fly·​wheel | \ ˈflī-ˌhwēl How to pronounce flywheel (audio) , -ˌwēl How to pronounce flywheel (audio) \

Definition of flywheel

: a heavy wheel for opposing and moderating by its inertia any fluctuation of speed in the machinery with which it revolves also : a similar wheel used for storing kinetic energy (as for motive power)

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A heavy wheel attached to a rotating shaft, a flywheel smooths out delivery of power from a motor to a machine. The inertia of the flywheel moderates fluctuations in the speed of the engine and stores the excess energy for intermittent use. In automobile engines, the flywheel smooths out the pulses of energy provided by combustion in the cylinders, and provides energy for the compression stroke of the pistons. In power presses, the punching, shearing, and forming are done in a fraction of the operating cycle. During the rest of the cycle, the speed of the flywheel is built up by a comparatively low-powered motor, and most of the required energy for the cycle is provided by the flywheel.

Examples of flywheel in a Sentence

Recent Examples on the Web An attractive restaurant design and that phalanx of flywheels could be a real pip. Laura Reiley, Washington Post, "Cherry needs to bring more heat to the W Hotel," 2 Oct. 2019 By spinning the electric motor backward, the car will be able to turn the kinetic energy of braking into potential energy that’s stored in something like a flywheel or a small battery. Sean O'kane, The Verge, "IndyCar will race 900-horsepower hybrid cars starting in 2022," 1 Aug. 2019 Identifying and building flywheels became second nature to Freed. Charles Duhigg, The New Yorker, "Is Amazon Unstoppable?," 10 Oct. 2019 The formation of the uneven duopoly of Live Nation and the smaller AEG, plus an industry shift toward a flywheel business model, will, analysts say, further push touring into a two-sided environment. Dave Brooks, Billboard, "What to Expect at the 2019 Billboard Live Music Summit," 31 Oct. 2019 So when there's fighting between the partners, or no common direction, that makes a place less attractive to top doctors, which throws the whole flywheel off. David Jesse, Detroit Free Press, "DMC, Wayne State fight for years with millions of dollars and care of poor at stake," 20 June 2019 The motor is about the size of a small pizza, and fits nicely into the bellhousing, the bit of the transmission that covers the flywheel and the clutch. Alex Davies, WIRED, "A Very Fast Spin Through the Hills in a Hybrid Porsche 911," 10 June 2019 To increase or decrease the heat on an Argentinian-style parrilla grill, like the Grillworks or NorthFork, simply raise or lower the grill grate with the flywheel. Steven Raichlen, New York Times, "Grilling Turns Back to an Ancient Fuel: Wood," 29 June 2018 The Pista sheds nearly 200 pounds compared with the standard 488 GTB road car—almost 40 pounds from the engine alone (titanium con-rods, lightweight flywheel). Dan Neil, WSJ, "I Drove a Screaming Fast Ferrari Among Ordinary Cars," 21 Feb. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'flywheel.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of flywheel

1784, in the meaning defined above

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Time Traveler for flywheel

Time Traveler

The first known use of flywheel was in 1784

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Last Updated

21 Jan 2020

Cite this Entry

“Flywheel.” The Dictionary, Merriam-Webster Inc., Accessed 23 January 2020.

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More Definitions for flywheel


How to pronounce flywheel (audio) How to pronounce flywheel (audio)

English Language Learners Definition of flywheel

: a heavy wheel that is part of a machine and that controls the speed of machinery

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More from Merriam-Webster on flywheel

Rhyming Dictionary: Words that rhyme with flywheel

Spanish Central: Translation of flywheel

Nglish: Translation of flywheel for Spanish Speakers Encyclopedia article about flywheel

Comments on flywheel

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out of the ordinary or unreasonable

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