Accidental dispersals of medically and agriculturally undesirable insects by sea and air transport are discussed, with attention to the relative importance of the roles of ships and aircraft. World-wide records of insects found on board aircraft and discovered to have been introduced at airfields are briefly reviewed, and consideration is given to ways of meeting the problem by insecticidal treatment and airport insect control. It is felt that the insecticidal treatment of aircraft, even when provided for by comprehensive international regulations and conscientiously undertaken, does not alone provide sufficient protection against insect introductions, and that greater attention should be paid to the preventive aspects of the problem, with particular regard to the control of insects of both medical and economic significance at international airports.

The effects of the model surface to free stream adiabatic temperature ratio (Tw/Tad) on periodic transonic flow over a 14% thick biconvex aerofoil are evaluated using a computational fluid dynamic approach. The analysis is based on the thin layer Navier Stokes equations with Baldwin-Lomax turbulence model. The results of computations showed that on biconves aerofoils there is a large effect of heat transfer on instantaneous pressure distributions and periodic buffet excitation level confirming some of the available experimental data. The effects observed have an implication in wind tunnel measurement of buffet associated periodic transonic flows.

Tests of the first experimental VTOL aircraft using tiltable wings and propellers indicated that practical operational aircraft are possible and can operate with a high degree of effectiveness.

The flight tests accomplished up to the present time with the second generation tilt-propeller and tilt-rotor aircraft are discussed and analysed. The XC-142 and the CL-84 tilt-wing aircraft have been performing well throughout their projected flight envelope and good pilot ratings have been obtained with each in hover, transition, and the normal cruise mode. The X-19 tandem wing tilt propeller was flown only up to 100 knots and was lost due to a structural failure in one nacelle. Although the operation of the aircraft had been satisfactory up to this point, this programme was terminated due to shortage of funds.

A study of the various VTOL aircraft configurations operating at low radius of action indicates that the tilt wing/ tilt propeller type are the most cost-effective as long as speed is an important parameter in the operating mission. There are missions where speed is of secondary importance, and therefore, the helicopter will continue to be one of the most effective VTOL for these missions.

Since the tilt-wing /tilt-rotor aircraft tend to be only slightly higher in cost than the helicopter and with development the complexity and maintainability will be reduced to acceptable levels, it is anticipated that further work will be done in the development of these vehicles, and successful and useful machines will be built in the future.

The advantages of using heavy gases in wind tunnels—reduced power consumption and scale size — have been appreciated for some time. To be sure of correct scaling of the results from such a tunnel, the working fluid should have a specific-heat-ratio γ equal to that of air (γ = 1·4); such a fluid can be obtained as a mixture of a monatomic gas with a polyatomic one. Here, general principles for choosing such a mixture are discussed, and estimates are given for the savings in size and scale which may be expected (compared to a conventional tunnel), following earlier work of Chapman.

When an aircraft lands on a runway on which there are extensive puddles, it appears that sometimes the water exerts a large upwards force on the wheels, so preventing them from making contact with the ground. The wheels are then said to “aquaplane”. In the aquaplaning condition the braking effectiveness of the wheels is reduced virtually to zero, and even at touch-down speeds insufficient to cause aquaplaning, when there is some contact between the wheels and the ground, water on the runway may cause appreciable reductions of runway friction forces. This note offers some tentative suggestions concerning the nature of the water flow when aquaplaning occurs, and is put forward as a basis for discussion of this important practical problem.

In 1949 F. H. Pollicutt, in the course of a discussion on a paper presented by P. B. Walker to the Royal Aeronautical Society, reported fatigue test results which indicated that when the aluminium alloy conforming to specification D.T.D.364 was tested, under , axial loads, in the form of Z-sections, its fatigue properties were extremely low. Z-sections with unmachined surfaces and even Z-sections with completely machined surfaces failed after short endurances at stress ranges under which small polished round test pieces would not have failed even after hundreds of millions of cycles. Pollicutt, in discussing these low values, advised that great caution should be exercised in their interpretation, warning equally against an unqualified acceptance of the testing technique and a too facile acceptance of small polished round bar test results.

The service life of aircraft structure includes the fatigue life and calendar life. The Aircraft Structural Life Envelop (ASLE) is a safe and reliable life scope of aircraft structures in service. The specific steps to establish the ASLE are developed, and a residual life prediction method for aircraft structure under service environments is established by combining the ASLE with the Miner theory. Furthermore, a service life extension method of aircraft structure is proposed based on a scope extension of the ASLE, including methods based on reliability analysis and structural repair. Finally, an application example of the ASLE is presented.

Air-breathing propulsion has the potential to decrease the cost per kilogram for access-to-space, while increasing the flexibility of available low earth orbits. However, to meet the performance requirements, fuel-air mixing inside of scramjet engines and thermal management still need to be improved.

An option to address these issues is to use intrinsically generated vortices from scramjet inlets to enhance fuel-air mixing further downstream, leading to shorter, less internal drag generating, and thus more efficient engines. Previous works have studied this vortex-injection interaction numerically, but validation was impractical due to lack of published experimental data. This paper extends upon these previous works by providing experimental data for a canonical geometry, obtained in the T4 Stalker Tube at Mach 8 flight conditions, and assesses the accuracy of numerical methodologies such as RANS CFD to predict the vortex-injection interaction.

Focus is placed on understanding the ability of the numerical methodology to replicate the most important aspects of the vortex-injection interaction. Results show overall good agreement between the numerical and experimental results, as all major features are captured. However, limitations are encountered, especially due to a localised region of over predicted heat flux.

In recent years, aerodynamics and thermodynamics have found common ground in the specialised field of gas dynamics. Developments in this subject have led to a much more complete and widespread knowledge of subsonic, sonic and supersonic flow of gases in the conventional type of convergent-divergent nozzle. When the back pressure is raised above the value against which the nozzle is designed to discharge, oblique and then normal shock waves are set up in the divergent cone at a position along the nozzle axis determined by the magnitude of that back pressure. The gas which has crossed the shock wave is subjected to a process of subsonic compression.

In this paper a theoretical investigation is made of the changes in pressure, temperature, density and Mach number which occur across a normal shock wave, when the position of the wave varies along the nozzle axis. The investigation illustrates the effect of change of medium, for which the relevant property is the ratio of specific heats. This ratio for certain polyatomic gases may approach unity (e.g. for Dichlorodifluoromethane CCl2F2, in gaseous form, γ=1·06), and for the inert monatomic gases γ= 1·667. The analysis is made non-dimensional by expressing such quantities as gas pressure, temperature, and density at any given position along the nozzle axis relative to the values of the particular parameter at entry to the convergent section.

The scope of this paper is necessarily restricted. A large aeroplane, within the new definition, has not yet flown in this country. This event, however, is not very far off and the preparatory work that makes it possible has brought to light many novel problems. In some cases these could be predicted with normal anticipation, whereas others have only emerged as analysis progressed. These latter are frequently good examples of the dangers of too facile extrapolation.

Some of the reasons for having large aeroplanes are examined and subsequently, the chief technical problems arising are described. These descriptions avoid mathematics, as in many cases this approach is extremely long and involved and merits individual publication.

The evaluation of rotorcraft performance and handling qualities in piloted flight using a desk-top simulation is a desirable facility. The development of the SYCOS pilot model has brought this capability closer by simulating piloted flight along prescribed trajectories such as the Mission Task Elements of ADS-33. This development has overcome some of the limitations of the precise control of inverse simulation, by adopting a structure which includes a corrective component that adjusts the control strategy to counteract departures from the desired flight path. The development and implementation of SYCOS for a range of rotorcraft types and applications is shown to be well defined and straightforward. The capability and reliability of SYCOS is demonstrated through a number of recent applications in performance, control strategy and pilot workload studies. Some of the applications benefit from enhancements to the basic structure and these are described in context. The accumulation of experience with the SYCOS pilot indicates that it is a significant advance as a predictor of human control activity during helicopter manoeuvring flight.

It was with the greatest pleasure that I accepted the invitation of the Council to deliver the Wilbur Wright Lecture this year. Not that I count myself worthy to follow in the footsteps of the many illustrious men, British and American, who have delivered it in the past, but rather that I feel we are on the verge of discoveries and advances almost as spectacular as that flight of Orville Wright's, forty-three years ago, and that my peculiar experience may enable me to present to you some of the results of recent researches which have led me to the above somewhat prophetic conclusion.

The twenty-first Louis Blériot Lecture was given in Paris on 5th April 1968 under the auspices of L’Association Françaises des Ingénieurs et Techniciens de L'Aéronautique et L'Espace. The lecture “Some Thoughts about the Future of European Aeronautics” by Handel Davies, CB, MSc, CEng, FRAeS, FAIAA, was read on his behalf in French by General Lecamus, FRAeS. The Lecture was attended by the President, Mr. M. B. Morgan, CB, MA, FRAeS, the Secretary of the Society, Dr. A. M. Ballantyne, OBE, TD, PhD, by several members of Council and a large and distinguished French audience.

The Chair was taken by Monsieur Robert Blum, President of AFITAE. Following the lecture a dinner was given by AFITAE.

This paper describes the market for air vehicles that offer Very Short Take Off and Landing (VSTOL) capabilities, also known as VSTOL aircraft. A commercial VSTOL aircraft will only succeed if it provides profits to both manufacturers and airlines. Being able to operate out of shorter fields offers airlines greater flexibility and therefore provides a benefit to the airline. However, adding VSTOL performance also adds cost. Successful VSTOL aircraft designs must balance the added cost against the additional benefits VSTOL performance will provide.

The first problem in any new VSTOL design is determining what field length provides the maximum benefit relative to cost. In order to be able to determine this one needs to know not only what it will cost to design and build the new aircraft, but its value to the airlines, as reflected by the demand for it and the price they are willing to pay. Only then is it possible to design the aeroplane the market wants at a sustainable price and in sufficient quantities to optimise the manufacturer’s return on investment.

This paper is a comprehensive parametric analysis of helicopters and aeroplanes that shows how much the market values short field performance by determining how much airline customers have been paying for it and how the market reacts to changes in its price. The analysis simultaneously considers over 230 currently produced models of fixed wing and rotary commercial aircraft, ranging in size from a Cessna 172 to an Airbus A380 and with balanced field lengths ranging from less than 150 to over 10,500ft.

The data show that a single, statistically significant demand curve exists for all of these vehicles, with prices that range across several orders of magnitude. This curve consists of several segments or sub-markets including those for regional and rotary wing aircraft. Both of those markets offer vehicles over a wide range of prices. The analysis shows that VSTOL price is a function of the balanced field length provided by the vehicles within these market segments. Comparing demand and sustained price against cost reveals particular field lengths for which it will be possible to make a profit building VSTOL aircraft.

Because the sustained price for a VSTOL aircraft is a function of its field length performance, and the quantity of a model sold is a function of its price, it follows that it is possible to predict the profit potential for a given VSTOL design in advance of its development. A thorough study of potential configurations therefore offers manufacturers the ability to design VSTOL aircraft that provide the maximum possible profit while fully satisfying the requirements of their airline customers.

According to multi-node model, the dynamics equations of conical parachute system for simulating shape deformation process of the flexible canopy in the opening process were established. With the combination of dynamics equations code and computational fluid dynamics (CFD) software, the fluid-structure interaction investigation of the conical parachute was carried out. Also the change of parachute shape and flow field, inflation time, the rate of descent, the distance of descent, and other relevant data were achieved. This paper has focused on analysing vortex structure of the flow field in the opening process of conical parachute, and laid the foundation for studying mechanics mechanism of flow field variation of conical parachute in future.

The solution of the general heat transfer problem for typical aircraft-type structures usually involves a finite element approach involving the solution of a large number of simultaneous equations. This may be performed by calculation using a digital computer or with an analogue simulator. For calculations involving both spatial and time intervals considerable care must be exercised to obtain solutions which are not divergent or oscillatory and this usually involves very small time increments and a large total computation time.

Velocity defect law has been accepted as a universal velocity distribution for a turbulent boundary layer along a flat plate. The two necessary conditions for such a similarity to exist are not fulfilled with flat plate boundary layer having smooth or uniformly rough surfaces. Rotta has proved that a linear increase of surface roughness in the stream direction is necessary to ensure such a similarity. This note is an experimental investigation into turbulent boundary layer along a flat plate with linear increase of roughness height. It is obvious that, under such conditions, complete similarity characteristics are fulfilled.

The purpose of this paper is developing an efficient flight control strategy in terms of time response characteristics, robustness with respect to both parametric uncertainties and un-modeled nonlinear terms, number of required measurements, and computational burden. The proposed method is based on combination of a classic controller as principal section of the autopilot and a multi-objective genetic algorithm-based fuzzy output sliding mode control (FOSMC). FOSMC not only modifies robustness of the classic controller against uncertainties and external disturbances, but also modifies its time response for wide range of commands. FOSMC is a single input-single output controller that is based on the system output instead of the system states. In this situation, the proposed autopilot does not require measurement of other variables and observer, and also it is practicable because of considerable reduction in rule inferences then computational burden. As a critical application, the proposed method is applied to design the altitude hold mode autopilot for an UAV which is non-minimum phase, uncertain, and nonlinear.