FLYING-MACHINE WORK. 171 
No. 16, another compressed air driven machine, Plates v., vi, 
has had a most varied experience: no less than twelve trials are 
recorded. Trial ten was the successful one. On that occasion it 
flew three hundred and forty-three feet in twenty-three seconds, 
with fifty-four and a-half double vibrations of the engine; the 
machine had a decided slope upwards, possibly 10°; it had 25-17% 
of the area in advance of the centre of gravity. Supposing the 
efficiency of the engine to be :29, the same as No. 14, and the 
reduced pressure 60 ibs. per square inch, seven hundred and forty- 
two foot-pounds of work drove it at 10:1 miles per hour. The 
bi-plane was fitted to No. 16 for the first trial, the forward section 
was 52 ins. x 18 ins., and the after one 64 ins. x 18 ins., leaving 
a distance of five feet between. The engine was twenty-six inches 
from the bow. This form is very stable, and, from the cross-bow 
models that were previously tried, the tendency to turn upward 
is much reduced. A trussed body-plane 10 ft. 24 ins. x 283 ins. 
was also tried, but itis difficult to balance. 
A piece of drawing-paper was curved by suitable cross bars and. 
battens, Plate vii, fig. 1, and attached to one of the cross-bow 
models, to see if any additional support could be obtained, but its. 
erratic flight showed that complications would ensue from its. 
adoption at the present stage of the experiments. 
The facts elicited by the action of this segment of a hollow 
cylinder cannot be generally known, therefore as concise a state- 
ment as possible is given. 
1. With the leading edge tangential to the direction of impulse, 
Plate vu., fig. 1, two or three back summersaults are: 
made before the apparatus falls to the ground. 
2. If the segment is detached from the cross-bow model and. 
dropped from a horizontal position convex side down, it 
falls vertically. 
3. If the segment is rotated on its longest axis, on being released 
it will fall at an angle of 45° towards the side that is. 
ascending. Plate vit, fig. 2. 
