In considering the design of marine aircraft, viz., flying boats andseaplanes, an entirely separate and additional subject is brought in forinvestigation, and upon which there would appear to be much reserve as todefinite formulations and data, etc. This subject, which I prefer to entitle“Hydrodynamics,” can become, besides interesting and absorbing, certainlymost deep in its complexity, and it is realised only too well by thoseactually engaged in such investigations, the more that time passes andexperience is gained.

Scientific and technological development over the past 20 years has been tremendous. It presents the military planner with a dazzling array of possible developments to meet a wide range of operational requirements. Unfortunately, in every country resources are limited and a choice between the various alternatives has to be made. An objective and, if possible, quantitative method of examining alternative proposals is required. This is what cost-effectiveness analysis attempts to do. It can be and is applied at any level. For example, the government may require a study examining the implications of the different allocations of national resources to defence, foreign aid, civil industrial research, social security benefits, etc.; the Ministry of Defence may require a study examining the balance between the forces on land, at sea or in the air (force structure) and the contribution each make in a number of scenarios; a single service may require a study of the resources that should be allocated to defensive or offensive action; within a single role a study may be required of the alternative weapons that could be deployed to meet a particular requirement. In this paper, only questions arising in the study of defence systems will be considered.

From Mr. A. M. Dobson's Note (July 1955 Journal, page 506) which dealt with the stability of an axially loaded continuous beam, and other contacts we have had with the Aircraft Industry, it would appear that the very considerable developments of structural theory which have taken place in relation to continuous beams subjected to axial load, as employed in normal structural steel work, are not well known in aircraft stress offices. The list of references appended may then be found helpful.

With the exception, possibly, of the detective thriller most stories are best enjoyed by starting at the beginning. My story is no exception and, if i am to give you some feeling for the accomplishments in aeronautical research in my Country during the past ten years, I must refer briefly to what had been done already in Canada during the earlier years of this century.

Simple means of checking contractants has been devised which is considered essential to a computor.

In a recent paper Macmillan describes the method of contractants as applied to the evaluation of determinants. The method is essentially based on the extensional identity

Now, any determinant of order n may be expressed as a determinant of order n - 1, all of whose elements are third order determinants. This process is now repeated (n - 2) times until the value of the original determinant is obtained.

A low Reynolds number turbulent boundary layer is subjected to a relatively strong rate of suction, which is applied through a short porous strip. Downstream of the strip, the effectiveness of a riblet surface is assessed by comparison,to that of a smooth wall. Measured mean velocity and longitudinal turbulence intensity profiles indicate that the riblets do not hinder the action the suction can have on the flow.

Heat transfer rates on a straight biconic, an attractive configuration for an aero-assisted orbital transfer vehicle, were made in the ANU T3 shock tunnel at various angles of attack and a stagnation enthalpy of 26 MJ/kg, equivalent to a flight speed of 7-2 km/s. The heat transfer database at this higher enthalpy has been compared with the data obtained on the same model in hypersonic and hypervelocity facilities elsewhere. The non-equilibrium flow effects on the model have been discussed in terms of the Hornung reaction rate parameter Ω.

Compared with most other industries a distinguishing feature of the air transport business throughout its history has been the rapid development and replacement of its flying equipment. Aircraft have evolved to meet the needs of expanding traffic and each generation has been succeeded by different, newer and better versions. The thirties saw the appearance of the all-metal monoplane with piston engines and propellers.

The two chief methods proposed by inventors for obtaining aerial flight are by means of aeroplanes or aerocurves, driven by screw propellers, and by wings worked as in nature.

Which of these designs will practically be best it is difficult to say. It can only be by actually trying the two methods that their merits can be compared. It may be that wings are the best, as they move a larger weight of air with less velocity than a screw propeller. The slip may on this account be less.

It may be that wings are the best, as they move a larger weight of air with less velocity than a screw propeller. The slip may on this account be less.

In a recent note Professor Duncan gives a method for finding the reciprocal of a matrix which is triply partitioned both horizontally and vertically. In spite of the apparent complication of the formulae, such a procedure may shorten the calculations in the case when the submatrices involved are especially simple (e.g. null or diagonal), or when their arrangement exhibits some symmetry. In Ref. 1, the submatrices a to j of the desired reciprocal are obtained by a series of operations summarised in equations (3) to (19); these operations consist altogether of 5 inversions of submatrices, 29 matrix multiplications of various orders and 15 matrix additions.

Gas-kinetic theory is also valid in the continuum regime: the Euler and Navier-Stokes equations can be obtained as projection of the Boltzmann equation on to the physical space (x,t). The numerical schemes derived from gas-kinetic theory are computationally more expensive than Navier-Stokes based ones, but offer advantages which have been attracting a growing level of attention: they can (i) accommodate discontinuities at cells interface, (ii) provide high-resolution fluxes, (iii) provide advantages in the simulation of turbulence, (iv) handle hypersonic and/or rarefied flows. This study extends the validation of gas-kinetic schemes investigating a few turbulent flow cases. At a slightly higher computational cost, gas-kinetic schemes provide results comparable to those obtained with well-validated Navier-Stokes schemes using the same turbulence model, grid and reconstruction order. In the case of shock-separated flows, the results obtained with the gas-kinetic scheme are even closer to experimental data. These findings are consistent with the idea that gas-kinetic theory is a physically more consistent framework for investigating the mechanics of fluids.

The New Zealand Government takes airspace safety very seriously. The level of safety in New Zealand airspace is measured by the number of recorded airspace incidents. An airspace incident can be thought of as a failure in the chain of operations in the air traffic system when it is provided with an air traffic service (ATS). Some of these incidents result in a loss of separation between aircraft, varying from slight to a very serious loss with a significant risk of collision, known as a near collision. New Zealand’s Civil Aviation Authority (CAA) identifies the causal factors for all airspace incidents using the Reason model of human error, divided into three areas; active failures committed by individuals involved in the incident, local factors relating to the task and the ATS environment and organisational factors originating in the managerial and organisation spheres of the ATS provider. Based upon the CAA’s database, this paper analyses trends in controller caused incidents in the NZ airspace during the period 1994 to 2002 in six controller caused categories. The results indicate that for controller caused incidents, execution errors dominate the active failures category, while in the case of local factors, poor concentration/lack of attention, inadequate checking and controller workload are the dominant factors. For the organisation category, poor planning and inadequate control and monitoring dominate. These results should form the basis of a robust and transparent framework for intervention mechanisms by the New Zealand Civil Aviation Authority for enhanced airspace safety.

Subsonic wind tunnel experiments were conducted to study the effect of forced transition on the pressure distribution in the concave portion of contraction. Further more, the effect of early transition on the turbulence level in the test section of the wind tunnel is studied. Measurements were performed by installing several trip strips at two different positions in the concave portion of the contraction. The results show that installation of the trip strips, have significant effects on both turbulence intensity and on the pressure distribution. The reduction in the free stream turbulence as well as the wall static pressure distribution varied significantly with the location of the trip strip. The results confirm the significant impact of the tripped boundary layer on the control of adverse pressure gradient. The trip strip at X/L = 0.115 improves pressure distribution in contraction and reduces turbulence intensity in the test section, considerably.

Stiffened wing and fuselage panels often have a postbuckling reserve of strength, enabling them to carry loads far in excess of their critical buckling loads. Therefore allowing for postbuckling in design can reduce their weight, hence reducing fuel consumption and environmental impact. The present paper extends the postbuckling analysis in the exact strip software VICONOPT to more accurately reflect the skewed mode shapes arising from shear load and anisotropy. Such mode shapes are represented by a series of sinusoidal responses with different half-wavelengths which are coupled together using Lagrangian multipliers to enforce the boundary conditions. In postbuckling analysis the in-plane deflections involve responses with additional half-wavelengths which are absent from the out-of-plane deflection series. Numerical results are presented and compared with finite element analysis for validation. The present analysis gives close results compared to the finite element and finite strip methods and saves computational time significantly.