The Fokkers late in 1915 had been fitted with guns which fired through the airscrew.
A good illustration of this may be found in the question of the airscrew.
The motive power was supplied by twisted strands of rubber which, as they untwisted, turned the airscrew.
On this scale he was successful with a machine driven by an airscrew and with a machine driven by the flapping of wings.
(p. 103) A later difficulty caused by the forward position of the airscrew had nothing to do with flying.
This ship, with an airscrew driven by manpower, attained a speed of five and a half miles an hour.
In all but a few types of machine the airscrew is now retained in the forward position.
The observer, being seated in the very prow of the machine, could fire a gun forward without being obstructed by the airscrew.
The machine gun soon followed, but its use in tractor machines was impracticable on account of the danger of hitting the airscrew.