Pull-type master cylinders are an alternative to push-type master cylinders and are common in the general aviation market. Pull-type master cylinders are used when the aircraft’s linkage is not set up for a push-type master cylinder due to cockpit design constraints or the air framer’s preference. The aircraft’s linkage is set up to pull 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 extends from 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. There are several important 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.
The pull-type master cylinder will require a larger bore than a pull-type master cylinder with the same volume output. The effective area of the piston is reduced due to the area of the master cylinder’s rod.
General aviation, light jets, turboprop passenger, and cargo aircraft.
FEATURES AND ATTRIBUTES:
• Adjustable clevis allows length adjustment for ease of installation on aircraft
• Anodized housing – corrosion protection
• Light weight
• American made
• Rod ends
• Fitting types
• Bore sizes
0.45 to 1.5 lb
Multiple fluids - MIL-PRF-5606, MIL-PRF-83282 and MIL-PRF-87257
1.06 to 1.6 inches
Minimum Operating Temperature (F)
Maximum Operating Temperature (F)