We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What is Propeller Balancing?

By Lori Kilchermann
Updated May 23, 2024
Our promise to you
WikiMotors is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At WikiMotors, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

Propeller balancing is the practice of taking vibration out of the propeller unit. Placed on a pivot axle, two-blade propeller balancing is accomplished by removing material from the heaviest blade to make both blades of the propeller weigh the same. Often, with multi-blade propellers, such as three-, four- and five-blade propellers, a propeller balancing level is used to accurately balance the propeller. Looking much like a bubble balancer used on automotive tires and wheels, the propeller is balanced by removing material from the heaviest blades until the level is zeroed.

Left unbalanced, a propeller could literally vibrate and shake a vessel apart. Bearing life is dramatically increased by propeller balancing as well. In an aircraft application, this is extremely important due to the propeller being attached to the engine's crankshaft. If propeller balancing is not accomplished, the engine could suffer crankshaft bearing failure, resulting in catastrophic engine failure. In a nautical application, propeller vibration could potentially sink the vessel if water seals are damaged.

Wooden aircraft propeller balancing is accomplished by sanding the heavier side of the propeller until it balances when placed on an axle between two points. With the propeller mounted on an axle, the axle is placed between two stands and allowed to rest. The propeller blades are then placed horizontally and released. If the blade begins to move, the propeller blade that begins to dip is the heaviest, so it is sanded. This operation is repeated until the propeller remains completely motionless when left to rest horizontally. When this occurs, propeller balancing has been accomplished.

With metal propeller blades, material is removed from the heavy blade by drilling into the propeller hub at the base of the propeller blade. As the drill bit makes its way into the hub, material is removed in the form of small curls of metal. In some instances, weight is added to the lighter side and then affixed to the propeller by welding, brazing or soldering. Often, the amount of weight by which the propeller is out of balance dictates the manner in which the unit is balanced.

In boat propeller balancing, the blades are often filed until the correct amount of weight has been removed to ensure the propeller is balanced. On very large ship propellers, balancing is often accomplished by adding slugs of Mallory metal to the lightest blades. Mallory metal is a very dense, and therefore very heavy, metal often used in balancing automobile crankshafts. When using this type of material to balance a propeller, the propeller is drilled, and the slug of Mallory metal is inserted and welded in place.

WikiMotors is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
By anon946507 — On Apr 20, 2014

What is meant by a propeller out-of-balance?

WikiMotors, in your inbox

Our latest articles, guides, and more, delivered daily.

WikiMotors, in your inbox

Our latest articles, guides, and more, delivered daily.