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Hodge, Jeffrey S.

Publications and source records attributed to Hodge, Jeffrey S..

Test Capabilities and Recent Experiences in the NASA Langley 8-Foot High Temperature Tunnel

The NASA Langley 8-Foot High Temperature Tunnel is a combustion-heated hypersonic blowdown-to-atmosphere wind tunnel that provides flight enthalpy simulation for Mach numbers of 4, 5, and 7 through an altitude range from 50,000 to 120,000 feet. The open-.jet test section is 8-ft. in diameter and 12-ft. long. The test section will accommodate large air-breathing hypersonic propulsion systems as well as structural and thermal protection system components. Stable wind tunnel test conditions can be provided for 60 seconds. Additional test capabilities are provided by a radiant heater system used to simulate ascent or entry heating profiles. The test medium is the combustion products of air and methane that are burned in a pressurized combustion chamber. Oxygen is added to the test medium for air-breathing propulsion tests so that the test gas contains 21 percent molar oxygen. The facility was modified extensively in the late 1980's to provide airbreathing propulsion testing capability. In this paper, a brief history and general description of the facility are presented along with a discussion of the types of supported testing. Recently completed tests are discussed to explain the capabilities this facility provides and to demonstrate the experience of the staff.

Hodge, Jeffrey S.↗

A flutter investigation of all-moveable NASP-like wings at hypersonic speeds

Six alternative all-moving wing configurations applicable to the NASP hypersonic/transatmospheric vehicle have undergone aeroelasticity testing in NASA-Langley's Mach-20-capable Helium Tunnel that yielded data for such parametric variations as airfoil profile and wing planform, wing-pivot flexure stiffness, and mass imbalance. While all wings fluttered at dynamic pressures lower than predicted by second-order piston-theory aerodynamics, this was of limited amplitude, suggesting nonlinear external-flow behavior. Slab airfoils were more stable than diamond-shaped ones; blunt leading edges enhance stability relative to sharp ones, and stiffer pivolts extert a stabilizing influence.

Spain, Charles V.↗

The Langley 15-inch Mach 6 High Temperature Tunnel

The Langley 15-Inch Mach 6 High Temperature Tunnel was recently converted from the former Mach 10 Hypersonic Flow Apparatus. This conversion was made primarily to provide the capability of testing in Mach 6 air at higher reservoir temperatures than previously possible at Langley. These elevated temperatures allow the matching of the Mach number, Reynolds number, and ratio of wall-to-adiabatic-wall temperatures (Tw/Taw) between this facility and the Langley 20-Inch Mach 6 CF4 Tunnel; Tw/Taw is also matched for Langley's 31-Inch Mach 10 Tunnel. A brief history and general description of this facility are presented along with a discussion of the recently completed modifications and upgrades.

Hodge, Jeffrey S.↗

Wind tunnel blockage study of a generic three-dimensional sidewall compression scramjet inlet at Mach 10

A large scale model of a generic three-dimensional sidewall compression scramjet inlet has been designed based on the results of a computational parametric study for testing in the 31-inch Mach 10 Hypersonic Wind Tunnel at the NASA Langley Research Center. In order to increase the instrumentation density in interaction regions for a highly instrumented model, it is desirable to make the model as large as possible. When the cross-sectional area of a model becomes large relative to the inviscid core size of the tunnel, the effects of blockage must be considered. In order to assess these effects, a blockage model (an inexpensive, much less densely instrumented version of the configuration) was fabricated for preliminary testing. Since it was desired to determine both the effect of the model on the performance of the wind tunnel and also to determine if the inlet would start, the model possessed a total of 32 static pressure orifices distributed on the forebody plane and sidewalls; seventeen static pressure orifices on the tunnel wall and 3 pitot probes on the model monitored the tunnel performance. This paper presents the design considerations in the development of the wind tunnel model and the blockage aspects of the effects of contraction ratio, cowl location, Reynolds number, and angle of attack.

Holland, Scott D.↗