· · · Aerospace Engineering reports

Reduction of spray drift is essential when herbicide sprays are applied from aircraft, so sprays with a narrow spectrxim and a volume median diameter of about 225μm. are required. Analysis of the performance of currently available atomisers suggest that one of the best is a flat fan hydraulic nozzle (8005) set at 45º downwards and backwards relative to the flight direction. This atomises about 33% of the volume emitted within 25% of this desired size. A new 50mm. diameter windmill disc atomiser produced 70% of the volume emitted in this size range with less than 5% in droplets smaller than 150μm. This is achieved by having far greater control over the actual atomising condition ensuring ligament formation even at flow rates approaching one litre per minute. A strong radial airflow at the atomising edges is found to be extremely beneficial. Starting in 1946 as the College of Aeronautics, the Cranfield Institute of Technology was granted university status in 1969. In 1993 it changed its name to Cranfield University.

Starting in 1946 as the College of Aeronautics, the Cranfield Institute of Technology was granted university status in 1969. In 1993 it changed its name to Cranfield University.

Starting in 1946 as the College of Aeronautics, the Cranfield Institute of Technology was granted university status in 1969. In 1993 it changed its name to Cranfield University.

Starting in 1946 as the College of Aeronautics, the Cranfield Institute of Technology was granted university status in 1969. In 1993 it changed its name to Cranfield University.

It has always been important for military commanders to be able to rely on their equipment being available to them during a conflict. Some recent published figures, however, showed that two modern fighter aircraft were only available for missions for 47% or 56% of the time. These figures prompted a study of the causes of unavailability and the development of an availability assessment technique. Initial studies concentrated on determining probability distributions of reliability, maintainability, battle damage repair and attrition. A simple operation simulation model was then derived to show an aircraft's sensitivity to the main availability parameters. This model can be applied to any aircraft type provided that the necessary inputs can be calculated. The simulated operations were as realistic as possible, although many assumptions had to be made. For reasons of national security it was not possible to relate this study directly to any current service aircraft, so a design project study has been used as the baseline aircraft in the simulation model. This aircraft was the 1980 Mini-CAS, developed at Cranfield Institute of Technology. This was used because all the necessary data were available or could be estimated with reasonable confidence and also the operating conditions are comparable to a number of current service types employed in the Close-Air-Support role. Thus the simulation was kept realistic and the results and conclusions are directly applicable to real and projected designs. The Operation Simulation Model proved to be a satisfactory means of assessing the effectiveness of a force of aircraft under war time conditions. It was far more flexible than the Availability and Mission Readiness equations commonly used to compare the in-service performance of aircraft and highlighted areas where resources could best be concentrated to improve availability. Starting in 1946 as the College of Aeronautics, the Cranfield Institute of Technology was granted university status in 1969. In 1993 it changed its name to Cranfield University.

Processes in the region between a driving piston or contact surface and a strong shock wave (e.g. Mach number > 1.5) can be modelled theoretically as relatively small-perturbation events. The combustion reaction is assumed to be of simple irreversible Arrhenius type; perturbations are then of the order of the dimensionless inverse activation energy (typically 1/25). Events behind the shock are then described by either an integral equation, which is solved by straightforward numerical iterative methods, or by a differential equation. The latter reveals the basic physics as a coupling between four limiting processes namely, explosion at constant pressure and at constant volume coupled with wave propagation at the isentropic and isothermal sound speeds. Illustrative results demonstrate that induction activity within a fluid element takes place midway between constantvolume and constant-pressure limits, with appropriate influence on the time to ignition. Thermal expansion of fluid elements produces significant gas dynamical activity, whose influence is also evident in the strong dependence of induction time on weak modifications of contact surface behaviour. Starting in 1946 as the College of Aeronautics, the Cranfield Institute of Technology was granted university status in 1969. In 1993 it changed its name to Cranfield University.

This report shows that thin monolithic Cabron Fibre Reinforced Panels impacted with small arms projectiles can be adhesively repaired restoring the damaged panel tensile strength to between 85% and 90% of the original. The compressive buckling strength of the thin CFC panels was found not to be significantly affected by ballistic impacting. The repair is primarily concerned with single-sided repairs utilizing a wet laminating repair patch technique and a precured patch technique. The repair research showed that for the particular impact damage sustained by the CFC panels there existed optimum repair patch physical parameters (i.e. overlap length and ply composition) for strength restorations above 85%. The research highlighted a number of repair techniques which adversely affected strength restorations. These techniques involved the removal of the damage area, use of precured square patches and the use of narrow repair patches. In addition to the damage panel repair analysis the report also details the construction and the testing of the laminates used in the research and attempts to present theoretical repair analysis which complements the actual repaired panel characteristics. Starting in 1946 as the College of Aeronautics, the Cranfield Institute of Technology was granted university status in 1969. In 1993 it changed its name to Cranfield University.