FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1925
1925 - 0812.PDF
DECEMBER 10; 1925 ROTATING WINGS [2105] I have just read the account of the first trials of the auto-giro, and upon reading the principles of the lifting vanes I was reminded of an experiment with a pair of sparrow's wings which I, and two other airmen, carried out at Howden Airship Base in 1921. Having found the wings while out walking, we decided to experiment with them and took them back to camp. I obtained a brass clamp and fastened the wings together with one reversed, one wing being at a positive angle and the other negative. A piece of wire was then twisted round the clamp, and to the end of this I attached a J-lb. chocolate box and half-filled it with small pebbles. We then went to the hangar known as the " Twin-rigid " shed (which was, I believe, over 200 ft. high), taking with us a scale-model parachute of about 12 ins. in diameter. My two friends then climbed to the cat-walk under the roof, while I stayed below to observe results. The weighted wings and parachute were then dropped simultaneously, the parachute opening at once, and the wings starting to revolve as soon as released. The parachute drifted a little, but the wings descended absolutely The Editor does not hold himself responsible for opinions expressed by correspondents. The names and addresses of the writers,' not necessarily for publication must in all cases accompany letters intended for insertion in these columns. supplied by the Gloucester Company proved incorrect, the horse-power of the engine being exceeded and the machine failing to develop the quoted speed. The propeller in these circumstances naturally required modifications, and following the preliminary test these were carried out. That the propeller was considered satisfactory by the Gloucester Company following these modifications is shown both by the conversation between Mr. Folland and our Maj. Barlow, and also by the fact that the Gloucester Company subsequently ordered further propellers, and stipulated that they were to be exactly the same as our original one after modification. We have further to state that no complaint was made whatsoever to this company following the modifications mentioned, and the tests were in every way satisfactory. The writer was himself at Bay Shore during the preliminary trials, as was also Mr. Longden and Mr. Folland, and there was ample opportunity to comment upon any fault in the propellers. The sole question raised was with reference to the fitting of the boss in that one of the spare propellers did not assemble on the boss provided, being too deep. We have since investi- gated this and found that all propellers delivered came within the quoted limits. The fact that the American machines were fitted with Reed propellers having the new type of boss, of which we had no knowledge other than that experiments were being carried out, is of no importance. The new construction permits of the correct pitch angle being carried right up to a spinner of very small diameter, such as was that fitted on the Curtiss machines, but the large diameter spinner of the Gloucester almost entirely covered the double bend in the centre of the propeller necessitated by the type of boss that we use. Reference to contemporary photographs of the machine will show that with the exception of a Very small portion close to the spinner the whole of the blade was working at the correct pitch angle We note that Mr. Longden states that he is taking the question up with the makers. It is now six weeks since the race, and we have received no complaint. Moreover, Mr. Longden travelled back with the writer on the Berengaria, and there was ample opportunity to raise the question. In view of the fact that Mr. Longden's company had undertaken to supply racing machines for which the power plant would require a form of propeller on which he was dependent on a rival company, it appears that he was fortunate not only in the fact that this company had taken up the manufacture of this propeller so that he was able to obtain one from a British source, but also provided him with a ready-made excuse if the performance of his machine should prove disappointing. vertically, and touched the ground four seconds after the parachute. I again put more pebbles into the box and the experiment was tried again. This time the wings were even slower than before in " grounding," although they appeared to be revolving faster. I repeatedly added pebbles till the box was full, yet at no time did the wings touch ground before the parachute except when one of the strings tore out of the box owing to the weight. This threw the wings off their balance, so that they did a sort of vertical bank and stopped revolving. I think that had Mr. Courtney throttled " right back," he would have made a perfectly vertical descent, unless the larger keel surface aft of the supporting pillar interferes with the balance in such a descent. Do you think that the same wing-formation, driven in the opposite direction it takes in descent, would give as powerful a lift as it did in our experiment, as an air brake ? I must apologise for wasting your precious time, but I write this in the hope that it may interest you. R.A.F., Helwan. ' L.-A.-C. BAILEY THE SCHNEIDER CUP PROPELLERS [2106] At the risk of prolonging a correspondence which must be becoming tiresome to your readers I am obliged to notice the letter from Mr. Longden in your latest issue, and to put forward our reply. In view of the fact that the power was developed at very high revolutions per minute, the propeller design was in any case extremely difficult and, moreover, the particulars THE FAIREY AVIATION CO., LTD., Hayes. C. R FAIREY, Chairman December 7, 1925. [2107] We notice in this week's issue of FLIGHT a letter from the Gloucester Aircraft Co., Ltd., regarding the ques- tion of propellers in the Schneider Cup race. Wre note that Mr. Longden deals with the question of the performance of the propellers, but no mention is made by him regarding the question of the spare propellers fitting the hubs. In view of the recent anxiety of various people to " face facts," no doubt your readers will be interested to know the facts regarding this point, which are as follows :— The spare propellers sent out direct from the makers' works would not fit the Napier hubs when they were required in America. This was not a case of " not fitting the hubs as well as they might have done," but a case of " not fitting the hubs at all," so that they could not be used and were completely useless. This, we hope, makes the position quite clear from our point of view. For and on behalf of THE SUPERMARINE AVIATION WORKS, LTD, (JAMES BIRD), Managing Director Southampton, December 9. 812
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
