Choosing a Weightclass - Novice
- Adam Wrigley
Last updated - July 2006

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Build Responsibly.

Robot Combat weightclasses are just like boxing, except there are a lot more of them. Your robot must be under a certain weight to compete in a class. This tutorial will concentrate on the classes used in America, however the classes used in other countries are usually close to these (though there will be many classes on this list not supported if you are located outside the US). The classes are split into three main groups; insects, sub-lights, and the big bots.

Insects:

150g - FairyWeight - IW
1lb - AntWeight - AW
1 kg - Kilobot - K
3lbs - BeetleWeight - BW
6lbs - Mantis - M

Sub-lights:

12lbs - HobbyWeight - YW
15lbs
30lbs - FeatherWeight - FW

Big Bots:

60lbs - LightWeight - LW
120lbs - MiddleWeight - MW
220lbs - HeavyWeight - HW
340lbs - SuperHeavyWeight - SHW
390lbs - Mechwars SHW

Each group of weightclasses has it's own unique set of challenges.

Insects:

Insects started off with the 1lb class in the US, and the 150g class in the UK. They were made so that builders could have fun in the pits while waiting to play with their big bots. Generally they were constructed with servos modified for continuous rotation, and had little or no weapon. Over time the bots progressed into a full blown class with their own events, separate from big bot events. The 3lb class was added to get even more out of the small bots. Kilobots are a popular class in Canada, and offer more weight than a 1lb robot, but are not as expensive as a 3lb robot might be.

Insect robots are small, and easily carried and transported around to events. Don't be fooled by their size however, these robots are not the cheapest class to get into, and are still very dangerous to handle. The use of miniaturized components makes their electronics more expensive per lb than the sub light classes. Since the robots are light however, you can save money on raw materials. Because of this, many people use carbon fiber and titanium to a great extent on their insects.

The 6lb class is not very wide spread, and neither is the 150g class (at least not in the US). We recommend starting with an ant or beetle if you are building an insect robot in the US. Consider a Kilobot if you are in Canada.

Sub-Lights:

The 12lb class is arguably the cheapest class to get into in the sport. The weight limit is large enough so that you can drive down to the hardware store and get most of your supplies there. Drill motors are great for drive in 12's (and 30's. Higher classes also use drill motors, however they are from extremely expensive drills, so the motors are usually purchased separately online). The 12 lb size is also small enough so that speed controllers are not as expensive as the larger robots (and you might be able to get away with buying them at the local hobby shop). The 30lb class is similar, but more expensive due to the increase in the amount of raw materials needed to get up to weight. 30lb is also the highest weight limit that many events run, especially in the North East.

The sub light classes are where you start to see construction methods and components that most people are used to. Welding, unibodies, pneumatics and gas engines start to show up in these classes. The size restrictions of the insects tend to limit this. The sub lights give you the fun and excitement of a larger robot, along with the ease of transportation found in the insect class. Because of this, they are the largest growing part of the robot combat weightclasses. We recommend starting in the 12lb class since this is the cheapest and easiest way to get into combat robotics.

Note: 15lb bots are supported by some events, but these are generally "student only" events. They are basically the same as 12lbers, you'll just be scaling everything to be a tiny bit larger.

Big Bots:

These are the weightclasses that carried over from the Battlebots days. These suckers are heavy. You'll be spending a lot of money on electronics to keep them running due to high current draws, and they can be a pain to travel with. 60lb robots can be tough to get on a plane, and 120lb robots will most definitely need to be shipped if you are flying. Also, lets not forget about the huge increase in the cost of raw materials.

If you have a leftover chainsaw engine you've been waiting to use, you just found an interesting piece of farm equipment to use as a weapon, or you like welding together scrap steel into interesting shapes, this is going to be the class for you. The high weight limits also allow for a great variety of power sources ranging from SLA batteries to hydraulics, which are never seen in the sub light or insect classes.

Big bots, like their names suggests, are big. They take a good amount of effort to build, they are expensive, and hard to transport, but the benefit is seen in the arena. These are the robots that draw the crowds, and it's not hard to see why. They are big, they are loud, and they are just plain fun to watch.

Currently the 340lb class seems to be dying out, and the 60 lb class is on the decline as well. We would recommend building in the 120lb class if you want to create a big bot. 120lbs is also the limit for the large class at BattleBots IQ, and there are hundreds of IQ teams around the country building to this standard (though, they don't tend to fight outside of IQ).

Choosing:

There is no "best class" for newcomers to the sport. A lot of veterans recommend 1lbers, however some might find them too small. 12lbers are bigger and still easy to travel with, but some still might prefer to build a HW right off the bat. It's up to you what class you want to start with. Be aware that anything 60lbs and up is going to cost thousands to build and compete with. Good sub lights and insects can also go into that range.

Be sure to factor in all the costs when building a bot. Items commonly left out of cost analysis are bolts, wiring, and even the raw materials. Aside from just parts(and spares!), there are other aspects of competing with a robot. Where are you going to compete with it? Is there an event nearby for the weightclass you want, or are you going to need to travel across the country(and with larger robots, need plane tickets + shipping costs)? You may really want a 120lber, but if you are industrious you could build a whole insect arena and hold an insect competition in your backyard for the same price as an average 120lber.

The choice, is yours!

 

© 2006 by T.i. Combat Robotics unless otherwise noted.