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The first touchdown moment of aircraft tyres on a runway is the critical phase where maximum of the vertical and horizontal ground loads is produced. Some valuable drop tests have been performed at Langley research centre to simulate the touchdown and the spin-up dynamics. However, a long impact basin and a huge power source to accelerate and decelerate the landing gear mechanism have been used. Based on a centrifugal mechanism, the purpose of this paper is to propose the conceptual design of a new experimental setup to simulate the spin-up dynamics.

A schematic view of the proposed mechanism is presented, and its components are introduced. Operating condition of the system and the test procedure are discussed in detail. Finally, tyre spin-up dynamics of Boeing 747 is considered as a case study, and operating condition of the system and the related test parameters are extracted.

It is shown that the aircraft tyre spin-up dynamics can be simulated in a limited laboratory space with low energy consumption. The proposed setup enables the approach velocity, sink rate and vertical ground load to be adjusted by low power actuators. Hence, the proposed mechanism can be used to simulate the tyre spin-up dynamics of different types of aircraft.

It is important to note that more details of the setup, including the braking and actuating mechanisms together with their control procedures, should be clarified in practice. In addition, the curved path introduced as the runway will cause errors in the results. Hence, a compromise should be made between the tyre pressure, path curvature, the induced error and the cost of the experimental setup.

The proposed experimental setup could be constructed in a limited space and at a relatively low cost. Low power actuators are used in the proposed system. Hence, in addition to the performance tests, fatigue tests of the landing gear mechanism will also be possible.

Based on a centrifugal mechanism, the conceptual design of a new experimental setup is presented for simulating the tyre spin-up dynamics of aircraft. Considering that the drag load developed during tyre spin-up following initial touchdown is an important factor governing the design of the landing gear mechanism and aircraft structure, the authors hope this paper encourages engineers to continuously make efforts to increase the transparency of the touchdown process, enabling optimisation of landing gear design.

A FEW brief words on the Total Quality Control concept where in embraced the whole brief of the Quality Engineer — the field of design (conformance with constructor's requirements), manufacture (conformance with specifications) and reliability (conformance with users' requirements). Ideally the Quality Engineer will liaise with both Sales and Design engineers to achieve complete drawing board conformance with customer requirements at the design stage and it is at this stage where, of course, a designer needs to know exactly what is wanted of him. More important, he needs room for manoeuvre, for alternative proposals. As far as concerns aircraft, it is not so long since the tyre designers used to be faced with the appalling difficulty of being presented with a hole of very limited dimensions in each wheel bay into which he had to fit a tyre or tyres come what may. Apart from the limited dimensions of the hole, its dimensions were usually by this time inviolable. If we were lucky we would have some idea of the aircraft take‐off and landing weights and speeds, essential parameters with which the tyre designer commences his calculations.

THE major problems concerning aircraft tyre design are the high ground speeds involved, very high braking torques which have to be transmitted, high temperatures which can be generated in the brakes and transferred to the tyres, as well as the stringent weight and space limitations imposed. These problems have all been magnified many times through the years with the great increases of aircraft speed and weight: modern jet airliners having ground speeds of up to 250 m.p.h.

IT is one of the hard facts of life that tyres tend to skid more readily under wet road or runway conditions — this is a most unsatisfactory basic situation and merits the greatest possible effort to make a substantial improvement. The problem has been studied basically by various bodies including N.A.S.A.

Due to the static condition of the wheels at touchdown, they skid on the runway, which may cause the tyres to burn and wear. This phenomenon occurs in a fraction of a second, known as the spin-up period. The purpose of this paper is to introduce a new strategy to reduce the horizontal force, tyre temperature and wear during the spin-up period.

First, the dynamics of two different phases of landing, namely, spin-up and breaking phases, are reviewed. Second, a strategy to prevent excessive temperature and wear of the tyre is presented.

It is found that using a lubricant and coolant, such as water, at the spin-up stretch of the runway is a simple and practical solution to prevent excessive temperature and wear of the tyre. It is revealed that, despite increasing the spin-up period, the rise of the tyre temperature is eliminated and the material properties are preserved for effective braking. A rough quantitative analysis demonstrates that the wetting of tyres in the spin-up phase decreases the loads and tyre wear effectively.

Wetting the touchdown region of the runway without significant areas of standing water is the most practical strategy with the technology available today.

A new strategy is presented for landing with reduced tyre wear. It is the hope that this paper can inspire continuous efforts to realize the implementation of the strategy.

Since the 1950's the radial ply tyre has gradually penetrated all fields of ground transportation to the situation today where it enjoys a dominant position, particularly in the Western World where road surfaces are of a high standard. The advantages offered by the radial ply construction for passenger car and road vehicle applications are well known, although their lack of robustness has prevented their more general adoption in areas where roads are of an inadequate standard.

States that aircraft tyres are critical for safety and they must have high reliability. Compares two policies for tyre replacement and their reliability and cost which are for Saudi aviation and the international standards.

The need for drastic standardisation of aero wheels and tyres in England is long over‐due. The U.S. Air Services have standardised five sizes of tyres for their needs, and these five sizes use only four axle diameters. In contrast, the English standards, covering the same range, list nineteen standard tyre sizes and fifty‐two axle diameters and length combinations.

THE need for drastic standardisation of aero wheels and tyres in England is long overdue. The U.S. Air Services have standardised five sizes of tyres for their needs, and these five sizes use only four axle diameters. In contrast, the English standards, covering the same range, list nineteen standard tyre sizes and fifty‐two axle diameters and length combinations.

A problem that is always with us is that of bird strikes on aircraft and it is no small task to collect information from such incidents, analyse it and give advice to flight crews, operators and other bodies. The size of the problem may be appreciated when it is realised that 3,975 incidents of this type were reported to ICAO in 1981. This total came from 36 states, chiefly from Europe, North America and the Pacific area. Only about one‐fifth of ICAO's members were reporting bird strikes and, taking into account the sparseness of some other parts of the world, it is conservatively estimated that the annual total of such occurrences may be said to be about 10,000.