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The work presented in this paper is concerned with mathematical modeling and experimental validation of mono-tube shock absorber. This paper aims to create damper model to predict accurately damping force, and experimental analysis is done by varying the various parameters, such as flow area in bleed(Ab), mass (M) and operating frequency(?).

Here, input is given in the form of sinusoidal excitation, and the output is received as a numerical data of the displacement transmissibility. These data are then processed to get the values of transmissibility and magnification factor for various frequency ratios. They are then plotted to have transmissibility and frequency response curves, as it is a generally accepted measure of how well the system is isolated from its surroundings.

It is better to have low transmissibility (larger bleed area), for lower suspension velocity, as it will reduce maximum acceleration transmitted to the sprung mass. However, for higher suspension velocity, bleed area should be low (higher transmissibility) to reduce displacement of tyre from road.

The development of faster vehicles and also the requirements of smoother and more comfortable rides have led to the fitment of dampers on almost on all present day vehicles. Shock absorbers have a significant influence on handling performance and riding comfort. Shock absorber plays an important role not only for comfort of the riders of the vehicle but also in the performance and life of the vehicle. However, no further reduction of vehicle vibration can be expected for using the optimum values of damping coefficient and spring stiffness for the shock absorber. Thus, it is necessary to make modification to improve the functions of shock absorber.

The shock absorber is an important component of vehicle suspension that attenuates the vehicle vibration. Its running state directly affects the performance of the vehicle suspension. The purpose of this paper is to quantitatively study the relationship between damping characteristics and air chamber and oil properties in single-tube pneumatic shock absorber.

Combined with the principle of fluid dynamics and hydraulic transmission technology, the rebound stroke and compression stroke mathematical models, and damping characteristics simulation model are established to investigate the effect of the air chamber and oil property on damping characteristics.

Research results show that the initial pressure of the air chamber is the key parameter which influences the damping characteristics of the shock absorber. The change of the initial pressure has more impact on damping force, and less impact on the speed characteristic; the initial volume of the air chamber almost has no effect on the damping characteristics. The density and viscosity of the oil have certain influence on the damping characteristics. Therefore, selecting suitable damping oil is very important.

Using Matlab/Simulink software to build simulation models, its results are very accurate. The conclusions can provide a theoretical reference for the structure design of a single-tube pneumatic shock absorber.

131A Aluminium Alloy Sand or Die Castings (suitable for Pistons, etc.).

AMONG the many problems of drag reduction engaging the critical attention of aircraft designers to‐day, that parasitic appendix known as the undercarriage stands out, in more ways than one, as probably the most serious single offender still challenging the ingenuity of the designing engineer in his unceasing quest for aerodynamic refinement. Not so many years ago, however, quite a number of designers were openly sceptical of the mechanical feasibility of retracting the undercarriage unit; at least, in such a manner as to make it economically worth while. One suspects that our devotion in this country to the thin‐wing biplane had something to do with that particular brand of aerodynamic astigmatism, because it was not until the cantilever low‐wing monoplane became an accepted type that the idea of wheel retraction became a fashionable formula.

DURING the past few years, the French Air Ministry has been conducting a Concours des Avions de Chasse, the object of which is to encourage the French Industry to design and construct new single‐seater fighters which, if successful in tests, will be adapted to replace older and obsolete flying equipment. Prominent French constructors have entered machines, which at present are being tested by the Service Technique de l'Aéronautique at Villacoublay. Principal among them are types constructed by Morane‐Saulnier, Dewoitine, Les Mureaux, Nieuport‐Delage, Bernard, Hanriot, Loire, and Wibault.

The purpose of this paper is to study the influence rules of geometric parameters on deformation of valve slices.

Based on the theory of flexural deformation of elastic thin slice, differential functions of deformation for both single and multi-slices are given and derived in detail. Furthermore, the effects of geometric dimensions on deformation are analyzed particularly by using Matlab/simulink.

The results indicated that the deformation decreases with the increment of fixed ring radius r_a, slice thickness h, and its number n. Meanwhile, the deformation increases with a rise of slice radius r_b, throttle position r_k, the radius ratio λ₁ and thickness ratio λ₂ of slices.

This research can provide some theoretical supports for the parametric and optimal design of adjustable damping shock absorber.

THE following is a brief account of how Monospar machines are being made, rather than a description of a completely worked‐out production system, and also of the considerations which were borne in mind while the machine was being designed. These considerations can be grouped under three headings: Design, Production and Maintenance, and will be dealt with after a brief description of the whole machine, which may be of assistance in visualising how the components to be described are combined.

An aeroplane adapted to remain controllable at low speeds and high angles of incidence has automatically moving slot‐forming planes along the leading edge of each wing, camber‐varying flaps at the trailing edge interconnected to the stabilising plane and capable of being locked by the pilot in various positions, and additional normally closed slots at the wing tips which open only when the main slots are open and the usual ailerons are depressed. The slot closing element connected to each aileron may also project above the upper surface of the wing to break up the air stream on that side of the machine on which for the time being the aileron is raised. These features are shown applied to a low‐wing monoplane with widely spaced landing wheels. Slot‐forming planes 35, Fig. 4, are carried by curved tubes 40 moving between guide rollers 41 carried by brackets on the front spar of the plane. They normally nest against the leading edge of the plane and move forwards automatically as the stalling angle is approached. Camber varying flaps 29, Figs. 4 and 9, and ailerons 28, Fig. 5, are pivoted to the trailing edge of the wing and have their forward edges so shaped that slots 47 are formed when the flaps or ailerons are depressed, the slots being substantially closed in the neutral and raised positions of the flaps and ailerons. The flaps 29 are interconnected to the stabilising plane 26, the leading edge of which is raised and lowered by links 55, and both are moved simultaneously by a lever 33 provided with a detent engaging with a locking quadrant 51. The air pressure on the plane 26 partially balances that on the flaps as regards their reaction on the lever 33. A rod 53 which actuates the plane 26 is connected to a lever 33a, Fig. 10, and the lever 33 has a quadrant 59 to which the flap cables are connected, the two levers 33, 33a being adjustably connected by screw‐and‐nut mechanism 34 in order to vary the relative adjustment of the stabiliser plane and flaps. At the forward edge of each wing tip opposite each aileron a slot 37, Fig. 5, is formed, which is normally closed at its lower end by a plate 63 connected by a lost‐motion link 64 to the slot‐forming plane 35, and at its upper end by a pivoted quadrant 67 connected to the corresponding aileron by a lost‐motion device 70. When the aileron is depressed, or raised beyond a certain amount, the quadrant is respectively withdrawn into the plane to open the slot or projected beyond the upper surface to disturb the streamline flow and reduce the lift on that wing tip. Springs 71, 72 normally centre the quadrant 67. The plate 63 only moves to open the slot 37 when the main slot is open. The wing spars 88, 89, Fig. 12, are connected to the lower edge of the fuselage and braced to the upper edge by struts 90, 91 with intermediate braces 92, 93, The rear struts 91 may be upwardly arched. The landing wheel axles are carried by hinged struts 95 and supported from the front spars by telescopic struts 96 with shock‐absorbers 82.

Type: Composite construction, strut braced, high wing mono‐plane.

Fuel Transfer by Pneumatic Pressure A simple lightweight fuel pressure‐transfer system has been produced by the Dunlop aviation division by which the tanks need only be pressurized while fuel transfer is taking place.