Here's the Air-Propelled Unicycle 



Some mechanical misgivings about a fantastic invention 



in the transmission of the engine is small. 

 The resistance in the wheel spindle-bearings 

 is evidently insignificant compared with 

 that to be looked for in the corresponding 

 bearings of the unicycle, which are those of 

 the three roller disks shown in the engine- 

 carrying frame, subject to constant side 

 pressure from a bevel-pinion drive. The 

 loss of engine power in the transmission of 

 the unicycle is enormous. There are con- 

 stantly in mesh a large number of elements. 

 At turns, there are, in addition, two hand- 

 operated worm-gears for turning the T- 

 shaft of the air-screw upon its vertical 

 pivot-pin (against a considerable resistance 

 when the screw is going), and this further 

 operates a train of three spur-gears to 

 make the front wheel participate in the 

 turn and — when it is on the ground — help 

 in directing or stopping the big wheel. 



The loss of efficiency due to the many 

 transmission gears is small, however, com- 

 pared with that of the air-screw, which 

 cannot be more than three and one-half 

 feet in diameter so each blade is less than 

 twenty inches long. An air-screw of these 

 dimensions, at the present stage of knowl- 

 edge, has about one-fifth of the efficiency 

 and one-tenth of the capacity of- a screw, 

 with forty-inch blades and can scarcely 

 absorb more than fifteen or utilize more 

 than two-horsepowers at the utmost ve- 

 locity that can be imparted to it through 

 gears. On hills, the machine would be 

 reduced to very low speed with high fuel 

 consumption. 



An air-screw even so small as three and 

 one-half feet in diameter would be dan- 

 gerous to bystanders and wayfarers; a 

 larger and more efficient one would be 

 entirely out of the question on the road. 



Ordinarily the front wheel, which some- 

 what spoils the unicycle idea, is supposed 

 to hover in the air when the machine is 

 running, the driver sitting on a sliding 

 seat, balancing his weight against that of 

 the front structure by pushing the seat 

 to the balancing position. The claim is 

 made that by shifting his seat he can make 

 the air-screw inoperative, but nothing is 

 shown to substantiate this assertion. To 

 the front wheel a brake mechanism is 

 secured, to be operated with a long rod, 

 and the inventor believes that this brake 



DO you remember the old "Star' 

 bicycle? If not, ask your father. 

 He will tell you that it had a little 

 wheel in front, and behind a very large 

 wheel over which you sat. The little 

 wheel in front was supposed to prevent 

 you from taking "headers." 



Show your father the accompanying il- 

 lustrations of A. F. d'Harlingue's air- 

 propelled unicycle and he will say at once: 

 "Why the man has simply put an air- 

 propeller and an engine on a big old Star!" 



But the difference between the old 

 "Star" and this curiously ingenious and 

 yet most impractical invention is this: 

 The old "Star" was a simple, operative 

 invention; the air-propelled unicycle is 

 much too complicated to operate success- 

 fully. 



The Popular Science Monthly has 

 not pictured every one of the businesslike 

 gears and elaborate controls which are 

 supposed to adapt this machine for high- 

 speed travel and racing. It's unnecessary 

 to do so. But it has emphasized the two 

 fanciful and fundamental features, namely, 

 the unicycle design intended to result in a 

 vehicle running normally on one wheel 

 only and, secondly, the use of an air-screw 

 for propulsion. The fascination of com- 

 bining these features may have arisen from 

 the recognized difficulty in applying engine 

 power in a unicycle by ordinary mechanical 

 means, so that the use of an air-screw 

 came to appear as the happy solution of a 

 problem. 



Compare this construction with a motor- 

 cycle and especially with a pace-making 

 machine having the driver's seat at the 

 extreme rear. With the motorcycle, the 

 practical speed is limited only by the 

 driver's ability to endure the jolts or his 

 willingness to take chances. The wastage 



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