In the Wilbur Wright lectures we commemorate, and pay our tribute to, that pioneer work upon which the art of flying is founded and it is only now that carrying our minds back to those early days we see how thorough were the methods which led to success. The work of Lilienthal in gliding with curved wings—brought to an untimely end through lack of control—had shown that the secret of success was to be found in free flight experiment. Then came the great contribution of the Wrights, who discarded Lilienthal's acrobatic control and carrying through the whole modern programme of wind tunnel research, detail design and construction, found out by practical flying that essential feature of control which has been used in practically every aeroplane that has been flown.

In the original Wright aeroplane, as in all its successors of fixed wing area, the only means used for varying the lift was by alteration of the angle of incidence or of the camber of the wing either by warping or by the equivalent use of ailerons.

In Strapdown Inertial Navigation System (SINS)/Odometer (OD) integrated navigation systems, OD scale factor errors change with roadways and vehicle loads. In addition, the random noises of gyros and accelerometers tend to vary with time. These factors may cause the Kalman filter to be degraded or even diverge. To address this problem and reduce the computation load, an Adaptive Two-stage Kalman Filter (ATKF) for SINS/OD integrated navigation systems is proposed. In the Two-stage Kalman Filter (TKF), only the innovation in the bias estimator is a white noise sequence with zero-mean while the innovation in the bias-free estimator is not zero-mean. Based on this fact, a novel algorithm for computing adaptive factors is presented. The proposed ATKF is evaluated in a SINS/OD integrated navigation system, and the simulation results show that it is effective in estimating the change of the OD scale factor error and robust to the varying process noises. A real experiment is carried out to further validate the performance of the proposed algorithm.

The Integral I occurs frequently in aerodynamics. To cite a particular case, Ward has shown that if S(x) is the cross-sectional area distribution of a slender body its wave drag D is given to a first approxition by D = qI/(2π), where q is the kinetic pressure. In this case, S(x) is often defined numerically, and the direct evaluation of I is then complicated by the presence of the logarithmic singularity. Several methods may be employed to avoid this complication. Legendre has recently suggested rewriting I in a non-singular form, which unfortunately is not well suited to numerical work. Here, a method for the evaluation of the unmodified integral is presented.

The theory of the flow past cascades or infinite series of aerofoils, regularly spaced, is of importance in connection with the design of turbo-blower blades, interference between propeller blade root sections, wind tunnel circuit design and kindred problems. The usual development of the theory involves some rather advanced applications of conformal representation which it is rather difficult to translate into numerical terms, and no general solution for an arbitrary form of aerofoil section is available.