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The latest tubing, fitting, and flexible line designs as well as the testing techniques presently used on production airplane hydraulic distribution systems are reviewed in this paper. Designs and materials that are being considered for future airplanes as well as their advantages are presented here in terms of weight and cost. Other major trade parameters such as reliability and maintainability are also considered along with the most significant of all distribution system areas requiring improvement-the installation criteria and techniques. Advanced tensile, impulse, and flexure testing techniques are evaluated and compared with actual airplane combined load environments encountered by hydraulic systems on large jet aircraft.

This paper describes a numerical method for solving three-dimensional incompressible flow problems and its use in predicting the aerodynamic characteristics of V/STOL aircraft. Arbitrary configuration and inlet geometry, fan inflow distributions, thrust vectoring, jet entrainment, angles of yaw, and flight speeds from hover through transition can be treated. Potential-flow solutions are obtained with the method of influence coefficients, using source and doublet panels distributed on the boundary surfaces. The results include pressure distributions, lift, induced drag and side force, and moments. Theoretical solutions are presented for clean lifting wings and for a NASA fan-in-wing model. Comparisons with the experimental NASA data demonstrate the validity of the approach and uncover the importance of viscous effects, fan inflow distribution, and jet entrainment.