Month in the Patent Office

An aircraft sustaining rotor blade having a main longitudinal structural member 10 of oval‐tubular cross‐section, the major axis of which is disposed substantially in the direction of the blade chord, a superstructure including former ribs mounted on the member 10 and a blade covering 27 supported on the superstructure and spaced thereby from the member 10. As shown, the minimum radius r of the member 10 is not less than one‐third of the minor axis 6. Clips 11 are mounted on the member 10 and carry a forward spruce part 16 to which is glued a nose fairing 28 and a rear part 17 grooved to receive a cord which secures the fabric cover. A trailing‐edge fairing 22 is secured to the part 17. The centre c of the member 10 lies in the forward quarter of the blade chord.