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At least 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

Review of factors affecting aircraft wet runway performance

Problems associated with aircraft operations on wet runways are discussed and major factors which influence tire/runway braking and cornering traction capability are identified including runway characteristics, tire hydroplaning, brake system anomalies, and pilot inputs. Research results from investigations conducted at the Langley Aircraft Landing Loads and Traction Facility and from tests with instrumented ground vehicles and aircraft are summarized to indicate the effects of different aircraft, tire, and runway parameters. Several promising means are described for improving tire/runway water drainage capability, brake system efficiency, and pilot training to help optimize aircraft traction performance on wet runways.

Yager, T. J.↗
NASA NTRS1985

Learjet Model 55 Wing Analysis with Landing Loads

The NASTRAN analysis was used to determine the impact of new landing loads on the Learjet Model 55 wing. These new landing loads were the result of a performance improvement effort to increase the landing weight of the aircraft to 18,000 lbs. from 17,000 lbs. and extend the life of the tires and brakes by incorporating larger tires and heavy duty brakes. Landing loads for the original 17,000 lb. airplane landing configuration were applied to the full airplane NASTRAN model. The analytical results were correlated with the strain gage data from the original landing load static tests. The landing loads for the 18,000 lb. airplane were applied to the full airplane NASTRAN model, and a comparison was made with the original Model 55 data. The results of this comparison enable Learjet to determine the difference in stress distribution in the wing due to these two different sets of landing loads.

Boroughs, R. R.↗
NASA NTRS1986

Aircraft accident report: NASA 712, Convair 990, N712NA, March Air Force Base, California, July 17, 1985, facts and analysis

On July 17, l985, at 1810 P.d.t., NASA 712, a Convair 990 aircraft, was destroyed by fire at March Air Force Base, California. The fire started during the rollout after the pilot rejected the takeoff on runway 32. The rejected takeoff was initiated during the takeoff roll because of blown tires on the right landing gear. During the rollout, fragments of either the blown tires or the wheel/brake assemblies penetrated a right-wing fuel tank forward of the right main landing gear. Leaking fuel ignited while the aircraft was rolling, and fire engulfed the right wing and the fuselage after the aircraft was stopped on the runway. The 4-man flightcrew and the 15 scientists and technicians seated in the cabin evacuated the aircraft without serious injury. The fire was not extinguished by crash/rescue efforts and the aircraft was destroyed.

Batthauer, Byron E.↗
NASA NTRS1989

Contact solution algorithms

Two algorithms for obtaining static contact solutions are described in this presentation. Although they were derived for contact problems involving specific structures (a tire and a solid rubber cylinder), they are sufficiently general to be applied to other shell-of-revolution and solid-body contact problems. The shell-of-revolution contact algorithm is a method of obtaining a point load influence coefficient matrix for the portion of shell surface that is expected to carry a contact load. If the shell is sufficiently linear with respect to contact loading, a single influence coefficient matrix can be used to obtain a good approximation of the contact pressure distribution. Otherwise, the matrix will be updated to reflect nonlinear load-deflection behavior. The solid-body contact algorithm utilizes a Lagrange multiplier to include the contact constraint in a potential energy functional. The solution is found by applying the principle of minimum potential energy. The Lagrange multiplier is identified as the contact load resultant for a specific deflection. At present, only frictionless contact solutions have been obtained with these algorithms. A sliding tread element has been developed to calculate friction shear force in the contact region of the rolling shell-of-revolution tire model.

Tielking, John T.↗
NASA NTRS1990

Evaluation of two transport aircraft and several ground test vehicle friction measurements obtained for various runway surface types and conditions. A summary of test results from joint FAA/NASA Runway Friction Program

Tests with specially instrumented NASA Boeing 737 and 727 aircraft together with several different ground friction measuring devices were conducted for a variety of runway surface types and conditions. These tests are part of joint FAA/NASA Aircraft/Ground Vehicle Runway Friction Program aimed at obtaining a better understanding of aircraft ground handling performance under adverse weather conditions and defining relationships between aircraft and ground vehicle tire friction measurements. Aircraft braking performance on dry, wet, snow and ice-covered runway conditions is discussed as well as ground vehicle friction data obtained under similar runway conditions. For a given contaminated runway surface condition, the correlation between ground vehicles and aircraft friction data is identified. The influence of major test parameters on friction measurements such as speed, test tire characteristics, type and amount of surface contaminant, and ambient temperature are discussed. The effect of surface type on wet friction levels is also evaluated from comparative data collected on grooved and ungrooved concrete and asphalt surfaces.

Yager, Thomas J.↗
NASA NTRS1989

Aircraft and ground vehicle friction measurements obtained under winter runway conditions

Tests with specially instrumented NASA B-737 and B-727 aircraft together with several different ground friction measuring devices have been conducted for a variety of runway surface types and wetness conditions. This effort is part of the Joint FAA/NASA Aircraft/Ground Vehicle Runway Friction Program aimed at obtaining a better understanding of aircraft ground handling performance under adverse weather conditions, and defining relationships between aircraft and ground vehicle tire friction measurements. Aircraft braking performance on dry, wet, snow-, and ice-covered runway conditions is discussed together with ground vehicle friction data obtained under similar runway conditions. For the wet, compacted snow- and ice-covered runway conditions, the relationship between ground vehicles and aircraft friction data is identified. The influence of major test parameters on friction measurements such as speed, test tire characteristics, and surface contaminant-type are discussed. The test results indicate that use of properly maintained and calibrated ground vehicles for monitoring runway friction conditions should be encouraged particularly under adverse weather conditions.

Yager, Thomas J.↗
NASA NTRS1989

Current status of Joint FAA/NASA Runway Friction Program

Tests with specially instrumented NASA B-737 and FAA B-727 aircraft together with several different ground friction measuring devices have been conducted for a variety of runway surface types and wetness conditions. This effort is part of the Joint FAA/NASA Aircraft Ground Vehicle Runway Friction Program aimed at obaining a better understanding of aircraft ground handling performance under adverse weather conditions and defining relationships between aircraft and ground vehicle tire friction measurements. Aircraft braking performance on dry, wet, snow-, and ice-covered runway conditions is discussed together with ground vehicle friction data obtained under similar runway conditions. For the wet, compacted snow- and ice-covered runway conditions, the relationship between ground vehicles and aircraft friction data is identified. The influence of major test parameters on friction measurements such as speed, test tire characteristics, and surface contaminant type are discussed. The test results indicate that use of properly maintained and calibrated ground vehicles for monitoring runway friction conditions should be encouraged particularly under adverse weather conditions. The current status of the runway friction program is summarized and future test plans are identified.

Yager, Thomas J.↗
NASA NTRS1991

Mission safety evaluation report for STS-39, postflight edition

After a delay of approximately 2 months due to a rollback from the pad to replace the External Tank door lug housing, Space Shuttle Discovery was launched from NASA-Kennedy at 7:33 a.m. Eastern Daylight Time on 28 April 1991. STS-39 was the first unclassified DoD Shuttle mission. On 28 April, countdown proceeded normally through the T-20 minute hold. No significant problems were encountered except for the Operations Sequence-2 recorder starting unexpectedly; it was stopped by an uplink command. Discovery landed on KSC runway 15 at 2:55 p.m. EDT on 6 May 1991. This was the second time in 6 months that the Space Shuttle was diverted to KSC for landing because of high winds at Edwards AFB, Calif. This was also the 7th of 40 Shuttle missions to land at KSC in the history of the Space Shuttle Program. The Main Landing Gear outer right tire shredded 3 of the 16 cords due to either an uneven landing or a maximum force breaking test during rollout. Contributing factors to the tire cord shredding were the development of last minute crosswinds and reluctance of the ground controllers to distract the Shuttle pilots with warnings of the low flight path. As a corrective action, communication procedures will be modified for future flights.

Hardie, Kenneth O.↗
NASA NTRS1990

Mission safety evaluation report for STS-38, postflight edition

After several months delay due to Liquid Hydrogen (LH2) leaks in the External Tank (ET) 17 in LH2 umbilical disconnect, Atlantis was launched at 6:48 p.m. Eastern Standard Time on 15 Nov. 1990. Atlantis was cleared for launch after the replacement of the ET 17 in umbilical disconnect and a successful tanking test on 24 Oct. 1990. No technical concerns were encountered during the countdown. The end of the STS-38 mission was extended by one day because of high crosswinds at the primary landing site, Edwards Air Force Base (EAFB), Calif. On the next day, 20 Nov. 1990, the winds were too high for a safe landing at EAFB, and a decision was made to select the Shuttle Landing Facility (SLF) at the Kennedy Space Center (KSC) at the primary landing site. The deorbit burn was performed on orbit 79 of the STS-38 mission. Reentry and descent were effected with no problems. Postlanding inspection of Atlantis' exterior found little evidence of damage. There has been a concern about returning an Orbiter to KSC, because the last mission to do so experienced tire failure. Atlantis' tires and brakes were in excellent condition with no indication of excessive wear.

Hill, William C.↗
NASA NTRS1993

Single-Tip Probe Senses Pressure Or Temperature

Single-tip probe designed for use in supersonic wind tunnel switched to sense pressure or temperature measurements nearly simultaneous at that point. Includes small valve like valves used in bicycle and automotive tires, called "Schraeder valve". Tire valve opened or closed by push rod and solenoid. In open position, flow past thermocouple enables measurements of temperature. In closed position, flow blocked and pressure in probe backs up to pressure transducer.

Trimarchi, Paul↗
NASA NTRS1955

An Experimental Study of Applied Ground Loads in Landing

Results are presented of an experimental investigation made of the applied ground loads and the coefficient of friction between the tire and the ground during the wheel spin-up process in impacts of a small landing gear under controlled conditions on a concrete landing strip in the Langley impact basin. The basic investigation included three major phases: impacts with forward speed at horizontal velocities up to approximately 86 feet per second, impacts with forward speed and reverse wheel rotation to simulate horizontal velocities up to about 273 feet per second, and spin-up drop tests for comparison with the other tests. In addition to the basic investigation, supplementary tests were made to evaluate the drag-load alleviating effects of prerotating the wheel before impact so as to reduce the relative velocity between the tire and ground. In the presentation of the results, an attempt has been made to interpret the experimental data so as to obtain some insight into the physical phenomena involved in the wheel spin-up process.

Milwitzky, Benjamin↗
NASA NTRS1995

NASA tire/runway friction projects

The paper reviews several aspects of NASA Langley Research Center's tire/runway friction evaluations directed towards improving the safety and economy of aircraft ground operations. The facilities and test equipment used in implementing different aircraft tire friction studies and other related aircraft ground performance investigations are described together with recent workshop activities at NASA Wallops Flight Facility. An overview of the pending Joint NASA/Transport Canada/FM Winter Runway Friction Program is given. Other NASA ongoing studies and on-site field tests are discussed including tire wear performance and new surface treatments. The paper concludes with a description of future research plans.

Yager, Thomas J.↗
NASA NTRS1996

NASA Landing Systems Research Aircraft

NASA Landing Systems Research Aircraft (LSRA) is Convair 990 airplane modified to incorporate tire-and-landing-gear test facility containing test fixture. Airplane instrumented to measure loads, velocities, and slip angles between tires and runways.

Carter, John F.↗
NASA NTRS2002

How Surface Treatments Enhance Ground Handling

Several runway surface treatments developed in recent years are described in terms of how aircraft tire landing and takeoff friction requirements are met, particularly during adverse weather conditions. Changing the surface texture with grooving, grinding and shot peening, use of chemicals to remove or prevent accumulation of natural or man-made contaminants, and the use of new techniques and materials are discussed as means of improving surface friction performance. Test data are presented to illustrate the effects of runway conditions on aircraft ground performance. The severity of the problem of operating on runway surfaces which cannot provide sufficient aircraft tire friction capability is also illustrated from documented aircraft accident/incident reports. The paper concludes with recommendations for future pavement research activities.

Yager, Thomas J.↗
NASA NTRS1960

Landing-Impact Characteristics of Load-Alleviating Struts on a Model of a Winged Space Vehicle

A brief experimental investigation was made of the landing-impact characteristics of a 1/9-scale dynamic model of a winged space vehicle. The landing tests were made by catapulting a free model onto a hard; surface runway and onto water. The model had a conical fuselage and a flat - plate wing with a basic delta planform and 75 deg sweepback of the leading edge. The use of yielding-metal shock absorbers and various landing-gear arrangements was investigated during landing impact. The basic landing gear consisted of a dual rubber-tired nose wheel and twin main skids aft of the center of gravity near the wing tips. landing motion and acceleration data were obtained over a range of landing attitudes, gross weights, and initial sinking speeds. Brief tests were made with an alternate nose-wheel location. An all-skid configuration also was briefly evaluated for hard-surface and water landings. The landing gear employing yielding struts for impact-energy absorption during hard-surface landings resulted in accelerations of approximately 5 1/2 g near the nose gear over a range of landing parameters. Replacing the nose wheel and tire with a skid did not significantly change the accelerations. Landings in smooth water with rigid struts and adequate planing area at the nose skid resulted in a maximum landing acceleration of approximately 4g.

Blanchard, Ulysse J.↗
NASA NTRS1978

Wall Covering

The attractive wall covering shown below is one of 132 styles in the Mirror Magic II line offered by The General Tire & Rubber Company, Akron, Ohio. The material is metallized plastic fabric, a spinoff from space programs. Wall coverings are one of many consumer applications of aluminized plastic film technology developed for NASA by a firm later bought by King-Seeley Thermos Company, Winchester, Massachusetts, which now produces the material. The original NASA use was in the Echo 1 passive communications satellite, a "space baloon" made of aluminized mylar; the high reflectivity of the metallized coating enabled relay of communications signals from one Earth station to another by "bouncing" them off the satellite. The reflectivity feature also made the material an extremely efficient insulator and it was subsequently widely used in the Apollo program for such purposes as temperature control of spacecraft components and insulation of tanks for fuels that must be maintained at very low temperatures. I Used as a wall covering, the aluminized material offers extra insulation, reflects light and I resists cracking. In addition to General Tire, King-Seeley also supplies wall covering material to Columbus Coated Fabrics Division of Borden, Incorporated, Columbus, Ohio, among others.

Source record↗
NASA NTRS2008

Computer Model Locates Environmental Hazards

Catherine Huybrechts Burton founded San Francisco-based Endpoint Environmental (2E) LLC in 2005 while she was a student intern and project manager at Ames Research Center with NASA's DEVELOP program. The 2E team created the Tire Identification from Reflectance model, which algorithmically processes satellite images using turnkey technology to retain only the darkest parts of an image. This model allows 2E to locate piles of rubber tires, which often are stockpiled illegally and cause hazardous environmental conditions and fires.

Source record↗
NASA NTRS1937

Stability of Castering Wheels for Aircraft Landing Gears, Special Report

In many installations of castering rubber-tired wheels there is a tendency for the wheel to oscillate violently about the spindle axis. This phenomenon, popularly called 'shimmy,' has occurred in some airplane tail wheels and has been corrected in two ways: first by the application of friction in the spindles of the tail wheels; and, second, by locking the wheels while taxiing at high speeds. Shimmy is common with the large wheels used as nose wheels in tricycle landing gears and, since it is impossible to lock the wheels, friction in the nose-wheel spindle has been the sole means of correction. Because the nose wheel is larger than the conventional tail wheel and usually carries a greater load, the larger amounts of spindle friction necessary to prevent shimmy are objectionable. the present paper presents a theoretical and experimental study of the problem of the stability of castering wheels for airplane landing gears. On the basis of simplified assumptions induced from experimental observations, a theoretical study has been made of the shimmy of castering wheels. The theory is based on the discovery of a phenomenon called 'kinematic shimmy' and is compared quantitatively with the results of model experiments. Experimental checks, using a model having low-pressure tires, are reported and the applicability of the results to full scale is discussed. Theoretical methods of estimating the spindle viscous damping and spindle solid friction necessary to avoid shimmy - lateral freedom - is introduced.

Kantrowitz, Arthur↗