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

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

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.

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

wrote in
oups.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.

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