The object in balancing any aerodrome with a single pair of wings is to be able to bring the c g2 under their c p2 without any reference to the tail, which supports nothing, unless specially ordered. But as this condition cannot now be obtained in Nos. 5 and 6, these at any rate, and perhaps future aerodromes, are to carry a second pair of wings. When this second pair of wings is of nearly equal size with the first it is to be assumed in preliminary adjustments for weight and center of pressure, that the second pair has two-thirds the lifting efficiency per unit area of the first.
Calling the whole distance from the mean center of pressure of the wings to the center of gravity M. M is to have a definite relation to the breadth of [p295] wings from tip to tip (b) and total fore and aft length (1), which is provisionally fixed at M =√(bl)8, and the line of thrust is to be not over one-fourth the way from c p2 to c g2.
Generally speaking the front pair of wings will be fixed in position and the adjustment for balancing made by moving the rear pair.
The individual weights of all parts checked by lump weighing are to be given by the caretaker (Mr. Huffaker), under the general scheme shown in the note. The work on the aerodromes being divided into two classes, viz.: metal work and all which is not metal, the two in charge of this work (Mr. Reed and Mr. Maltby) are severally responsible for knowing the weight in grammes of any of the parts they have put into their work, giving these weights to Mr. Huffaker, together with any data for filling out the annexed tables,[51] on his request.
Until further orders, Mr. Huffaker is charged with the responsibility of seeing that these conditions are met before any aerodrome is boxed, and will keep the record of weights of the aerodromes and their principal parts as already completed, in a book, to be preserved in your keeping, which will also be arranged to show with signed photographs and descriptions, and with sketches where needed, the condition and weight (as far as constructed) of every aerodrome, and of any new construction of any part, on the first of each month.
Particular attention is directed to the preceding paragraph, and to the need that evidence of a definite character is to be obtained and preserved of everything already done, and being done.
Without special orders to the contrary, you will not authorize the boxing of any aerodrome which does not, to your knowledge, meet these conditions.
Each aerodrome is to have the following parts in duplicate or in triplicate:
- 2 pairs wings;
- 2 pairs tails;
- 2 pairs light silk covered rudders;
- 3 pairs wheels;
with any other parts in duplicate or triplicate, which experience has shown to be necessary.