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Aspects of internal-flow-system design for helicopter propulsive units

Description: A discussion of pertinent items related to the design of internal-flow systems for reciprocating engine, turbine engine, and pressure-jet installations in helicopters. The following items are emphasized: controllable exit and ram recovery for reciprocating-engine cooling, performance penalties possible in turbine-engine installations, the effects of high subsonic flow velocities on the performance of duct elements, and the effects of centrifugal forces on the flow in a ducted helicopter rotor.
Date: September 14, 1954
Creator: Henry, John R.
Partner: UNT Libraries Government Documents Department

Some internal-flow characteristics of several axisymmetrical NACA 1-series nose air inlets at zero flight speed

Description: Report presenting testing of six 1-series axisymmetrical nose air inlets of 8-inch maximum diameter at zero forward velocity in the 8-foot transonic tunnel. Total-pressure surveys, pressure-recovery measurements, and flow-visualization studies were made through a range of mass-flow ratio from below the normal operating range to choking. Results indicate that the performance characteristics of the inlets with differing amounts of roundness varied widely.
Date: July 15, 1954
Creator: Bryan, Carroll R. & Fleming, Frank F.
Partner: UNT Libraries Government Documents Department

Internal-flow systems for aircraft

Description: An investigation has been made to determine efficient arrangements for an internal-flow system of an aircraft when such a system operates by itself or in combination with other flow systems. The investigation included a theoretical treatment of the problem and tests in the NACA 5-foot vertical wind tunnel of inlet and outlet openings in a flat plate and in a wing.
Date: 1941
Creator: Rogallo, F. M.
Partner: UNT Libraries Government Documents Department

Internal-flow systems for aircraft

Description: An investigation has been made to determine efficient arrangements for an internal-flow system of an aircraft when such a system operates by itself or in combination with other flow systems. The investigation included a theoretical treatment of a problem and tests in the NACA 5-foot vertical wind tunnel of inlet and outlet openings in a flat plate and in a wing. When an internal-flow system tends to decrease the final velocity of it's wake, the results showed that it should be arranged in series with the propulsive system; the inlet opening should be located at a forward stagnation point; and the outlet opening should be so shaped and located as to recover the kinetic energy of the jet without increasing the drag of other portions of the aircraft. When an internal-flow system tends to increase the final velocity new b's wake, as does a propeller, location of the inlet opening in the boundary layer or in the wake of the wing or in the fuselage may be desirable.
Date: October 1940
Creator: Rogallo, F. M.
Partner: UNT Libraries Government Documents Department

An Experimental Investigation of NACA Submerged-Duct Entrances

Description: The results of a preliminary investigation of submerged duct entrances are presented. It is shown that an entrance of this type possess desirable critical speed and pressure recovery characteristics when used on a fuselage or nacelle in a region of low incremental velocity and thin boundary layer. The data obtained indicate that submerged entrances are most suitable for use with internal-flow systems which diffuse the air only a small amount: for example, those used with jet motors which have axial-flow compressors. Where complete diffusion of the air is required, fuselage-nose or wing leading edge inlets may prove to be superior. The results of the investigation have been prepared in such a form as to permit their use by a designer and the application of these data to a specific design is discussed.
Date: October 1945
Creator: Frick, Charles W.; Davis, Wallace F.; Randall, Lauros M. & Mossman, Emmet A.
Partner: UNT Libraries Government Documents Department