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Old 11-01-2016, 12:03 PM   #9
Tony Godonis
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Join Date: Jun 2016
Location: Exton, PA
Posts: 18
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I agree about the HS-2L in the Canadian Air Museum having two propellers stacked. I attached another picture of that HS-2L from a different perspective. And most of my HS-2L pictures, clearly showing blades, indicate the very distinctive curl of the blade of the normal HS-2L propeller. I also attached five other pictures showing HS-2L propellers with four, straight looking style, blades, versus the curl style, or side views showing a single hub propeller, indicating a single propeller. The HS-2L used the much higher horsepower Liberty V-12 engine at 350 HP, that would seem to require four blades to transfer the horsepower to four blades of traction. This is especially true because engine top RPM at the time was still much slower than later era engines, and this RPM would have required a longer two bladed propeller like the tractor style planes with propeller on front of a longer length. The four bladed configuration was the largest length to still fit the pusher style HS-2L with engine above the fuselage. I would make an assumption that the later model of the HS-1L or early models of the HS-2L, for the Liberty engine, may have started with a single, four bladed, one piece propellers, for prototyping and with the first engines having shorter bolts on the drive hub. However, knowing the Curtiss airplane design philosophy of keeping manufacturing costs, shipping cost, and storage costs as low as possible, they switched to stacking two 2-bladed propellers together and had the engine with longer hub bolts. Manufacturing cost would be less, much less mahogany wood would be used, shipping would take less space, and storage would take less space. The HS-2L was shipped all over the world in pieces and then assembled by the buyer. I have a PDF of the HS-1L assembly instructions. And if a blade was damaged, only one 2-bladed propeller would need to be replaced, versus the whole propeller. I attached five other pictures indicating a single propeller on the HS-2L. I tried a prior post that doesn't look like it went. So I posted this one. If the earlier post went, I'll delete it. Also this posting has pictures with reduced file size. Are there pictures of four bladed propellers and reference to the respective airplane in the forum files? I know there were a couple tractor style airplanes using four bladed propellers, which are easy to see with the propeller in the front. And I think the single, two bladed, propellers on the tractor style planes had a longer length to use the Liberty horsepower a the slower RPM. The HS-1L used a Curtiss 200 HP engine. I cannot find any info or pictures of it, since it didn't last that long and is overwhelmed with HS-2L information. I would suggest that the HS-1L used one, single bladed, propeller for the Curtiss engine. The HS-1L was designed right before WWI and the Navy wanted a flying boat with heavier load capacity, which required longer wings and higher horsepower engines. To save precious time for the war effort with a whole redesign, modifications were made to the HS-1L fuselage and wings, and the almost twice the horsepower engine was put into the same engine position. Because of requiring to use the same engine mounting position to the fuselage, the same length blade was required as the HS-1L. To use the added horsepower, while still at the slower RPM, four blades were required and provide the extra push for the modified HS-1L design. And hence, the rest of the explanation already made. And I'd be willing to bet that the pictures I show of a one hub looking configuration were really shown for a HS-1L style. The following is a cut and paste from Wikipedia. "The HS-1L and -2L were built in vast quantities: 675 by Curtiss themselves, and nearly as many again by various contractors that included L-W-F (250), Standard (80), Gallaudet Aircraft Company (60), Boeing (25) and Loughead (2). A further 25 were assembled by the US Navy from spare parts postwar....Surplus HSs were also widely exported. Amongst Military users was Brazil, who received six aircraft in 1918.[15] Two HS-2Ls were used in an attempt to bomb the rebel held Forte de Copacabana during the 1922 Tenente revolt.[12] Many were used in Canada as the first bush plane. One survives in the Canada Aviation Museum in Ottawa after being rescued from a Quebec lake." Another notes was just found oat the FlyingMachines.ru website. "HS-1 - A traditional pusher flying-boat with 200 hp Curtiss V-X-3 engine driving a three-blade propeller, converted from the unsuccessful H-14 airframe. On 21 October, 1917, the HS-1 prototype was the test bed for the first flight of the US Government's new 360 hp twelve-cylinder Liberty engine and was later converted to HS-1L standard."
Attached Images
File Type: jpg 1 hs2la.jpg (26.8 KB, 4 views)
File Type: jpg 2curtiss-hs-2l-wrecked-c1919-DYX3XGa.jpg (77.5 KB, 3 views)
File Type: jpg 3curtiss_HS2L-3a.jpg (18.3 KB, 2 views)
File Type: jpg 4 1548-2a.jpg (21.8 KB, 2 views)
File Type: jpg 5Curtiss hs-2l1550-1a.jpg (19.6 KB, 2 views)
File Type: jpg 6Curtiss_HS1L_Sidea.jpg (98.9 KB, 2 views)

Last edited by Tony Godonis; 11-01-2016 at 02:05 PM.
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