· · · Aerospace Engineering reports

The College of Aeronautics was founded in 1946 and was granted university status in 1969 becoming the Cranfield Institute of Technology. In 1993 it changed its name to Cranfield University.

The College of Aeronautics was founded in 1946 and was granted university status in 1969 becoming the Cranfield Institute of Technology. In 1993 it changed its name to Cranfield University.

The College of Aeronautics was founded in 1946 and was granted university status in 1969 becoming the Cranfield Institute of Technology. In 1993 it changed its name to Cranfield University.

Our understandirig of the noise from jets, compressors; boundary layers, and sonic booms is still developing. In this lecture current concepts are presented, drawn in part from recent theoretical and experimental research. Where possible simple physical models of the major features of the noise and vibration phenomena are given. The noise from combustion and from propellers and rotors, being better known, is dealt with more briefly. Some mention is made of acoustical fatigue .

The College of Aeronautics was founded in 1946 and was granted university status in 1969 becoming the Cranfield Institute of Technology. In 1993 it changed its name to Cranfield University.

The College of Aeronautics was founded in 1946 and was granted university status in 1969 becoming the Cranfield Institute of Technology. In 1993 it changed its name to Cranfield University.

The College of Aeronautics was founded in 1946 and was granted university status in 1969 becoming the Cranfield Institute of Technology. In 1993 it changed its name to Cranfield University.

The College of Aeronautics was founded in 1946 and was granted university status in 1969 becoming the Cranfield Institute of Technology. In 1993 it changed its name to Cranfield University.

Optimization of low thrust transfer between coplanar hyperbolic orbits has been analyzed, on the basis of an approximate analytical solution, in the case of constant thrust set at a constant angle to the velocity vector. The investigation bears upon minimization of fuel consumption and selection of an ideal initial orbit. For given initial and final orbits it is shown that optimum conditions can be obtained with tangential thrust. Further refinement consists of a proper selection of the angular momentum of the initial orbit, so as to either initiate or terminate low thrust propulsion as close as possible to perigee, depending upon the direction of transfer.

Approximate analytical solutions are derived for the problem of low thrust propulsion, in the case of constant thrust, set at a constant angle to the velocity vector, for any type of initial orbit (elliptic, parabolic or hyperbolic). Simple expressions a re obtained , giving energy, angular momentum and excentricity in terms of the excentric anomaly .The solutions allow for calculation of the fuel consumption. Their validity is restricted to t he field of orbit correction.

An attempt has been made to optimize the problem of recovering an interplanetary vehicle through the earth's atmosphere. Optimum conditions are defined as the ones which would minimize the dead weight, which includes the fuel required for eventual rocket braking outside the atmosphere, and the mass which is ablated for heat protection during the flight into the atmosphere. It is shown that when chemical or nuclear propulsion is considered, pure atmospheric braking is always the best solution, but when electrical propulsion can be used, an optimum compromise between partial rocket and atmospheric braking may exist, depending upon the respective qualities of the propulsion system and ablating material.

The problem of obtaining approximate solutions to ordinary differential equations is discussed with reference to methods which are already in existence. In addition, the possibility has been considered of using direct expansions in Chebyshev polynomials. The analysis indicates that such a method compares favourably with other methods. and may offer further advantages. It is also shown that its application can also be easily extended to the case of non linear equations.

The coupling of vibrational relaxation and dissociation behind strong shock waves is discussed. The flow for various coupling models is calculated, with the CVDV model of Treanor and Marrone, giving the most reasonable description of the process. The effects of various parameters is indicated, including the uninhibited dissociation rate, and the upstream Mach number, temperature and pressure.

A study has been made of hypersonic flow deceleration by means of a plane oblique shock and its reflection from a flat surface. A theoretical analysis was made of an inlet diffuser using this arrangement followed by a terminal normal shock. The optimum deflection angles were found, and it is shown that the total pressure recovery through such a system of shocks is nearly the optimum for a 3-shock configuration. The optimum is given by the Oswatitsch analysis, which was extended to a Mach number of 10. The performance of this system was checked experimentally at a Mach number of 5.4, with the terminal normal shock simulated by an impact probe. The results agreed well with the theory; the maximum kinetic energy efficiency was 0.91.

Some (measurements of pitching moment derivatives of AGARD calibration model D have been performed. A rigidly forced technique with a mass balance system has been used Tests have been made for a reduced frequency parameter in the range from 0.003 to 0.18 (0.5 to 12 cps). The results for the damping and 'stiffness term show reasonable agreement with tests made in other low speed wind tunnels.

La solution analogique du problème de la propagation de la chaleur dans un domaine fini, à une dimension, est considéré pour une température de surface pouvant être représentée par un polynome en t. Les expressions exactes de la température et du flux thermique sont obtenues pour une classe de terminaisons à laquelle appartiennent les cas particuliers extrèmes à savoir, extrémité parfaitement conduqtrice ou parfaitement isolée. Les solutions sont comparées et les différences écrites sous les formes les mieux adaptées d'une part à une étude analytique, d'autre part à un calcul numérique.

The errors resulting in the determination of temperatures and heat fluxes by a finite one-dimensional analog network are computed for the following conditions. The boundary temperature. at the origin, is of the form t N , where t is the time and N is a non-negative integer, the end of the slab is held at constant temperature or is perfectly insulated. The results for both cases are given in tables and represented graphically for values of n ranging from zero to ten.