Here is what Hildebrandt wrote about this machine :"We seldom find a man imbued with the ideas of the balloon, adapting himself to the principles of the flying machine with any success. Yet it was done by the most popular balloonist of our time, Santos Dumont. On January 2nd, 1905, he announced himself to the Aero Club as a competitor for the Deutsch and Archdeacon prize, after he had quietly built himself a flying machine. As shown in the appended diagram, the two upper propellers C C have a diameter of 20 ft., and produce motion in a vertical direc  tion ; the propeller D has a diameter of 6 ½ ft., and drives the machine for  wards. Each of the propellers C has a total surface of 43 square feet, and together with the transmission gear it weighs 30 lbs. The one revolves in the opposite direction to the other, so as to prevent a rotation of the entire apparatus about a vertical axis. The car is constructed of bamboo, and contains a Levavasseur motor with eight cylinders, giving 28 horse power. The weight of this motor together with the necessary supply of water is 1 cwt. At the back of the driver's stand is placed a vertical rudder. The preliminary trials are said to have been successful and each of the lifting pro  pellers was found to be able to raise a weight of 200 lbs. ; the total lift was therefore 400 lbs., and this could raise the machine and driver, besides about 30 lbs. of cargo. He used no sails, and this would add greatly to the danger of an accident caused by stoppage of the motor. In such a case he would scarcely get off so easily as he has done in the past. No doubt this fact weighed on his mind, for he proceeded forthwith to build himself a kite, intending to drive it by propellers placed at the sides of the sails. The rudder is in the shape of a cross, and capable of being turned about both horizontal and vertical axes. The sails are of silk, stretched over bamboo, and are 50 ft. long and 26 ft. broad, with an area of 237 square feet ; the weight of the whole machine together with the driver is only 310 lbs. He has already made two ascents in this airship. On the first attempt, it rose in the air, but after a short distance it came to the ground with rather severe injuries. Santos Dumont immediately built another, and in this he is stated to have travelled a distance of 200 ft. at a height of 12 ft. from the ground. This aeroplane is of a totally different nature from the original design of flying machine adopted by Santos Dumont ; and it cannot be doubted that it is the thing of the future. It would be exceedingly dangerous to propose to do without sails of any kind ; a motor is capricious enough, even when standing on solid earth ; in mid air, it is likely to be more so. The weight of kites or aeroplanes is small, and they have the further advantage of presenting a small surface to the wind, in consequence of their horizontal motion."
Unknown
1908
<p>AIRSHIPS PAST AND PRESENT, ... by A. Hildebrandt, Captain and Instructor in the Prussian Balloon Corps,  1908
</p>
<a rel="nofollow" class="external autonumber" href="https://ia601609.us.archive.org/6/items/airshipspastpres00hild/airshipspastpres00hild.pdf">[1]</a>