h a l f b a k e r yThis would work fine, except in terms of success.
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gyro sailor
small catamaran with a autogyro-like sail/rotor | |
This idea is based on some boat
i saw on TV long time ago, and
the bensen autogyro 'kites' or
gliders of the '50-'70 of the
last century.
Basically it is a small but
fast catamaran. On it is a
spaceframe pyramid about 4
meters high made of aluminium
tubing. The top of
this pyramid
has a rotor
attached to it, about 6 meters
in diameter. Turning this rotor
partly into the wind will make
it rotate and generate lift
along the axis of the rotor.
The same mechanism works in
autogyro's or in helicopters
when they lose power.
The rotor acts just like a sail
most of the time. It will be a
bit less efficient because of
the friction losses from the
rotor etc, but will have some
benefits that you can use the
momentum of the rotor to move
forwards when normal sails
would stall or be forced to
tack.
The kicker is in the fact that
the rotor can be tilted from
vertical-starbord to horizontal
to vertical-portside. When you
set it horizontal, you could
turn into the wind and: Fly
Away!
You wont be able to fly very
far as you will be a not very
efficient glider after takeoff.
But with enough flywheel
momentum in the rotor that you
can convert into height, you
will be able to make jumps of
about 10-50 meters.
Offcourse you need to reach the
optimal rotorspeed first,
probably by tacking downwind.
Then you turn into the wind and
with the help a a wavetop as
ski-jump, you fly over the surf
to the beach to make a gentle
touchdown in front of your
admirers :-o
Practical implementation:
The rotorhead consists of a
plate with a big ballbearing
(from a car maybe?). The user
can hook on more rotorblades
depending on the wind
conditions. (you need something
to counteract imbalances, have
not thought of something yet).
beneath the rotorhead are two
hinges:
The first hinge is to set the
angle of the rotor to the wind,
and is moved by a small wing
mounted on a boom pointing aft
(& down to allow for flapping
of the rotorblades). The angle
of attack of this wing is set
by the user via a
bowden(clutch)-cable. This
ensures a constant angle of
attack in shifting winds.
The second hinge (perpendicular
to the first) is used to move
the rotor from vertical to
horizontal and is operated by
the user.
The hinge-rotorhead assembly is
mounted on a mast that can
rotate 360 degrees. The hinge
and brake controls are mounted
on the lower end of this mast.
A breaking system allows the
rotor to be stopped or slowed
down. (this was the problem
with the ancient design I saw
on tv once)
So there you have it: a
rotorboat with a gyrosail?
(?) Autogiro Boats
http://www.users.gl...chts/auto/hist1.htm
Scroll down for Brab's 1933 autogiro Redwing. [phlogiston, Oct 04 2004]
(?) Autogiro sailboat pages
http://uk.geocities...chts/auto/hist1.htm
I think is the same doc as the above link lost. [blimpyway, Jul 27 2006]
[link]
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Catamarans do not have any
ballast weight apart from the
crew. The weight of the
rigging comes into play mostly
when heeled over. With a cat
you don't want to put it that
far anyway, because the
stability quicly decreases
once you lift one hull out of
the water.
It is pretty straightforward
to increase a cat's stability
by increasing it's beam. A
gyro driven cat falls out of
every class regulation anyway,
as these mostly restrict cat's
beam. |
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//and generate lift along the axis
of the rotor// |
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How is this supposed to work?
You expect to generate enough lift
to propel the boat to
windward? Not likely. When a
helicopter loses power, it gets
enough lift by auto-gyrating to
slow it's fall, but not to enough to
fly. I think you'll need some
horizontal gravity to get this thing
going. |
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[oxen] The horizontal gravity
is not needed. The thing that
makes the rotor turn is air
passing over the rotor. On a
auto-gyro this is called
airspeed, on a sailboat it is
called wind. (after all it is
not gravity rotating the
rotor;) The rotor's axis is
held at 80-85 degrees to the
wind by a wind vane. |
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You can sail to windward
(tacking) just like other
sailboat. Just zig zag until
you are there. |
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[13lack]: sorry no picture
(yet) what is it you can't see
for yourself? |
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This was actually nicely baked back in 1933 by the extraordinary Lord Brabazon of Tara (later Britain's Air Minister). He owned a Bembridge Redwing (Isle of Wight) and since one of the class rules stipulates a maximum sail area, but no limits on how the area is arranged, he constructed probably the first successful autogyro rig. See link. I think the AYRS guys are still exploring how this could be applied using modern materials and airfoil technologies. |
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Kevin Costner - Water World. A Darrius rotor, I believe. |
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Wow. Looks like it can work. Two
questions remain. 1. Why the
elaborate pyramid structure then?
Seems like extra windage to slow
you down. 2. How would this
handle extra light air? I mean if
you are becalmed, and then you
get a light puff, if the rotors aren't
turning, and the wind is too light
to get them going, won't you end
up going backward? If so, this is a
huge drawback compared to
regular rigs, which can easily take
advantage of light puffs to get
moving, if you know what you're
doing. |
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