Manuscripts/Mixed Material Bulletins, from October 5, 1908 to December 28, 1908
Our aerodrome No. 4, McCurdy's “Silver-Dart” is now completed and ready for trial.
Mr. McCurdy :— It is all finished except the motor.
Dr. Bell :— After Mr. McCurdy has had sufficient time to test out this machine, Mr. Curtiss and Mr. McCurdy will proceed to Nova Scotia where all the surviving members will come together at Beinn Bhreagh to assist me with my tetrahedral structures.
At Beinn Bhreagh we have two new aerodromes employing tetrahedral structures in process of construction. The first which is expected to be our aerodrome No. 5 is of pure tetrahedral construction, in which oblique surfaces alone are employed. It is practically the “Cygnet” over again with improvements and the latest form of motor developed by Mr. Curtiss will be used in the attempt to propel it through the air. The great advantage of the pure tetrahedral form of construction in large machines employing multitudes of small winged cells is the automatic stability displayed by such structures. The chief disadvantage is the poor lifting power of oblique surfaces when compared with the lifting power of the same surfaces horizontally arranged. From which it results that a structure intended to support a man and an engine in the air must be made of very large size in order to afford sufficient supporting surface. The large size of such a structure and the great head resistance offered by the multitude of cells composing it render it exceedingly problematical whether the motors at our disposal will be able to drive it at a supporting velocity. The only way, however, to solve the problem is to make the experiment and this