Part 8

The helicopter may be regarded as the limiting type of aeroplane, the sail area being reduced nearly to zero; the wings becoming mere fins, the smaller the better. It therefore requires maximum motor power and is particularly dependent upon the development of an excessively light motor. It is launched and descends under perfect control, without regard to horizontal velocity. It has very little exposed surface and is therefore both easy to steer and independent of wind conditions. By properly arranging the screws it can be amply balanced: but it must have a particularly stout and strong frame.

The development of this machine hinges largely on the propeller. It is not only necessary to develop _power_ (which means force multiplied by velocity) but actual propulsive vertical _force_: and this must exceed or at least equal the whole weight of the machine. From ten to forty pounds of lifting force per horse-power have been actually attained: and with motors weighing less than five pounds there is evidently some margin. The propellers are of special design, usually with very large blades. Four are commonly used: one, so to speak, at each "corner" of the machine. The helicopter is absolutely dependent upon its motors. It cannot descend safely if the power fails. If it is to do anything but ascend and descend it must have additional propulsive machinery for producing horizontal movement.

Composite Types

The aeroplane is thus particularly weak as to stability, launching, and descending: but it is economical in power because it uses the air to hold itself up. The dirigible balloon is lacking in power and speed, but can ascend and descend safely, even if only by wasteful methods; and it can carry heavy weights, which are impossible with the structurally fragile aeroplane. The helicopter is wasteful in power, but is stable and sure in ascending and descending, providing only that the motor power does not fail.

Why, then, not combine the types? An aeroplane-dirigible would be open to only one objection: on the ground of stability. The dirigible-helicopter would have as its only disadvantage a certain wastefulness of power, while the aeroplane-helicopter would seem to have no drawback whatever.

All three combinations have been, or are being, tried. An Italian engineer officer has designed a balloon-aeroplane. The balloon is greatly flattened, or lens-shaped, and floats on its side, presenting its edge to the horizon--if inclination be disregarded. With some inclination, the machine acts like an aeroplane and is partially self-sustaining at any reasonable velocity.

The use of a vertically-acting screw on a dirigible combines the features of that type and the helicopter. This arrangement has also been the subject of design (as in Captain Miller's flexible balloon) if not of construction. The combination of helicopter and aeroplane seems especially promising: the vertical propellers being employed for starting and descending, as an emergency safety feature and perhaps for aid in stabilizing. The fact that composite types of flying machine have been suggested is perhaps, however, an indication that the ultimate type has not yet been established.

What is Promised

The flying machine will probably become the vehicle of the explorer. If Stanley had been able to use a small high-powered dirigible in the search for Livingstone, the journey would have been one of hours as compared with months, the food and general comfort of the party would have been equal in quality to those attainable at home, and the expense in money and in human life would have been relatively trifling.

Most readers will remember the fate of Andrée, and the projected polar expeditions of Wellman in 1907 and 1909. Misfortune accompanied both attempts; but one has only to read Peary's story of the dogged tramp over the Greenland ice blink to realize that danger and misfortune in no less degree have accompanied other plans of Arctic pioneering. With proper design and the right men, it does not seem unreasonable to expect that a hundred flying machines may soar above Earth's invisible axial points during the next dozen years.[C]

The report of Count Zeppelin's Spitzbergen expedition of last year has just been made public. This was undertaken to ascertain the adaptability of flying machines for Arctic navigation. Besides speed and radius of action, the conclusive factors include that of freedom from such breakdowns as cannot be made good on the road.

For exploration in other regions, the balloon or the aeroplane is sure to be employed. Rapidity of progress without fatigue or danger will replace the floundering through swamps, shivering with ague, and bickering with hostile natives now associated with tropical and other expeditions. The stereoscopic camera with its scientific adjuncts will permit of almost automatic map-making, more comprehensive and accurate than any now attempted in other than the most settled sections. It is not too much to expect that arrangements will be perfected for conducting complete topographical surveys without more than occasional descents. If extremely high altitudes must be attained--over a mile--the machines will be of special design; but as far as can now be anticipated, there will be no insurmountable difficulties. The virgin peaks of Ruwenzori and the Himalayas may become easily accessible--even to women and children if they desire it. We may obtain direct evidence as to the contested ascent of Mt. McKinley. A report has been current that a Blériot monoplane has been purchased for use in the inspection of construction work for an oil pipe line across the Persian desert; the aeroplane being regarded as "more expeditious and effectual" than an automobile.

The flying machine is the only land vehicle which requires no "permanent way." Trains must have rails, bicycles and automobiles must have good roads. Even the pedestrian gets along better on a path. The ships of the air and the sea demand no improvement of the fluids in which they float. To carry mails, parcels, persons, and even light freight--these applications, if made commercially practicable tomorrow,[D] would surprise no one; their possibility has already been amply demonstrated. With the dirigible as the transatlantic liner and the aeroplane as the naphtha launch of the air, the whole range of applications is commanded. Hangars and landing stages--the latter perhaps on the roofs of buildings, revolutionizing our domestic architecture--may spring up as rapidly as garages have done. And the aeroplane is potentially (with the exception of the motorcycle) the cheapest of self-propelled vehicles.

Governments have already considered the possibilities of aerial smuggling. Perhaps our custom-house officers will soon have to watch a fence instead of a line: to barricade in two dimensions instead of one. They will need to be provided with United States Revenue aeroplanes. But how are aerial frontiers to be marked? And does a nation own the air above it, or is this, like the high seas, "by natural right, common to all"? Can a flying-machine blockade-runner above the three-mile height claim extraterritoriality?

The flying machine is no longer the delusion of the "crank," because it has developed a great industry. A now antiquated statement put the capitalization of aeroplane manufactories in France at a million dollars, and the development expenditure to date at six millions. There are dozens of builders, in New York City alone, of monoplanes, biplanes, gliders, and models. A permanent exhibition of air craft is just being inaugurated. We have now even an aeronautic "trust," since the million-dollar capitalization of the Maxim, Blériot, Grahame-White firm.

According to the New York _Sun_, over $500,000 has been subscribed for aviation prizes in 1911. The most valuable prizes are for new records in cross-country flights. The Paris _Journal_ has offered $70,000 for the best speed in a circling race from Paris to Berlin, Brussels, London, and back to Paris--1500 miles. Supplementary prizes from other sources have increased the total stake in this race to $100,000. A purse of $50,000 is offered by the London _Daily Mail_ for the "Circuit of Britain" race, from London up the east coast to Edinburgh, across to Glasgow, and home by way of the west coast, Exeter, and the Isle of Wight; a thousand miles, to be completed in two weeks, beginning July 22, with descents only at predetermined points. This contest will be open (at an entrance fee of $500) to any licensee of the International Federation. A German circuit, from Berlin to Bremen, Magdeburg, Düsseldorf, Aix-la-Chapelle, Dresden, and back to the starting point, is proposed by the _Zeitung am Mittag_ of Berlin, a prize of $25,000 having been offered. In this country, a comparatively small prize has been established for a run from San Francisco to New York, _via_ Chicago. Besides a meet at Bridgeport, May 18-20, together with those to be held by several of the colleges and the ones at Bennings and Chicago, there will be, it is still hoped, a national tournament at Belmont Park at the end of the same month. Here probably a dozen aviators will contest in qualification for the international meet in England, to which three American representatives should be sent as competitors for the championship trophy now held by Mr. Grahame-White. It is anticipated that the chances in the international races favor the French aviators, some of whom--in particular, Leblanc--have been making sensational records at Pau. Flights between aviation fields in different cities are the leading feature in the American program for the year. A trip is proposed from Washington to Belmont Park, _via_ Atlantic City, the New Jersey coast, and lower New York bay. The distance is 250 miles and the time will probably be less than that of the best passenger trains between Washington and New York. If held, this race will probably take place late in May. It is wisely concluded that the advancement of aviation depends upon cross-country runs under good control and at reasonable speeds and heights rather than upon exhibition flights in enclosures. It is to be hoped that commercial interests will not be sufficiently powerful to hinder this development.

We shall of course have the usual international championship balloon race, preceded by elimination contests. From present indications Omaha is likely to be chosen as the point of departure.

The need for scientific study of aerial problems is recognized. The sum of $350,000 has been offered the University of Paris to found an aeronautic institute. In Germany, the university at Göttingen has for years maintained an aerodynamic laboratory. Lord Rayleigh, in England, is at the head of a committee of ten eminent scientists and engineers which has, under the authority of Parliament, prepared a program of necessary theoretical and experimental investigations in aerostatics and aerodynamics. Our American colleges have organized student aviation societies and in some of them systematic instruction is given in the principles underlying the art. A permanent aeronautic laboratory, to be located at Washington, D.C., is being promoted.

Aviation as a sport is under the control of the International Aeronautic Federation, having its headquarters at Paris. Bodies like the Royal Aero Club of England and the Aero Club of America are subsidiaries to the Federation. In addition, we have in this country other clubs, like the Aeronautic Society, the United States Aeronautical Reserve, etc. The National Council of the Aero Clubs of America is a sort of supreme court for all of these, having control of meets and contests; but it has no affiliation with the International body, which is represented here by the Aero Club of America. The Canadian Auto and Aero Club supervises aviation in the Dominion.

Aviation has developed new legal problems: problems of liability for accidents to others; the matter of supervision of airship operators. Bills to license and regulate air craft have been introduced in at least two state legislatures.

Schools for instruction in flying as an art or sport are being promoted. It is understood that the Wright firm is prepared to organize classes of about a dozen men, supplying an aeroplane for their instruction. Each man pays a small fee, which is remitted should he afterward purchase a machine. Mr. Grahame-White, at Pau, in the south of France, conducts a school of aviation, and the arrangements are now being duplicated in England. Instruction is given on Blériot monoplanes and Farman biplanes, at a cost of a hundred guineas for either. The pupil is coached until he can make a three-mile flight; meanwhile, he is held partially responsible for damage and is required to take out a "third-party" insurance policy.

There is no lack of aeronautic literature. Major Squier's paper in the _Transactions_ of the American Society of Mechanical Engineers, 1908, gave an eighteen-page list of books and magazine articles of fair completeness up to its date; Professor Chatley's book, _Aeroplanes_, 1911, discusses some recent publications; the Brooklyn Public Library in New York issued in 1910 (misdated 1909) a manual of fourteen pages critically referring to the then available literature, and itself containing a list of some dozen bibliographies.

Aerial Warfare

The use of air craft as military auxiliaries is not new. As early as 1812 the Russians, before retreating from Moscow, attempted to drop bombs from balloons: an attempt carried to success by Austrian engineers in 1849. Both contestants in our own War of Secession employed captive and drifting balloons. President Lincoln organized a regular aeronautic auxiliary staff in which one Lowe held the official rank of chief aeronaut. This same gentleman (who had accomplished a reconnaissance of 350 miles in eight hours in a 25,000 cubic foot drifting balloon) was subjected to adverse criticism on account of a weakness for making ascents while wearing the formal "Prince Albert" coat and silk hat! A portable gas-generating plant was employed by the Union army. We are told that General Stoneman, in 1862, directed artillery fire from a balloon, which was repeatedly fired at by the enemy, but not once hit. The Confederates were less amply equipped. Their balloon was a patchwork of silk skirts contributed (one doubts not, with patriotic alacrity) by the daughters of the Confederacy.

It is not forgotten that communication between besieged Paris and the external world was kept up for some months during 1870-71 by balloons exclusively. Mail was carried on a truly commercial scale: pet animals and--the anticlimax is unintended--164 persons, including M. Gambetta, escaped in some sixty-five flights. Balloons were frequently employed in the Franco-Prussian contest; and they were seldom put _hors de combat_ by the enemy.

During our war with Spain, aerial craft were employed in at least one instance, namely, at San Juan, Porto Rico, for reconnoitering entrenchments. Frequent ascents were made from Ladysmith, during the Boer war. The balloons were often fired at, but never badly damaged. Cronje's army was on one occasion located by the aid of a British scout-balloon. Artillery fire was frequently directed from aerial observations. Both sides employed balloons in the epic conflict between Russia and Japan.

A declaration introduced at the second international peace conference at the Hague proposed to prohibit, for a limited period, the discharge of projectiles or explosives from flying machines of any sort. The United States was the only first-class power which endorsed the declaration. It does not appear likely, therefore, that international law will discountenance the employment of aerial craft in international disputes. The building of airships goes on with increasing eagerness. Last year the Italian chamber appropriated $5,000,000 for the construction and maintenance of flying machines.

A press report dated February 4 stated that a German aeronaut had been spending some weeks at Panama, studying the air currents of the Canal Zone. No flying machine may in Germany approach more closely than within six miles of a fort, unless specially licensed. At the Krupp works in Essen there are being tested two new guns for shooting at aeroplanes and dirigibles. One is mounted on an armored motor truck. The other is a swivel-mounted gun on a flat-topped four-wheeled carriage.

The United States battleship _Connecticut_ cost $9,000,000. It displaces 18,000 tons, uses 17,000 horse-power and 1000 men, and makes twenty miles an hour. An aeroplane of unusual size with nearly three times this speed, employing from one to three men with an engine of 100 horse-power, would weigh one ton and might cost $5000. A Dreadnought costs $16,000,000, complete, and may last--it is difficult to say, but few claim more than ten years. It depreciates, perhaps, at the rate of $2,000,000 a year. Aeroplanes built to standard designs in large quantities would cost certainly not over $1000 each. The ratio of cost is 16,000 to 1. Would the largest Dreadnought, exposed unaided to the attack of 16,000 flying machines, be in an entirely enviable situation?

An aeroplane is a fragile and costly thing to hazard at one blow: but not more fragile or costly than a Whitehead torpedo. The aeroplane soldier takes tremendous risks; but perhaps not greater risks than those taken by the crew of a submarine. There is never any lack of daring men when daring is the thing needed.

All experience goes to show that an object in the air is hard to hit. The flying machine is safer from attack where it works than it is on the ground. The aim necessary to impart a crippling blow to an aeroplane must be one of unprecedented accuracy. The dirigible balloon gives a larger mark, but could not be immediately crippled by almost any projectile. It could take a good pounding and still get away. Interesting speculations might be made as to the outcome of an aerial battle between the two types of craft. The aeroplane might have a sharp cutting beak with which to ram its more cumbersome adversary, but this would involve some risk to its own stability: and the balloon could easily escape by a quick ascent. It has been suggested that each dirigible would need an aeroplane escort force for its defense against ramming. Any collision between two opposing heavier-than-air machines could not, it would seem, be other than disastrous: but perhaps the dirigible could rescue the wrecks. Possibly gas-inflated life buoys might be attached to the individual combatants. In the French man[oe]uvers, a small aeroplane circled the dirigible with ease, flying not only around it, but in vertical circles over and under it.

The French war office has exploited both types of machine. In Germany, the dirigible has until recently received nearly all the attention of strategists: but the results of a recent aerial war game have apparently suggested a change in policy, and the Germans are now, without neglecting the balloon, actively developing its heavier-than-air competitor. England seems to be muddled as to its aerial policy, while the United States has been waiting and for the most part doing nothing. Now, however, the mobilizations in Texas have been associated with a considerable amount of aeroplane enthusiasm. A half-dozen machines, it is expected, will soon be housed in the aerodrome at San Antonio. Experiments are anticipated in the carrying of light ammunition and emergency supplies, and one of the promised man[oe]uvers is to be the locating of concealed bodies of troops by air scouts. Thirty army officers are to be detailed for aeroplane service this year; five training schools are to be established.

If flying machines are relatively unsusceptible to attack, there is also some question as to their effectiveness _in_ attack. Rifles have been discharged from moving balloons with some degree of accuracy in aim; but long-range marksmanship with any but hand weapons involves the mastery of several difficult factors additional to those present in gunnery at sea. The recoil of guns might endanger stability; and it is difficult to estimate the possible effects of a powerful concussion, with its resulting surges of air, in the immediate vicinity of a delicately balanced aerial vessel.

But aside from purely combative functions, air craft may be superlatively useful as messengers. To send despatches rapidly and without interference, or to carry a general 100 miles in as many minutes--these accomplishments would render impossible the romance of a "Sheridan's Ride," but might have a romance of their own. With the new sense added to human equipment by wireless communication, the results of observations may be signaled to friends over miles of distance without intervening permanent connections of however fragile a nature.

Flying machines would seem to be the safest of scouts. They could pass over the enemy's country with as little direct danger--perhaps as unobserved--as a spy in disguise; yet their occupants would scarcely be subjected to the penalty accompanying discovery of a spy. They could easily study the movements of an opposing armed force: a study now frequently associated with great loss of life and hampering of effective handling of troops. They could watch for hostile fleets with relatively high effectiveness (under usual conditions), commanding distant approaches to a long coast line at slight cost. From their elevated position, they could most readily detect hostile submarines threatening their own naval fleet. Maximum effective reconnaissance in minimum time would be their chief characteristic: in fact, the high speeds might actually constitute an objection, if they interfered with thorough observation. But if air craft had been available at Santiago in 1898, Lieutenant Blue's expedition would have been unnecessary, and there would have been for no moment any doubt that Admiral Cervera's fleet was actually bottled up behind the Morro. No besieged fortress need any longer be deprived of communication with--or even some medical or other supplies from--its friends. Suppose that Napoleon had been provided with a flying machine at Elba--or even at St. Helena!

The applications to rapid surveying of unknown ground that have been suggested as possible in civil life would be equally possible in time of war. Even if the scene of conflict were in an unmapped portion of the enemy's territory, the map could be quickly made, the location of temporary defenses and entrenchments ascertained, and the advantage of superior knowledge of the ground completely overcome prior to an engagement. The searchlight and the compass for true navigation on long flights over unknown country would be the indispensable aids in such applications.

During the current mobilization of the United States Army at Texas, a dispatch was carried 21 miles on a map-and-compass flight, the round trip occupying less than two hours and being made without incident. The machine flew at a height of 1500 feet and was sighted several miles off.