Subject:
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Re: hoovercraft with lift, thrust and steering
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Newsgroups:
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lugnet.technic
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Date:
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Thu, 6 Mar 2003 08:09:50 GMT
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Viewed:
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1976 times
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"Øyvind Steinnes" <senniets@online.no> wrote in message news:HBAoL9.9CH@lugnet.com...
>
> "pixel" <pixsrv@poczta.onet.pl> wrote in message
> news:HB9n89.DzD@lugnet.com...
> > "Paul Krieg" <pdkrieg@epix.net> wrote in message • news:HB9KH9.8H1@lugnet.com...
> >
> > > Well, my rotor blades are a bit big (about 12 x 36 L).
> > oh G! :)
> > what motor will rotate it?
> With those big blades you do not need the high speed to get lift, so you can
> use a geared down motor for this I think? But that sounds more like an
> helicopter then an hoovercraft...
when we see helicopters
they have slim blades with very high rpm
so i think wide blades are not too good
but keep working...
i saw few applications just prototypes
(maybe it was just picture)
of an helicopter with jet engines
ther the blades was wide because the stop diring fly
and then they was acting as wings
but you know it was jet-something machine so... :)
> > it has to create much resistance on the air
> > > They are made this way to save weight as
> > > your hoover craft is
> > but it could cause the hovercraft will rotate instead of propeller :)))
> > (joke)
> Well it is not a joke, my craft is now so light that it actually spinns the
> craft almost in about half the speed of the fan if I dont hold it back with
> something...
> How can I stop the air under the craft go spinning?
> Some fins under the skirt hanging down? Some airtunnels going outwards?
1. do 2 propellers rotating in oposite sides
2. do the propeller which will act as small rotor in helicopter (it's just for this effect)
3. forme some kind of tunnels inside the body which will redirect the air flow in the oposite side
> I do not want the air to go straight downwards like pixel's fan is doing,
> but I would like the fan move the air outwards to the edge of the skirt and
> then down...
so the #3 is good idea
> Is this not the best way? Or have I missed something again in the
> hoovercraft idea?
some air is directed exaxtly downward
and some to seal the skirt is directed as you said
> Actually my simple made fan push the air in a angel outwards and down, and
> move about the same amount of air as the fan made by pixel at the same RPM.
> But I need a higer voltage to get the same RPM on pixel's fan. Mine can be
> driven with just a 9v battery box on an 9v motor and still get lift.
> (I use the tuned 4.5v motor because I would like to drive two motors with
> one 9v battery box.)
my second version of hovercraft works perfectly ok with just 9V
i used 12V to lift my roller :)))
> > > > 2. the problem of exploding rotor still stays
> > > One way of preventing friction pins from coming loose at high rpm's is • to put a
> > > small antenna or pneumatic "T" etc. in the holes so it can't contract.
> > where was my brain when i've been thinking of it?
> Same here! Where do I keep my brain while building with LEGO? In my pocket?
> ;)
> That so brilliant and simple... like an "Columbo egg"...
now i'm working on fixed blades only
i just have to make them lighter
br
pixel
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Message has 1 Reply:
 | | Re: hoovercraft with lift, thrust and steering
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| (...) I think one reason helicopter blades are so thin is because they are changing pitch every cycle with the cyclic control. Thicker blades would require much more torque to change the pitch, making the hub much bigger. Also the length of blade (...) (21 years ago, 6-Mar-03, to lugnet.technic)
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Message is in Reply To:
| | Re: hoovercraft with lift, thrust and steering
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| "pixel" <pixsrv@poczta.onet.pl> wrote in message news:HB9n89.DzD@lugnet.com... (...) news:HB9KH9.8H1@lugnet.com... (...) With those big blades you do not need the high speed to get lift, so you can use a geared down motor for this I think? But that (...) (21 years ago, 5-Mar-03, to lugnet.technic)
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