see wide adoption by groups across the world. This is a great thing for everyone. Universal adoption enables pilots to move from one location to another without having to purchase different equipment. It also allows inter-group competition, simplifying the path from local to regional to national events. Universal adoption demands that manufacturers take notice, and as a result more equipment becomes available everywhere that fits the spec. Buying, selling, and trading equipment is simplified when most parts conform.

Encourage Innovation

Don’t make the mistake of thinking that a performance-limiting spec restricts innovation. On the contrary, it encourages it by cutting off the easy path of increased power. There will always be a market for more powerful parts, and they can be supported with an “open” class. For all other classes, getting faster means looking for an advantage in other areas such as handling or aerodynamics. As long as we allow manufacturers to simply deliver increasingly powerful parts, they will take the easy road and do that—but creatively improving in other areas is where real innovation happens.

With well-defined and universally accepted specifications, manufacturers will stay within them in order to get a bigger share of the market. Giving manufacturers incentive to stop chasing power will shift product development to provide more reliable and efficient equipment. To understand the kind of innovation that comes from working within regulations, research the history of Chaparral Racing. A great many ground-breaking advancements in racing were quite wild at the time but paved the way for features that exist on most consumer vehicles today.

To encourage innovation, though, the spec has to be well-written. A good spec is forward-thinking and doesn’t lock into any individual technology unless it’s absolutely necessary for defining the class experience. For example, a “Tiny Whoop” class that specifies brushed motors. This isn’t a helpful specification because it restricts the ability of manufacturers to develop motor technology for this class. Limiting the amount of power output instead might result in more offerings in this size and power range that are equipped with superior brushless motors.

Limit Size Creep and Control Costs

efaw motors

Switching to 2407 motors and 5051 props is not “innovation”. How often will you pay to upgrade and replace burnt-out batteries before you stop racing?

A few years ago, a typical race motor might have an 18mm stator. Racers quickly moved to 22mm. Today, 23mm and 24mm stators are common. Manufacturers see that users want to have an edge, and the simplest way to get that edge means drawing more power. Other parts have had the same creep: props were mostly 3″ with two standard blades, but moved to 4″, 4.5″, bullnose, tri-blade, and now insane high-pitch props kill batteries worse than ever before. If you bought 1806 motors with 5030 props just two years ago, you’re not competitive today. Without a spec that caps performance, the result is a costly arms race of increasing size and power.

For those that like pushing the top edge, a single open class is all that is necessary. But if all classes continue to be subject to this kind of performance creep, the number of competitors will diminish to only those with the income to support it. A group will lose its less affluent members as their equipment becomes uncompetitive and they don’t have the means, or will, to upgrade.

Inversely, a spec that’s properly performance-capped serves as a cost-controlling measure. This is true even at the highest levels of motorsport and teams often request stricter regulations for this reason—even top-level race teams have limited budgets. There’s less need to upgrade when a machine built a few years ago can reach very close to the performance cap. Perhaps newer machines are more efficient, smoother, or have better handling—but these upgrades can be beat by pilot skill. The racer on a budget can stay competitive, and pilots are no longer forced to stay current or give up on placing well. Manufacturers still benefit, too—from a greater number of racers staying in the sport.

Cost control isn’t just about part upgrades. There’s an ongoing cost to maintaining a high-performance machine and replacing its consumables. Large motors and high-pitch props like the RaceKraft 5051 offer huge performance boosts, but exert massive strain on a battery. It’s not unusual for a 5S quad pushed to 100mph to have a battery surface temperature above 170°F. Manufacturers often rate the internal temperature maximum at 140°F. Batteries operated well beyond the rated spec like this will shorten their lifespan considerably. Killing batteries drives up cost! Limiting performance stops this from happening and brings the costs down for everyone.

Cost control helps retain membership this way, but also serves to grow new membership. Think about the process of a novice selecting a build/kit, setting up software and initial configuration, learning to fly LOS, learning to fly FPV, acquiring race knowledge, and so on. It could easily be 6 months before someone has any hope of completing a course without a DNF. Making that initial investment of both money and time, and then being completely outclassed once they finally arrive ready to compete, is a sure way to upset new hobbyists that are just starting to really dig in.

Going Forward

Our sport has a bit of a problem right now: we don’t have a universally accepted set of class specs that offer performance-capping. We’d like to see this change! Authoring a class specification is difficult and complicated, so we’re exploring it in a separate article, “Toward a Better Race Spec”. Until we have this spec, race groups should be exploring classes and sharing their experience to figure out what works.

Where we go from here depends on your situation.

  • If you’re an organizer for a group that’s not currently using classes, hold a meeting or start an online discussion with your members. Your goal will be to set classes that give your group the kind of race experiences it wants.
  • If you’re an organizer for a group that has already started using classes, please join in the discussion we’re advocating for. Your experience is valuable!
  • If you’re a group participant, speak to your race organizers and offer to be part of the discussion. Share this article if it helps.
  • If you’re a new racer looking to join a group, find out what is being used for classes before purchasing equipment. Attend a group event and speak with organizers and participants; you’re sure to learn a lot about what to buy or build.
  • If you’re creating a new racing group, way to go! Setting your classes before you reach out to many people will help with early organization, but be open to change as your group forms. You might also be interested in our two-part series on organizing community race events.

A group that has been running without a class spec can ease the transition by setting an “open” class which includes everything you’ve previously allowed. This provides one kind of race experience and doesn’t give most of the benefits of performance-based classes, but prevents you from excluding any existing member. Your other classes should provide experiences that are unique and different from this in order to provide group members with more variety.

We hope you’ll join us in carrying the community forward toward better race specs.

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