Control surface effectiveness is an important parameter for any aeroplane. For a hypersonic aircraft, though the power required to operate the flaps is determined by low speed flying conditions, it is imperative to know the effect of flaps at hypersonic speeds. Hence, studies have been done on this topic by aerodynamicists for over 40 years. In spite of this, only a limited data is available in the literature on this subject.

This paper discusses the experimental study of the effect of sweep on the aerodynamic characteristics of thin slab delta wings with flaps at hypersonic speeds. For the purpose of this investigation, a novel special thin six-component balance, which has a thickness of 4mm and can be housed inside wings with 8mm thickness, has been designed. The wings had a sweep of 76°, 70° and 65°, t/c of 0.053 and flaps with 12% of wing area and 12% of wing chord. Testing were done at Mach 8.2, Re number of 2.13 x 106 (based on chord), from α = –12° to 12° and flap angle of 20°, 30° and 40°. Separation lengths, measured from Schlieren pictures, clearly show that there is ‘no appreciable’ effect of sweep on them. Also, using a simple local flow field calculation, the separation has been identified to be transitional in nature. These features of separation reflect in the force data. Because of the small separation length, the flaps (inspite of their small size) were very effective in generating additional CN, CM and Cl, which increased with increase in flap angle. In general, the CN, CM and XCP were unaffected by sweep for symmetric flap deflection at positive incidences and asymmetric flap case. For symmetric flap case at negative incidences, only CN was not influenced by the sweep but CM decreased and XCP moved upstream as the sweep is decreased. The wing with lower sweep produces higher CA and lower (L/D)max for both symmetric and asymmetric flaps. The rolling moment and adverse yaw increased with decrease in sweep for asymmetric flap deflection. Newtonian theory is shown to be incapable of predicting the effect of sweep on Cl, Cn and on the incremental values of CN, CM and CA.

In conclusion, it can be said that a small flap is generally adequate for hypersonic aeroplanes provided they operate at altitudes where transitional and turbulent separation can be expected to occur. This would make the flaps effective and thus enable ample control authority.

In this paper two numerical procedures are presented: the first algorithm allows for the determination of the geometric characteristics of the maximum efficiency propeller for a given operative condition and profile distribution along the blade; the output of this numerical procedure is the chord distribution and twist angle of the blade, together with its efficiency and its torque and thrust coefficients for the prescribed operative condition. The aerodynamic characteristics of the optimum propeller when operating in a condition different from the design one are obtained by a second algorithm that allows for the evaluation of the efficiency, the thrust and torque coefficients of a propeller of known geometry, when the blade pitch and operative condition are varied.

In the paper the formulation used for deriving the geometry of the optimum propeller and determining its performances when operating off-design is described in detail. The results obtained from the proposed propeller model have been validated by comparison with experimental data.

This paper discusses selected aviation human factors challenges in the air transport environment. Because of the authors’ background, much of this paper will be based upon the growth of human factors and airline training in transport aviation in the United States. However, parallel growth and advancements have been made in other parts of the world from the beginning of air transport and are being made in many parts of the world today. This is certainly true of Great Britain. One should never forget that air transport is a world enterprise and has been since its beginning. While it is important to recognise that cultural and other differences should be considered if they are relevant, it is equally important in air transport to recognise that common problems are solved by common solutions and can be addressed by, but are not limited to, common approaches.

It is recognised that the behavioral aspect of aviation human factors deserves considerable attention, particularly in the area of training and evaluation. We have also learned that previous training criteria are not satisfactory for operation with increasingly complex aircraft being operated in an increasingly complex environment. Human errors occur with greater frequency than is often believed and can be made by anyone — even an airline captain. An inevitable consequence of this entirely human characteristic is that the role of the co-pilot has been considerably enhanced. Furthermore, the monitoring function of the pilot-not-flying, whether he/she is the captain or co-pilot, is now recognised as a critical safety function by virtually all serious operational experts.

High altitude span loader aircraft experience significant wing bending mainly due to turbulence of spanwise scale comparable to the wing. These moments are often the primary wingspar design loads. Spanloaders with a few concentrated loads on the wing are called semi-span loaders. Typical of this class is a family of unmanned solar-powered vehicles developed by AeroVironment of California, which have spans up to 250ft and flight speeds of about 30fts-’ equivalent. An aeroelastic model of the wing moments induced by turbulence varying in both spanwise and flightwise directions has been developed. The model treats flexural displacements and torsional deflection, runs rapidly in Excel® format, and can be used to study many different design and gust cases, thus it is a powerful tool for multi-disciplinary optimisation. The procedure was exercised for a generic semi-spanloader. Calculations were made for the effects of turbulent scale, of altitude, and of centrebody mass, all of which are shown to be small. Stiffness sensitivity calculations show that, although the composite wing is very flexible, the turbulence-induced moment is not greatly attenuated by flexibility. Effects of flexural deformation dominate the bending moments and torsional effects are very small. Seven different cases of the type used to define gust loads were examined. These indicated that gust models that do not contain spanwise variation seriously underestimate wing bending.

In this paper, a new transport equation for the intermittency factor is proposed to model the transition flows. The intermittency behaviour of the transition flows is incorporated into the differential methods for solving the boundary-layer equations, which deal numerically with the basic partial differential equations. The present model accuracy and validity have been tested against a series of recent published experiments, for low Reynolds number, including flows with different freestream turbulence intensities and different pressure-gradients, such as aerofoil and flat plate flows. A comparison of the present method and two different prediction techniques is also given.

The significance of the proposed transport intermittency equation is to reproduce the streamwise variation of the intermittency factor in the transition zone. This method is found suitable and reliable to predict flows with positive or favourable pressure-gradient cases and with turbulence intensity level up to 6%.The method also confirmed the importance of estimating the start of transition, present formula. The present formula is suitable and straightforward to use. For all test cases good agreement between the computed results and the experimental data are observed.