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THE advantages and disadvantages of the fixed wing for gyroplanes are examined. On the simplest assumptions an expression for the percentage load taken by the fixed wing of a gyroplane is derived. The values so arrived at are compared with those found by experiment and the discrepancy between the two is explained in terms of the increased downwash at the centre of the disc of the gyroplane. It is shown that as much as 50 per cent of the weight of the aircraft can be taken by the wing at top speed with moderate wing area and the most suitable setting. The advantages of an adjustable wing from the point of view of rotor speed control are pointed oat. The Lift/Drag of the combination is raised by 2 over the L/D of the rotor alone. The stability of gyroplanes is discussed.

ASSUMING that the resultant pressure on the nose is zero in the absence of the screw, which is roughly true of a number of shapes, then the resultant P of the pressure over the whole nose with airscrew running may be inserted in the momentum relation in the form

TO facilitate airscrew performance calculations an entirely new series of charts have been developed embodying wider use than hitherto of the term solidity ratio. These charts are applicable to airscrews with any number of blades. Whilst the number of blades is incorporated in the solidity ratio no further inclusion has been made of their tip speed effect on the interference velocity through the actuator disc. This effect has been investigated by Lock in conjunction with tip speed losses, but it was felt that its inclusion did not justify the added complication to the charts. In fact it makes their simple presentation impossible. The effect, however, can be incorporated with a correction factor to the power input to the airscrew. This factor is not dealt with in detail in this article and would form the subject‐matter of a separate work.

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Committee, Reports and Technical Notes of the U.S. National Advisory Committee for Aeronautics, and publications of other similar research bodies as issued

A PROPOSAL to replace the 7‐ft. No. 1 wind tunnel at the N.P.L. by two new tunnels of the open jet type, housed in the old tunnel building, was put forward in 1930, and one of the new tunnels has now been completed and tested. The present report deals mainly with preliminary experiments on models, which were carried out to ensure that the projected tunnels should give the best possible aerodynamic performance.

IN the design of hypothetical airscrews an4 general investigations on performance thc calculations are often based on values of torque and thrust coefficients from a family of airscrews or by the use of Lock's method assuming an elliptical grading. It is sometimes desirable to ascertain whether the corresponding stresses in thc blades are satisfactory. This is a laborious process as far as the aerodynamic bending stresses are concerned, since before calculating thc bending moments at each section, it is necessary to calculate the aerodynamic forces.

Under this heading are published regularly abstract of all Reports and Memoranda of the Aeronautical Research Committee, Reports and Technical Notes of the U.S. National Advisory Committee for Aeronautics, and publications of other similar research bodies as issued.

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Committee, Reports and Technical Notes of the United States National Advisory Committee for Aeronautics and publications of other similar Research Bodies as issued

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Council, Reports and Technical Notes of the United States National Advisory Committee for Aeronautics and publications of other similar Research Bodies as issued.

THE present paper gives, in abbreviated form, the theory of blade motion and of static and dynamic stability of single‐rotor helicopters. Limitations of space do not permit of full discussion and the article should be taken as only an introduction to the somewhat complex problems of helicopter stability and control.