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Soaring vs. Flapping



 
 
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  #11  
Old September 19th 03, 12:42 AM
Dave Hyde
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patrick timony wrote:

I think flexible winged craft could be safer.


Most wings flex to some extent, and the flexibility
serves the structural purpose you mentioned. There's
a big difference between flex for load alleviation
and flex for control, however.

Dave 'flex2rigid' Hyde

  #12  
Old September 19th 03, 01:55 AM
Morgans
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"patrick timony" wrote in message
om...
OK, how long before we can employ this in homebuilt aircraft?

Dan, U. S. Airforce, retired


I wouldn't recommend it, as flutter is a BIG problem with flexible
wings, tails, fins, etc.

The safety issues outweigh any performance gains here for a homebuilt --
especially for a high-performance one.


I think flexible winged craft could be safer. A really flexible and
evenly-tapered wing, gradated from high to low density toward the
core, would bend to allow its force to be spread over a large enough
area to keep the force constant. A wing suit with both arm and leg
wings would enable a person to "run" through the air, except that the
motion would be closer to doggy paddling. Flying would be easier than
scrambling up a flight of stairs on all fours. See the
"SphericonWing" design at my webpage:
http://patricktimony.tvheaven.com/photo3.html

Patrick Timony


Kid, get your HEAD OUT OF THE CLOWDS. Man does not have enough strength to
support or directly control flight loads. If he did, someone else would
have done it by now.

This is a sophisticated group, with much knowledge and experience on making
flying machines, and man's muscles are used via mechanical advantage only,
to direct flight, not support or sustain it.

Make a deal with yourself. Build an airplane or two, then try building
whatever you want to dream up. Then, you will clearly see what the problems
and solutions are.
--
Jim in NC


  #13  
Old September 19th 03, 01:42 PM
nafod40
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Morgans wrote:
"patrick timony"...
I think flexible winged craft could be safer. A really flexible and
evenly-tapered wing, gradated from high to low density toward the
core, would bend to allow its force to be spread over a large enough
area to keep the force constant. A wing suit with both arm and leg
wings would enable a person to "run" through the air, except that the
motion would be closer to doggy paddling.


Kid, get your HEAD OUT OF THE CLOWDS. Man does not have enough strength to
support or directly control flight loads. If he did, someone else would
have done it by now.

This is a sophisticated group, with much knowledge and experience on making
flying machines, and man's muscles are used via mechanical advantage only,
to direct flight, not support or sustain it.


Yea, and man doesn't have enough muscle to lift a thousand pounds of
dirt in one load, which is why he invented the backhoe.

You could make a man-powered suit with power assist, ala power steering,
power brakes, or any other number of analogies. It just takes smaller
power sources and actuators, and we're moving in that direction. Keep
the dream alive.

Here's a sort of rigid/flexible concept that works now.
http://www.freewing.com/

Mike "never say never" Y.

  #14  
Old September 19th 03, 08:49 PM
Morgans
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"nafod40" wrote
Yea, and man doesn't have enough muscle to lift a thousand pounds of
dirt in one load, which is why he invented the backhoe.

You could make a man-powered suit with power assist, ala power steering,
power brakes, or any other number of analogies. It just takes smaller
power sources and actuators, and we're moving in that direction. Keep
the dream alive.

Here's a sort of rigid/flexible concept that works now.
http://www.freewing.com/

Mike "never say never" Y.


Let's see, if we have a power steering type assist, and then we need power
to run the assist, then that means we need a power source, like an engine.
Do we still have man powered flight?

NOPE

By the way, anyone seen one of those man powered, power assisted flying
units at your airport? Come on now, there must be at least one out there
somewhere.
--
Jim in NC




  #15  
Old September 20th 03, 05:17 AM
Corrie
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One issue with your wing design is that the sphericon is a geometric
solid. (http://mathworld.wolfram.com/Sphericon.html) It rolls in a
straight line by wobbling from side to side along its continuous face.
An interesting novelty, with perhaps some utility in mechanical
devices - wobbling bearings, maybe? But an efficient propulsor? Just
because something is a neat shape doesn't make it deeply meaningful or
wonderfully useful.

There was a similar situation in the late 30's early 40's with the
"Davis wing". Davis designed an airfoil based on some obscure and
difficult geometric mathematics - a curve described by a point on a
circle as it rolls along a line that's... eh, I forget. It was
complicated. But convincing, if confusing. Davis' dazzling/baffling
mathematical presentations convinced Consolidated to use the airfoil
for the B-24 Liberator.

It turned out that the airfoil was a very close approximation to a
laminar-flow design. That combined with the high aspect ratio of the
B-24's wing gave the machine its excellent performance. It also
turned out in the final analysis that the mathematics were bunk.
There was no connection between Davis' derivations and aeronautical
reality. (See the excellent book, "What Engineers Know and How They
Know It" for the full story.) Davis lucked out, is all.

The wing drawings and doodles on your website look as though you've
been inspired by the graceful, undulating movements of rays, squid,
and other sea creatures. The big difference between them and your
concept is that the ocean denizens have neutral bouyancy. They need
expend no energy overcoming gravity. The design would be very
interesting in a microgravity environment.


(patrick timony) wrote in message . com...
OK, how long before we can employ this in homebuilt aircraft?

Dan, U. S. Airforce, retired


I wouldn't recommend it, as flutter is a BIG problem with flexible
wings, tails, fins, etc.

The safety issues outweigh any performance gains here for a homebuilt --
especially for a high-performance one.


I think flexible winged craft could be safer. A really flexible and
evenly-tapered wing, gradated from high to low density toward the
core, would bend to allow its force to be spread over a large enough
area to keep the force constant. A wing suit with both arm and leg
wings would enable a person to "run" through the air, except that the
motion would be closer to doggy paddling. Flying would be easier than
scrambling up a flight of stairs on all fours. See the
"SphericonWing" design at my webpage:
http://patricktimony.tvheaven.com/photo3.html

Patrick Timony

  #16  
Old September 20th 03, 05:47 AM
Eric Miller
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P.S. It would also help if all the sketches didn't look like the "flier"
wasn't out of control and just about to crash... hard.
Unless inducing an epilectic fit was a pre-requisite for flight =D

Eric


  #17  
Old September 20th 03, 03:07 PM
Tim Ward
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"Eric Miller" wrote in message
. net...

I don't want to stifle creativity... but this was my first reaction too.
Especially when I saw the seemingly random inclusion of the golden mean as
one of the concepts.

snip
Eric


I'd like to point out something often forgotten...
Before you can "think outside the box", you have to have some idea of where
the box is.

Tim Ward


  #18  
Old September 20th 03, 08:37 PM
Orval Fairbairn
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In article ,
"Tim Ward" wrote:

"Eric Miller" wrote in message
. net...

I don't want to stifle creativity... but this was my first reaction too.
Especially when I saw the seemingly random inclusion of the golden mean as
one of the concepts.

snip
Eric


I'd like to point out something often forgotten...
Before you can "think outside the box", you have to have some idea of where
the box is.

Tim Ward



Not only that, but you have to know what is INSIDE the box, too!
  #19  
Old September 21st 03, 05:32 AM
Corrie
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Del Rawlins wrote in message ...
On 17 Sep 2003 07:09 PM, Bill Higdon posted the following:
Keith, You forgot the "controlled crash" that a Albatross makes when
it lands.


Well, they *are* seagoing birds.


And they're clearly designed to take the punishment. Grumman builds
'em strong. ;-p
  #20  
Old September 21st 03, 07:35 AM
Robert Bonomi
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In article ,
Corrie wrote:


"Eric Miller" wrote in message
v.net...

Water and air are both fluids, but with densities of different magnitudes.
I'd think that you'd want to develop your idea to work in water before you
tried the thinner and vastly more difficult fluid of air.

If air were more dense or gravity was less...
BTW I remember something similar in a Heinlein book, maybe "The Moon Is A
Harsh Mistress".


I knew I'd come across it somewhere!


Heinlein's most detailed discussion of man-powered flight is in "Podkayne of
Mars". The Icarus variety -- i.e. strap on wings that you flap.

There's an interesting aside in "Killer Station" by Martin Caiden, regarding
the manouvering difficulties of flapping flight in a virtually zero-g
environment. Also, in Clarke's "Rendevous with Rama" regarding a man-powered
propeller-driven craft, being operated inside Rama.
 




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