fly·​wheel | \ ˈflī-ˌ(h)wēl 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 Activating launch control raises revs to a relatively lazy 2500 rpm before clutch slaps against flywheel, but at that rpm, the 8.0-liter W-16 is already making up to 562 horses. Tony Quiroga, Car and Driver, "Bugatti Chiron Is Now the Quickest Car We've Ever Tested," 1 Jan. 2021 Fitness experts recommend the Schwinn IC3 Indoor Cycling Bike for its 40-pound flywheel that’s powered by a smooth and silent belt drive. Zoe Malin, NBC News, "Exercise bike bestsellers: Most purchased stationary bikes we covered," 24 Dec. 2020 The flywheel of hope and angst that had driven the writing lost its momentum. James Parker, The Atlantic, "What Drives Writers to Drink?," 24 Dec. 2020 Friction resistance systems work much in the same way that a vehicle brake pad functions, with varying degrees of resistance directly correlating to the amount of pressure the pad applies to the flywheel. Popsci Commerce Team, Popular Science, "Best exercise bike: Get your miles in without leaving the house," 19 Dec. 2020 Can regulators put the brakes on’s flywheel? Dan Gallagher, WSJ, "Crashing Amazon’s Third Party," 10 Nov. 2020 This machine features a 30-pound flywheel, as well as adjustable pedals, seat and handlebars. Nicole Saunders, NBC News, "14 best affordable indoor spin bikes to up your home workout in 2020," 29 Oct. 2020 Indeed, during the pandemic, many people are reacquainting themselves with a common household flywheel: the exercise bike. Caroline Delbert, Popular Mechanics, "To Keep Energy Flowing, the U.K. Is Turning to the Flywheel," 9 July 2020 Learning on one car is also way easier than cadging rides here and there because every clutch pedal, every flywheel, every transmission is a little different. Jared Gall, Car and Driver, "Learn to Drive a Manual With This One Easy Trick," 22 Aug. 2020

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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Statistics for flywheel

Last Updated

6 Jan 2021

Cite this Entry

“Flywheel.” Dictionary, Merriam-Webster, Accessed 24 Feb. 2021.

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More Definitions for flywheel



English Language Learners Definition of flywheel

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

More from Merriam-Webster on flywheel

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

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