RobotRobot: New weight-class page: Lightweight

2026-10-17T23:23:27Z

New weight-class page: Lightweight

New page

The '''Lightweight''' class is for robots weighing up to '''60 lb''' (27.2 kg) in the US, or '''30 kg''' (about 66 lb) in the UK. It's the first of the "big bot" classes: a lightweight is too heavy for one person to carry comfortably, hits hard enough to need a welded steel arena, and costs far more than an insect. Very few events run it as of 2026, so check the schedule before you start a design. NHRL's starter guide doesn't recommend even 30 lb as a first robot, and the same advice applies here with more force.[https://wiki.nhrl.io/wiki/index.php/Combat_Robotics_Starter%27s_Guide]

__TOC__

==Rules==
* '''SPARC''': 60 lb (27.22 kg), called Lightweight in the '''[[SPARC Tournament Procedures]]'''.[https://sparc.tools/SPARC%20Tournament%20Procedures%20v1.2.pdf] Shufflers can weigh 75 lb, non-traditional drives 90 lb, and walkers 120 lb (see '''[[SPARC Robot Construction Specifications]]''' and '''[[Multibots, Walkers and Shufflers]]''').[https://sparc.tools/SPARC_Robot_Construction_Specifications_v1.7.pdf]
* '''UK (FRA)''': 30 kg. The FRA lets event organisers grant bonus weight, for example to walkers, but leaves the amount to each event.[http://www.fightingrobots.co.uk/documents/Build-Rules.pdf]
* '''BattleBots (historical)''': the Comedy Central-era BattleBots ran a lightweight class, which grew from 58 lb to 60 lb by the final seasons. The modern BattleBots has only one class, 250 lb (see '''[[Heavyweight]]''').[https://en.wikipedia.org/wiki/BattleBots]
* '''RoboGames''' lists a 60 lb / 27.3 kg combat class.[http://robogames.net/events.php]

The UK and US limits differ by about 6 lb, so a robot built to the FRA limit is overweight at a SPARC event.

==Typical builds==
At this size, most builders stop using hobby parts and switch to industrial and electric-vehicle parts.
* '''Frame:''' welded steel or aluminum tube, or machined and bolted aluminum plate. Many builders have plates cut by '''[[Fabrication Services|online laser or waterjet services]]''' and then weld or bolt them together. SendCutSend, for example, cuts AR500 steel from 0.119" to 0.500" thick.[https://sendcutsend.com/materials/ar500/]
* '''Armor and weapons:''' AR500 and similar hardened plate, titanium, thick UHMW, and tool-steel weapons (see '''[[Armor and Materials]]''').
* '''Drive:''' large brushed motors, such as the AmpFlow-family motors that BattleKits offers with its drive platforms, or brushless outrunners in the 63–70 mm range through a gearbox or chain reduction (see '''[[Drive Systems]]''' and '''[[Speed Reduction]]''').[https://battlekits.com/order/]
* '''ESCs:''' high-voltage, high-current controllers. Many builders use '''[[VESC]]'''-based controllers such as the Flipsky 75200, which is rated 14–84 V.[https://flipsky.net/products/flipsky-75200-84v-high-current-with-aluminum-pcb-based-on-vesc-for-fighting-robot-surfboard-agv-robot] Brushed robots use large brushed controllers (see '''[[ESCs]]''').
* '''Batteries:''' LiPo or LiFePO4 packs, usually at higher voltage than in insects. SPARC requires the event's approval for anything above 48 V nominal (see '''[[Batteries]]''').[https://sparc.tools/SPARC_Robot_Construction_Specifications_v1.7.pdf]
* '''Arena:''' SPARC's arena guide says that above 30 lb, welded steel is the only commonly used frame material. It recommends 3/4" polycarbonate walls for events up to 30 lb and 1.5" for events up to 220 lb, so a 60 lb event needs an arena well beyond a typical featherweight box.[https://sparc.tools/SPARC_Arena_Construction_Best_Practices_v1.1.pdf]

===What it costs===
There's no ready-to-fight lightweight kit. The closest thing, as of October 2026, is BattleKits' assembled drive platform: the Light Weight Kit is listed at $990 without motors, batteries or controllers. Adding a pair of its economy E30-150 motors costs $178 more, and a pair of A28-150 motors costs $818 more. With motors, batteries and a controller, the platform alone weighs about 37 lb.[https://battlekits.com/order/][https://battlekits.com/] On the brushless side, Flipsky lists the 75200 ESC at $120–162 and its "battle hardened" 63100 motor at $137–143 each.[https://flipsky.net/products/flipsky-75200-84v-high-current-with-aluminum-pcb-based-on-vesc-for-fighting-robot-surfboard-agv-robot][https://flipsky.net/products/flipsky-sensored-outrunner-brushless-dc-motor-battle-hardened-63100-140kv-170kv-190kv-5500w] Add armor plate, a weapon system, spares and a charger, and a competitive lightweight costs several thousand dollars. Compare this with the insect-class figures on '''[[What Your First Robot Costs]]'''.

==Safety requirements==
Rules that are optional or relaxed for insects become mandatory at this weight. This is an overview only. Read the full documents and your event's rules, and see '''[[Safety]]''', '''[[Failsafes]]''' and '''[[LiPo Battery Safety]]'''.
* '''Mechanical power disconnect:''' SPARC requires a manual disconnect for weapon and drive power that can be operated within 15 seconds without putting anyone in the path of the weapon. This must be a mechanical switch (for example a Hella or Whyachi switch) or a removable link; relays alone don't count. The whole robot must be fully deactivated in under 60 seconds, and a power light must be visible from outside.[https://sparc.tools/SPARC_Robot_Construction_Specifications_v1.7.pdf] See '''[[Switches]]'''.
* '''UK removable link:''' FRA rules require an insulated removable link that can be pulled without tools; a key or switch isn't allowed. The link must be in a marked, visible spot away from the weapon and drive. LiPo packs also need a fuse rated below the pack's burst current.[http://www.fightingrobots.co.uk/documents/Build-Rules.pdf]
* '''Pneumatics and hydraulics:''' SPARC exempts robots of 12 lb and under from most of its pneumatic and hydraulic rules. A lightweight gets no such exemption, so the full rules on rated components, relief valves and dump valves apply.[https://sparc.tools/SPARC_Robot_Construction_Specifications_v1.7.pdf] The FRA likewise limits pneumatics to air or CO<sub>2</sub> at up to 1000 psi with certified components, and requires a test point on hydraulic systems.[http://www.fightingrobots.co.uk/documents/Build-Rules.pdf] Don't attempt a fluid-power weapon without an experienced mentor.
* '''Spinners:''' under FRA rules, a spinning weapon over 500 RPM, over 500 mm across, or heavier than 10% of the robot needs the organiser's approval in advance, and every spinner must stop within 60 seconds.[http://www.fightingrobots.co.uk/documents/Build-Rules.pdf] See '''[[Spinner Design]]'''.
* '''Handling:''' locking bars, sharp-edge covers, and a stand that keeps the wheels off the ground in the pits are standard requirements (see '''[[Pit Kit and Event Checklist]]''').
* '''Insurance:''' events at this scale need liability cover that explicitly includes robot combat, and some venues won't host large robots at all. See '''[[Running an Event]]'''.

==Getting started==
* '''Build smaller first.''' Most lightweight builders have already fought insects or a '''[[Featherweight]]''', because mistakes cost more, and hurt more, at 60 lb.
* '''Crew:''' plan on at least two people. One person drives; others handle the battery, repairs and lifting. Lifting a 60 lb robot safely is a two-person job.
* '''Shop space:''' you'll want a garage or shared makerspace with a welder, a drill press or mill, and an angle grinder, plus somewhere safe to test-drive. Never test a live weapon outside an enclosure (see '''[[Test Boxes]]''').
* '''Transport:''' a robot this size fits in a car, but you'll also need a dolly, a robot stand, batteries in fire-safe containers, and a tool kit.
* '''Check the events first.''' Contact the event organiser before you start building to confirm they'll run the class and what their arena can handle.

==Where they fight==
As of October 2026, 60 lb combat is rare.
* '''RoboGames''' (San Francisco Bay Area) lists a 60 lb class. Its most recent world championship was its 20th, held April 18–21 at the San Jose Convention Center, and its site says the next event is "to be announced".[http://robogames.net/index.php][http://robogames.net/events.php]
* '''[https://www.robotcombatevents.com/searches?search%5Bcategory%5D=event&search%5Bterms%5D=&search%5Btype_id%5D=10 RobotCombatEvents.com]''' lists only a handful of 60 lb events in recent years, among them the RoboGames events and the SmashBotz Wasteland Weekend events in California (2022–2024). Its 2026 rankings cover classes only up to 30 lb.[https://www.robotcombatevents.com/types?year=2026]
* '''NHRL''' tops out at 30 lb.[https://wiki.nhrl.io/wiki/index.php?title=NHRL_Rules]
* In the '''UK''', the FRA rules define a 30 kg class; the FRA site lists event organisers you can ask about lightweight fights.[http://www.fightingrobots.co.uk/documents/Build-Rules.pdf]

See '''[[Events]]''' and '''[[Major Competitions]]''' for current listings.

==Notable robots==
The best-documented lightweights come from the original BattleBots series. According to Wikipedia's results table:[https://en.wikipedia.org/wiki/BattleBots]
{| class="wikitable"
! Season !! Lightweight champion
|-
| BattleBots 1.0 (2000) || Backlash
|-
| BattleBots 2.0 (2000–2001) || Ziggo
|-
| BattleBots 3.0 (2001) || Dr. Inferno Jr.
|-
| BattleBots 4.0 (2002) || Ziggo
|-
| BattleBots 5.0 (2002) || Dr. Inferno Jr.
|}
Ziggo also won the 55 lb "Kilobots" class at Long Beach in 1999.[https://en.wikipedia.org/wiki/BattleBots] See '''[[Robot Combat History and TV]]''' for more history.

==See also==
* '''[[Featherweight]]''' (30 lb) and '''[[Middleweight]]''' (120 lb)
* '''[[Heavyweight]]''' (250 lb)
* '''[[RobotClasses|Robot Classes]]'''
* '''[[Armor and Materials]]''', '''[[VESC]]''', '''[[Switches]]'''
* '''[[Safety]]''' and '''[[Failsafes]]'''

Lightweight - Revision history

RobotRobot: New weight-class page: Lightweight