Prompted by claims made in the popular aviation literature, analysis is used in an attempt to estimate the turning performance of certain fighter aircraft flown during the Battle of Britain. In this it is necessary to provide values for such aerodynamic quantities as the drag coefficient at zero lift and these are estimated from published flight data.

The inertia characteristics of symmetrically finned projectiles are shown to be invariant of roll angle. This special property is used to derive ‘despun’ equations of motion so avoiding the rapid rates of change associated with the use of body fixed axes. By exploiting the special inertia and aerodynamic characteristics of symmetrically finned spinning projectiles it is possible to reduce the computer solution time required for long down range calculations. By combining the system with the use of quaternions for attitude determination, firings at high elevation can also be accommodated. A speed up by an order of magnitude is observed for the example of a 40mm shell.

A study has been carried out of the aerodynamic interference flow arising at the junction of a cambered, swept-forward wing and a flat plate on which a fully-developed turbulent boundary layer approached the junction. CFD predictions of the pressure field in the junction region were carried out. Flow visualisation tests and surface pressure measurements over a wind-tunnel model were conducted at incidences from -3° to +9°. With the wing at zero incidence, a single-tube yawmeter was used to explore the flow around the leading edge of the junction arid an X-wire anemometer to examine the mean velocity and turbulence fields in the streamwise corners and at the trailing edge. The Reynolds number of the tests, based on the streamwise chord and a free-stream velocity of 30ms-1, was 1·03 x 106.

At low incidence, a very weak separation occurred in the plate boundary layer, a very short distance upstream of the junction. However the oncoming stream converges into the junction, appearing to confine any vortical motion at the leading edge to within a very thin layer below the closest point of measurement to the plate. Rudimentary vortical flow developed slightly downstream of the leading edge, but dissipated further downstream. Although weak vortices were measured in the trailing-edge cross-flow plane, these were attributed to separations just upstream. The turbulence activity in the streamwise corners was found to be surprisingly low, especially on the compression side of the junction. Estimates of the skin-friction showed that it was lower over the majority of the trailing-edge crossplane than in the plate boundary layer upstream of the junction. At higher incidences, flow visualisations revealed severe stall in the junction, with large three-dimensional recirculating regions forming.

Market research predicts a large growth in numbers of passengers as well as airfreight volume for the aircraft industry. An expected concomitant increase in competition for the European aircraft industry demands that the efficiency of new aircraft has to be drastically improved. One approach to achieve this is the aerodynamic optimisation of the wing. The fixed wing is designed optimally only for one flight condition. This flight condition is described by the parameters altitude, Mach number and aircraft weight which vary continuously during the mission of the aircraft. Therefore, the aircraft is just periodically near the chosen design point. To compensate for this major disadvantage, an adaptive wing for optimal adaptation and variation of the profile geometry to the actual flight conditions is under development. DaimlerChrysler Aerospace Airbus, DaimlerChrysler Research and the German Aerospace Centre (DLR) are working as project partners on concepts for a variable camber and a local spoiler bump. In this paper structural concepts developed by the German Aerospace Centre for both objectives will be presented. The concepts are designed under the aspect of adaptive structural systems and require a high integration of actuators, sensors and controllers in the structure. Special aspects of the design will be discussed and first results, analytical, numerical as well as experimental, will be presented. Part of the concept design is also the development of new actuators optimised for the specific problem. A new actuator concept for the spoiler bump based on a cylindrical tube and activated either by pressure or multifunctional materials (e.g. shape memory alloys) will additionally be shown.

This paper addresses the problem of the complex nature of low velocity impact damage in fabricated structures made of laminated carbon-epoxy composites. The structures chosen are stiffened compression panels since these are the most vulnerable to delamination and debonding. Four ‘top-hat’ stiffened panels were tested and predicted using a dynamic finite element code. The panels all had considerable postbuckling strength so the impact sites were carefully chosen to inflict maximum loss of strength. It was shown that the threshold energy for onset of delamination can be predicted using a dynamic finite element code. The amount of delamination or debonding is also predicted using a crude strength-based criterion, which seems to work only because the maximum impact force is a transient phenomenon of short duration.