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Old September 23rd 06, 07:08 PM posted to rec.aviation.homebuilt
Charlie[_1_]
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Posts: 10
Default 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