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#11
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retractable floats?
Ernest Christley wrote:
Morgans wrote: "Ernest Christley" wrote Well, it was until you showed how it is clearly impossible 8*) Actually, the original post wasn't asking about putting floats on a Delta, I was just saying that the mechanism chosen by John Dyke might possibly be a solution for retracting floats. If I were to pick a solution for floating a Delta, I'd change to a rear mounted ducted fan engine and seal the belly. Humm, what about CG issues? Are you going to put the people way up in the nose, or just add a large chunk of concrete where the engine used to be? g As for all the aerodynamic effects or moving around a large portion of the airplane, you weren't expecting a fully engineered solution in an off-hand internet post, were you? Well, from you, I expected nothing less, than an engineered design modification plan, with all of the "t's" dotted, and the "i's" crossed! Or something like that! ;-)) You set the bar much to high. CG issue. It would have to be a nearly complete re-design, moving the pilot really far forward with his feet crammed up into the nose, much like the Air-Cam. It's worth noting that the wheels on the Delta cause a nose-down vector when in the down position. This goes away when they're retracted, but is compensated for by the CG shift aft just slightly. The net effect is no pitch change. Many of the aerodynamic issues you brought up earlier could be dealt with a combination of choosing different lengths for the front and rear legs, and having the floats retract behind a stationary faring. I'll work out some exact numbers some day AFTER I get the current one flying with boring wheels 8*) Hi Earnest. Is this thread dead yet? I had this brilliant idea about a decade ago for a very low drag amphib by building the cleanest fuselage possible aerodynamically (sealed to water so it would float, of course), then use a retractable hydrofoil to lift the hull out of the water & onto plane. I was really impressed with myself until I saw an article about a NASA experiment 2 or 3 decades ago where they tried it, both with 'airfoil' shaped foils & with wedge shaped foils, using a Lake amphib as the test bed. IIRC, it worked fine & allowed the plane to operate in significantly higher waves (something like 2 feet) than it was designed for. Charlie |
#12
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retractable floats?
On Sat, 16 Sep 2006 14:19:02 -0500, "dlevy" wrote:
Any designs out there? ..... just curious. I've never seen anything like that. http://www.people.nnov.ru/maslov/index.html#accord201 Wayne |
#13
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retractable floats?
AFAIK, the step on the floats causes large amounts of drag due to the
turbulence of the air created behind it. What about a retractable fairing to streamline the step while in air? It seems like this would be fairly simple to accomplish, but I'm not sure how much drag it would actually eliminate. Richard Riley wrote in : On Sat, 16 Sep 2006 18:51:57 -0500, "dlevy" wrote: Wouldn't it be cool to retract conventional floats? Cool? I guess. It would be complex - probably significantly more complex than retracable landing gear. I'm not sure you'd actually save any drag. Floats are big, when compared to the fuselage. So you'd have to increase the size of the fuselage to contain them when they retract. You'd reduce your wetted area some. Weight would go up. My guess is you'd end up with an airplane that wasn't any faster. OTOH, you could think of a flying boat as one with the floats permanantly retracted and faired in. |
#14
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retractable floats?
Jackal24 wrote: AFAIK, the step on the floats causes large amounts of drag due to the turbulence of the air created behind it. What about a retractable fairing to streamline the step while in air? It seems like this would be fairly simple to accomplish, but I'm not sure how much drag it would actually eliminate. How about if you eliminate the step by using air injected under the float instead? Lapstrake floats maybe? -- FF |
#15
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retractable floats?
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#16
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retractable floats?
On Feb 1, 2:06 am, Jackal24 wrote:
wrote groups.com: Jackal24 wrote: AFAIK, the step on the floats causes large amounts of drag due to the turbulence of the air created behind it. What about a retractable fairing to streamline the step while in air? It seems like this would be fairly simple to accomplish, but I'm not sure how much drag it would actually eliminate. How about if you eliminate the step by using air injected under the float instead? Lapstrake floats maybe? While it might work, it sounds a lot more complicated. A retractable fairing could be purely mechanically operated with only a few moving parts. Lapstrake construction has no moving parts. It may have excessive drag in the air, as a lapstrake float would have a larger wetted surface than would a smooth one. But air can do funny things. -- FF |
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