SAE AIR4002A

1 SCOPE
2 TEST PROGRAMS
   2.1 Exploratory Development Programs
   2.2 Navy Program
   2.3 Fire Resistant Hydraulic Systems Program - Air Force
3 HYDRAULIC FLUID DEVELOPMENT
   3.1 Physical Properties at 8000 psi
       3.1.1 System Fluid
       3.1.2 Physical Properties
       3.1.3 CTFE Fluid
4 SEAL DEVELOPMENT
   4.1 8000 psi MIL-H-83282 Fluid System Seals - Navy
       4.1.1 Rod Seals
       4.1.2 Piston Seals
   4.2 8000 psi CTFE Fluid System Seals - Air Force
5 8000 psi HYDRAULIC SYSTEMS - GENERAL
   5.2 Analysis and Design
       5.2.1 Fluid Viscosity
       5.2.2 Actuator Stiffness
       5.2.3 Pressure Surges
       5.2.4 Heat Generation
6 PRESSURE LEVEL SELECTION CRITERIA
   6.2 Pump Performance
   6.3 Power Transmission Systems
   6.4 Pressure Level Selection
7 WATER HAMMER
   7.1 Water Hammer - 3000 psi Systems
   7.2 Reduction of Water Hammer Transients - 8000 psi FC Systems
   7.3 Reduction of Water Hammer Transients - 8000 psi Utility
       Systems
   7.4 Water Hammer Transients - Design Margins
8 SELECTION OF 8000 psi PROOF AND BURST PRESSURES
9 TUBING AND FITTINGS
   9.1 Tubing Selection
   9.2 Coiled Tubing
   9.3 Fittings
   9.4 Hoses
10 ACTUATION SYSTEM
   10.1 Servovalve Null Leakage
   10.2 Actuator Sizing
11 PUMP DEVELOPMENT
12 GROUND SUPPORT EQUIPMENT
13 SAFETY
14 LIST OF ABBREVIATIONS
APPENDIX A SUMMARY OF PUBLISHED REPORTS RELATED TO 8000 psi
APPENDIX B LIST OF SPECIFICATIONS (LHS)
Figures
Tables

Outlines experience and test results to date when operating hydraulic systems at 8000 psi.

Shortly after World War II, as aircraft became more sophisticated and power-assist, flight-control functions became a requirement, hydraulic system operating pressures rose from the 1000 psi level to the 3000 psi level found on most aircraft today. Since then, 4000 psi systems have been developed for the U.S. Air Force XB-70 and B-1 bombers and a number of European aircraft including the tornado multirole combat aircraft and the Concorde supersonic transport. The V-22 Osprey incorporates a 5000 psi hydraulic system. The power levels of military aircraft hydraulic systems have continued to rise. This is primarily due to higher aerodynamic loading, combined with the increased hydraulic functions and operations of each new aircraft. At the same time, aircraft structures and wings have been getting smaller and thinner as mission requirements expand. Thus, internal physical space available for plumbing and components continues to decrease.