The Beginnings of Flight
[Illustration: Hot-air balloon]
In the spring of 1783, as the American Revolution was nearing a
successful conclusion, two brothers named Montgolfier sitting before a
fire at a little town in France found themselves wondering why smoke
went up into the air.
That was just as foolish as Newton wondering why an apple, detached from
the tree, fell down. Smoke had always gone up and apples had always come
down. That was all there was to it.
But when men wonder momentous events may be in the making. In these
instances epochal discoveries resulted: the law of gravitation and the
possibility of human flight.
The legends of Icarus and the narrative of Darius Green are symbols of
the long ambition of earth-bound men, even before the days of recorded
history, to leave the earth and soar into the air. The Montgolfiers had
found the key.
But a hundred years would pass before the discovery would be put to use.
It was in 1903 that another pair of brothers, the Wrights, made their
first flight from Kill Devil Hill in North Carolina. The first Zeppelin
took off from the shores of Lake Constance in 1900.
The Montgolfiers wasted no time testing out their conclusion that smoke
rose because it was lighter than the air. They built a great paper bag
35 feet high, hung a brazier of burning charcoal under it, and off it
went. Annonnay is a small town but the story of that miracle spread far
and wide. The Academy of Science invited them to the capital to repeat
the experiment.
But while they were building a new bag a French physicist, Prof. J. A.
C. Charles, stole a march on them. He knew that hydrogen was also
lighter than air, so constructed a bag of silk, inflated it with
hydrogen, sent it aloft before the Montgolfiers were ready.
Still the countrymen were not to lose their hour of glory. Merely to
repeat what had already been done was not enough. Their balloon was to
be flown from the grounds of the Palace of Versailles, before the king
and court and all the great folk of Paris, with half the people of the
city craning their necks to watch it pass over. So they loaded aboard a
basket containing a sheep, a duck and a rooster, and these three became
aircraft’s first passengers.
When the U. S. Army Air Corps years later sought an appropriate insignia
for its lighter-than-air division, it could think of nothing more
fitting than a design which included a rooster, a duck and a sheep.
Everyone was ready for the next step. A French judge had the solution.
He offered the choice to several prisoners awaiting execution—a balloon
flight or the guillotine. Two volunteered, felt they had at least a
chance with the balloon, whereas the guillotine was distressingly final.
They had nothing to lose. That word rang through Paris. A young gallant
named De Rozier objected.
“The chance might succeed,” he said. “The honor of being the first man
to fly should not go to a convict, but to a gentleman of France. I offer
my life.”
Even the king protested at this needless risk, but De Rozier took off
the following month, flew half way over Paris, landed safely. This
happened on Nov. 21, 1783.
Among the witnesses to these experiments was Benjamin Franklin, the
American ambassador, himself a scientist of no small renown. He
predicted great things for aeronautics.
“But of what use is a balloon?” asked a practical-minded friend.
“Of what use,” replied the American, “is a baby?”
A little later, on January 7, 1785, Jean Pierre Francois Blanchard, a
Frenchman, and Dr. John Jeffries, an American, practicing medicine in
England, inflated a balloon, took off from the cliffs of Dover at one
o’clock in the afternoon, arrived safely in Calais three hours later.
[Illustration: Santos Dumont startled Paris in 1910, when he let an
American girl fly one of his airships over the city. To descend she
threw her weight forward, to climb she moved back a step.]
[Illustration: A dramatic meeting of two rivals for the honor of
making the first Atlantic crossing. The Navy’s NC flying boats and
the non-rigid C-5, photographed shortly before their take-off.]
[Illustration: Blimps too may use masts aboard surface ships as
anchorage point on long cruises, as the U.S.S. Los Angeles
successfully demonstrated when moored to the U.S.S. Patoka. (U. S.
Navy photo)]
[Illustration: The Army’s TC-7 demonstrates the first airplane
pick-up at Dayton. Army pilots found that at flying speed the plane
weighed nothing, was sustained by dynamic forces. (U. S. Army
photo)]
Flight was here, though it would be a long time becoming practical. Dr.
Charles and many others contributed, even at that early day. Knowing
that hydrogen expanded as the air pressure grew less, at higher
altitudes, Charles devised a valve at the top of the balloon, so that
the surplus gas could be released, not burst the balloon. He devised a
net from which the basket could be suspended, distributing its load over
the entire bag.
The drag rope was evolved, an ingenious device to stabilize the
balloon’s flight in unstable air. If the balloon tended to rise it would
have to carry the entire weight of the rope. If it grew sluggish and
drifted low, it had less weight to carry, as much of the rope now lay on
the ground. These ballooning principles, early found, are still in use.
But the “dirigible” balloon, or airship must wait for light weight,
dependable motors, despite the hundreds of ingenious experiments made by
men over a full century.
Since this is an airship story, we should first make clear the
difference between the airship and the airplane.
The French hit on an apt phrase to distinguish them, dividing aircraft
into those which are lighter than the air, such as airships, and those
which are heavier than the air, like airplanes.
Airships are literally lighter than air. So are all free balloons, used
for training and racing, and all anchored balloons, such as the
observation balloon widely used in the last war and the barrage balloons
of the present war.
The airship goes up and stays up because the buoyancy given by its
lifting gas makes it actually lighter than the air it displaces, and
even with the load of motors, fuel, equipment and passengers, must still
use ballast to hold it in equilibrium.
The airplane, on the other hand, is heavier than the air. Even the
lightest plane can stay up only if it is moving fast enough to get a
lifting effect from the movement of air along the wings, similar to that
which makes a kite stay up. A kite may be flown in calm weather only if
the one who holds the cord keeps running. On a windy day, the kite may
be anchored on the ground, and the movement of the wind alone will have
sufficient lifting effect. So powerful are these air forces that a plane
weighing 20 tons may climb to an altitude of 10,000 feet if its speed is
great enough, and its area of wing surface broad enough to produce this
kiting effect.
But an airplane can remain aloft only as long as it is moving faster
than a certain minimum speed. Cut the motors, or even throttle down
below this stalling speed, and the plane will start earthward.
The airship needs its motors only to propel it forward. It can cut its
speed, even stop its engines, and nothing happens. It retains its
buoyancy, continues to float. The airplane’s lift is dynamic, that of
the airship is static.
The airship has some dynamic lift, also, because its horizontal fins or
rudders, and the body of the airship have some kiting effect in flight.
The blimp pilot, starting on a long trip, will fill up his tanks with
all the fuel the ship can lift statically, then take on another 2,000
pounds, taxi across the airport till he gets flying speed and so get
under way with many more miles added to his cruising speed.
This dynamic lift however, while useful in certain operations is still
incidental. Primarily the airship gets its lift from the fact that the
gas in the envelope is much lighter than the air.
Hydrogen is only one-fifteenth the weight of air, helium, the
non-inflammable American gas, is a little heavier, about one-seventh.
The practical lift is 68 pounds to the thousand cubic feet of hydrogen,
63 pounds in the case of helium.
Lighter-than-air ships are of three classes, rigid, semi-rigid and
non-rigid. The rigid airship has a complete metal skeleton, which gives
the ship strength and shape. Into the metal frame of the rigid airship
are built quarters, shops, communication ways, even engine rooms in the
case of the Akron and Macon, with only the control car, fins, and
propellers projecting outside the symmetrical hull. The lifting gas is
carried in a dozen or more separate gas cells, nested within the bays of
the ship.
The non-rigid airship has no such internal support. The bag keeps its
taut shape only from the gas and air pressure maintained within. Release
the gas and the bag becomes merely a flabby mass of fabric on the hangar
floor. Ship crews do not live in the balloon section, but in the control
car below.
The British, apt at nicknames, differentiated between the two types of
airships by calling them “rigid” and “limp” types, and since an early
“Type B” was widely used in the first World War, quickly contracted “B,
limp” into the handier word “Blimp.”
The third type, semi-rigid, has a metal keel extending the length of the
ship, to which control surfaces and the car are attached, and with a
metal cone to stiffen the bow section.
The rigid ship is of German origin. Developed by Count Zeppelin, retired
army officer, and largely used by that nation during the war of 1914-18,
it was taken up after the war started, by the British and Americans, and
to a small extent later by France and Italy.
Non-rigid ships were widely used by the British and French, to a less
extent by Italy and United States.
The intermediate semi-rigid was largely Italian and French in war use,
though United States bought one ship after the war from the Italians,
built one itself. The Germans also built smaller Parseval semi-rigids.
The rigid airships are the largest, the non-rigids smallest. The rigid
has to be large to hold enough gas to lift its metal frame along with
the load of fuel, oil, crew, supplies, passengers and cargo. The blimps
can be much smaller.
The Army’s first airship, built by Major Tom Baldwin, old time
balloonist, had 19,500 cubic feet capacity. Goodyear’s pioneer helium
ship “Pilgrim” had 51,000 cubic feet. These contrast with the seven
million feet capacity of the Hindenburg, and the ten million cubic feet
of ships projected for the future.
The following table will show the range of sizes:
Rigid Airships: Hindenburg (German) 7,070,000 cubic feet
Akron-Macon (U. S.) 6,500,000 cubic feet
R-100, 101 (British) 5,000,000 cubic feet
Graf Zeppelin (German) 3,700,000 cubic feet
Los Angeles (U. S.) 2,500,000 cubic feet
R-34 (British) 2,000,000 cubic feet
Semi-Rigids: Norge (Italian) 670,000 cubic feet
RS-1 (U. S.) 719,000 cubic feet
Non-Rigids: Navy K type (Patrol) 416,000 cubic feet
Navy G type (Advanced Training) 180,000 cubic feet
Navy L type (Trainer) 123,000 cubic feet
Goodyear (Passenger) 123,000 cubic feet
Pilgrim (Goodyear) 51,000 cubic feet
The Akron and Macon were 785 feet in length, the K type non-rigid, 250
feet long, the Navy “L’s” 150 feet long.
Let’s cut back now to the Montgolfiers. Progress was disappointingly
slow. The simple balloon would only go up and down, and in the direction
of the wind. Before it could be practical, men must be able to drive it
wherever they liked, make it dirigible, or directable.
Ingenious men, Meusnier, Giffard, Tissandier, Renard, Krebs, many others
worked over that problem through the entire nineteenth century. They
devised ballonets or air compartments to keep the pressure up. They
built airships of cylinder shape, spindle shape, torpedo shape, airships
shaped like a cigar, like a string bean, like a whale. But the stumbling
block remained, the need of an efficient power plant.
The steam engine was dependable, but once you had installed firebox,
boiler and cord wood aboard, there was little if any lift remaining for
crew or cargo. Giffard in 1852 built an ingenious small engine using
steam but it still weighed 100 pounds per horsepower, drove the ship at
a speed of only three miles an hour. Automobile engines today weigh as
little as six pounds per horsepower, modern airplane engines one pound
per horsepower.
Man experimented with feather-bladed oars, with a screw propeller,
turned by hand, using a crew of eight men. Haenlein, German, built a
motor that would use the lifting gas from the ship—coal gas or hydrogen.
Rennard in 1884 built an electric motor, taking power from a storage
battery.
But real progress would have to wait for the discovery of petroleum in
Pennsylvania and the invention of the internal combustion engine. When
the gasoline engine came in, in the 90’s, the dirigible builders saw the
long sought key to their problem.
While Count Zeppelin was experimenting with his big ships in Germany,
Lebaudy, Juliot, Clement Bayard in France and most conspicuously the
young Brazilian, Santos Dumont, were working with the smaller
dirigibles. Santos Dumont built 14 airships in the first decade of the
century, brought the attention of the world to this project. He won a
100,000 franc prize in 1901 for flying across Paris to circle Eiffel
Tower and return to his starting point—and gave the money to the Paris
poor.
The Wright Brothers made their historic flight at Kitty Hawk, in 1903,
opening a different field of experiment. France pushed both lines of
research. After Santos Dumont’s dirigible flight, Bleriot started from
the little town of Toury in an airplane, flew to the next town and back,
a distance of 17 miles, making only two en route stops,—and the town
erected a monument to him.
In 1909, Bleriot flew a plane across the English Channel and in the
following year the airship Clement Bayard II duplicated the feat,
carrying a crew of seven, made the 242 miles to London in six hours.
The year 1910 was a momentous one for all aircraft, with France as the
world center. Bleriot and Farman, Frenchmen, Latham, British, the
Wrights and Curtiss, Americans, broke records almost daily at a big meet
in August that year, while at longer range the French and English
dirigibles and the Parsevals of Germany, and still more important the
great Zeppelins at Lake Constance droned the news of a new epoch.
A young American engineer, P. W. Litchfield, attended the Paris meet,
saw these wonders, made notes. He stopped in Scotland on his way back,
bought a machine for spreading rubber on fabric, hired the two men
tending it (those men, Ferguson and Aikman, were still at their posts in
Akron thirty odd years later), hired two young technical graduates on
his return, tied in the fortunes of his struggling company with what he
believed was a coming industry.
The next five years would see the nations of the world bending their
efforts toward perfecting these vehicles of flight,—little realizing
they were building a combat weapon which would revolutionize warfare.