Master cylinders are located in the cockpit on each of the pilot’s rudder pedals. They are used to turn a force into a pressure to actuate the brakes on an aircraft. Parker’s push-type master cylinders require a separate remotely-mounted reservoir or connection to a low-pressure aircraft return system.

Push-type master cylinders are the most common type of master cylinder in the general aviation market. The aircraft’s linkage is set up to push the rod of the master cylinder. This action is achieved when the pilot puts a foot on the brake pedal to stop the aircraft.

As the pilot depresses the pedal, the master cylinder’s rod retracts into the master cylinder’s housing. This action causes three things to happen. First the master cylinder’s internal check valve closes in order to isolate the reservoir from the brakes. As the pilot continues to push on the brake pedal, the piston in the master cylinder pushes a volume of fluid out of the master cylinder and into the brake pistons until they engage the brake discs.

Once the brake discs are engaged, the master cylinder transforms the pilot’s input force into a hydraulic pressure at the brakes. The brake pistons then reverse the process and transform the hydraulic pressure into a force against the brake discs. This force is used to stop the discs from rotating and ultimately stop the aircraft.

Selection of the properly sized master cylinder is very important, and there are several key performance features to consider when choosing a master cylinder. Volume output is perhaps the most important and is governed by the volume requirement of the brakes and the compliance of the rest of the system. Choosing a master cylinder with too low a volume output will not allow the brakes to be filled properly and perhaps not pressurized high enough to adequately stop the aircraft. This may suggest that a large master cylinder should be used in every application.

In reality, there is a balance between pedal effort, mechanical advantage, volume output, and bore size of the master cylinder. The master cylinder’s bore size directly affects the amount of pedal effort. A large bore master cylinder will make the pedal effort higher than one with a smaller bore when both master cylinders are pressurized to the same levels. Some of this can be adjusted by changing the mechanical advantage at the pedal, but only to a point.    

APPLICATIONS:
General aviation, light jets, turboprop passenger, and cargo aircraft.

BENEFITS AND FEATURES:
• American made
• Corrosion protection with an anodized housing
• Light weight

OPTIONAL FEATURES:
• Rod ends
• Fitting types
• Bore sizes
• Strokes