I YIELD TO THE STEERABLE BALLOON IDEA
During my ascent with M. Machuron, while our guide rope was wrapped
around the tree and the wind was shaking us so outrageously, he improved
the occasion to discourage me against all steerable ballooning.
"Observe the treachery and vindictiveness of the wind," he cried between
shocks. "We are tied to the tree, yet see with what force it tries to
jerk us loose." (Here I was thrown again to the bottom of the basket.)
"What screw propeller could hold a course against it? What elongated
balloon would not double up and take you flying to destruction?"
It was discouraging. Returning to Paris by rail I gave up the ambition
to continue Giffard's trials, and this state of mind lasted with me
for weeks. I would have argued fluently against the dirigibility of
balloons. Then came a new period of temptation, for a long-cherished
idea dies hard. When I took account of its practical difficulties I
found my mind working automatically to convince itself that they were
not. I caught myself saying: "If I make a cylindrical balloon long
enough and thin enough it will cut the air ..." and, with respect to the
wind, "shall I not be as a sailing yachtsman who is not criticised for
refusing to go out in a squall?"
At last an accident decided me. I have always been charmed by
simplicity, while complications, be they never so ingenious, repel me.
Automobile tricycle motors happened to be very much perfected at the
moment. I delighted in their simplicity, and, illogically enough, their
merits had the effect of deciding my mind against all other objections
to steerable ballooning.
"I will use this light and powerful motor," I said. "Giffard had no such
opportunity."
Giffard's primitive steam-engine, weak in proportion to its weight,
spitting red-hot sparks from its coal fuel, had afforded that courageous
innovator no fair chance, I argued. I did not dally a single moment
with the idea of an electric motor, which promises little danger, it is
true, but which has the capital ballooning defect of being the heaviest
known engine, counting the weight of its battery. Indeed, I have so
little patience with the idea that I shall say no more about it except
to repeat what Mr Edison said to me on this head in April 1902: "You
have done well," he said, "to choose the petroleum motor. It is the only
one of which an aeronaut can dream in the present state of the industry;
and steerable balloons with electric motors, especially as they were
fifteen or twenty years ago, could have led to no result. That is why
the Tissandier brothers gave them up."
In spite of the recent immense improvements made in the steam-engine it
would not have been able to decide me in favour of steerable ballooning.
Motor for motor it is, perhaps, better than the petroleum motor, but
when you compare the boiler with the carburator the latter weighs
grammes per horse-power while the boiler weighs kilogrammes. In certain
light steam-motors, that are lighter even than petroleum motors, the
boiler always ruins the proportion. With one pound of petroleum you can
exert one horse-power during one hour. To get this same energy from
the most improved steam-engine you will want many kilogrammes of water
and of fuel, be it petroleum or other. Even condensing the water, you
cannot have less than several kilogrammes per horse-power.
Then if one uses coal fuel with the steam-motor there are the burning
sparks; while if one uses petroleum with burners you have a great amount
of fire. We must do the petroleum motor the justice to admit that it
makes neither flame nor burning sparks.
At the present moment I have a Clement petroleum motor that weighs but 2
kilogrammes (4-1/2 lbs.) per horse-power. This is my 60 horse-power "No.
7," whose total weight is but 120 kilogrammes (264 lbs.). Compare this
with the new steel-and-nickel battery of Mr Edison, which promises to
weigh 18 kilogrammes (40 lbs.) per horse-power.
The light weight and the simplicity of the little tricycle motor of
1897 are, therefore, responsible for all my trials. I started from
this principle: To make any kind of success it would be necessary to
economise weight, and so comply with the pecuniary, as well as the
mechanical, conditions of the problem.
Nowadays I build air-ships in a large way. I am in it as a kind of
lifework. Then I was but a half-decided beginner, unwilling to spend
large sums of money in a doubtful project.
Therefore I resolved to build an elongated balloon just large enough to
raise, along with my own 50 kilogrammes (110 lbs.) of weight, as much
more as might be necessary for the basket and rigging, motor, fuel, and
absolutely indispensable ballast. In reality I was building an air-ship
to fit my little tricycle motor.
I looked for the workshop of some small mechanic near my residence in
the centre of residential Paris where I could have my plans executed
under my own eyes and could apply my own hands to the task. I found
such an one in the Rue du Colisée. There I first worked out a tandem
of two cylinders of a tricycle motor--that is, their prolongation, one
after the other, to work the same connecting-rod while fed by a single
carburator.
To bring everything down to a minimum weight, I cut out from every part
of the motor whatever was not strictly necessary to solidity. In this
way I realised something that was interesting in those days--a 3-1/2
horse-power motor that weighed 30 kilogrammes (66 lbs.).
I soon had an opportunity to test my tandem motor. The great series
of automobile road-races, which seems to have had its climax in
Paris-Madrid in 1903, was raising the power of these wonderful engines
by leaps and bounds year after year. Paris-Bordeaux in 1895 was won with
a 4 horse-power machine at an average speed of 25 kilometres (15-1/2
miles) per hour. In 1896 Paris-Marseilles-and-return was accomplished
at the rate of 30 kilometres (18-1/2 miles) per hour. Now, in 1897, it
was Paris-Amsterdam. Although not entered for the race it occurred to
me to try my tandem motor attached to its original tricycle. I started,
and to my contentment found that I could keep well up with the pace.
Indeed, I might have won a good place in the finish--my vehicle was the
most powerful of the lot in proportion to its weight, and the average
speed of the winner was only 40 kilometres (25 miles) per hour--had I
not begun to fear that the jarring of my motor in so strenuous an effort
might in the long run derange it, and I imagined I had more important
work for it to do.
For that matter, my automobiling experience has stood me in good
stead with my air-ships. The petroleum motor is still a delicate and
capricious thing, and there are sounds in its spitting rumble that are
intelligible only to the long-experienced ear. Should the time come
in some future flight of mine when the motor of my air-ship threatens
danger I am convinced that my ear will hear, and I shall heed, the
warning. This almost instinctive faculty I owe only to experience.
Having broken up the tricycle for the sake of its motor I purchased at
about this time an up-to-date 6 horse-power Panhard, with which I went
from Paris to Nice in 54 hours--night and day, without stop--and had
I not taken up dirigible ballooning I must have become a road-racing
automobile enthusiast, continually exchanging one type for another,
continually in search of greater speed, keeping pace with the progress
of the industry, as so many others do, to the glory of French mechanics
and the new Parisian sporting spirit.
But my air-ships stopped me. While experimenting I was tied down to
Paris. I could take no long trips, and the petroleum automobile, with
its wonderful facility for finding fuel in every hamlet, lost its
greatest use in my eyes. In 1898 I happened to see what was to me an
unknown make of light American electric buggy. It appealed alike to my
eye, my needs, and my reason, and I bought it. I have never had cause
to regret the purchase. It serves me for running about Paris, and it
goes lightly, noiselessly, and without odour.
I had already handed the plan of my balloon envelope to the
constructors. It was that of a cylindrical balloon terminating fore
and aft in cones, 25 metres (82-1/2 feet) long, with a diameter of
3·5 metres (11-1/2 feet) and a gas capacity of 180 cubic metres (6354
cubic feet). My calculations had left me only 30 kilogrammes (66 lbs.)
for both the balloon material and its varnish. Therefore I gave up
the usual network and _chemise_, or outer cover; indeed, I considered
this second envelope, holding the balloon proper within it, to be not
only superfluous but harmful, if not dangerous. Instead I attached the
suspension cords of my basket directly to the balloon envelope by means
of small wooden rods introduced into long horizontal hems sewed on both
sides to its stuff for a great part of the balloon's length. Again, in
order not to pass my 30 kilogrammes (66 lbs.), including varnish, I
was obliged to have recourse to my Japanese silk, which had proved so
staunch in the "Brazil."
After glancing at this order for the balloon envelope M. Lachambre at
first refused it plumply. He would not make himself a party to such
rashness. But when I recalled to his memory how he had said the same
thing with respect to the "Brazil," and went on to assure him that, if
necessary, I would cut and sew the balloon with my own hands, he gave
way to me and undertook the job. He would cut and sew and varnish the
balloon according to my plans.
The balloon envelope being thus put under way I prepared my basket,
motor, propeller, rudder, and machinery. When they were completed I made
many trials with them, suspending the whole system by a cord from the
rafters of the workshop, starting the motor, and measuring the force
of the forward swing caused by the propeller working on the atmosphere
behind it. Holding back this forward movement by means of a horizontal
rope attached to a dynamometer, I found that the traction power
developed by the motor in my propeller with two arms, each measuring
one metre across, was as high as 11·4 kilogrammes (25 lbs.). This
was a figure that promised good speed to a cylindrical balloon of my
dimensions, whose length was equal to nearly seven times its diameter.
With 1200 turns to the minute the propeller, which was attached
directly to the motor shaft, might easily, if all went well, give the
air-ship a speed of not less than 8 metres (26-1/2 feet) per second.
[Illustration: Fig. 3.]
The rudder I made of silk, stretched over a triangular steel frame.
There now remained nothing to devise but a system of shifting weights,
which from the very first I saw would be indispensable. For this purpose
I placed two bags of ballast, one fore and one aft, suspended from the
balloon envelope by cords. By means of lighter cords each of these two
weights could be drawn into the basket (see Fig. 3), thus shifting the
centre of gravity of the whole system. Pulling in the fore weight would
cause the stem of the balloon to point diagonally upward; pulling in
the aft weight would have just the opposite effect. Besides these I had
a guide rope some 60 metres (200 feet) long, which could also be used,
at need, as shifting ballast.
All this occupied several months, and the work was all carried on in the
little machine-shop of the Rue du Colisée, only a few steps from the
place where later the Paris Aéro Club was to have its first offices.