Horizontal flywheels

Horizontal flywheels
Hypno-Disc tears into Splinter
Weapon Category	Heavy rotating weapons
Robots
Pioneer(s)	Hypno-Disc
Notable Robots	Botwork, Disc-O-Inferno, 13 Black, Destructive Criticism, Supernova, Ninjitsu

"Since Hypno-Disc has come on the scene, people have started building very powerful spinning discs..."

— Martin Smith

Horizontal flywheels are a type of heavy rotating weapon, and among the most famous and destructive weapons seen in Robot Wars. Their pioneer - and most successful example - was Hypno-Disc in Series 3, which finished runner-up on its debut and inspired numerous derivatives and imitations.

Alongside Hypno-Disc, machines including 13 Black, Destructive Criticism, Botwork, Disc-O-Inferno and Supernova also achieved success with horizontal flywheels in the Classic Series. However, they were less prevalent in the Revival Series, owing to a more distinct variety between these, bar, drum and vertical flywheel types.

Definition

• A flywheel (alternatively referred to as a spinning disc or simply disc) is a comparatively heavy disc weapon that spins at high speeds. One or more 'teeth' are welded or integrated into certain parts of the disc with the intention of gouging, tearing and concussing other robots.
• These flywheels were mounted horizontally, to leave gashes in the sides of other robots as well as ripping off whole armour sections and tearing off exposed components such as wheels.

Advantages and Disadvantages

Advantages

Hypno-Disc destroys Stealth's lifter

Supernova tears through Ming 3's self-righting mechanism

The gyroscopic forces of Hypno-Disc's disc allowed it to remain upright after being flipped by Bulldog Breed in Series 6

• Horizontal kinetic flywheels are amongst the most destructive weapons, capable of slashing, tearing and ripping off components and entire sections of armour, as well as knocking opponents out in one blow. Hypno-Disc was especially notable for this throughout its appearances, effectively destroying robots such as Robogeddon, Stealth, V-Max and Splinter, as well as landing one-hit knockout blows to Firestorm 3 and Barber-Ous 2.
  • They are even capable of causing enough damage to force opponents to retire and withdraw from future battles. Atomic 2, Bulldog Breed 3 and Steg-O-Saw-Us were all forced to forfeit places in battles held after their defeats against Hypno-Disc due to the damage the latter inflicted on them, whilst Team Velocirippa had to build a new model of Velocirippa after the original was severely damaged by Disc-O-Inferno.
• These flywheels, as with horizontal bar spinners, can provide the robot with a large degree of protection from the front or sides, making it difficult for opponents to attack the robot from where the disc was positioned.
• A horizontal flywheel offers a larger attack range than its vertical counterpart, offering them a considerable advantage over vertical flywheels.
• These types of flywheels are easily compatible with an invertible design, with Disc-O-Inferno, Supernova and DisConstructor being among numerous examples of this. Indeed, in Series 7, only three of the fourteen entrants wielding horizontal flywheels were not invertible.
  • Unlike their vertical counterparts, horizontal flywheels on invertible robots can also operate equally as effectively while upside-down without requiring a reversible speed controller. If designed to spin in one direction while upright, the weapon will simply keep spinning in the opposite direction once the whole robot is inverted.
• Depending on their size and power, the gyroscopic forces of a horizontal flywheel can prevent the robot wielding it from being flipped over when the weapon is spinning, in a similar way to horizontal bar spinners. This was demonstrated during Hypno-Disc's Series 6 battle with Bulldog Breed, where the gyroscopic forces of its flywheel allowed it to land on its wheels when it was thrown into the air by the latter.

Disadvantages

Disc-O-Inferno catches fire en-route to victory against Killer Carrot 2

Hypno-Disc's disc lies dormant after Shunt axes through it

Supernova hurtles towards the pit, after losing its teeth and being lifted at an angle by TR2

• To make flywheels powerful, it was necessary for the disc to take up a significant amount of the robot's weight. Robots such as Supernova and Topbot were forced to wield less durable armour and have small holes drilled through the disc, wheels or armour in order to keep them within the weight limit.
• As with other heavy rotating weapons, the higher kinetic energy of a horizontal flywheel, and increased power required for them to function, can reduce the reliability of a robot's weapon. This factor caused most of Hypno-Disc's defeats throughout its appearances, as did Disc-O-Inferno's near-loss in Series 6 to Killer Carrot 2.
• Horizontal flywheels often have a pronounced gap between the disc and the part of the chassis where they are mounted, which can allow them to be hooked from underneath by lifting or flipping weapons. A-Kill and Devastator were especially susceptible to this issue.
• These flywheels are especially vulnerable to getting stopped or severely damaged by overhead weapons. Shunt's axe blow on Hypno-Disc during its Series 4 Grand Final battle with Pussycat was enough to not only stop the disc, but also leave a hole through its cover and cause severe damage to the robot's gearing.
• The gyroscopic forces of a flywheel can adversely affect the robot's control and stability, particularly when spinning at full speed. Supernova's flywheel was notable for aggravating the robot's control problems whenever it was damaged or positioned at an angle, once carrying it towards the pit in Series 8 after losing its teeth and being positioned on its side by TR2.

List of Robots with Horizontal Flywheels

Robots are listed alphabetically.

DESKTOP MODE ONLY: Robots which are not heavyweight entries are listed with a green background.

Robot	Series Appearances with Horizontal Flywheels	Notes	Image
13 Black	Series 5-7, Extreme 2	Had two flywheels, one resembling a roulette wheel, the other with the number 13 painted on it. Each disc could be operated independently in either direction. Was capable of "walking" on its discs whilst inverted. Series 6 Semi-Finalist.
A-Kill	Series 6	Was described by Jonathan Pearce as looking like 'two dustbin lids squashed together'.
Botwork	Dutch Series 1	Dutch Series 1 Grand Finalist.
Chip	Extreme 2, Series 7	Forced to replace with a static spike after the disc - capable of running on multiple voltages - broke in Extreme 2. Series 7 incarnation used a 1,500rpm disc powered by a 4.5hp Magmotor.
Coffin-Bot	US Season 1	Loanerbot; competed in the US Championship as a substitute for Skullmania.
Demolition Man	Series 7	11kg, 2,000rpm disc had four teeth and could be pivoted upwards to act as a srimech.
Destructive Criticism	US Season 2, Nickelodeon	US Season 2 Grand Finalist.
Devastator	Series 7
Diabolus	Series 7	Pair of 18-inch, 1,000rpm horizontal discs mounted at the front; both machined with weight-saving holes.
Direct Action	Extreme 2	25kg flywheel with bolt-cutting teeth, spinning at 850rpm. Tip speed increased to 120mph following initial testing.
Disc-O-Inferno	Series 4, 6-7, Extreme 1	Extreme 1 Annihilator Champion.
DisConstructor	Series 7-8	Titanium disc was mounted at a 15-degree angle; rotated at 2,000-3,000rpm in the Revival Series.
Double Trouble	Series 6	Had two small motorcycle flywheels located side-by-side, similar to Shredder, capable of rotating at up to 6,000rpm.
Dragbot	US Season 2	2,200rpm rear disk, used in conjunction with the robot's wedge shape and front catching spikes.
Expulsion	Series 9	'Blade sandwich' flywheel made out of 10mm military grade steel; featured four retractable teeth which emerged from the disc as it spun up. Bi-rotational capability to 'slash' or 'skewer' opponents. Returned for Series 10 with an angled face spinner.
Hodaf The Bad	Series 7	Small undercutting disc, used alongside a rear-hinged flipper.
Hypno-Disc	Series 3-6, Extreme 1-2	First and most notable robot with a horizontal flywheel. Three-time Grand Finalist and winner of the Most Original Entry award in Series 3. Weighed at 18-20kg and spun up to 900rpm by the time of Series 6.
MaxiMill	Dutch Series 1, Extreme 1	Four-bladed flywheel incorporated a thin construction, but 1kg steel blocks as 'teeth'.	MaxiMill (Extreme 1)
Mayhem	Series 7	Four-bladed 'high energy' disc, weighing 16kg and spinning at 2,000rpm.
Mazakari	Series 4	70cm diameter; two-toothed disc had to have holes cut in as the robot arrived at filming overweight.
Mean Streak	Series 7	Two small horizontal discs made from motorcycle flywheels, connected together with gear-like teeth at the top. Rotated at 3,000rpm. Erroneously stated to have four discs on its statistics board and by Jonathan Pearce.
Mega Morg	Series 7	Rear horizontal spinner used in tandem with a front lifter/flipper. Disc had previously been mounted vertically on the Extreme 2 build of Mini Morg.
Militant	Extreme 2	The only non-heavyweight competitor to be armed with a horizontal spinner.
Ninjitsu	US Season 2, Nickelodeon	24-inch, square-shaped disc with four teeth; rotated at 3,000rpm.
PP3D	Series 8-9	An 'undercutting' HARDOX flywheel, mounted beneath the robot's chassis and weighing 31kg. Built by Gary Cairns. Rotated at 1,800rpm in Series 8, and at 2,500rpm in Series 9, generating up to 65 kilojoules in the latter.
S.M.I.D.S.Y.	Series 5-7, Extreme 1-2	Rear 15kg disc added following the introduction of the 100kg weight limit in Extreme 1/Series 5. Considered a secondary weapon used in tandem with a set of lifting/grabbing jaws, itself later replaced with a full-sized lifter for Series 6-7. Series 5 and 7 Heat Finalist with the disc, though S.M.I.D.S.Y. often relied on its front weapons and pushing power to win battles.	Series 6 incarnation
Scorpion	Series 6-7	Competed in Series 6 as Spirit of Scorpion. 40cm rear disc often described as a 'sting in the tail'; spinning at up to at 7,000rpm in Series 6. Weapon reduced to 5,500rpm for Series 7, by this time powered by an LEM motor rated at 36V.
Short Circuit	Series 6	Small front disc used alongside a larger ramming spike at the rear.
Spin Doctor	US Season 2	Built by Team LOGICOM; 29lb, six-bladed disc experimentally made out of urethane. Spun at up to 3,000rpm. Runner-up of the Nickelodeon International Tag Team, partnered with The Revolutionist.
Supernova	Series 5-9	Runner-up in The Third World Championship. Powerful 22kg, two-toothed disc spinning at 2,000rpm in earlier incarnations. Series 9 incarnation included a new hardened steel disc with two integrated teeth, rotating at up to 2,500rpm.
The Cat	Series 9	Stock robot built for the Battle of the Stars specials. Designed by celebrity captain Suzi Perry with a rear disc weighing 30kg, spinning at up to 1,200rpm. Finished runner-up in the first Battle of the Stars episode.
The Scrapper	Series 7	20kg front disc spinning at 950rpm.
Tip-Top	Series 5	Four-bladed substantial inertia flywheel, powered by a 72cc petrol disc cutter engine. Used the gyroscopic forces from its disc to move the robot.
Topbot	Series 7	30kg, 64cm diameter flywheel. Mounted underneath the robot's chassis in the upright orientation, similarly to modern undercutters. Powerful enough to damage the polycarbonate arena wall panels.
Tornado	US Season 2	Mounted on a metal frame surrounding the robot, as part of an 'anti-crusher weapon' designed specifically to fight against Razer. Only used once in the Extreme Warriors Season 2 International Championship, before being replaced with a horizontal bar spinner for Series 6 and Extreme 2.	Tornado with the first version of its 'anti-crusher weapon' (US Season 2)
Trouble 'n' Strife	Series 5	20kg, rear-mounted flywheel with two teeth, spinning at 1,000rpm and mounted beneath the chassis. Combined with a rear-hinged flipper at the front.
Twisted Metal	Dutch Series 1-2	Dutch Series 1 Grand Finalist; flywheel weighed 17kg and rotated at 800rpm in this original incarnation. Competed in Dutch Series 2 as Twisted Metal EVO.
Unibite 2.0	US Season 2	Replaced the large cutting disc weapon used by the original Unibite.
Vortex Inducer	Dutch Series 2	Mounted on an arm which could twist in either horizontal or vertical positions.
Wild Thing	Series 5	Disc was fixed at a 45-degree angle; used in tandem with a lifting arm which acted as a srimech.

Trivia

• In Series 7, eleven of the fourteen competitors with horizontal flywheels lost in Round 1. Only S.M.I.D.S.Y., featuring the smallest flywheel, made it to the Heat Final stage.