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Aviation History
1911
1911 - 0833.PDF
SEPTEMBER 23, 1911. 2.30 to 4.30 in the afternoon and 5.30 to 7 o'clock in the evening, so, naturally, on Saturday morning I had expectations of seeing my first flight; but Fate intervened! It appears that the wrong truck was sent to take the machines to Plymouth, so that they did not arrive until Sunday morning. On Monday I arrived outside the ground at 4.30, and was just in time to see a machine of the Farman (1910) type flit over the trees, and stay about five minutes in the air before it glided to the earth. This ended flying in the afternoon session. It appears that the "remous" were very treacherous, and Blondeau sensibly declined to smash his machine for the sake of a small crowd. I then motored over to PlymDton, and arrived back to the flying ground at 5.40, and after waiting outside for about fifteen minutes I went into the ground just in time to see the machine pass over my head, and after three circuits Blondeau came down. Unfortunately his throttle refused to work at the right moment, and the machine was carried on further than he intended, and ran into some small woodwork outside the hangar, unfortunately puncturing both tyres. He complained of the condition of the air being in a most unsuitable state for flying, and so it was decided not to fly any more that evening. Tuesday it appears that a grave misunderstanding arose. It seems that the air was in a very troubled state early in the after noon, and M. Blondeau refrained from going up. However, later on he tried his machine, and found that one of his cylinders was knocking and required some slight adjustment. At this point, the management appeared on the scene and wanted to know why there was no flying and when he would fly. M. Blondeau informed them that flying would take place in a quarter ofan hour, and it would only take a short time to effect the necessary repairs to his machine, but this answer did not satisfy the impatient management, who had the crowd dispersed, and said that there would be no more flying at all. Here Mrs. Hewlett intervened with a slight argument; the details and causes it is not necessary to relate. Mrs. Hewlett handed the management back their cheque, and so the meeting came to an abrupt ending. A little after this time«t a quarter to six, I ariived with a gentle man on the staff of the Western Morning News and got entry to the ground. We were immediately jostled about by some of the policemen, but fortunately a short interview with M. Blondeau was all that was required for us to remain. M. Blondeau then got into his machine and executed some of the finest flights of the meeting. Making a magnificent and short rise off the ground he rose to a height of about 120 ft., and proceeded to do several circles around the course ; then he made various circles round the trees, of which this ground, unfortunately, abounds, and after giving us most excellent demonstrations of aerial flight, he made a very pretty short vol plani, with a glide to the ground to follow. He then decided to take up a lady friend of Mrs. Hewlett as a passenger, and he again gave us some excellent demonstrations of flying, ending with a very fine vol plane with a glide to the earth. Thus the flying closed for the evening, and after wheeling the machine back to the shed M. Blondeau and myself had a very interesting chat in the hangar, where he pointed out that the ground was most unsuit able for flying in. George Street, Plymouth. T. R. JOHNS. British and Foreign Brevets. [1367] I have often wondered what is to account for the difference in the amount of information divulged in the lists that appear from time to time in FLIGHT of the latest certificate holders in France and England respectively. The extent of the knowledge in your English lists seems to be limited to the name of the holder and the number of his brevet, whereas your French lists contain fullest particulars of the date and place of birth of the pilot, the type of machine on which he qualified, and the aerodrome at which the tests were carried out. Surely such a list of our latest English certified aviators would be much more interesting and instructive to your readers and much more worthy of being placed on record than the meagre one that is at present published in your otherwise very helpful journal. Golders Green. " CANARD." What is? Torque. Torque is another word for twist, but whereas twist implies that the actual material is appreciably distorted, torque is merely a technical expression indicating that the shaft has a twisting effort applied to it. In other words it is an expression denoting the turning force on a shaft and corresponds to the term leverage. It is measuered in pound-feet, ounce-inches, or any other convenient combination of units. Gliding Angle. The gliding angle is the slope of the path followed by the centre of gravity of the machine during a glide in still air. The aagle of incidence represents the attitude of the wings to the line of flight as measured by the slope of the chord. t/jJGHT] MODELS. The Limit of Long:-Distance Flyers Propelled by Elastic. [1368J A good deal has been written lately about the design of long-distance models, or " flying-sticks " as they are termed by some, in the columns of FLIGHT. Several correspondents seem to be labouring under erroneous ideas about the efficiency of elastic-driven models, and it is before these people we would bring our suggestions. First of all, it is commonly thought that the larger the number of strands in an elastic motor the more powerful it is, but really the power is not necessarily greater, for another factor has to be taken into consideration, namely, the speed of the propeller. Suppose we have a given elastic motor, the elastic will weigh a certain amount and will store a certain number of foot-pounds of energy. Now the power of this motor being measured in foot-pounds per second, all depends upon how many foot-pounds are given out per second; if it be fitted with a large or coarse-pitched propeller it will give out its energy more or less slowly, and consequently will not develop as much power as if it were fitted with a smaller or finer-pitched high-speed propeller. It all depends upon the fact that power is rate of doing work, the work in this case being the revolving of the propeller, and the power is measured by the rate of revolving the propeller besides its own weight. So we see that cramming on elastic does not mean cramming on power, provided that the elastic can be made to take a long time to run out. Now there are three ways in which it can be made to do this : (i) by having a long fuselage, and getting a long length of elastic with few strands ; (ii) by having a comparatively short fuselage with many strands and gearing up with gear-wheels, making the elastic revolve slowly and the propeller quickly ; (iii) by having the elastic as before, but instead of gearing up with gear-wheels, making the elastic revolve slowly by using large or coarse-pitched slow-speed propellers. Most flying-stick designers employ the first method of obtaining length of time in which the elastic may run out; the second is hardly used at all, chiefly owing to the friction of gear-wheels, when the same object may be attained just as easily by the third method. Thus the successful flying-stick of the future will be both long and large-propellered, fitted with enormous skeins of elastic, though, of course, it will not be overpowered. As to the greatest distance which an elastic-driven model will fly, there certainly is a greatest distance, as may be seen from the following simple calculation :— Suppose the whole of the weight, say 1 lb., were in the elastic, and the weight of the aeroplane part, whose gliding angle we will put at 1 in 8, is minimised so as to be negligible, then the whole of the energy of the elastic, which is somewhere near 1,300 ft.-lbs., will be used in propelling itself through the air, for which a thrust of I lb. is necessary, therefore the elastic, storing 1,300 fl.-lbs. of energy exerting a thrust of \ lb., will propel itself 1,300 x 8 ft., or nearly 2 miles. Also it is quite obvious that any weight of clastic will propel through the same distance ; this is analogous to the fact that the pull of gravity on stones of different sires, being proportional to the weights of the stones, will cause them to fall the same distance in a given time. Of course the weight of the framework, planes, and propellers could never really be negligible, but if it could be reduced to one quarter the weight of the whole, the elastic making up the other three-quarters, the aeroplane ought to fly ii miles. So this distance seems to be about the limit to elastic-driven models unless the gliding angle can be decreased, for if a model could glide at an angle of 1 in 16, it could be made to fly twice as far, so that the aim of those who seek to make their models fly far should be to make them glide better. The case of the Mann monoplane described in FLIGHT bears out exactly what I have said about the distance which a flying-stick can fly. Taking its total weight as 4 ozs., the weight of the elastic as 1 oz., and the gliding angle 1 in 8, we find that it will store HIP ft.-lbs. of energy, it requires \ oz. or ^ lb. thrust, and should go ^ P x 32 or 2,600 ft., which is just about what it has done ; but if the weight of the planes, fuselage and propellers could be reduced to 2 ozs., and 2 ozs. of elastic employed while altering the propellers suitably, it would seem as if it could double the distance it has already covered. In conclusion, we think that much greater distances than have as yet been attained will soon be flown by real model aeroplanes, power driven scale models, not flying sticks or " flying elasticks " as they will in the process of time become. G. T. R. HILL. [It is a pleasure to receive a well thought out and carefully written letter like the above, which we can publish absolutely unedited. Moreover, we congratulate our correspondent on his clear thinking and well-ordered arguments. Elastic materials are capable of storing energy by physical dis-
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