Mattullath’s proposed air ship consisted of two parallel torpedo-shaped hulls sustained by superposed plane or slightly arched surfaces, and propelled by feathering-paddle disk wheels embedded in the planes; the engines, cargo and passengers to be placed within the hulls.[40] This arrangement would enhance the comfort of the passengers at high speeds, eliminate resistance, distribute the load on the framing, and increase the moment of inertia of the vessel, thereby rendering it less sensitive to side gusts. To improve the projectile stability and steadiness, the centroid was placed as high as practicable. Large steering planes were used fore and aft on both sides of the vessel, whose inclination could be changed independently, to turn the ship about its longitudinal or transverse axis. A vertical rear rudder steered to right or left, in conjunction with the side planes. All the posts were of double wedge shape; all the planes were canvassed above and below to shield the framing, after the style of Maxim. The hulls, the posts, the planes, all parts, were keenly sharpened to economize power. The ship was to run over its smooth launching field till it acquired a rising speed of forty to fifty miles an hour, then continue accelerating up to velocities sufficient for competition with passenger trains in all weather. While one may easily point out certain questionable features in Mattullath’s project, as for example, its odd propellers, one can not so easily estimate its true merits. The torsion wing device for lateral control and steering, which he claimed in his patent application, abandoned after his death, now constitutes a very important feature of every flying machine. His planes for fore and aft control, introduced by Maxim, are also in general use to-day. The principle of load distribution, which he greatly prized for diminishing stress and adding stability, has still to be evaluated by practical test in larger craft than any now in operation. The closed hull, for comfort and economy at high speed, is at present popular with many designers.