Inflatable Rotors (Flying Car?)

To add a little more to the goodyear plane.
The bags had built in leaks so that they would not overinflate with altitude
The motor ran an airpump to keep it full.
You would have the same inflation problem with your rotor.
Now that would be one piece of engineering.......


"TIM WARD" wrote in message
...

"Ernest Christley" wrote in message
.com...
Big John wrote:
Sanman

On a parallel plane to your rotor blades.

The DOD (Goodyear) some years ago built a inflatable airplane (XAO-3).
It folded up the size of a big suitcase. The wing and control surfaces
were 'blown up' an provided lift and control surface. The unit was
designed for dropping to downed pilots behind enemy lines. They would
blow it up and start a little put put motor and fly to a safe area.
Had a renge of over 300 miles as I recall. Think a air pump was on the
little motor to provide air to inflate.


I saw this on the Wings channel. The airbag had a lot of yarn like
attachments that ran from the top to bottom of the wing so that it
stayed flat instead of blowing up.

With enough pressure and inflated structure can be extremely hard,
compressive wise, but it still doesn't have much buckling strength.
Think of a long thin balloon that they make animals out of at the
carnivals. Get it bent a little, and the rest goes very easily. A
rotor would be a REALLY long, thin balloon.


--
----Because I can----
http://www.ernest.isa-geek.org/
------------------------

Yeah, but it doesn't _stay_ broken. Relieve the load, and it pops right
back out.
The problem is with air pressure. If you use high pressure, atmospheric
pressure doesn't bother you, but a leak is catastrophic. If you use low
pressure, leaks aren't catastrophic, but altitude changes affect the
rigidity of the structure.

Tim Ward

Well, polymers and reinforcement fiber technology are continuing to
improve. You can even buy carbon-fiber reinforced polymers these days,
with superduper tensile strength. But I would imagine that kevlar,
spectra, vectran would have enough strength to do the job for a small
personal transportation vehicle. They would be able to handle the high
pressures.

To ease the load requirements, the rotor could be 4-vaned. Each pair
of opposing vanes could have a commonly inflated structure -- that way
if a single vane suffered a rupture, then it and its opposing partner
could be deflated/depressurized, while the remaining pair of rotor
vanes would take the load while you landed. Or why not even a 6-way
rotor?

Someone who responded to my posting suggested weighting the rotor tips
for flywheel effect. The centrifugal force from the weighted tips
would help to keep the rotors rigid and reduce the possibility of
buckling. Flywheel energy could also help in the event of an unpowered
landing due to engine failure.

sanman wrote:
Well, polymers and reinforcement fiber technology are continuing to
improve. You can even buy carbon-fiber reinforced polymers these days,
with superduper tensile strength. But I would imagine that kevlar,
spectra, vectran would have enough strength to do the job for a small
personal transportation vehicle. They would be able to handle the high
pressures.

To ease the load requirements, the rotor could be 4-vaned. Each pair
of opposing vanes could have a commonly inflated structure -- that way
if a single vane suffered a rupture, then it and its opposing partner
could be deflated/depressurized, while the remaining pair of rotor
vanes would take the load while you landed. Or why not even a 6-way
rotor?

Someone who responded to my posting suggested weighting the rotor tips
for flywheel effect. The centrifugal force from the weighted tips
would help to keep the rotors rigid and reduce the possibility of
buckling. Flywheel energy could also help in the event of an unpowered
landing due to engine failure.

Another idea to strengthen the rotor. Make it like one of those flat,
roll-up water hoses. 3 or 4 narrow tubes running parallel. It will be
stonger since you have to crimp the 'side wall' to get it to 'break'.
If each tube section is pressurized seperately, it give redunancy in the
design.

Here's another possibility...Pressurize with helium, and you might end
up with an ultralight that has a negative empty weight!! OK, maybe that
one is a long shot.

--
----Because I can----
http://www.ernest.isa-geek.org/
------------------------