Flight, January 31, 1914.
SOME EXPERIMENTS WITH DIFFERENT SYSTEMS OF LATERAL CONTROL.
Mr. W. E. SOMERVILLE, of Coal City, Illinois, U.S.A., sends us the following interesting account of some experiments with different systems of lateral control, which he has carried out during the years 1910, 1911, 1912 and 1913, in order to determine the best form of ailerons:-
"Machines Nos. 1, 2 and 3, as shown in the accompanying photographs, all had shutters, which were not interconnected, and which were operated by opening the shutters on the higher wing, thereby partly reducing the area and consequently the lift, whilst the added resistance caused a drag, which retarded the speed of the higher wing tip.
"System No. 1 was found to be inefficient when the machine was near the ground, and so was discarded in favour of No. 2. This was quite good, and the machine would right itself almost immediately, while this form of ailerons also proved to be quite good as a rudder, in fact while the experiments were being carried out the rudder was very seldom used. However, as the shutters were kept closed by means of a heavy spring the action of opening them against the pull of the spring entailed some rather hard work, so this system was discarded.
"System No. 3 was fairly good, but not so effective as No. 2. It was used, however, on the 1912 machines by the aviators E. Korn and E. S. Daugherty. On my 1913 biplane a new design (No. 4) was tried. This system is practically the same as the Farman, but operates exactly the opposite way.
In order to correct a bank the aileron on the higher side is raised, thus causing a downward pressure as well as a drag on the higher wing. This, of course, accelerates the speed of the lower wing, and consequently increases the lift so that the machine rights itself without the use of the rudder. Then another system was tried in which the ailerons were interconnected, as in the modern Farman and Curtiss machines, but with the exception that when in their normal position the ailerons presented a negative angle of incidence to the line of flight. The ailerons were so adjusted that when the controls were moved to their full limit the aileron on the lower wing was in line with the trailing edge, whilst that on the higher wing presented the necessary resistance and downward pressure to right the machine. I consider this system the best because it is easy to operate, and produces practically no resistance on the lower side. It also appears to add considerably to the general stability of the machine. My object in testing so many systems was to produce a design which would be effective, efficient and safe, without causing any drag on the lower wing, and one which would at the same time work independently of the rudder. Nos. 2 and 4 are particularly suitable, since either ailerons or rudder may be used for both purposes.
"Although my machine has been flown repeatedly by M. Daugherty without ailerons and with only the rudder to maintain lateral stability, it is my opinion that ailerons are necessary if only to make one feel secure. The upturned wing tips assist greatly in giving one this confidence, as it prevents that sideslip which has proved fatal to many an aviator. Not only that, but they practically maintain lateral stability. This may seem a very strong claim, but it is a fact which has been proved on numerous occasions.
"I engaged a supposed aviator to fly my machine (later he informed me that he had never been in an aeroplane before). However, the 80 h.p. H. Scott was started, and away he went, climbing at a terrible angle. It was evident from the start that he knew nothing whatever about flying. When he had reached an altitude of about 250 ft. he did a banked turn, climbing all the while, and in this critical position he stopped the engine! The machine of course lost all headway and began to drop vertically. Gradually the lower wing and the tail rose to a level, and the machine commenced to glide forward and landed heavily, smashing two wheels and the skids, but suffering no further damage. The 'pilot' escaped without a scratch, but was half dead from fright!
"The upturned wing tips have saved my life on more than one occasion, for in my early experiments my machine was underpowered and very unreliable. I unfortunately, one day in June, 1910, gave a private exhibition to my family and a few friends in order to demonstrate my ability as an aviator. Well, the flight terminated with half of the machine in some trees, and the other half, with myself, piled on the ground. The engine being in front I was not much hurt, but the same cannot be said about my feelings, seeing that my family and friends had witnessed the performance. This finished my ambition to become a great aviator, and later, when I have occasionally tried my machines I have always taken good care to do so when my friends were not in sight."