Experimental aircraft represent a vibrant and innovative segment of the aviation world. While the term might sound like it refers only to high-tech laboratory projects, it actually covers a wide range of planes built by individuals in their own garages or hangars. These aircraft offer a unique way for pilots to experience flight, often at a lower cost and with more customization than standard factory-built planes.
In this guide, you will learn what qualifies as an experimental aircraft and the rules that govern them. We will also cover the benefits of building your own plane and the steps required to get one into the air safely. Whether you are a curious observer or a prospective builder, this information will help you understand this fascinating area of general aviation.
What is an Experimental Aircraft?
In the United States, the Federal Aviation Administration (FAA) uses the term “Experimental” to describe aircraft that do not have a standard type certificate. The most common sub-category is Experimental-Amateur Built (E-AB). These are aircraft where the builder has completed at least 51% of the construction for their own education or recreation.
Other types of experimental aircraft include those used for research and development, crew training, or exhibition. However, when most people talk about “experimentals,” they are referring to homebuilt planes. These can range from simple, single-seat ultralights to high-performance, four-seat cross-country machines.
Unlike standard aircraft, which must be built exactly to a manufacturer’s certified design, experimental aircraft allow for significant modification. This flexibility is why many new technologies, such as glass cockpit displays and efficient engine designs, often appear in the experimental market years before they reach commercial production.
The 51% Rule Explained
The “Major Portion” rule, commonly known as the 51% rule, is the cornerstone of the amateur-built category. This regulation requires that the builder perform the majority of the fabrication and assembly tasks. The intent is to ensure the aircraft is built for educational or recreational purposes rather than commercial profit.
To help builders meet this requirement, many manufacturers offer “quick-build” kits. These kits come with some of the more difficult structural work already completed by the factory. As long as the remaining work constitutes more than half of the total effort, the aircraft still qualifies for the experimental category.
It is important to keep a detailed builder’s log during the construction process. This log serves as proof to the FAA that you personally performed the work. Photos, dates, and descriptions of tasks are essential pieces of documentation for the final certification process.
Why Choose an Experimental Aircraft?
There are several reasons why a pilot might choose an experimental aircraft over a certified one like a Cessna or a Piper. For many, the primary motivation is the ability to maintain and repair the aircraft themselves. This can lead to significant cost savings over the life of the plane.
- Customization: You can choose your own avionics, engine, interior, and paint scheme.
- Performance: Many experimental designs are faster and more fuel-efficient than older certified designs.
- Education: Building an aircraft provides an unparalleled understanding of how every system on the plane works.
- Cost: While not always “cheap,” experimental aircraft often provide more performance for the dollar than new certified aircraft.
Additionally, experimental aircraft owners can perform their own annual inspections if they were the primary builder of the plane. This is a privilege not granted to owners of standard-category aircraft, who must hire a certified mechanic for every major inspection.
Types of Construction Methods
Experimental aircraft come in various construction styles, each requiring different skills and tools. Choosing the right method depends on your personal preferences and the space you have available for building.
Metal Construction
Aluminum is the most traditional material for aircraft. These planes are held together with thousands of rivets. Metal aircraft are known for being durable and easy to inspect for structural issues. Many popular kits, such as those from Van’s Aircraft, use this method.
Composite Construction
Composite planes are made from fiberglass or carbon fiber held together with epoxy resin. This method allows for smooth, aerodynamic shapes that are difficult to achieve with metal. Builders use foam cores and fabric layers to create a very strong and lightweight structure.
Wood and Fabric
This is the oldest method of aircraft construction. The frame is built from spruce or other high-quality woods and then covered with a specialized polyester fabric. While it requires a high level of craftsmanship, wood-and-fabric planes are often very light and have a classic aesthetic.
Safety and Regulations
A common misconception is that experimental aircraft are unregulated or unsafe. In reality, they are subject to strict FAA oversight. Before an experimental aircraft can fly, it must be inspected by an FAA official or a Designated Airworthiness Representative (DAR).
Once the aircraft passes inspection, it is issued an Operating Limitations document. This document outlines exactly where and how the plane can be flown. Initially, the aircraft must undergo a “Phase I” flight test period, which usually lasts between 25 and 40 hours.
During Phase I, the aircraft is restricted to a specific flight test area away from populated regions. The pilot must test the plane’s handling, stall speeds, and engine reliability. Only after these tests are successfully completed and logged can the aircraft enter “Phase II,” which allows for normal operations across the country.
Pilot Requirements
You do not need a special “experimental license” to fly an amateur-built aircraft. However, you must hold a valid pilot certificate and the appropriate ratings for the type of aircraft you are flying. For example, if the plane has a tailwheel, you must have a tailwheel endorsement.
Safety is the top priority when transitioning to an experimental plane. Because every experimental aircraft is unique, the handling characteristics may differ from the trainer planes used in flight schools. It is highly recommended to seek transition training from an instructor who has experience in that specific model.
The Experimental Aircraft Association (EAA) offers many resources for pilots, including flight advisor programs. These advisors help builders prepare for the first flight and ensure they are mentally and technically ready for the task.
How to Start Your Journey
If you are interested in experimental aircraft, the best first step is to join a local chapter of the EAA. These groups are filled with experienced builders and pilots who are often eager to share their knowledge and show off their projects.
- Research Designs: Look at different kits and plans to see which fits your mission (e.g., cross-country travel or aerobatics).
- Visit a Fly-in: Events like AirVenture in Oshkosh, Wisconsin, allow you to see hundreds of experimental aircraft in person.
- Take a Workshop: Many organizations offer weekend classes on riveting, composites, or engine maintenance.
- Assess Your Space: Ensure you have a garage, basement, or shop with enough room for the wings and fuselage.
Building an aircraft is a long-term commitment that can take anywhere from 500 to over 3,000 hours of labor. However, the reward of flying a machine you built with your own hands is considered by many to be the pinnacle of aviation achievement.
Conclusion
Experimental aircraft offer a pathway to affordable, high-performance flying while fostering a deep understanding of aviation mechanics. While the building process requires patience and attention to detail, the result is a customized aircraft that meets your specific needs. By following FAA regulations and engaging with the builder community, you can safely navigate the world of homebuilt aviation.
For more information on aviation and technical hobbies, explore our other articles on pilot certifications and DIY workshop safety. If you are ready to begin your project, reaching out to your local aviation community is the best way to ensure your success.