On Nov 13, 12:49?pm, Ken Roberts <for...@[EMAIL PROTECTED]
> wrote:
> On Nov 12, 5:55 pm, Barry Palmer <sev...@[EMAIL PROTECTED]
> wrote:
>
>
>
>
>
> > On Nov 12, 12:45?pm, Chicago Paddling-Fi****ng <j...@[EMAIL PROTECTED]
> wrote:
>
> > > Buy_Sell <werksp...@[EMAIL PROTECTED]
> wrote:
>
> > > : That's funny, John. You bring a whole new meaning to the word
> > > : 'hovering'.
>
> > > Well, depending on how much it'll hold (I thought someone else was
talking
> > > about how much inflatables weigh), it might make the difference
between
> > > hovering and scooting...
>
> > > : On Nov 11, 6:45 pm, Chicago Paddling-Fi****ng <j...@[EMAIL PROTECTED]
>
wrote:
> > > : > ben_2_go <ben_2...@[EMAIL PROTECTED]
> wrote:
> > > : > Personally, I've always wanted to fill my inflatable kayak with
helium to
> > > : > see how much it weighed. I believe one cubic foot of helium will
lift .62
> > > : > pounds, course, how much helium does it take to turn a
inflatable hovercraft
> > > : > into a blimp...
>
> > > --
> > > John Nelson
> > >
---------------------------------------------------------------------------
--
> > > Chicago Area Paddling/Fi****ng Page
> > > http://www.chicagopaddling.orghttp://www.chicagofi****ng.org
> > > (A Non-Commercial Web Site: No Sponsors, No Paid Ads and Nothing to
Sell)
>
> > I am afraid the helium lift is grossly overstated. Air weighs about .
> > 07lb per cubic foot at so called "standard" temperature and pressure,
> > and helium that would replace the air weighs
> > about .01 lb per cubic foot, giving a total lift of .06lb per cubic
> > foot of lift at standard conditions. To fly a single individual of
> > 175 lb in a "weightless" helium balloon would require 2900 cubic feet
> > of helium and would be about 18 feet in diameter at standard
> > conditions.
>
> > In the real world, where we do not have the luxury of "weightless"
> > air****ps, a one place modestly powered air****p would be about 70 feet
> > long and 18 feet in diameter, part of the volume taken up with air
> > that could be forced into or out of the envelope depending on altitude
> > (pressure, temperature) flown.
>
> > There is an inflatable sev on the Sevtec website that I built in the
> > 1970's, including building the inflatable ****tion. A purpose built
> > inflatable can be built very lightly and this craft is the only one I
> > ever built that made hump accidentally.
>
> > The noted craft does look more than a bit heavy, and exciting things
> > might happen when the Kohler exhaust finds a way to burn through the
> > hull. I am guessing, the propeller is driven via a planetary gear
> > system, causing a high engine location and high center of gravity.
>
> > Barry Palmer, for Sevtec
>
> That's gotta be an awesome way to fly, though, doesn't it? You could
> be totally silent by turning off your engines, and just hang there.
>
> I heard that air****ps are being investigated for modern applications
> again. I say bring it on....- Hide quoted text -
>
> - Show quoted text -
Although this is a bit off subject, but, oh, well, this forum is very
quiet, air****ps are a true absurdity, as one can do the same things
with a fixed wing aircraft with a wing spring decoupled from the
fuselage, and do it vastly cheaper and simpler than with a lighter
than air craft (a misnomer in itself, as most air****ps fly with some
heaviness to allow for such as landing and fuel exhaustion.)
This writer's fixed wing aircraft flew in the speed areas of the
air****ps, and could easily take off within the length of the air****ps
(which require at very least two air****p lengths to be ground handled
due to being the world's largest weathervanes, sensibly vastly more
room) and the aircraft could gain some altitude in that distance.
While the fixed wing craft could not hover, (neither can an air****p
due to flying with heaviness) it certainly could fly into very light
winds that are almost always present.
There was an attempt to get some significant lift out of air****p hulls
(called "hybrid" air****ps) . Analysis and experience always boils
down to a lightly loaded fixed wing aircraft, maybe with a small
amount of helium just to keep the aircraft upright when on the ground.
An unusual hybrid air****p had multiple parallel hulls with an air
cu****on at each corner so that it could be landed easily and the air
cu****ons could be reversed to hold the craft down, much as "ground
effect" devices are used to hold down a race car.
Stupid and expensive, yes, but the air****p era must have been a whole
lot of fun. We still do things like that stupid, expensive, but fun
and showy effort, like the space shuttle that cannot do space
exploration, (but can explore high Mach No flight) and a space station
that cannot do anything beyond human physiology, (maybe explore novel
crystal growth or some high school kid's "worms in space" project, and
be a destination for the space shuttle. (Maybe we could abandon the
shuttle and space station so we could afford to really explore space.)
And, would you believe, I worked on a blimp for a short period.
Barry Palmer, for Sevtec
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