Men now fly and will probably keep on flying; but aviation is still
too hazardous to become the popular sport of the average man. The
overwhelmingly important problem with the aeroplane is that of
stability. These machines must have a better lateral balance when
turning corners or when subjected to wind gusts: and the balance must
be automatically, not manually, produced.
[Illustration: BLANC MONOPLANE]
Other necessary improvements are of minor urgency and in some cases
will be easy to accomplish. Better mechanical construction, especially
in the details of attachments, needs only persistence and common sense.
Structural strength will be increased; the wide spread of wing presents
difficulties here, which may be solved either by increasing the number
of superimposed surfaces, as in triplanes, or in some other manner.
Greater carrying capacity--two men instead of one--may be insisted
upon: and this leads to the difficult question of motor weights.
The revolving air-cooled motor may offer further possibilities: the
two-cycle idea will help if a short radius of action is permissible:
but a weight of less than two pounds to the horse-power seems
to imply, almost essentially, a lack of ruggedness and surety of
operation. A promising field for investigation is in the direction of
increasing propeller efficiencies. If such an increase can be effected,
the whole of the power difficulty will be greatly simplified.
[Illustration: MELVIN VANIMAN TRIPLANE]
[Illustration: JEAN DE CRAWHEZ TRIPLANE]
[Illustration: A TRIPLANE]
This same motor question controls the proposal for increased speed.
The use of a reserve motor would again increase weights; though not
necessarily in proportion to the aggregate engine capacity. Perhaps
something may be accomplished with a gasoline turbine, when one
is developed. In any case, no sudden increase in speeds seems to
be probable; any further lightening of motors must be undertaken
with deliberation and science. If much higher maximum speeds are
attained, there will be an opportunity to vary the speed to suit the
requirements. Then clutches, gears, brakes, and speed-changing devices
of various sorts will become necessary, and the problem of weights of
journal bearings--already no small matter--will be made still more
serious. And with variable speed must probably come variable sail
area--in preference to tilting--so that the fabric must be reefed on
its frame. Certainly two men, it would seem, will be needed!
Better methods for starting are required. The hydroplane idea promises
much in this respect. With a better understanding and control of the
conditions associated with successful and safe descent--perhaps with
improved appliances therefor--the problem of ascent will also be partly
solved. If such result can be achieved, these measures of control must
be made automatic.
The building of complete aeroplanes to standard designs would be
extremely profitable at present prices, which range from $2500 to
$5000. Perhaps the most profitable part would be in the building of the
motor. The framing and fabric of an ordinary monoplane could easily
be constructed at a cost below $300. The propeller may cost $50 more.
The expense for wires, ropes, etc., is trifling; and unless special
scientific instruments and accessories are required, all of the rest
of the value lies in the motor and its accessories. Within reasonable
limits, present costs of motors vary about with the horse-power. The
amateur designer must therefore be careful to keep down weight and
power unless he proposes to spend money quite freely.