Changes, many of them extremely radical in their nature, are continually
being made by prominent aviators, and particularly those who have won
the greatest amount of success. Wonderful as the results have been
few of the aviators are really satisfied. Their successes have merely
spurred them on to new endeavors, the ultimate end being the development
of an absolutely perfect aircraft.
Among the men who have been thus experimenting are the Wright Brothers,
who last year (1909) brought out a craft totally different as regards
proportions and weight from the one used the preceding year. One marked
result was a gain of about 3 1/2 miles an hour in speed.
Dimensions of 1908 Machine.
The 1908 model aeroplane was 40 by 29 feet over all. The carrying
surfaces, that is, the two aerocurves, were 40 by 6 feet, having a
parabolical curve of one in twelve. With about 70 square feet of surface
in the rudders, the total surface given was about 550 square feet.
The engine, which is the invention of the Wright brothers, weighed,
approximately, 200 pounds, and gave about 25 horsepower at 1,400
revolutions per minute. The total weight of the aeroplane, exclusive of
passenger, but inclusive of engine, was about 1,150 pounds. This result
showed a lift of a fraction over 2 1/4 pounds to the square foot of
carrying surface. The speed desired was 40 miles an hour, but the
machine was found to make only a scant 39 miles an hour. The upright
struts were about 7/8-inch thick, the skids, 2 1/2 by 1 1/4 inches
thick.
Dimensions of 1909 Machine.
The 1909 aeroplane was built primarily for greater speed, and relatively
heavier; to be less at the mercy of the wind. This result was obtained
as follows: The aerocurves, or carrying surfaces, were reduced in
dimensions from 40 by 6 feet to 36 by 5 1/2 feet, the curve remaining
the same, one in twelve. The upright struts were cut from seven-eighths
inch to five-eighths inch, and the skids from two and one-half by one
and one-quarter to two and one-quarter by one and three-eighths inches.
This result shows that there were some 81 square feet of carrying
surface missing over that of last year's model. and some 25 pounds loss
of weight. Relatively, though, the 1909 model aeroplane, while actually
25 pounds lighter, is really some 150 pounds heavier in the air than the
1908 model, owing to the lesser square feet of carrying surface.
Some of the Results Obtained.
Reducing the carrying surfaces from 6 to 5 1/2 feet gave two
results--first, less carrying capacity; and, second, less head-on
resistance, owing to the fact that the extent of the parabolic curve
in the carrying surfaces was shortened. The "head-on" resistance is
the retardance the aeroplane meets in passing through the air, and is
counted in square feet. In the 1908 model the curve being one in twelve
and 6 feet deep, gave 6 inches of head-on resistance. The plane being
40 feet spread, gave 6 inches by 40 feet, or 20 square feet of head-on
resistance. Increasing this figure by a like amount for each plane, and
adding approximately 10 square feet for struts, skids and wiring, we
have a total of approximately, 50 square feet of surface for "head-on"
resistance.
In the 1909 aeroplane, shortening the curve 6 inches at the parabolic
end of the curve took off 1 inch of head-on resistance. Shortening the
spread of the planes took off between 3 and 4 square feet of head-on
resistance. Add to this the total of 7 square feet, less curve surface
and about 1 square foot, less wire and woodwork resistance, and we
have a grand total of, approximately, 12 square feet of less "head-on"
resistance over the 1908 model.
Changes in Engine Action.
The engine used in 1909 was the same one used in 1908, though some minor
changes were made as improvements; for instance, a make and break spark
was used, and a nine-tooth, instead of a ten-tooth magneto gear-wheel
was used. This increased the engine revolutions per minute from 1,200 to
1,400, and the propeller revolutions per minute from 350 to 371, giving
a propeller thrust of, approximately, 170 foot pounds instead of 153, as
was had last year.
More Speed and Same Capacity.
One unsatisfactory feature of the 1909 model over that of 1908,
apparently, was the lack of inherent lateral stability. This was caused
by the lesser surface and lesser extent of curvatures at the portions
of the aeroplane which were warped. This defect did not show so plainly
after Mr. Orville Wright had become fully proficient in the handling of
the new machine, and with skillful management, the 1909 model aeroplane
will be just as safe and secure as the other though it will take a
little more practice to get that same degree of skill.
To sum up: The aeroplane used in 1909 was 25 pounds lighter, but really
about 150 pounds heavier in the air, had less head-on resistance, and
greater propeller thrust. The speed was increased from about 39 miles
per hour to 42 1/2 miles per hour. The lifting capacity remained about
the same, about 450 pounds capacity passenger-weight, with the 1908
machine. In this respect, the loss of carrying surface was compensated
for by the increased speed.
During the first few flights it was plainly demonstrated that it would
need the highest skill to properly handle the aeroplane, as first one
end and then the other would dip and strike the ground, and either tear
the canvas or slew the aeroplane around and break a skid.
Wrights Adopt Wheeled Gears.
In still another important respect the Wrights, so far as the output
of one of their companies goes, have made a radical change. All the
aeroplanes turned out by the Deutsch Wright Gesellschaft, according to
the German publication, _Automobil-Welt_, will hereafter be equipped
with wheeled running gears and tails. The plan of this new machine is
shown in the illustration on page 145. The wheels are three in number,
and are attached one to each of the two skids, just under the front edge
of the planes, and one forward of these, attached to a cross-member. It
is asserted that with these wheels the teaching of purchasers to operate
the machines is much simplified, as the beginners can make short flights
on their own account without using the starting derrick.
This is a big concession for the Wrights to make, as they have hitherto
adhered stoutly to the skid gear. While it is true they do not control
the German company producing their aeroplanes, yet the nature of their
connection with the enterprise is such that it may be taken for granted
no radical changes in construction would be made without their approval
and consent.
Only Three Dangerous Rivals.
Official trials with the 1909 model smashed many records and leave the
Wright brothers with only three dangerous rivals in the field, and with
basic patents which cover the curve, warp and wing-tip devices found on
all the other makes of aeroplanes. These three rivals are the Curtiss
and Voisin biplane type and the Bleriot monoplane pattern.
The Bleriot monoplane is probably the most dangerous rival, as this make
of machine has a record of 54 miles per hour, has crossed the English
channel, and has lifted two passengers besides the operator. The
latest type of this machine only weighs 771.61 pounds complete, without
passengers, and will lift a total passenger weight of 462.97 pounds,
which is a lift of 5.21 pounds to the square foot. This is a better
result than those published by the Wright brothers, the best noted being
4.25 pounds per square foot.
Other Aviators at Work.
The Wrights, however, are not alone in their efforts to promote the
efficiency of the flying machine. Other competent inventive aviators,
notably Curtiss, Voisin, Bleriot and Farman, are close after them. The
Wrights, as stated, have a marked advantage in the possession of
patents covering surface plane devices which have thus far been found
indispensable in flying machine construction. Numerous law suits growing
out of alleged infringements of these patents have been started, and
others are threatened. What effect these actions will have in deterring
aviators in general from proceeding with their experiments remains to be
seen.
In the meantime the four men named--Curtiss, Voisin, Bleriot and
Farman--are going ahead regardless of consequences, and the inventive
genius of each is so strong that it is reasonable to expect some
remarkable developments in the near future.
Smallest of Flying Machines.
To Santos Dumont must be given the credit of producing the smallest
practical flying machine yet constructed. True, he has done nothing
remarkable with it in the line of speed, but he has demonstrated the
fact that a large supporting surface is not an essential feature.
This machine is named "La Demoiselle." It is a monoplane of the dihedral
type, with a main plane on each side of the center. These main
planes are of 18 foot spread, and nearly 6 1/2 feet in depth, giving
approximately 115 feet of surface area. The total weight is 242
pounds, which is 358 pounds less than any other machine which has been
successfully used. The total depth from front to rear is 26 feet.
The framework is of bamboo, strengthened and held taut with wire guys.
Have One Rule in Mind.
In this struggle for mastery in flying machine efficiency all the
contestants keep one rule in mind, and this is:
"The carrying capacity of an aeroplane is governed by the peripheral
curve of its carrying surfaces, plus the speed; and the speed
is governed by the thrust of the propellers, less the 'head-on'
resistance."
Their ideas as to the proper means of approaching the proposition
may, and undoubtedly are, at variance, but the one rule in solving the
problem of obtaining the greatest carrying capacity combined with the
greatest speed, obtains in all instances.