RobotRobot: Link new pages (round 3)

2026-10-17T23:26:44Z

Link new pages (round 3)

RobotRobot: New weapon-type page: Horizontal Spinners

2026-10-17T17:08:32Z

New weapon-type page: Horizontal Spinners

New page

A '''horizontal spinner''' is a robot whose weapon spins flat, parallel to the floor, on a vertical axis. The weapon usually sticks out past the front (or all round) of the robot, so it can hit opponents from a wide range of angles. Horizontals are popular in every insect class, partly thanks to famous robots like Tombstone. This page covers what's specific to horizontals; for the shared engineering (stored energy, tip speed, bite, spin-up, materials, shafts and bearings) see '''[[Spinner Design]]'''. For other weapon types see '''[[Weapons]]'''.

''Safety: a horizontal throws broken parts sideways, which is where people stand. Only spin it up in an arena or a '''[[Test Boxes|test box]]''', and always fit a weapon lock outside the arena. See '''[[Safety]]''', '''[[Failsafes]]''' and the '''Safety''' section below.''

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==Variants==
* '''Bar:''' a long bar with a tooth at one or both ends, usually extending well beyond the chassis. Long reach and simple to make, but a bar stores the least energy of the common shapes for its mass and diameter.[https://runamok.tech/AskAaron/spinner_FAQ.html] Single-tooth (asymmetric) bars give more bite.
* '''Disc:''' a round plate with one or more teeth. Stores more energy than a bar of the same mass and size and is harder to bend, but has less reach for its weight.[https://runamok.tech/AskAaron/spinner_FAQ.html]
* '''Shell and ring spinners''' spin the robot's whole outer body or a ring around it. They are full-body weapons with their own challenges; see '''[[Weapons#Shell spinner|Weapons – Shell spinner]]''' and '''[[Weapons#Ring spinner|Ring spinner]]'''.
* '''Undercutters''' mount the weapon low, just above the floor, under or in front of the chassis. They attack wheels, wedge edges, forks and the underside of opponents.
* '''Overhead / high-mounted''' horizontals sit above the chassis. They can reach over wedges to hit the opponent's body and top-mounted weapons, but leave the low front edge open to wedges and verts (see '''[[Weapons#Horizontal spinner|Weapons]]''').

Some designs are invertible: the weapon sits mid-height, so the robot works either way up, acting as an undercutter one way and a high spinner the other.

==Strengths and weaknesses==
'''Strengths'''
* '''Wide attack zone.''' A horizontal can hit from the front and sides, and it's easier to aim than a vert.
* '''No gyroscopic wheel lift when turning.''' The weapon's axis points straight up and doesn't change direction when the robot turns, so a horizontal can turn quickly with the weapon at full speed.[https://runamok.tech/AskAaron/spinner_FAQ.html]
* '''Long reach''' with a bar keeps opponents away from the chassis.
* '''Good against exposed wheels and parts.''' Undercutters in particular can tear off wheels and break forks.

'''Weaknesses'''
* '''Recoil.''' The hit pushes the horizontal sideways and backward across the floor. Against a heavy, stable opponent, a big hit can throw the horizontal into the wall or a hazard, and the shock can damage its own frame.[https://runamok.tech/AskAaron/weapon.html]
* '''Tipping and gyro tumble.''' If the robot gets tilted (by riding up a wedge, or being hit from below), the gyroscopic effect can make it tumble or "dance" uncontrollably.[https://runamok.tech/AskAaron/spinner_FAQ.html]
* '''Low wedges and verts''' can get under the weapon.
* '''Usually only one effective way up''' unless designed to be invertible.

==Matchups==
Weapon matchups are often compared to rock-paper-scissors: no design beats everything, and driving and build quality usually matter more than the weapon type.[https://runamok.tech/AskAaron/design.html][https://runamok.tech/AskAaron/spinner_FAQ.html] Typical tendencies:
{| class="wikitable"
! Opponent !! How it usually goes for a horizontal
|-
| '''[[Vertical Spinners|Vertical spinner]]''' or '''[[Drum Spinners|drum]]''' || Often difficult. The vert or drum can hit the horizontal's weapon from below and throw the whole robot, and its recoil goes into the floor while the horizontal's goes sideways. A horizontal can still win by hitting the vert's weapon, forks, wheels or side, especially with a strong, low weapon.
|-
| '''[[Wedges and Control Robots|Wedge or control bot]]''' || Depends on the wedge. A low, hard, well-supported wedge can deflect hits and push the horizontal into walls. A horizontal can break hinged forks or wedgelets and attack wheels; high-mounted horizontals can reach over the wedge.
|-
| '''[[Flippers and Lifters|Flipper or lifter]]''' || Often favorable if the horizontal keeps the flipper away with its reach. If the lifter gets underneath, it can tip the horizontal and set off a gyro tumble.
|-
| Another horizontal || A weapon-on-weapon fight. Strong weapons, good bearings and good weapon height matter most; both robots can get thrown hard.
|-
| '''[[Hammers and Axes|Hammer or axe]]''' || Usually favorable, since the horizontal's reach can hit before the hammer is in range.
|}

==Design considerations==
===Recoil and wall bounce===
Every hit pushes the horizontal back as hard as it pushes the opponent. Since a horizontal can't push that force into the floor the way a vert can, it gets knocked sideways and often bounces off the arena wall, which can damage it or leave it facing the wrong way. Ways to cope:
* A '''stiff, strong frame''' and well-supported weapon mount so the robot survives its own hits.
* '''Good traction''' and a low center of gravity.
* '''Drive control after the hit:''' expect to be knocked around and be ready to recover.
* '''Bite matters:''' a weapon that grips the opponent transfers energy into it; one that glances off mostly sends both robots spinning. See '''[[Spinner Design#Bite|Bite]]'''.
Horizontals can also reach the arena walls. Under SPARC rules, spinning weapons that can hit the outer arena walls in normal use need the event's approval in advance.[https://sparc.tools/SPARC_Robot_Construction_Specifications_v1.7.pdf]

===Weapon height===
Weapon height decides what you hit. A low weapon hits wheels, wedge edges and forks; a high one hits bodies, top armor and weapons. Undercutters shouldn't be too low: leave enough clearance that floor bumps, seams and jolts from hits don't make the blade touch the floor.[https://runamok.tech/AskAaron/weapon.html] Some builders make weapon height adjustable with spacers, to suit each opponent.

===Gyroscopic lifting===
A horizontal turns freely, but its weapon still resists tilting. If the robot rides up a wedge or gets hit from below, the weapon can push it into a wobble or tumble, and spin-up torque can also tilt the chassis. A low, wide chassis and a weapon close to the chassis help. See '''[[Spinner Design#Gyroscopic effects|Gyroscopic effects]]'''.

===Shafts and mounting===
The weapon shaft takes big sideways loads on every hit. Many insect horizontals use a '''dead shaft''' (a fixed bolt or shaft supported top and bottom by the chassis) with bearings in the weapon hub, rather than relying on the motor's own shaft. Undercutters often look like an upside-down full-body spinner mount, with the shaft ends rounded and sticking out below the blade and above the chassis.[https://runamok.tech/AskAaron/weapon.html]

==Powering a horizontal in the insect classes==
''As of 2026; parts change quickly.''
* '''Brushless outrunner motors''' are the standard weapon motor at every insect weight (see '''[[Motors]]''', '''[[Insect Class Motors]]''' and '''[[ESCs]]'''). For beetleweights, Ask Aaron suggests about 150 W per pound of robot and about 6% of the robot's weight, typically a 28 mm or 36 mm outrunner.[https://runamok.tech/AskAaron/spinner_FAQ.html]
* '''Belt drive''' from a motor beside the weapon is common because the belt can slip a little and protect the motor from shock.[https://runamok.tech/AskAaron/weapon.html] Outrunners aren't designed for heavy sideways loads on their cans, so get the belt tension right and support the pulley close to the motor.[https://runamok.tech/AskAaron/weapon.html]
* '''Direct drive / hub motors''' (the weapon bolted to the motor's can) are common in 150 g and plastic ant horizontals because they're compact, but every impact goes straight into the motor bearings.
See '''[[Spinner Design#Driving the weapon|Spinner Design]]''' for more.

==Safety==
* '''[[SPARC Robot Construction Specifications|SPARC rules]]''' require a clearly visible weapon lock whenever the robot is out of the arena, and it must be in place when you power on. Spinners must stop within 60 seconds of power being removed, using their own braking, and must not spin outside the arena or a testing area.[https://sparc.tools/SPARC_Robot_Construction_Specifications_v1.7.pdf] Check your event's own rules too.
* A long horizontal bar is easy to lock with a strap or pin through the chassis; make sure the lock really stops the weapon and can't fall off.
* Test the weapon only in a '''[[Test Boxes|test box]]''' or arena. Horizontals throw debris sideways, so stand well clear of the weapon's plane even outside the box.
* Check your '''[[Failsafes|failsafe]]''' every time you change radio settings, and see '''[[LiPo Battery Safety]]'''.

==Famous examples==
''From BattleBots robot profiles, as of 2026.''
* '''Tombstone''' – horizontal bar spinner; BattleBots Season 2 (2016) champion.[https://battlebots.com/robot/tombstone-2019/][https://battlebots.com/robot/tombstone/]
* '''Valkyrie''' – horizontal disc spinner.[https://battlebots.com/robot/valkyrie/]
* '''Blade''' – horizontal bar spinner from South Korea.[https://battlebots.com/robot/blade/]

==Open-source designs==
A few printable horizontal spinners from the list on '''[[3D Printing]]''' (more there):
* '''[https://www.printables.com/model/1394252-nemo-plastic-antweight Nemo]''' (1 lb plastic ant) – a beginner-friendly spinner with only three printed parts.
* '''[https://www.printables.com/model/397240-tombstone-tribute-3d-printed-1lb-combat-robot Tombstone Tribute]''' (1 lb).
* '''[https://github.com/Zoomwag/Undercutter-Battlebot Undercutter Battlebot]''' (150 g) – undercutter with STEP files.
* '''[https://github.com/Adambomb210/DNS-Combat-Robot DNS]''' (3 lb) – forked undercutter.
* '''[https://www.printables.com/model/1453255-endbots-vector-beetleweight-3lb-combat-robot-remix Endbots Vector Remix]''' (3 lb) – a remix of the popular Endbots Vector.

==See also==
* '''[[Spinner Design]]''' – energy, tip speed, bite, gyroscopic effects, materials
* '''[[Vertical Spinners]]''' and '''[[Drum Spinners]]'''
* '''[[Weapons]]''' – all weapon types, including shell and ring spinners
* '''[[Melty Brain]]''' – full-body spinners that can drive while spinning
* '''[[Hardening Motors]]'''
* '''[[Test Boxes]]''', '''[[Safety]]''', '''[[Failsafes]]'''
* '''[https://runamok.tech/AskAaron/spinner_FAQ.html Ask Aaron – Spinning Weapon FAQ]'''

← Older revision		Revision as of 23:26, 17 October 2026
Line 59:		Line 59:

	===Shafts and mounting===		===Shafts and mounting===
		+	See '''[[Weapon Shafts, Bearings and Mounting]]''' for details.
		+
	The weapon shaft takes big sideways loads on every hit. Many insect horizontals use a '''dead shaft''' (a fixed bolt or shaft supported top and bottom by the chassis) with bearings in the weapon hub, rather than relying on the motor's own shaft. Undercutters often look like an upside-down full-body spinner mount, with the shaft ends rounded and sticking out below the blade and above the chassis.[https://runamok.tech/AskAaron/weapon.html]		The weapon shaft takes big sideways loads on every hit. Many insect horizontals use a '''dead shaft''' (a fixed bolt or shaft supported top and bottom by the chassis) with bearings in the weapon hub, rather than relying on the motor's own shaft. Undercutters often look like an upside-down full-body spinner mount, with the shaft ends rounded and sticking out below the blade and above the chassis.[https://runamok.tech/AskAaron/weapon.html]

Horizontal Spinners - Revision history

RobotRobot: Link new pages (round 3)

RobotRobot: New weapon-type page: Horizontal Spinners