FROM SHEET NO. 3, U. S. COAST AND GEODETIC SURVEY CHART OF POTOMAC RIVER, ISSUE OF 1882 SCALE 1 1-16 INCH TO STATUTE MILE PL. 85. LOCATION OF HOUSE BOAT IN CENTER OF POTOMAC RIVER, JULY 14, 1903 [◊] [lgr]

Had it been possible to foresee the great delay which finally occurred before the large aerodrome was actually launched, and the great expense arising from the necessity of maintaining one or more expensive tug-boats constantly, it is very certain that an experimental station nearer Washington would have been selected, even though the nearer places on the river which were available were much less suitable, both on account of the river being much narrower and the traffic very much heavier. In fact, at the time that the house-boat was taken down the river on July 14, with the expectation that the experiments with the [p257] large aerodrome would certainly be concluded within four weeks, the expenses of the work, which had been met from the Hodgkins Fund of the Smithsonian Institution since the original allotment from the Board of Ordnance and Fortification was exhausted more than a year previously, had already made such heavy drafts on this fund that Mr. Langley was most reluctant to draw further on it, even to the extent which seemed necessary to meet the expenses of a month of “field-work.”

Before making the tests of the large aerodrome, it was intended to give the quarter-size model a preliminary trial to test the balancing which it was proposed to use on the large machine. For this test it was planned to employ the small launching apparatus mounted on top of the small house-boat, which had been used in the experiments with the steam-driven models Nos. 5 and 6 in 1899, and later with the quarter-size model in 1901. However, after arriving down the river, it was found that the small house-boat which had been anchored at Chopawamsic Island since the experiments in 1901 had deteriorated to such an extent that it was unsafe to take it out into the river. The launching apparatus for the model was, therefore, removed from it and placed on the turn-table of the large house-boat, alongside the launching track for the large machine. After completing this transfer of the model-launching apparatus everything was thought to be in readiness for a test of the quarter-size model, but upon making a shop test of the model to make sure that its engine was working properly, it was found impossible to get it to work at all. A few explosions could be obtained once in a while, but very irregularly. After spending considerable time in trying to locate the difficulty, it was found that the commutator which distributes the high-tension sparking current to the proper cylinder at the proper time was short-circuited. This commutator had been made of “insulating fibre” and had never caused any previous trouble. It was now found, however, that the very damp atmosphere which had been experienced during the preceding two weeks, when the fog for a large portion of the time was so heavy that objects at a short distance across the water could not be seen, had caused the moisture to penetrate the fibre and thus destroy its insulating qualities. After much trouble some vulcanite and mica were secured and a new commutator made to replace the fibre one, and, then, after some minor difficulties had been remedied, the engine for the model was got into good condition again. After getting satisfactory shop tests on the model aerodrome, and having everything in readiness for a flight, it was necessary to wait many days before the weather was calm enough for a test. However, on August 8 the weather quieted down and the model was launched at 9.30 a. m. into a wind blowing about 12 miles per hour from E. SE.

Referring to Plate [86], which shows the quarter-size model mounted on its launching car on top of the large house-boat, and which was taken only a few [p258] minutes before the model was actually launched, it will be noted that a board (A) projects from the front of the launching car. This board, which is mounted in a false floor of the launching car, is so arranged that when it strikes the two blocks (B) at the end of the track it is driven backward in the car against the triggers which prevent the uprights (D), supporting the aerodrome, from being folded down against the floor. When this board strikes the triggers it releases them and the springs (C), which in this case were rubber bands, immediately fold the vertical posts or uprights (D) against the brace posts (E), which are immediately folded down flat against the floor of the car through the action of the spring hinges, by which they are connected to it. These uprights (D), which support the aerodrome at the front and rear, respectively, are not released until a fraction of a second after the release of the clutch hook (F), which is attached to the middle upright (G), and which, grasping the lower pyramid, holds the machine down firmly against the uprights (D) previously referred to. In order to prevent the possibility of the aerodrome being released prematurely while the car is held at the extreme rear end of the track by the hook (H), a steel pin (J), which can just be seen in the photograph, is pushed through a hole in the board (A), and into a hole in a cross-member on the bottom of the car, thus holding the board in its proper position. After the engine is started up one of the mechanics who has assisted in starting it is under orders to remove the pin at the word “Ready,” and at the word “Go” the other mechanic who has assisted in starting the engine is under orders to release the hook (H), and thus allow the car to dash down the track. In the experiment on August 8 the mechanic failed to remove the pin (J) at the proper time, and it was only after the machine had been released and started down the track that it was seen that the pin had not been removed. It was then, however, too late to stop it, so the car dashed down the track. Although the striking of the board against the blocks caused the pin to split the board to pieces, the launching apparatus worked perfectly and the aerodrome started off on a perfectly even keel, the propellers revolving at an exceedingly high rate of speed. The aerodrome flew straight ahead for a distance of 350 feet, when it began to circle towards the right, descending slightly as it circled. Upon completing a quarter circle it again began to rise, flying straight ahead until it had gone a similar distance, when it again lost headway, but before it reached the water the engine increased its speed and the aerodrome again rose. When the engine slowed down for the third time, however, the aerodrome was not many feet above the river, so that before the engine regained its normal speed the aerodrome touched the water with its propellers still revolving, but very slowly. While the total distance covered was only about 1000 feet, and the time that it was actually in the air 27 seconds, yet in this brief time it had served the main purpose for which it had been built, which was to find out if the balancing of [p259] the large aerodrome, which had been determined by calculation from the results obtained with the steam-driven models, was correct. For it was assumed that if the quarter-size model, which was an exact counterpart of the large machine, should fly successfully with the same balancing as that calculated for the large one, the large one could reasonably be expected to act similarly. It was at first thought best to make another test with the model immediately after recovering it from the water, but by the time it could be brought into the house-boat and the water which had got into the engine cylinders could be removed and the engine made to work properly quite a strong wind had sprung up and rendered further tests of the model on this day impossible. If the launching track for the small machine could have remained on the top of the boat without interfering with the completion of the preparations for testing the large machine, it would have been left there and other tests made with the model when the weather was suitable, but as this could not be done without interfering with the work on the large machine, and the delays with the model had already been so great, the small track was immediately removed and the model stored away in the house-boat for possible later tests.

At the first it was impossible to account for the engine on the model running so irregularly and slowing down so soon after it was launched, as it was felt very certain that the cylinders could not in so short a time, and with the aerodrome actually moving through the air, have heated up sufficiently to cause it. After a while, however, one of the workmen volunteered the information that in his zeal to fill the fuel tank completely so as to insure a long flight, he had caused the tank to overflow so that some of the gasoline had run into the intake pipe, and that he had noticed gasoline dripping from the intake pipe as the machine went down the track. This excess gasoline in the intake pipe had caused the mixing valve which controls the quality of the explosive mixture to be improperly set, so that it would not furnish the proper mixture when the fuel was supplied in the proper way by the carburetor, and consequently when this excess gasoline had evaporated, the mixture furnished to the engine was not proper, and it consequently slowed down, there being no human intelligence on board to correct the adjustment of the mixing valve.

A series of seven photographs of this flight of the quarter-size model is given in Plates [87] to [93]. Plate [87], taken with a kodak from the tug-boat stationed several hundred yards directly ahead of the house-boat, shows the machine in full flight heading directly for the tug-boat. Although the aerodrome was about fifteen or twenty feet higher above the level of the water than the camera, still, at the considerable distance from which the photograph was taken, this view would not show so much of the under side unless the machine had been pointing upward. The photograph also proves very clearly that at the time it was taken the machine had certainly not dropped at all below the level [p260] at which was launched. In Plate [88] the camera was unfortunately not well aimed, and only the front guy-post, bearing points, float and bowsprit are visible, besides the blur of the propellers, which, it will be noted, were moving very rapidly. The camera with which this and the succeeding plates were taken was one of the two special telephoto cameras belonging to the Zoological Park, but built in the course of the aerodromic work and used where especially rapid shutters were needed. As the shutters on these cameras give an exposure of only 1500 of a second, and consequently are sufficiently rapid to show the individual feathers in a rapidly moving bird’s wing, any distortion of the machine in flight would certainly have been shown, but, as will be seen from the later photographs, no distortion of any kind occurred, both the surfaces and the framework remaining in a perfectly straight condition. Near the bottom of Plate [88] is the tug from which Plate [87] was taken, and a careful inspection of Plate [87] shows two persons standing on the roof of the house-boat, below the upper works, the gentleman on the left being Mr. Thomas W. Smillie, the official photographer of the Smithsonian Institution, who took all of the photographs except Plate [87], and, as stated above, used therefor the special telephoto cameras with the rapid shutters. Plate [89] is an exceedingly good view, and shows the propellers revolving very rapidly while Plates [90], [91] and [92] show very clearly that the speed of the propellers had greatly decreased between the successive photographs. Plate [93] shows the aerodrome shortly after it touched the water and had been almost completely submerged, in spite of its floats, by the very strong tide which was running. Though these plates show all that photographs can, they give no adequate idea of the wonder and beauty of the machine when actually in flight. For while the graceful lines of the machine make it very attractive to the eye even when stationary, yet when it is actually in flight it seems veritably endowed with life and intelligence, and the spectacle holds the observer awed and breathless until the flight is ended. It seems hardly probable that anyone, no matter how skeptical beforehand, could witness a flight of one of the models and note the almost bird-like intelligence with which the automatic adjustments respond to varying conditions of the air without feeling that, in order to traverse at will the great aerial highway man no longer needs to wrest from nature some strange, mysterious secret, but only, by diligent practice with machines of this very type, to acquire an expertness in the management of the aerodrome not different in kind from that acquired by every expert bicyclist in the control of his bicycle.

PL. 86. QUARTER-SIZE MODEL AERODROME MOUNTED ON LAUNCHING-CAR [◊] [lgr]

PL. 87. QUARTER-SIZE MODEL AERODROME IN FLIGHT, AUGUST 8, 1903 [◊]