The following text may have been generated by Optical Character Recognition, with varying degrees of accuracy. Reader beware!

March, 1925 ever, due to lack of means to carry them out on a large scale. In this connection it is interesting to note that in England as the result of news about the Flettner ship, experiments are being made for using horizontal rotating cylinders on airplanes which, if successful, will solve the problem of the heliocopter. Flettner first set out to improve the sail of the ordinary sailing ship which in its essential feaures had never been improved since the earliest days of navigation. Flettner found it to be extremely inefficient as compared with an airplane wing, and experimented with metal sails having the shape of airplane wings, steered by small flaps IMM MMC How Leviathan s OVUVVAGTHTAARLLUULLOLUCHEOTAUULLUCLOLUOUCUUULOGEAOEEOED AUHUVUVUUTHTLUELUUCUATLUCUUUUHAOLUUUCUUAHHULLCUULH UL LCUULA LUO This illustration shows with re- markable clearness the inside face of the burner wall of one of the oil burning furnaces of the S. S. Leviathan. The intense heat may be judged by the way the fire brick wall has fluxed and run down into the monolithic refractory of which the burner ring cones are made. Subjected to the same heat as the fire brick the refractory material seems to stand up very well. TUTUUTTCUHTUTETUELETUCTITGLEU CULL ELLER GT TTT TTT TUTTTTTTTTTTTHATTTITUUULUCUUOTOHATTAAROIUOUUOOOEROOOOOUATTUUOOOOORHOTOTOTITOTUCQUOUOOOTORIIITUTUTTUUT much the same as the well known Flettner rudder. He actually obtained an increase of propelling force of about 50 to 60 per cent but discarded the ideas on account of impracticability in heavy seas and high winds. In his endeavor to find other means of directing the wind in the most efficient manner, he finally conceived the idea of using rotating cylinders which at that time were being tested out in the wind tunnel at the University of Goet- tingen, Germany. When the tests showed unexpectedly large forces, Flet- tner at once developed the idea fur- ther and with the assistance of a large shipping company, had the rotor sail- ing ship Buckau _ equipped with two rotating cylinders. The appear- ance of the BucKau is well known to the American public from the illus- trations published everywhere. A _ ro- MARINE REV PE Ww tating cylinder when subjected to a current of air will have a pressure area on one side and a suction area on the other with the result that a pressure is exerted on the cylinder approximate- ly at a right angles to the direction of the wind. An interesting feature of this phenonomen is that while in every other mechanical device friction is minimized as far as possible, the Flettner rotors depend on friction for working, that is on the friction of moving strata of air against each other and against the smooth surface of the rotor cylinder. The Buckau- was originally a motor sailing ship, a square rigged schooner of 600 tons displace- ment. The rotor shells are made of ETHTTTTTTUTUTITTTTTTOUUNUMTTTTRUUCUUTTATOCOUUUUROTTTOUCUUMTOOOUUOTTTOUEEUITHTOOOOUTUOUUTOOOUULULTUTOUUUUUCCOTOUUUULUUCCUUULUCUUIOOCUULLLCICCULULCLLHLCULLOULL CCUM LUOLCLUUULLCCOLULULLUCOCCULLLLCOOUULLELCOLUULELCLOO LULL OLLLCLLLCE LOL eLLLOLecoLLLLLc LLL. LLL LLL cL steel 3/64 of an inch thick, stiffened by longitudinal and cross braces. They rotate on two stationary pivots which reach to about two-thirds of their height. The upper bearing has_ to carry the weight of the shell and at the same time must take care of the lateral pressure. The cylinders have a diameter of 9 feet 3 inches and are 52 feet high, corresponding to a total projected area for the two cylinders of 874 square feet, or not quite one tenth of the former sail area of the RUCKAU. Electric power is fur- nished by a- small two cylinder 45 brake horsepower diesel engine. The rotors are revolved by two 11 kilowatts 15 horsepower reversible direct cur- rent motors, running at 750 revolutions per minute and are geared to the ro- tors in the ratio of six to one. The accompanying illustration shows ~ Furnaces Look from Inside 91 how the Magnus effect was demon- strated by means of an electric fan and a small rotor cylinder mounted on wheels and revolved by a small elec- tric motor. <A series of slides were shown giving polar diagrams of metal sails as well as rotating cylinders with and without end plates, the latter play- ing a very important part since they prevent the leakage of outside air into the pressure and suction area. Other diagrams obtained from actual experi- ments were shown to demonstrate how the increase of the speed of the rotor surface as compared with the wind velocity, will affect the resulting driving force. Also how at a certain velocity the pressure on the cylinders l= AUAUUUUHAATUUUHTALUGUAEUOUOUAUUUUGHULUUCULAUILUOHTULUOOATOTUUOHAOUOOHOOTOCUOAT ITD WUUVUSTHMUUUTHTTRUUCTTTLTOUTTAUUUTHUUUUOTHTUUUHTIUUUCOTULGCOAOUROCOHOCUCOATOUUUAAAUOLONAUUCOGHOTDOGHOULOOVTOTUUNHOVCUUOTITOONHTILUOPHTI UG =il : does not continue to increase which is of great importance in stormy weath- er. Other diagrams were shown to bring out the efficiency of sails as compared with rotating cylinders and how the pressure is distributed on the circumference of the cylinders. At the present the Buckau_ rep- resents the first practical application of the invention and the results ob- tained so far certainly encourage the belief that this new method of ship propulsion is bound to lead to very interesting results. Just how far these will go, no one can predict at the present moment. If further experience with this type of ship confirm the ex- pectations based on the first trips of the BucKkau, it will not exactly mean the coming back of the sailing ship, but rather the solution of the problem of the auxiliary sailing ship.