To the layman the parachute is often no more than a large pocket handkerchief which brings men safely to earth without a bump, but to the aeronautical engineer it is a complex aerodynamic decelerator, which has a large number of degrees of freedom and dynamic characteristics which are often difficult to account for by classical aerodynamic theory. Whichever view one may care to take of the parachute what is certain is that advances in parachute technology are nearly always the result of a balanced programme of both theoretical and experimental work, and for this reason equal attention will be given in this paper to both the experimental and theoretical aspects of parachute technology.

As military aircraft become more multi-role in design, the use of externally carried ordnance has increased both in frequency and variety resulting in increased use of wind tunnels for store load measurement. It is intended that this report may be useful in predicting loads on a variety of isolated stores at speeds up to transonic and in providing loading data on a new store carried on an aircraft by converting wind-tunnel measurements made on an existing store.

The estimation of aerodynamic loads uses linear methods for forebody and fin-wing normal forces with cross-flow terms on body and fin and also tail recovery effects represented by higher-order predictions. Allowance is made for body to lifting surface and lifting surface to body carry-over effects. The effect of the location of the fins and wings with respect to the body and their dihedral is also accounted for in the prediction.

Forward Swept Wings have a number of advantages over Aft Swept Wings which have been appreciated for a number of years. In the past, however, their use has been restricted to limited degrees of sweep because of the severe weight penalty necessary to prevent aerolastic divergence. Recently, it has been shown that the outstanding directional properties of fibrous composites could help overcome this problem by adequate selection of ply orientations and laminate thickness distribution of the wing skin.

The arguments for the trend from tail-wheel to nose-wheel undercarriage configurations, which appear to be completely pervasive so far as current aircraft designs are concerned, are examined in the light of modern technological developments.

It appears that many of the problems that have led to the demise of the tail-wheel undercarriage configuration are surmountable in an actively controlled, undercarriage management system. There seems some prospect of performance gains from a system of this kind but a more detailed study than is attempted here is necessary to determine if these performance gains can offset the added complexity of the undercarriage management system to result in more cost effective designs.

Reference 1 provides the stimulus for this note, containing, as it does, a trap into which many engineers and statisticians fall. Referring to Fig. 6 of that paper (this was incorrectly labelled — it should have been Fig. 4), a set of observed data is presented on normal probability paper, together with a straight line representing the fitted normal distribution. Since none of the points is far from the line, the conclusion is drawn that the data are well-fitted by a normal distribution.

However, a closer look at the figure shows that the scatter of the ‘observed’ points about the fitted line is not random, but systematic; the first four points all lie above the line, the next six below the line, the next eight above the line, and the last two below the line.

A rotor concept is described that enables the generation of a controlled thrust vector in any direction within the rotor’s sphere of action. It is suggested that a rotor of this kind might replace the entire tail unit of the ‘conventional’ single-rotor helicopter to provide a lighter, more compact layout of improved performance. An active control system might be required for the ‘flying-tail’ layout envisaged.

Some of the structural and mechanical design problems that are posed by a vectored-thrust (VT) rotor are briefly discussed and are seemingly tractable by exploiting the potential of advanced composite materials.

No assessment is made of the aerodynamic performance of a VT rotor, nor of the helicopter configurations or operational scenarios where a VT rotor might prove advantageous. Some limited assessments of this kind seem merited.