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 a Longeron?

Mary McMahon
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.

A longeron is part of the structure of an aircraft, designed to add rigidity and strength to the frame. It also creates a point of attachment for other structural supports, as well as the skin of the aircraft. They provide lengthwise support and the number of longerons present in an aircraft varies, depending on the size and how it is designed. Like other structural members, they need to be checked periodically for signs of damage that might compromise their function.

Materials like wood, carbon fiber, and metal can be used in longeron construction. Older aircraft were made almost entirely with wood, while it is a more rare construction material today because it does not provide as much strength and flexibility as other materials. The materials are carefully tested before being installed to make sure there are no cracks or other flaws that might cause them to fail once in place or while the plane is in use.

Each longeron attaches directly to the frame of the aircraft using bolts. In some planes, shorter longitudinal supports called stiffeners or stringers are fastened to the longerons. Confusingly, these terms are also sometimes used as alternate names for the longeron. The skin, whether made from metal, leather, canvas, or other materials, can be attached to the aircraft once the longerons are in place. Insulating material and lining may be installed on the other side, depending on how the plane is going to be used.

Historically, planes were skinned by stretching fabric over the body of the plane and doping it, which is to paint it with a chemical solution designed to stiffen and waterproof it. In addition, the dope also forced the fabric to shrink, creating a tight, even shell across the body of the aircraft. Unfortunately for pilots, doping materials were also extremely flammable and a single spark could send an aircraft up in flames. Modern aircraft usually use metal skins and have fire suppression systems to add to their safety.

People building a plane from scratch may custom-fabricate each longeron for their needs. In other cases, mass-produced structural supports are used. Most kits designed to help people build planes have all the components of the frame, and commercial aircraft manufacturers use their own fabrication facilities to produce longerons and other structural components for their assembly lines. When working with new aircraft designs, engineers spend time determining the required number, size, and shape of structural components to meet or exceed the load requirements.

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.
Mary McMahon
By Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a WikiMotors researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Discussion Comments
By Charred — On Dec 04, 2011

@miriam98 - I can’t imagine flying in a plane with fabric skins. Even without the flammable nature of the skin as a consideration, I wouldn’t feel safe knowing that fuselage was covered with little more than cloth.

I suppose these were single passenger airplanes, however, or aircraft used for farming missions or things like that. It’s hard to imagine a large passenger jet draped with cloth.

By miriam98 — On Dec 03, 2011

Whether made of metal or wood, I think longerons and stringers are an important part of the plane to ensure stability of its structure, especially when you experience turbulence that can shake the fuselage of the airplane.

I’ve also heard that some airplane crashes happened as a result of cracks in the longeron of the airplane. These may have been defects in manufacturing or as a result of wear and tear and poor maintenance.

I don’t recall what the exact reasons were, but if you’ve ever seen clips of an airplane skidding on a runway with its fuselage breaking up in two, you realize how important the longeron is.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a...

Learn more
WikiMotors, in your inbox

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

WikiMotors, in your inbox

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