For a delta wing it is not sufficient to consider spanwise bending and chordwise rotation only. Chordwise bending must be added. It is therefore necessary to calculate the…
Abstract
For a delta wing it is not sufficient to consider spanwise bending and chordwise rotation only. Chordwise bending must be added. It is therefore necessary to calculate the aerodynamic coefficients accordingly. The theory of Lawrence and Gerber dealing with aerodynamic coefficients of oscillating delta wings in incompressible flow is extended to give the coefficients at any station of the wing. It is shown that for practical reasons the assumption is made that induction may be neglected. This means that the coefficients are theoretically only correct for a rigid wing in pitching and plunging. However they will be used for a flexible wing with spanwise bending, chordwise bending and rotation. For the oscillating delta wing with subsonic leading edges in supersonic flow the theory of Watkins and Berman will be discussed. Here again the original report is extended to give the coefficients at any station of the wing. The calculation of the natural modes of vibration of the wing, based on the methods of Scanlan and Rosenbaum, is presented for completeness. Finally it is shown how the coefficients and the modes may be combined to give the aerodynamic forces. As an appendix the differences between the British and the American techniques for calculating the aerodynamic coefficients are discussed.
To determine the flutter speed, it is customary to introduce all factors into the Lagrange equations with the flutter speed as one of the variables. This paper deals with the…
Abstract
To determine the flutter speed, it is customary to introduce all factors into the Lagrange equations with the flutter speed as one of the variables. This paper deals with the energies to be substituted, and the ways and means to solve the problem. There are two distinct approaches to the solution, one which is well suited for calculation on digital computors, and one which is convenient for solutions by way of analogue computors.
ANOTHER Annual Meeting has come and gone. It was scarcely to be expected that the meeting at Bradford would be a record in the number of members attending, seeing that it is only…
Abstract
ANOTHER Annual Meeting has come and gone. It was scarcely to be expected that the meeting at Bradford would be a record in the number of members attending, seeing that it is only three years ago since the Association met in the neighbouring city of Leeds, and that Bradford cannot boast either the historical associations or the architectural and scenic setting of many other towns. For the most part therefore the members who did attend, attended because they were interested in the serious rather than the entertainment or excursion side of the gathering, which was so far perhaps to the advantage of the meetings and discussions. Nevertheless, the actual number of those present—about two hundred—was quite satisfactory, and none, we are assured, even if the local functions were the main or an equal element of attraction, could possibly have regretted their visit to the metropolis of the worsted trade. Fortunately the weather was all that could be desired, and under the bright sunshine Bradford looked its best, many members, who expected doubtless to find a grey, depressing city of factories, being pleasingly disappointed with the fine views and width of open and green country quite close at hand.