LIQUID AIR FOR MOTOR CYCLES.

Otago Witness, Issue 2390, 21 December 1899, Page 46

LIQUID AIR FOR MOTOR CYCLES.

THE POSSIBILITIES AND ADVANTAGE 3 JF THE NEW POWER POINTED OUT. - It -is still difficult to speak with any certainty as to the possibilities of liquid air as a motive power, but the question ef applying it to the propulsion of vehicles is, .nevertheless, engaging serious attention, and no doubt in some respects it would be an ideal power lor driving motor cycles. Liquid air represents, among other tilings, itored energy, and energy which may partially, at least, be reconverted and employed for our service. Liquid air is compressed air in an easily portable form. The advantage which it has over high-pressure, non-liquefied, compressed air is that v is not dangerous to convey or to hold, amd that it does not require many an£ -costly bottle 3to contain it. The liquid may be carried in a milk can or in anything that will hold water, and which is merely . strong enough for the weight of the** -water without • any added pressure, although it is quite imperative to surround the vessel with large quantities ofJfieat-inßtilating material. Even with abundant insulation provided, a given charge of compressed air in liquid form must weigh much less than the same charge under high pressure^ and not liquefied, but contained in xhe necessary steel bottles. The shape of vessel in which the liquid may be conveyed may be*made to conform to the convenience of the vehicle, while high-pressure air insists upon its long cylindrical receivers, which must U? disposed of as best they maj\ In the case of the automobile, says F. Richards, iv the American Machinist, all the liquid air for a trip, or for a run between charging stations, would be carried in the •liquid state, and usually in a single receptacle, "and there would be practically no compressed air reservoir or any receptacle required for any considerable volume of comnress&d air after its re-evaporation. The liquid air would be pumped into the working compressed air system just as it was wanted for use, and almost precisely as the feed water is pumped into a steam boiler. The boiler in this case would necessarily be of thetubular type, .with the important difference from the steam bailer that the requirements For the evaporation of the air would not call for the assembling of the tubes in clore proxdmity to each other and around or over the Hre, for there would be no fire. The heat required would be obtained from the surrounding atmosphere, and the tubes, or the single continuous tube, would be so disposed as to get the best -exposure to the air. In the automobile it would bs most natural and proper to have the oil traverse a coil spread out in front of the machine, so that the-air would strike it with some velocity when the vehicle was in motion. After the air ha^ by this means attained the temperature of ihe external atmosphere, its mechanical status and value would be precisely the same as that .of compreesed air which had been produced directly by compression in the usual way, .except that the liquefied and re-evaporated air would be absolutely dry air, and would tie entirely incapable of causing any trouble by freezing up in the passages '.f the motor. The air, alter attaining normal temperature, might be passed through a re heater, heated jby a little oil lamp or other means, and the consequent increase of volume would add considerably to the efficiency of the air as in other cases. If the air was used in a compound motor, it should certainly be passed through a -re-heater first, and aiso again before entering tlie low pressure cylinder. If the latter ro-heating were not effected, there would be little or no reason for compounding. With this general scheme for using liquid air for an .autocar motor, the vehicle that I have in mind just at present is a tricycle for a single person, and to be used for service Ennilar to that of the present bicycle. Say ihat we have a receptacle that will hold sQlb of liquid air, or something over 6gal, and that 101b of the liquid will be evaporated and lost during our trip, leaving 401b of liquid air available for use. Our working pressure -■vill be. -say, 1001b to the inch. Ab a cubicloot of air at 1001b weigh, say. .61b, we have available 40 divided by .6. equals 66 cubic feet of air at 1001b. Our motor Jias a 1-inch diameter cylinder, 2-inch stroke, normal epeed 300 revolutions per minute; connected to the driving •wheels by differential gearing of wide range. Cutting off at quarter stroke, the mean effective pressure will be 44, the theoretical power developed will bo .1047 horsepower, and the air consumption per minute will be .1363 cubic feet, to which we should add 10 per cent., making the consumption .15 cubic feet per minute. As wo have 66 cubic feel available, fhe charge should laft 66 divided by .15, equals, 440 minutes, or, say, 7 hourc, which, at 8 milee an hour, should be as far as anyone would want to ride at one time, mid it would be necessary to -our in tho liquid air again to be ready for a ride as far again. With liquid air in sight ai> low us one penny per pound, this riding is distinctly cheaper than the maintenance of a horee. ■In the few figures here given nothing is taid •about the gain that might lie accomplished by re-heatiug. Tliis it would be very 7)roper to go into -for larger vehicleß, and also the • compounding of the motof. With air at an initial pressure of 200 pounds, and re-heated *oth before entering the first cylinder and ■also intermediately, it should be easily possible to show results 50 per cent, better than "Jiere indicated. — The Cycle. Mr J. Rennet's vote of 1758 is the largwt in the history of Tuapeka. Influenza cured by taking- a iow doses Tussicura ; write for testimonials ; it will do ■all that is claimed for it.