Showing papers on "Landing gear published in 1971"

Landing gear wheel drive system for aircraft

Abstract: The invention comprises a light weight auxiliary drive mechanism carried by an aircraft for applying driving torque to wheels of a landing gear of the aircraft for taxiing the aircraft along the ground In particular, the mechanism consists of a driving drum arranged for friction driving engagement with the tire of a wheel of a landing gear having a telescopic, shock-absorbing strut, and an auxiliary motor drivably connected to the drum, with the drum being supported on said landing gear

A mathematical procedure for predicting the touchdown dynamics of a soft-landing vehicle

Abstract: A mathematical procedure for predicting the touchdown dynamics of a soft-landing vehicle is presented. The vehicle is idealized as a pseudorigid structure to which a landing gear system is attached. The landing gear system is made up of telescoping struts which house shock-absorbing mechanisms and connect the vehicle structure with footpads that contact the landing surface. The forces acting on the idealized vehicle during landing are from the vehicle landing gear system, the reaction control system, the descent-stage rocket engine thrust, rocket-engine-nozzle-crushing loads, and grav- ity. Forces acting on footpads are due to forces from the landing gear struts and from the landing surface. gear system are approximated by assuming that the structure deforms linearly with the applied load. 1/6-scale lunar module model. The elastic properties of the vehicle structure and of the landing Correlation between analytical and experimental data is presented for a Conclusions from these data are presented.

Automatic landing gear device

Abstract: Apparatus to raise or lower the landing gear of semi-trailers, operatable by the driver of the tractor from his cab. A reversible electric motor powers a worm gear that drives a planetary gear system to rotate the gear system which conventionally operates the landing gear ring.

Pressure operated retractable landing gear

Abstract: The present invention provides a retractable landing gear system for model aircraft comprising a double-acting, fluid-pressureoperated piston and cylinder means, said piston being connected to a link which link is pivotally connected to a pivoted landing gear, the ends of the said connecting link being guided in straight-line movement by a pair of opposed parallel slots, a reservoir for the fluid under pressure, means for supplying the pressurized fluid to the piston and cylinder means controlled by servo-operated valve means to extend and retract the landing gear.

Analyses and limited evaluation of payload and legged landing system structures for the survivable soft landing of instrument payloads

Abstract: Two computer programs for investigation of wide variety of legged planetary landing gear configurations

Multiwheel Landing Gear-Soils Interaction and Flotation Criteria - Phase 3, Part 1

Abstract: : The operational use of military aircraft in forward area situations has necessitated a comprehensive look at the critical factors which define the aircraft flotation performance and operations capability on semi- and unprepared soil runways. The investigation was directed primarily at defining the drag- sinkage response of multiple wheel landing gear on soil and the development of multiwheel flotation criteria to permit comparative evaluation of the relative merits of various landing gear configurations. The total multiwheel/soil interaction study consisted of four parts. Part 1 was an evaluation of existing full scale field test data from aircraft or test carts operating with multiple tire configurations (twin and tandem). The results of the study show that certain multiwheel configurations and spacing are beneficial in terms of sinkage-drag performance. The results of the multiwheel/soil interaction study were used to develop multiwheel flotation criteria (guidelines for evaluating performance). The flotation variable of braking was also studied on a preliminary basis. Braked tire/soil interaction equations suitable for defining the braking coefficient on soil were developed, and the results of a comparative study using these braked tire equations were favorable.

Theory of an Air Cushion Landing System for Aircraft

Abstract: : The Air Cushion Landing System is a scheme to replace the wheeled landing gear on aircraft by a peripheral jet air cushion. The concept employs a flexible elastic membrane or 'trunk' which is attached to the bottom of the aircraft fuselage. During flight, the trunk shrinks elastically and hugs the bottom of the fuselage like a de-icing boot. When a flow of air is applied to the inside of the trunk, the elastic material stretches and forms an elongated doughnut-shaped protrusion on the underside of the aircraft. The air flow is ducted by the trunk to the fuselage periphery and exhausted through a large number of holes or slots. As a result, a pressure builds up under the aircraft when the ground is approached. The pressure is sufficient to support the aircraft and absorb its vertical landing velocity. The study develops analytical relationships between the variables associated with the Air Cushion Landing System. Included are the following: The derivation of a theory which predicts the static characteristics of the system; Analytical methods for predicting flow, jet height and power requirements; Curves which illustrate the interrelationships among the design variables; Computer programs for predicting the cross-sectional area and shape of the elastic trunk; The development and test of an analytical model which predicts the dynamic response of the system to landing impact; A discussion of the design considerations for the system.

Air Cushion Pressure During Stiff-Operation for Air Cushion Landing System. Part 1. Theory

Abstract: : The report studies the performance characteristics of the air cushioned landing and takeoff system for aircraft during its stiff-operation mode. Stiff-operation is obtained during the early stage of the takeoff period or the later stage of landing. Its chief feature is that the penumatic supply chamber of bleed air is in almost parallel configuration with the ground. The supply air flows vertically down through the bleed holes and is then deflected outward. This part of the report contains the theoretical treatment of the problem. The results are in the form of a cushion pressure ratio in terms of the supply (trunk) pressure. Analysis was performed, based on incompressible viscous theory.

Ultra High Tensile Steel Landing Gear Components—Material Selection and Manufacture

Abstract: Perhaps I had better start this paper by denning exactly what is meant by ultra high tensile steel. During the Second World War and for some years afterwards, 80 to 90 tsi (i.e. 180 to 200 ksi) ultimate tensile strength was considered to be the highest safe range at which structural steel could be used, due to the lack of sufficient toughness or ductility at higher strength levels. This lack of toughness and ductility is particularly important in applications such as landing gears, in the design of which it is often impossible to avoid conditions where the principal stresses are perpendicular to the grain direction: in such applications, adequate transverse toughness and ductility are vital necessities. In more recent years, steels of higher strength, combined with adequate toughness have been developed, and thus the term “uhts” has become to mean those structural steels capable of attaining a tensile strength of over 90 tsi (200 ksi), combined with adequate toughness. In practice, the current state-of-the-art is that landing gears are now being regularly manufactured in steel in the 122–134 tsi (275–300 ksi) range, while designers are asking for steels of still higher strength combined with adequate toughness (up to 220 tsi, 500 ksi), and claim that the gross weight of the aircraft could be substantially reduced if and when such materials become available. It is interesting to note, however, that although the strength of uhts has in general increased from 90 tsi in 1947 to 130 tsi (300 ksi) in 1970, there is no evidence of the future availability of stronger steels than this latter figure, i.e. it looks as though we are stuck with this strength level as a maximum for future applications.

Aircraft Ground Flotation Analysis Procedures--Paved Airfields

Abstract: : The report describes standardized methods for analyzing ground flotation characteristics for aircraft of various designs based on the type of airfield construction. The methods described were applied in an analysis of the KC-135 aircraft to illustrate the techniques. These methods can be applied to any aircraft to determine its flotation characteristics in relation to a given type runway.