Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Thrust Load”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
NASA NTRS1970

Design and Manufacture of Wheels for A Dual-Mode (Manned - Automatic) Lunar Surface Roving Vehicle. Volume 2: Proposed Test Plan

A developmental test plan for the wheel and wheel drive assembly of the dual-mode (manned/automated) lunar surface roving vehicle is presented. The tests cover performance, as well as critical environmental characteristics. Insofar as practical, the environmental conditions imposed will be in the sequence expected during the hardware's life from storage through the lunar mission. Test procedures are described for static load deflection and endurance tests. Soft soil tests to determine mobility characteristics including drawbar-pull and thrust vs slip, and motion resistance for various wheel loads are also discussed. Test designs for both ambient and thermal vacuum conditions are described. Facility, transducer, and instrumentation requirements are outlined.

Source record↗
NASA NTRS1974

Propulsion system sizing for powered lift and mechanical flap quiet aircraft

A method of propulsion system sizing for mechanical flap and externally blown flap aircraft is demonstrated. Included in this study is the effect of various levels of noise suppression on the aircraft final design characteristics. Both aircraft are sized to operate from a 3000-ft runway and perform the same mission. For each aircraft concept, propulsion system sizing is demonstrated for two different engine cycles - one having a fan pressure ratio of 1.5 and a bypass ratio of 9 and the other having a fan pressure ratio of 1.25 and a bypass ratio of 17.8. The results presented include the required thrust to weight ratio and wing loading and the resulting gross weight and direct operating costs as functions of the engine noise level for each of the four combinations of engine cycles and aircraft concepts.

Bowles, J. V.↗
NASA NTRS1975

Compatibility of take-off and landing with mission and manoeuvre performance requirements for fighter aircraft

By means of an aircraft synthesis program, the effect of engine cycle, thrust to weight ratio, and wing parameter combination on field and flight performance has been investigated. For three different engine/intake configurations, thrust to weight ration and wing loading were varied. Each combination represents an aircraft designed to meet a specified mission radius. Using different lift systems and ground deceleration devices, the conditions are shown under which a matching of flight and field performance is economically feasible.

Reich, D.↗
NASA NTRS1984

Hover test of a full-scale hingeless helicopter rotor: Aeroelastic stability, performance and loads data

A hover test of a full-scale, hingeless rotor system was conducted in the NASA Ames 40- by 80-foot wind tunnel. The rotor was tested on the Ames rotor test apparatus. Rotor aeroelastic stability, performance, and loads at various rotational speeds and thrust coefficients were investigated. The primary objective was to determine the inplane stability characteristics of the rotor system. Rotor inplane damping data were obtained for operation between 350 and 425 rpm (design speed), and for thurst coefficients between 0.0 and 0.12. The rotor was stable for all conditions tested. At constant rotor rotational speed, a minimum inplane dampling level was obtained at a thrust coefficient approximately = 0.02. At constant rotor lift, a minimum in rotor inplane damping was measured at 400 rpm.

Peterson, R. L.↗
NASA NTRS1985

Study of an efficient long-range Mach 2.7 supersonic transport configuration concept

A long range Mach 2.7 supersonic transport configuration concept was studied utilizing linear theory methods. The configuration was sized to carry 290 passengers 6,000 nautical miles nonstop. The final configuration has a maximum takeoff gross weight of 687,200 pounds, a wing loading of 69.8 lbf/sq.ft. and a thrust weight ratio of .278. The most significant result is that a significantly improved trimmed maximum lift drag ratio of 11.04 can be obtained for a supersonic transport at Mach 2.62 and 55,000 feet.

Gall, P. D.↗
NASA NTRS1991

Scorpion: Close Air Support (CAS) aircraft

The objective is to outline the results of the preliminary design of the Scorpion, a proposed close air support aircraft. The results obtained include complete preliminary analysis of the aircraft in the areas of aerodynamics, structures, avionics and electronics, stability and control, weight and balance, propulsion systems, and costs. A conventional wing, twin jet, twin-tail aircraft was chosen to maximize the desirable characteristics. The Scorpion will feature low speed maneuverability, high survivability, low cost, and low maintenance. The life cycle cost per aircraft will be 17.5 million dollars. The maximum takeoff weight will be 52,760 pounds. Wing loading will be 90 psf. The thrust to weight will be 0.6 lbs/lb. This aircraft meets the specified mission requirements. Some modifications have been suggested to further optimize the design.

Allen, Chris↗
NASA NTRS1993

Analysis and optimization of preliminary aircraft configurations in relationship to emerging agility metrics

This paper discusses the development of a FORTRAN computer code to perform agility analysis on aircraft configurations. This code is to be part of the NASA-Ames ACSYNT (AirCraft SYNThesis) design code. This paper begins with a discussion of contemporary agility research in the aircraft industry and a survey of a few agility metrics. The methodology, techniques and models developed for the code are then presented. Finally, example trade studies using the agility module along with ACSYNT are illustrated. These trade studies were conducted using a Northrop F-20 Tigershark aircraft model. The studies show that the agility module is effective in analyzing the influence of common parameters such as thrust-to-weight ratio and wing loading on agility criteria. The module can compare the agility potential between different configurations. In addition one study illustrates the module's ability to optimize a configuration's agility performance.

Sandlin, Doral R.↗
NASA NTRS1994

Modification of ACSYNT aircraft computer program for preliminary design

This paper presents the development of a computer simulation of agility flight test techniques. Its purpose is to evaluate the agility of aircraft configurations early in the preliminary design phase. The simulation module is integrated into the NASA Ames aircraft synthesis design code. Trade studies using the agility module embedded within the design code to simulate the combat cycle time agility metric are illustrated using a Northrop F-20 aircraft model. Results show that the agility module is effective in analyzing the influence of common parameters such as thrust-to-weight ratio and wing loading on agility criteria. The module can also compare the agility potential between different configurations and has the capability to optimize agility performance early in the design process.

Biezad, Daniel J.↗
NASA NTRS1993

Development of a Computer Program for Analyzing Preliminary Aircraft Configurations in Relationship to Emerging Agility Metrics

This paper discusses the development of a FORTRAN computer code to perform agility analysis on aircraft configurations. This code is to be part of the NASA-Ames ACSYNT (AirCraft SYNThesis) design code. This paper begins with a discussion of contemporary agility research in the aircraft industry and a survey of a few agility metrics. The methodology, techniques and models developed for the code are then presented. Finally, example trade studies using the agility module along with ACSYNT are illustrated. These trade studies were conducted using a Northrop F-20 Tigershark aircraft model. The studies show that the agility module is effective in analyzing the influence of common parameters such as thrust-to-weight ratio and wing loading on agility criteria. The module can compare the agility potential between different configurations. In addition, one study illustrates the module's ability to optimize a configuration's agility performance.

Bauer, Brent↗
NASA NTRS2005

Fluid Distribution for In-space Cryogenic Propulsion

The ultimate goal of this task is to enable the use of a single supply of cryogenic propellants for three distinct spacecraft propulsion missions: main propulsion, orbital maneuvering, and attitude control. A fluid distribution system is sought which allows large propellant flows during the first two missions while still allowing control of small propellant flows during attitude control. Existing research has identified the probable benefits of a combined thermal management/power/fluid distribution system based on the Solar Integrated Thermal Management and Power (SITMAP) cycle. Both a numerical model and an experimental model are constructed in order to predict the performance of such an integrated thermal management/propulsion system. This research task provides a numerical model and an experimental apparatus which will simulate an integrated thermal/power/fluid management system based on the SITMAP cycle, and assess its feasibility for various space missions. Various modifications are done to the cycle, such as the addition of a regeneration process that allows heat to be transferred into the working fluid prior to the solar collector, thereby reducing the collector size and weight. Fabri choking analysis was also accounted for. Finally the cycle is to be optimized for various space missions based on a mass based figure of merit, namely the System Mass Ratio (SMR). -. 1 he theoretical and experimental results from these models are be used to develop a design code (JETSIT code) which is able to provide design parameters for such a system, over a range of cooling loads, power generation, and attitude control thrust levels. The performance gains and mass savings will be compared to those of existing spacecraft systems.

Lear, William↗
NASA NTRS2003

Characterization of Space Shuttle Reusable Rocket Motor Static Test Stand Thrust Measurements

Space Shuttle Reusable Solid Rocket Motors (RSRM) are static tested at two ATK Thiokol Propulsion facilities in Utah, T-24 and T-97. The newer T-97 static test facility was recently upgraded to allow thrust measurement capability. All previous static test motor thrust measurements have been taken at T-24; data from these tests were used to characterize thrust parameters and requirement limits for flight motors. Validation of the new T-97 thrust measurement system is required prior to use for official RSRM performance assessments. Since thrust cannot be measured on RSRM flight motors, flight motor measured chamber pressure and a nominal thrust-to-pressure relationship (based on static test motor thrust and pressure measurements) are used to reconstruct flight motor performance. Historical static test and flight motor performance data are used in conjunction with production subscale test data to predict RSRM performance. The predicted motor performance is provided to support Space Shuttle trajectory and system loads analyses. Therefore, an accurate nominal thrust-to-pressure (F/P) relationship is critical for accurate RSRM flight motor performance and Space Shuttle analyses. Flight Support Motors (FSM) 7, 8, and 9 provided thrust data for the validation of the T-97 thrust measurement system. The T-97 thrust data were analyzed and compared to thrust previously measured at T-24 to verify measured thrust data and identify any test-stand bias. The T-97 FIP data were consistent and within the T-24 static test statistical family expectation. The FSMs 7-9 thrust data met all NASA contract requirements, and the test stand is now verified for future thrust measurements.

Mart L. Cook↗
NASA NTRS1959

An Investigation of a 0.05-Scale Model of the XSM-64A Navaho Missile and Booster: Force Study at Mach Numbers from 1.77 to 3.51 - Part 1

An investigation has been conducted in the Langley Unitary Plan wind tunnel to determine the aerodynamic loads and the static longitudinal and lateral stability of a 0.05-scale model of the XSM-64A Navaho missile and booster and its various components. Tests were conducted through a Mach number range of 1.77 to 3.51 with a corresponding Reynolds number range of 2.4 x 10(exp 6) to 2.9 x 10(exp 6). Results are presented for an angle-of-attack range of -8 deg to 4 deg for the missile-booster combination and -10 deg to 10 deg for the missile-alone configuration. Tests for both configurations were conducted through an angle-of-sideslip range of -8 deg to 8 deg. Also presented are some effects on the model characteristics of the deflection of various components including canard, tip aileron, vertical stabilizer, speed brakes, and booster pitch and yaw thrust chambers. The various components on which loads were measured include the wing, tip aileron, rudder, booster, booster separating surface, booster fin, and booster yaw and pitch thrust chambers. These data are presented without analysis.

Church, James D.↗
NASA NTRS2000

X33 Transient Liftoff Analysis

The successful design of a launch vehicle requires the careful characterization of the various loads the structure will experience over its lifetime. Many of the most demanding load environments occur during the launch/ascent phase of a mission, typically defined as the point of engine start through engine cut off. One of the critical events during the launch phase is the liftoff event. This event imparts high loads on the vehicle due to transient events such as thrust build-up and vehicle release. This paper describes the theory and procedures used to calculate structural loads due to the liftoff event for the Lockheed-Martin X33 technology demonstrator vehicle. These procedures were developed at NASA's Marshall Space Flight Center and verified previously on other advanced launch system concepts and the Space Shuttle system.

Peck, Jeff↗
NASA NTRS1966

Liquid impact on tank bulkheads

Propellant impact loading on tank bulkheads induced by maneuvering or docking of spacecraft in low gravity environment, and thrust termination in atmosphere

DOCKING↗
NASA NTRS1976

Thrust bearing

A gas lubricated thrust bearing is described which employs relatively rigid inwardly cantilevered spokes carrying a relatively resilient annular member or annulus. This annulus acts as a beam on which are mounted bearing pads. The resilience of the beam mount causes the pads to accept the load and, with proper design, responds to a rotating thrust-transmitting collar by creating a gas film between the pads and the thrust collar. The bearing may be arranged for load equalization thereby avoiding the necessity of gimbal mounts or the like for the bearing. It may also be arranged to respond to rotation in one or both directions.

Anderson, W. J.↗
NASA NTRS2012

Performance of Simple Gas Foil Thrust Bearings in Air

Foil bearings are self-acting hydrodynamics devices used to support high speed rotating machinery. The advantages that they offer to process fluid lubricated machines include: high rotational speed capability, no auxiliary lubrication system, non-contacting high speed operation, and improved damping as compared to rigid hydrodynamic bearings. NASA has had a sporadic research program in this technology for almost 6 decades. Advances in the technology and understanding of foil journal bearings have enabled several new commercial products in recent years. These products include oil-free turbochargers for both heavy trucks and automobiles, high speed electric motors, microturbines for distributed power generation, and turbojet engines. However, the foil thrust bearing has not received a complimentary level of research and therefore has become the weak link of oil-free turbomachinery. In an effort to both provide machine designers with basic performance parameters and to elucidate the underlying physics of foil thrust bearings, NASA Glenn Research Center has completed an effort to experimentally measure the performance of simple gas foil thrust bearing in air. The database includes simple bump foil supported thrust bearings with full geometry and manufacturing techniques available to the user. Test conditions consist of air at ambient pressure and temperatures up to 500 C and rotational speeds to 55,000 rpm. A complete set of axial load, frictional torque, and rotational speed is presented for two different compliant sub-structures and inter-pad gaps. Data obtained from commercially available foil thrust bearings both with and without active cooling is presented for comparison. A significant observation made possible by this data set is the speed-load capacity characteristic of foil thrust bearings. Whereas for the foil journal bearing the load capacity increases linearly with rotational speed, the foil thrust bearing operates in the hydrodynamic high speed limit. In this case, the load capacity is constant and in fact often decreases with speed if other factors such as thermal conditions and runner distortions are permitted to dominate the bearing performance.

Bruckner, Robert J.↗
NASA NTRS1976

Acoustic-loads research for powered-lift configurations

Data presented from large-scale model tests with jet engines having thrusts of 9 kN (2000 lb) and 36 kN (8000 lb) include acoustic loads for an externally blown wing and flap induced by a TF34 jet engine, an upper surface blown (USB) aircraft model in a wind tunnel, and two USB models in static tests. Comparisons of these results with results from acoustic loads studies on configurations of other sizes are made and the implications of these results on interior noise and acoustic fatigue are discussed.

Schoenster, J. A.↗