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SCIENTIFIC AMERICAN 129 [[top margin]] Dec. 1911 [/top margin]] which it once enjoyed without the aid of liberal government subsidies in one form or another. My subsequent reading and reflection have corroborated that conviction. Preferential duties may have been all well enough a century ago, when other governments probably discriminated in favor of their own merchant shipping, but owing to the changes wrought by time and by various treaties with foreign countries, their revival at the present day, so far from being productive of beneficial results, would in my judgement work positive injury to our shipping interests, as they would invite retaliation, which would produce vexation and irritation in our commercial relations with other countries. With regard to the much-discussed subject of free ships, the writer must reserve his judgment until he can ascertain the facts in the case. American shipyards and shipbuilders should be amply protected as well as shipowners; but it is contended that our shipyards are already taxed to their full capacity in the construction of domestic shipping, and hence, it is argued, would suffer no detriment from admission to American registry of foreign-built ships. If this condition exists, so urgent is the necessity for the immediate construction of the vessels, it would seem that we should have free ships at least until American yards can enlarge their capacity for building all the ships we need. Canto, Miss. JAMES G. McBRIDE. Difficulties in Steering Aeroplanes To the Editor of the SCIENTIFIC AMERICAN: x In glancing over the daily papers, it is not an uncommon thing once in a while to learn of accidents, some them fatal, which attend aviators here and abroad, a large percentage of which the reporters attribute to a "loss of control" in the air - an expression which leaves in doubt the real cause of the aviator's loss of control. Being a practical aviator, I venture through the columns of your esteemed paper to bring up the question before the reading public for mutual discussion and exchange of opinions. Meanwhile, permit me to throw some light, from a scientific standpoint, on "the difference between a right-hand, and a left-hand, turn in an aeroplane, and the danger involved therein." x In running the aeroplane on the ground, it can be easily noticed that the machine tends to turn to the opposite direction of the revolving propeller; and if no steering is applied to counteract that tendency, the aeroplane turns round and round in small circles until the power is shut off. This is due to the gyroscopic force created by the reaction of the revolving propeller. The aeroplane then possesses the same tendency while traveling through the air, which tendency if not counteracted by means of steering by the rudder, gives the aeroplane a declinatory motion causing it to dive to the ground. Therefore, to keep the aeroplane straight in flight, the rudder is, most of the time, set slightly to the same direction as the revolving propeller, that is, in the opposite direction of the gyroscopic force. From the foregoing, it is understood then that there must be some difference in turning right or left with an aeroplane. For the sake of illustration, let us consider a monoplane in which the propeller, from the view point of the pilot, usually revolves from left to right. Owing to the effect of the gyroscopic force, the monoplane always tends to turn left, and therefore, the left turn is effected with a little steering by the rudder. That is to say, that the left turn is caused by the effect of the rudder plus that of the gyroscopic force. At the same time the machine points a little downward, and as it points downward its speed of flight increases with the decreased resistance. With the increased velocity a sharp turn then can be made. But in making a right turn which is in opposition to the gyroscopic force, more steering by the rudder is needed than in a left turn. That is to say that the right turn is effected by the action of the rudder minus that of the gyroscopic force. In this instance, the machine points a little upward. And as it points upward, its speed of flight decreases with increased resistance. With the decreased velocity, the right turn is made almost twice as wide as the left turn; and in some cases the velocity decreases to such an extent that the supporting power may be lost and the machine sinks to the ground. In a rotary-motored monoplane, the reaction of the rotary motor adds more gyroscopic force to that of the propeller, giving a greater effect on either turn. Therefore, when the machine points downward in turning left, it should be pulled up a little by operating the elevator to prevent the inclination which accompanies the gyroscopic force and causes the aeroplane to plunge to the ground. However, this is usually done instinctively by aviators in order to keep the machine on an even keel. But when the machine points upward in turning right, care should be taken not to lower the head too much by operating the elevator in order to bring the machine to an even keel, because the gyroscopic force might overcome the action of the rudder, in which case the pilot is apt to lose control and the machine plunges down to the ground. In conclusion, let me add that the above explanation does not apply to an aeroplane with two propellers revolving in opposite directions, unless it is equipped with a rotary motor which might show only half the effect of what it would were it equipped with one propeller. S.S. Jerwan, Aviator. (Licensed by the Aero Club of America.) New York City. The Eight-hour Law and the Navy To the Editor of the SCIENTIFIC AMERICAN : I have been a subscriber to your magazine for several years, and consider the reading of it as one of the main necessaries of life, in the broad sense of the latter. And because of the respect and admiration which I entertain toward your publication, it pains me the more to find in its pages statements partial and prejudicial to a section of society large in numbers but having few defenders. In speaking of the eight-hour law in your article on "Navy Yard Politics" and its effect on the shipbuilding industry, you do not for a moment admit that advisability of reducing the shipbuilder's margin of profit, finding the alternative in an increased cost of ships for our navy or in reducing the laborer's wage. And here is how you proceed in a not at all scientific wise: "In all of the shops where tools are worked, the decrease in production due to the shorter hours will be directly in the proportion to the time, or a decrease of twenty-five per cent, while the wages of the men will unquestionably be increased, so that their yearly income will be unchanged - a further burden on the cost of production of twenty-five per cent." This is as much as to say that the enhanced cost of production due to the establishment of the eight-hour schedule is equal to fifty per cent. Now, for a little plain arithmetic: if it takes 200 men in 300 working days of 10 hours each to build a ship for the navy, or 600,000 man hours at a labor cost of $120,000 (20 cents per hour), it will require 250 men to deliver the same number of man-hours of productivity on an eight-hour schedule: and if the laborer's pay is increased to 25 cents per hour, the total labor cost will be $150,000. In other words, [[ print obstructed ]] ship is 600,000 man-hours, which should be absolute value, the comparative value changing as the rate of labor's compensation changes. All this shows that there are not "further" burdens on the cost of production, but just one of twenty-five per cent, as you at one point suggest. In regard to higher wages and correspondingly higher efficiency of production, a point which you fail to see, permit me to quote from the Tariff Board's report on the wool schedule of the "best ever" Payne-Aldrich tariff. Speaking of "Wages and efficiency," it says: "The productive efficiency per one-man-hour for machine operatives and machines in the scouring, carding, combing, drawing, and spinning departments with 168 separate labor costs per pound, show wide differences in efficiency and cost, but indicate in general that the lowest labor costs per pound were in mills paying the highest wages." There is another feature of the shipbuilding industry, and that is of foreign competition, which serves many people as an excuse for demanding subsidies from the government (much as they hate paternalism in government). In regard to this foreign competition, permit me to quote from Henry Clay's speech in Congress on March 30th, 1824. In arguing for a temporary protective tariff he said this (according to the New York Times): "In considering the fitness of a nation for the establishment of manufactures, we must no longer limit our views to the state of its population and the price of wages. All circumstances must be regarded, of which that is, perhaps, the least important. Capital, ingenuity in the construction and adroitness in the use of machinery, and e possession of the raw materials, are those which deserve the greatest consideration. All these circumstances (except capital, of which there is no deficiency) exist in our country in an eminent degree, and more than counterbalance the disadvantage, if it really existed, of the lower wages of the labor in Great Britain. The pamphlet to which we have had occasion so often to refer, in enumerating the causes which have brought England their manufactures to such a state of perfection, and which now enable them, in the opinion of the writer, to defy all competition, does not specify, as one of them, low wages." From the mouth of a protectionist, it sounds like a plea to encourage at home backwardness and inefficiency in production, admitting the unimportance of the wage circumstance. I hope you will pardon my disagreeing with you, and you may find consolation in Shakespeare's "no might nor greatness in mortality can censure escape." Brooklyn, N.Y. S. STRIEZHEFF.
