Is the Practical Helicopter in Sight?, Measuring Vapor Pressures, and more

George Gaulois
1921 Scientific American  
held as a classic j.oke in aer.onautical circles, may be c.oming int.o its .own at last. This d.oes n.ot mean t.o say that the practical heli· c.opter is already realized, but it d.oes mean t.o c.onvey the very definite impres si.on that , at last the helic.opter invent.ors are getting d.own t.o real engineering principles and are devel.oping designs which h.old s.ome pr.omise .of future sue <!ess. 'L'he day .of the t.oy helic.opter with rubber-band m.otors, intended t.o repre sent the merits
more » ... f a given type .of pr.o posed helic.opter, is Invent.ors are n.ow building full-sized machines, equipped with real aviati.on engines and man carrying bodies, in .order t.o pr.ove the w.orthiness .of their designs. And in s.o d.oing they are rapidly c.onvincing us that there is s.ome h.ope after all f.or heli c.opter flight. CoP7rbrbt. Koptono View (;0. Measuring Vapor P�ssures W HERE accuracy in measuring vap.or pressures t.o a fi neness .of .one part in three t.o five th.ousand divisi.onal units is the desired .objective, tw.o types .of instruments recently perfected by the United States Bureau .of Standards meet the requirements. The tw.o mechanisms, although widely differing in appearance, have much in c.omm.on, · and in func ti.oning in the G.overnment lab.orat.ory their uses are well-nigh interchangeable. Each, h.owever, varies in c.onstructi.on and p.ossesses respective merits. The sh.ortc.omings .of the airplane have paved the way f.or the helic.opter. First of all, the airplane has t.o maintain a nigh rate .of speed in .order t.o sustain it self in the air. By the same t.oken it must take .off at a high rate .of speed, and land at a c.onsiderable rate .of speed, b.oth of which c.ontain many elements .of dan ger. Then again, the way in which the Oehmichen helic.opter in flight, said t.o be the first helic.opter t.o make a free flight, alth.ough it is equipped with gas bag
doi:10.1038/scientificamerican06041921-447 fatcat:gkxr57sutvfe7cqjhh4a33is24