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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1947

Investigation of a Spoiler-Type Lateral Control System on a Wing with Full-Span Flaps in the Langley 19-Foot Pressure Tunnel

Tests of a partial-span model of a large bomber-type air1ane were conducted to determine the. aerodynamic characteristics of the wing equipped with full-span flaps and a retractable spoiler end aileron lateral control system. The arrangement consisted of (1) a double slotted flap extending over aproximate1y 86 percent of the wing semispan, (2) a 20-percent constant-percentage-chord aileron extending from the outboard end of the flap to the wing tip, and (3) a retractable spoiler, located at the 65-percent wing-chord station and extending from approximately 63 percent of the wing semispan to the wing tip. In addition, tests were made of a wing vent (of 1 and 2 percent of the wing chord located directly behind the spoiler), perforations in the spoiler, a blot or cut-out along the lower edge of the spoiler and spoilers of various spans. With full-span flaps deflected and with the 2-percent vent open or closed the initial stalling of the wing occurred at the tips, but with the vents closed there probably would be no appreciable loss in lateral control until maximum lift was reached. The l-percent vent increased the rolling effectiveness of the spoiler at small spoi1er deflections, particularly at high angles of attack with flaps deflected. With flaps deflected the 2-percent vent caused a large reduction in both the wing lift and rolling effectiveness of the spoiler at large angles of attack. However, at small angle of attack the 2-percent vent increased the rolling effectiveness of the spoiler at small spoiler deflections. The simultaneous operation of the spoiler and vent (in contrast to a vent fixed in the wing) would result in a large increase in the effectiveness of the spoiler and would avoid any loss in wing lift as in a fixed vent arrangement. The tests of the spoiler modifications revealed that (1) the spoiler perforations reduced the rolling-moment and yawing-moment coefficients but caused the spoiler hinge-moment coefficients to become more positive; (2) the spoiler slot had no notable effect on the rolling-moment and yawing-moment characteristics but produced a positive increase in the spoiler hinge-moment coefficients at large spoiler deflections; (3) the effects produced by the individual modifications were additive when the various modifications were combined. In general, progressively decreasing the spoiler span by removing the segments from the inboard end of the spoiler caused a decrease in rolling effectiveness approximately proportional to the span of the segment.

WING FLAPS, SLOTTED & AILERONS↗
NASA NTRS1943

The exact solution of shear-lag problems in flat panels and box beams assumed rigid in the transverse direction

A mathematical procedure is herein developed for obtaining exact solutions of shear-lag problems in flat panels and box beams: the method is based on the assumption that the amount of stretching of the sheets in the direction perpendicular to the direction of essential normal stresses is negligible. Explicit solutions, including the treatment of cut-outs, are given for several cases and numerical results are presented in graphic and tabular form. The general theory is presented in a from which further solutions can be readily obtained. The extension of the theory to cover certain cases of non-uniform cross section is indicated. Although the solutions are obtained in terms of infinite series, the present developments differ from those previously given in that, in practical cases, the series usually converge so rapidly that sufficient accuracy is afforded by a small number of terms. Comparisons are made in several cases between the present results and the corresponding solutions obtained by approximate procedures devised by Reissner and by Kuhn and Chiarito.

STRESSED SKIN-PLATES, FLAT↗
NASA NTRS1944

The inward bulge type buckling of monocoque cylinders I : calculation of the effect upon the buckling stress of a compressive force, a nonlinear direct stress distribution, and a shear force

In the present part I of a series of reports on the inward bulge type buckling of monocoque cylinders the buckling load in combined bending and compression is first derived. Next the reduction in the buckling load because of a nonlinear direct stress distribution is determined. In experiments nonlinearity may result from an inadequate stiffness of the end attachments in actual airplanes from the existence of concentrated loads or cut-outs. The effect of a shearing force upon the critical load is investigated through an analysis of the results of tests carried out at GALCIT with 55 reinforced monocoque cylinders. Finally, a simple criterion of general instability is presented in the form of a buckling inequality which should be helpful to the designer of a monocoque in determining the sizes of the rings required for excluding the possibility of inward bulge type buckling.

Hoff, N J↗
NASA NTRS1940

Some data on the static longitudinal stability and control of airplanes : design of control surfaces

In the solution of a number of problems on the stability and controllability of airplanes, there arises the necessity for knowing the characteristics of the tail surfaces of the types in common use today. Of those characteristics, the most important are the effectiveness and hinge moments of the tail surfaces. As has been shown in the present paper, there exists the possibility of determining these characteristics by the formulas obtained with a degree of accuracy sufficient for the purposes of preliminary computation. These formulas take into account a number of fundamental tail characteristics such as tail cut-outs on the control surface and the form of the control surface leading edge.

Martinov, A↗
NASA NTRS1991

Lunar campsite concept: Space transfer concepts and analysis for exploration missions

The lunar Campsite concept responds to a perceived need to identify early manned science and exploration missions that require minimal initial funding. The Campsite concept defers the build-up of many infrastructure components without escalating total program costs. The lunar Campsite has been sized nominally for four crew for 42 days (1 lunar night and 2 lunar days), but can be modified to span two lunar nights up to 60 days. Total mission fulfillment requires five Earth-to-LEO launches, four (100 mt class launch vehicle) for the two vehicle assemblies and one (PLS or NSTS) for the crew. The lunar Campsite mission mode is tandem direct using a booster stage and a lander stage. The booster is separated from the lander after the TLI burn and is expended into the Earth's atmosphere. In the Campsite mode, the lander lands on the surface not to be returned. In the crew delivery mode, the lander is guided to a precision landing about 500 m from the Campsite, and with enough propellant to return the crew to Earth. The Campsite consists of a habitat and airlock, body mounted radiators with a surface shield, sun tracking solar arrays, and an Earth-tracking high-gain antenna. The CV is very similar to the campsite delivery vehicle. The CV does not, however, have radiators or solar arrays. The vehicle stacks are essentially common in that they utilize the same structure system and engines, the same propellant tanks, the same 'cut-out' in which the CRV and payloads are incorporated, and the same RCS locations. The booster and lander stage propellant tank propellant capacities are identical and have margins which would allow additional fueling for propulsive capture of the boost stage into Earth orbit. This contractual study was performed to identify Campsite and vehicle interfaces and vehicle requirements, and to surface issues related to the integration of the Campsite and LTV's.

Source record↗
NASA NTRS1994

Aircraft system aft telescope cavity configuration study for Stratospheric Observatory for Infrared Astronomy (SOFIA), phase 2

The SOFIA Aircraft System (AS) Phase 1 Study was a broad-based study which addressed itself to satisfying technical and programmatic requirements by drawing from existing technology and applying cost-efficient commercial approaches to the aircraft modification. In this SOFIA AS Phase 2 Study, five critical areas of the aircraft were selected for more detailed investigation: forward pressure bulkhead, aft bulkhead, 'free' shell to bulkhead interface, shell cut-out to bulkhead interface, and flooring. The in-depth investigation of these areas upon a finite element model (FEM), with a fine grid model in areas of particular interest, is discussed. The FEM code used is called 'STRAP' and was developed by the engineering firm, Rasmussen and Associates. STRAP is NASTRAN compatible to within 1%. The loads applied to the model were approximated from known 747 envelope conditions. The areas of investigation, and a section through the fuselage is shown. The thrust of this investigation was to develop the design concepts conceived under phase 1 to the point where detailed design could be undertaken with a high level of confidence.

Source record↗
NASA NTRS1996

Novel Composites for Wing and Fuselage Applications

Design development was successfully completed for textile preforms with continuous cross-stiffened epoxy panels with cut-outs. The preforms developed included 3-D angle interlock weaving of graphite structural fibers impregnated by resin film infiltration (RFI) and shown to be structurally suitable under conditions requiring minimum acquisition costs. Design guidelines/analysis methodology for such textile structures are given. The development was expanded to a fuselage side-panel component of a subsonic commercial airframe and found to be readily scalable. The successfully manufactured panel was delivered to NASA Langley for biaxial testing. This report covers the work performed under Task 3 -- Cross-Stiffened Subcomponent; Task 4 -- Design Guidelines/Analysis of Textile-Reinforced Composites; and Task 5 -- Integrally Woven Fuselage Panel.

Suarez, J. A.↗
NASA NTRS1993

Gamma ray collimator

A gamma ray collimator including a housing having first and second sections. The first section encloses a first section of depleted uranium which is disposed for receiving and supporting a radiation emitting component such as cobalt 60. The second section encloses a depleted uranium member which is provided with a conical cut-out focusing portion disposed in communication with the radiation emitting element for focusing the emitted radiation to the target.

Casanova, Edgar J.↗
NASA NTRS1946

Stresses in and General Instability of Monocoque Cylinders with Cutouts I : Experimental Investigation of Cylinders with a Symmetric Cutout Subjected to Pure Bending

Ten 24S-T alclad cylinders of 20-inch diameter, 45- or 58-inch length, and 0.012-inch wall thickness, reinforced with 24S-T aluminum alloy stringers and rings were tested in pure bending. In the middle of the compression side of the cylinders there was a cutout extending over 19 inches in the longitudinal direction, and over an angle of 45 degrees, 90 degrees, or 135 degrees in the circumferential direction. The strain in the stringers and in the sheet covering was measured with metal electric strain gages. The stress distribution in the cylinders deviate considerably from the linear law valid for cylinders without a cutout. The maximum strain measured was about four-thirds of the value calculated from the Mc/I formula when I was taken as the moment of inertia of the cross section of the portion of the cylinder where the cutout was situated. A diagram is presented containing the strain factors defined as the ratios of measured strain to strain calculated with the Mc/I formula. All the 10 cylinders tested failed in general instability. Two symmetric and one antisymmetric pattern of buckling were observed and the buckling load appeared to be independent of the method of manufacture and the length of the cylinder. The buckling load of the cylinders having cutouts extending over 45 degrees, 90 degrees, and 135 degrees was 66, 47, and 31 percent, respectively, of the buckling load of the cylinder without a cutout.

CYLINDERS, MONOCOQUE-BUCKLING↗