The Evolution of Aircraft Brakes
The idea of stopping an aircraft without brakes may seem absurd, yet early aircraft had no braking systems at all. In their earliest forms, aircraft were relatively light and slow, relying on long landing distances, headwinds, and engine shutdowns to decelerate after touchdown.
Over the decades, aircraft braking systems have progressed from non-existent to rudimentary mechanical designs, advancing to now incorporate hydraulic and electronically augmented systems that enable heavy aircraft to land safely at high speeds. This blog will explore how aircraft brakes have improved over time, touching on the most notable milestones.
Expander Tube Brakes
One of the first true braking systems used in aviation was the expander tube brake, introduced around the 1930s and continuing in use through the mid-20th century in small, light aircraft. This system worked by expanding a rubber tube inside a brake drum, pressing brake linings outward against the drum to create friction. Mechanically simple, this type lacked the heat resistance and braking power required for heavier or faster aircraft, leading to its eventual obsolescence.
Single Disc Brakes
The introduction of single disc brakes in the post-WWII period marked a huge improvement in stopping power. Still used in many light aircraft, this system features a single metal disc bolted to the wheel with hydraulic calipers pressing brake pads against both sides to create friction. Its relatively simple design, light weight, and ease of maintenance make it ideal for general aviation planes that do not depend on high-speed braking performance.
Dual and Multiple Disc Brakes
As aircraft started to grow larger and demand higher braking forces in shorter distances, notably with the rise of jet-powered military and commercial aircraft, engineers turned to dual-disc and multiple-disc brakes to deliver the necessary stopping force. These systems added additional friction surfaces by stacking more discs within a compact housing. However, they also produced more heat, which prompted the development of better thermal management solutions in later braking technologies.
Floating and Fixed Disc Brakes
By the late 20th century, refinements to disc brake systems led to the widespread adoption of floating and fixed disc brakes in various aircraft builds to improve responsiveness, wear characteristics, and reliability under repeated landings or asymmetric loading. Floating disc brakes allow the disc to move laterally within the wheel assembly. When the outboard brake pads press against the disc, the disc shifts slightly, causing the inboard pads to engage as well, promoting even pressure distribution and wear. Meanwhile, fixed disc brakes use a stationary disc while the caliper assembly floats, enabling symmetrical pressure for better consistency under variable loading conditions.
Segmented Rotor Brakes
First introduced in the late 1980s and gaining broader use through the 1990s, segmented rotor brakes were developed to improve thermal management and maintenance efficiency. Unlike solid discs, these brakes consist of multiple arc-shaped rotor segments mounted around a carrier. This segmented design presents better heat dissipation to lessen the risk of thermal distortion, as well as allows for individual segment replacement during maintenance.
Other Braking Advancements
Carbon Brakes
Though not a specific brake variant, a particularly major invention in braking technology are carbon brakes, which came about in the 1980s. Made from carbon-carbon composite materials, these brakes are exceptionally heat resistant during high-energy braking events, significantly lighter, and have a longer service life. Carbon brakes are standard on most large commercial airliners and high-performance military aircraft today, presenting especially effective performance during operations such as short-field landings or rejected takeoffs, where braking energy and thermal loads are substantial.
Hydraulic Brake Actuation Systems
Aircraft brakes, specifically hydraulic ones, need actuation systems to function effectively. As brake hardware evolved, the systems responsible for actuating them followed. The three main types employed are:
- Independent Systems: These self-contained hydraulic circuits have their own reservoir and pump, used mainly in light aircraft for reliable braking independent of the main aircraft hydraulics.
- Booster Systems: These systems augment manual pedal force with hydraulic pressure from the main system, providing improved braking performance for medium-sized aircraft that do not require full automation.
- Power Brake Systems: Fully reliant on an aircraft’s hydraulic infrastructure, these systems provide the consistent, high-pressure actuation demanded of large aircraft.
Safety Features
Modern aviation places heavy emphasis on safety and backups in case of emergency. One such example are emergency brake systems, which operate independently of the main hydraulic supply. Often powered by dedicated accumulators or alternate hydraulic sources, they allow aircraft to decelerate safely during a primary system failure.
Additionally, anti-skid systems, first introduced in commercial aviation in the 1960s and continually refined since, automatically modulate brake pressure to prevent wheel lockup during heavy braking. They are especially imperative on slippery or uneven runway surfaces, improving control and reducing the risk of skidding.
Explore Various Aircraft Brake Components on Aerospace Aviation 360
From the earliest skid-stopped landings to the advanced braking systems seen on modern aircraft, the evolution of aircraft brakes has been a testament to the progress of aviation engineering. Each iteration brings with it more increased precision, reliability, and safety. To maintain these high standards, only reliable and compliant brake components should be used in repairs, which Aerospace Aviation 360 provides.
As an ASAP Semiconductor-operated platform, you can find a vast inventory of aircraft brake parts and more items from reputable entities, all thoroughly vetted for quality and traceability. Additionally, with a streamlined procurement process and dedicated experts to assist, securing the exact parts you need has never been easier. To see how we can save you time and money while accommodating your requirements, connect with our team today.
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