diameter and a two-inch stroke; between this and
the crank shaft was a bevelled gear giving three revolutions of the
propellers to every stroke of the engine; the propellers, right and left
screw, were four-bladed and 16 inches in diameter. The total weight of
the model with engine was 8 lbs. Its successful flight is ascribed to
the fact that Stringfellow curved the wings, giving them rigid front
edges and flexible trailing edges, as suggested long before both by Da
Vinci and Borelli, but never before put into practice.

Mr F. J. Stringfellow, in the pamphlet quoted above, gives the best
account of the flight of this model: 'My father had constructed another
small model which was finished early in 1848, and having the loan of a
long room in a disused lace factory, early in June the small model was
moved there for experiments. The room was about 22 yards long and
from 10 to 12 ft. high.... The inclined wire for starting the machine
occupied less than half the length of the room and left space at the end
for the machine to clear the floor. In the first experiment the tail was
set at too high an angle, and the machine rose too rapidly on leaving
the wire. After going a few yards it slid back as if coming down an
inclined plane, at such an angle that the point of the tail struck the
ground and was broken. The tail was repaired and set at a smaller angle.
The steam was again got up, and the machine started down the wire, and,
upon reaching the point of self-detachment, it gradually rose until
it reached the farther end of the room, striking a hole in the canvas
placed to stop it. In experiments the machine flew well, when rising as
much as one in seven. The late Rev. J. Riste, Esq., lace manufacturer,
Northcote Spicer, Esq., J. Toms, Esq., and others witnessed experiments.
Mr Marriatt, late of the San Francisco News Letter brought down from
London Mr Ellis, the then lessee of Cremorne Gardens, Mr Partridge, and
Lieutenant Gale, the aeronaut, to witness experiments. Mr Ellis offered
to construct a covered way at Cremorne for experiments. Mr Stringfellow
repaired to Cremorne, but not much better accommodations than he had
at home were provided, owing to unfulfilled engagement as to room.
Mr Stringfellow was preparing for departure when a party of gentlemen
unconnected with the Gardens begged to see an experiment, and finding
them able to appreciate his endeavours, he got up steam and started the
model down the wire. When it ar