Of course, the idea of pontoons as applied to aerial craft was by no means a novelty. Glen Curtiss, pioneer in this field, already had a fleet of successful hydro-aeroplanes, and many other inventors were laboring along these lines. It was in the application of the idea that the boys had radically departed from anything hitherto known. At the risk of being tedious we must now describe the _Wondership_ at some length, in order that what is to follow of her marvelous adventures may be clear.
Readers of former books relating the experience of the Boy Inventors know that the _Flying Road Racer_ was a craft built like an immense automobile with a semi-cylindrical body. It seated six persons, and at a pinch could accommodate more. The lower part of the cylinder was a big tank in which gas was generated from a concentrated powder which, upon being mixed with water, formed a vapor of extraordinary buoyancy. In the upper part were padded seats, storage chambers for food and supplies, and a machinery chamber housed under a hood.
Above this auto-like structure rose a framework of vanadium and aluminum alloy, on which was folded, when not in use, the gas-bag which lifted the _Flying Road Racer_ from the earth when it was desired to fly. Pumps filled the bag with gas, or withdrew it, as was desired. Provision allowing for the expansion and contraction of the bag had also been made, as was fully described in another volume.
What the boys had done was this: They had extended the semi-cylindrical formation till they had formed a full cylinder of light but strong metal. Roughly, the _Flying Road Racer_ now resembled a huge, gleaming white cigar on wheels. Along her sides stretched hollow aluminum planes, or wings.
In the air these took the place of the former planes used in ascending or descending. On the water it was hoped that they would act as hydroplanes, buoying up the craft. But for buoyancy they did not depend on these hydroplanes, or pontoons, alone. The body of the _Flying Road Racer_ was, by a singular stroke of inventive ingenuity, made to be in itself a buoyant craft.
When running along the road, or while flying, the top of the cylindrical body could be opened for air and observation. On a calm sea or lake the boys believed also that the craft, with the aid of the hydroplanes, would float, just like a boat. The hydroplanes at the side would, of course, correct a tendency to roll over, which an unsupported cylindrical body would naturally have. But in case of rough water, during which they might, in the course of the long flights they meant to take, be compelled to descend, the waves would be apt to break over the craft and swamp it.