CHAPTER VI. 

 THE COMPONENT PRESSURE RECORDER. 



The experiments with the Plane-Dropper in the preceding chapter give the 

 soaring speeds of wind-planes of different shapes set at varying angles, and enable 

 us by the use of a fundamental formula of mechanics to make a provisional com- 

 putation of the work expended per minute in their uniform horizontal flight, 

 neglecting frictional resistances. 



Among several conclusions, one of prime importance, namely, that in such 

 aerial motion of heavy inclined planes the higher speeds are maintained with less 

 expenditure of power than the lower ones, presents an appearance so paradoxical 

 that, in view of its obviously extraordinary importance, I have endeavored to 

 establish it independently wholly by exjjeriment, without the use of any formula 

 whatever. For this purpose it is desirable to measure by means of a suitable 

 dynamometer the number of foot-pounds of work done in overcoming the resist- 

 ance to advance when a wind-plane is driven at soaring speeds (i. e., speeds at 

 which it maintains a horizontal course by virtue of the vertical component of 

 pressure, which in this case is just equal to the weight), by means of the whirling- 

 table, yet under conditions strictly assimilable to those of free flight, in the case 

 of an actual aerodrome propelled by its own motor. 



After much study and much experiment, I gradually perfected an instru- 

 ment (that described here as the Component Pressure Recorder)^ to be used in 

 connection with the Dynamometer- Chronograph in recording the speed, the resist- 

 ance to forward motion at the instant of soaring, and other attendant phenomena. 

 Its use in connection with the Di/namometer-Chronograph will also be further 

 described in chapter YII. 



In the present chapter, I shall not consider further the action of the self- 

 propelling model, but treat of it as reduced to its simplest type of an inclined 

 plane, the "wind-plane," or system of planes driven forward by the turn-table 

 arm until they are raised from it by the wind of rotation and soar. The imme- 

 diate objects of experiment are, therefore, to determine soaring speeds and the 

 horizontal resistances corresponding thereto. 



DESCRIPTION. 



The Component Pressure Recorder (or Component Recorder), plate VII, may 

 be compared to a balance which rocks on a knife-edge bearing, in the ordinary 

 Avay, but which also oscillates horizontally about a vertical axis. With respect 



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