Aircraft Hydraulic Systems AIAA Design Group II Basic

Aircraft Hydraulic Systems AIAA Design Group II

Basic Hydraulic System • A valve is opened, the hydraulic flows into the actuator and presses against the piston, causing it to move and in turn move the attached control surface Reference: http: //www. allstar. fiu. edu/AERO/Hydr 02. htm

General Uses n n Used for flight control, actuation of flaps, slats, weapons bays, landing gear, breaks Provides the extra force required to move large control surfaces in heavy aerodynamic loads.

General Specifications n Several different Fluids • MIL-H-5606, MIL-H-83282, and MIL-H 81019 • General Temperature Ranges : -65°F to 295°F n Pressures: • Airbus A 380 has 5000 psi hydraulic system • Typical commercial airline pressure is 3000 psi • http: //aerospace. eaton. com/news. asp? articledate=06/01/03 &News. Command=View. Month • http: //www. tpub. com/content/aviation/14018/css/14018_17 8. htm

Problems with Hydraulics n n Heavy High maintenance • Adds cost and creates a logistics problem n Requires space (pumps, hydraulic lines, etc. )

Possible Improvements n Electric Actuators • Consists of a small electric motor, pump and actuator ram requiring about 1 pint of hydraulic fluid • Flight tested by NASA’s Dryden Flight Research Center on a modified F-18. • Provides significant weight savings by eliminating pumps and hydraulic lines • Also could decrease required maintenance Reference: NASA Dryden Flight Research Center. News Release 98 -84

Electro – Mechanical Actuator Reference: Air Force Research Laboratory http: //www. afrlhorizons. com/Briefs/0006/VA 9902. html

Impact on Design n n Need to allow sufficient space for required hydraulic systems Weight of the system must be accounted for