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 t
e 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


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


"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.