The Necessities of Inventions

Evening Post, Volume CXV, Issue 94, 22 April 1933, Page 16

The Necessities of Inventions

• A leally successful invention must pass three tests —the theoretical, the practical,, and the economical. Inventions that only- make tho first hurdle are legion—the designs of "cranks" ,which never get • further than an imaginative drawing and a model that, refuses to work. But it is not generally realised that there are a number of ingenious inventipns which (even on full-sizo scale) | work perfectly, and yet must be labelled failures, because they cannot compete , economically with older rivals. A re-' cent example was the "rotor ship" of Anton Flettner. By equipping a ship with tall spinning towers liko elongated vertical cotton reels, Flettner found it possible to dispense with sails. The towers ■were spun by a- small motor, and acted on the wind similarly' to sails, giv.i'ng -slightly more drive. A large rotor ship, the Baden Baden, was'built on these :-lines and put in commission in .1928. | But economically the vessel was a failure, says an overseas paper. :As practical seamen pointed out, the 'rotor ship was just as much at the mercy of the wind as the wind-jammer, and yet had to carry the added equipment of. a.motor. If the latter was necessary, why not use it to drive an auxiliary screw, be independent of the .wind, and cut ont the rotors altogether? -The Jogic was unanswerable. Tho Baden 'Baden is running' today,' ■ but she carries no rotors and is screw-driven Dy k Diesel engine. Edison himself patented an invention which failed dismally to-take tin; third hurdle,' It was a motor to be run by sound-vibration, otherwise by noises or the human \-oico. It contained an ingenious mechanism for .transforming into rotary motion tlic vibrations of a microphone disc. It ■ worked perfectly, "but it delivered ;hardly a fraction of one mosquito power —in fact, anyone could get a thousand times more power simply by .turning a crank by hand. This was one of the ifew cases in which the great inventor sodded. " An invention which ■is rediscovered ■from time-td time'arid yot fails at the third test is tho flying puah.bicycle. Orie'form is just'an ordinary bicycle provided with wings liko an ■aeroplane. Time and againit has been shown that the speed given by pedalling in only enough just td Taise the cycle from the ground in'a hop; way is then immediately lost, and the machine thuds,to earth again;;usuelly qverturnjng. Practically, .suc'n' a 'method is" but

of the question for street travelling; if used for gliding, why tho cycle at all, as an elastic rope is better for getting the glider into the air, after which the bicycle is just dead weight* A more ambitious formv is the winged cycle in which the pedals work an air-propeller. The idea is that, having got into the air by coasting down a steep hill, the pedals will drive the Bailing cycle fast enough to sustain it in the air like an erigined aeroplane. But experiments show that to do this latter requires more horse-power for a mate's weight than he can create per pedals and propeller. Anyhow, why worry over propelling, when a skilled elider can manoeuvre a sailplane for hours in any direction' or in circles without any motive power whatever? A fourth factor in success of an invention is public fancy. An invention may be a success theoretically, practically, and economically, yet be coldshouldered by the public. Such was Elihu Thompson's deodoriser for exhaust gases from motor-cars. It was^ such a huge, unsightly contraption stick- ■ ing out of the back of tho car that no maker or owner would fit it. Another was Leo De Forest's petrol-gauge for cars, which whistled, shrilly when the contents of the tank ran low. In spite of the prestige of tho inventor (he is the father of the radio valve), the public seemed to sense something ludicrous (like the old style whistling kettle) in the idea, and the invention fell' absolutely flat.