Head Resistance of Strut Sockets.
A point calling for comment is the apparent oversight or neglect of the amount of head resistance offered by the average strut fitting, although great care is taken to ensure the strut and wing sections being of correct form. It seems probable that some difference must occur, especially at the high speeds now prevalent, between the air flow across the plane and that which meets the strut terminal. Anyway, some discontinuity of flow exists, and whether or no the aggregate resistance of all the fittings is of any great moment provides matter for discussion. It is quite possible to fair off any irregularities in air-flow due to the strut connections by the attachment of sheet-aluminium fairings, which could be beaten, pressed, or spun with little difficulty. Although examples of this practice are very little in evidence, the writer inclines to the belief that the additional weight would be negligible compared with the ensuing reduction in head resistance.
The foregoing examples cannot be said to constitute the latest practice, nor is it possible under present conditions to give such details, but sufficient has been said to indicate the progress and trend of design.
CHAPTER VII.
WING-TRUSSING SYSTEMS.
Although the trussing of aeroplanes is carried out along certain well-defined lines, there are occasional divergences from the orthodox. The differences now existing are not nearly so great as those of former days, this being explained by the fact that the progress of any science or industry tends towards uniformity of method, while practical experience eliminates the undesirable systems. This does not necessarily mean that the present methods in vogue are incapable of improvement, but merely denotes their suitability for present requirements.