*THE THEORY AND PRACTICE OF MODEL AEROPLANING.* By V. E. Johnson, M.A. The object of this book is to give in plain language the general practice and principles of Model Aeroplaning. Model propellers and motors have been carefully dealt with, and much valuable data included from the author’s own experiments. Contents of Chapters.—Glossary of Terms used in Model Aeroplaning. Introduction. The Question of Weight. The Question of Resistance. The Question of Balance. Motive Power. Rubber Motors and other forms of Motors. Propellers or Screws. The Question of Sustention. The center of pressure. Materials for Aeroplane construction. Hints on the building of Model Aeroplanes. The Steering of the Model. The Launching of the Model. Helicopter Models. Experimental records. Model Flying competitions. Useful notes, tables, formulae, etc., etc. 163 pages, 82 illustrations, 12mo cloth, $1.50.
*RESISTANCE OF AIR AND THE QUESTION OF FLYING.* By A. Samuelson. An important lecture of considerable interest to those interested in Aeronautics. Contents: Introduction. The Resistance of Plastic Bodies. Air-pressure on Flat Bodies. The Centre of Air-pressure. Distribution of the Air-pressure on the Single Elements of an Inclined Plane. The Normal Air-pressure on a Thin Plane Inclined at an Angle to the Direction of Motion. Lilienthal’s Balance of Rotation. The Numerical Value of the Normal Pressure. Flying in General. Flying in Reality. Horizontal Flight by Wing-Flapping. Steering and other Effects of the Stroke. Conclusions. *23 illustrations, 8vo., paper. 75c.
*FLIGHT-VELOCITY.* By A. Samuelson. This work is a short comprehension of extensive scientific investigation and experimental work. Contents: The Rowing Flyer No. 5. The Motor Mechanism. The Fundamental Conditions of Flying by Wing Flapping. The Wings. The Re-sail. Flight Velocity. Living Flyers. Plane or Concave Supporting Surfaces. The False Resolution of Forces. The Erroneous Opinion: the Breadth of an Incline Plane Prevails over its Length. The Centre of Air-pressure, and the Distribution of the Pressure. On the Single Parts of an Inclined Plane. The Principle: the Normal Air-pressure of an Inclined Plane is independent of the Angle of Inclination. Tables of Motion at Varying Angles. The Human Flight. Conclusions. *With five plates, 8vo., paper. 75c.