Re: Inflatable Rotors (Flying Car?)

[Ken Sandyeggo]

(sanman) wrote in message >...
> I was reading about inflatable wings:
>
> http://www.spacedaily.com/news/plane-inflatable-wing-01a.html
> http://www.ilcdover.com/EngineeredInfl/inflatwing.pdf
>
> and I wondered why these couldn't be implemented as rotor
> configuration, for a
> "flying car" type of vehicle -- ie. a car that could instantly convert
> to helicopter flight.
>
> If you look back at those older Hiller helicopters, they had big,
> thick, rigid aluminum rotors:
>
> http://avia.russian.ee/vertigo/hiller_x-2-235-r.html
> http://avia.russian.ee/vertigo/hiller_xh-44-r.html
>
> An inflatable equivalent might be somewhat thicker and yet not be so
> rigid, and would not have the high mass penalty.
>
> So you'd be riding a sort of lightweight automotive vehicle along the
> road, and you could switch to helicopter mode, with inflatable rotors
> popping out on the top of your vehicle. Your engine would then power
> the rotors, and you'd fly away. Once you landed again, the deflated
> rotors would be tucked back into whatever compartment they'd popped
> out from.
>
> Cmon, there are all kinds of wierd-looking lightweight concept cars
> out there, so why not this? What would be the main difficulties with a
> concept like this?

Getting anyone to stop laughing long enough to think about it. Are
you related to Moller?

KJSDCAUSA

[Wright1902Glider]

Seriously though, a helicopter has an extremely small wing area compared to an
equivalant fixed-wing aircraft, and therefore has a tremendous wing loading
The type of loading that would rip the wings off a GA airplane. The reason it
works on helicopters is because of rotor speed and cintrifugal (sp?) force. A
relatively high rotor speed (speed of the rotor blades through the air nearing
the sound barrier) creates a great deal of lift per square foot. However,
because the rotor blades are spinning, cintrifugal force puts the blades under
tremendous tension. This holds the blades in a relatively level plane and
keeps them from flexing upwards excesively and breaking off.

While more blade area can be traded for lower rotor speeds (Hughes built one
with a rotor speed of 16 RPM), you cannot ignore the necessity of cintrifugal
force. A group of students from MIT tried to build a human powered helicopter
a few years ago. They used a 2-blade 60" chord 100+ foot disk setup with
extremely low rotor speeds. While the blades made plenty of lift, the students
could not make them strong enough for the given weight to keep them from either
coning upwards or breaking off. The same would be true of inflatable blades.

Harry

[Mark Hickey]

(sanman) wrote:

>I was reading about inflatable wings:
<snip>
>So you'd be riding a sort of lightweight automotive vehicle along the
>road, and you could switch to helicopter mode, with inflatable rotors
>popping out on the top of your vehicle. Your engine would then power
>the rotors, and you'd fly away. Once you landed again, the deflated
>rotors would be tucked back into whatever compartment they'd popped
>out from.
>
>Cmon, there are all kinds of wierd-looking lightweight concept cars
>out there, so why not this? What would be the main difficulties with a
>concept like this?

I think perhaps Barnyard BOb would be the one to give you the best
feedback on your idea...

Mark Hickey

[AnyBody43]

Mark Hickey > wrote in message >...
> (sanman) wrote:
>
> >I was reading about inflatable wings:
> <snip>
> >So you'd be riding a sort of lightweight automotive vehicle along the
> >road, and you could switch to helicopter mode, with inflatable rotors
> >popping out on the top of your vehicle. Your engine would then power
> >the rotors, and you'd fly away. Once you landed again, the deflated
> >rotors would be tucked back into whatever compartment they'd popped
> >out from.
> >
> >Cmon, there are all kinds of wierd-looking lightweight concept cars
> >out there, so why not this? What would be the main difficulties with a
> >concept like this?

Given that centrifugal force keeps the rotors from folding upwards
anyway it seems a relatively small change in the principles of operation
to have such a mechanism.

If inflatible was no good how about folding/telescopic . . .
or just ribbon/strip with a weight on the end.


## Miniature emergency parachute hat ##

Since the "wing" area of a helicopter is much less than that of
a parachute, and that a helicopter CAN land softly without an engine
why not have a small device that:-

Is an auto gyro that infates out of a bag
Uses gas jets to accelerate the blades to operating speed
lowering the wearer safely to the ground.
Would be smaller and lighter than a conventional parachute?
Maybe a pyrotechic charge could be used as a gas source?

Perhaps a small hand grenade would be enough to get it going:)

[wmbjk]

"sanman" > wrote in message
om...
>
> So you'd be riding a sort of lightweight automotive vehicle along the
> road, and you could switch to helicopter mode, with inflatable rotors
> popping out on the top of your vehicle. Your engine would then power
> the rotors, and you'd fly away. Once you landed again, the deflated
> rotors would be tucked back into whatever compartment they'd popped
> out from.
>
> Cmon, there are all kinds of wierd-looking lightweight concept cars
> out there, so why not this? What would be the main difficulties with a
> concept like this?

Woodpeckers.

Wayne

[Big John]

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.

Never made it into production but the test articles flew.

You might want to research this to see if you can get any ideas and
not have to reinvent the complete wheel <G>

Big John


On 29 Jul 2003 15:51:24 -0700, (sanman) wrote:

>I was reading about inflatable wings:
>
>http://www.spacedaily.com/news/plane-inflatable-wing-01a.html
>http://www.ilcdover.com/EngineeredInfl/inflatwing.pdf
>
>and I wondered why these couldn't be implemented as rotor
>configuration, for a
>"flying car" type of vehicle -- ie. a car that could instantly convert
>to helicopter flight.
>
>If you look back at those older Hiller helicopters, they had big,
>thick, rigid aluminum rotors:
>
>http://avia.russian.ee/vertigo/hiller_x-2-235-r.html
>http://avia.russian.ee/vertigo/hiller_xh-44-r.html
>
>An inflatable equivalent might be somewhat thicker and yet not be so
>rigid, and would not have the high mass penalty.
>
>So you'd be riding a sort of lightweight automotive vehicle along the
>road, and you could switch to helicopter mode, with inflatable rotors
>popping out on the top of your vehicle. Your engine would then power
>the rotors, and you'd fly away. Once you landed again, the deflated
>rotors would be tucked back into whatever compartment they'd popped
>out from.
>
>Cmon, there are all kinds of wierd-looking lightweight concept cars
>out there, so why not this? What would be the main difficulties with a
>concept like this?

[Ernest Christley]

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/
------------------------

[TIM WARD]

"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

[Lee Willcox]

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
>
>

[sanman]

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.

[Ernest Christley]

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/
------------------------

[Dan & Jan Hollenbaugh]

I don't recall inflatable wings, but both telescoping and "ribbon" blades
have been tried. IIRC, the cloth rotor had a wire "spar" with a tip weight,
and a cloth single panel sail-like "blade". Also IIRC, the idea was to use
it in autorotation mode, as a deceleration device in place of a parachute.

Rigid telescoping blades have also been tried experimentally. The variable
diameter allowed for two flight regimes - high speed (with outer portion
retracted) and low speed (outer portion extended, more lift for hover
profiles).

I've got some info on my work computer, I'll try to post it later.

Dan Hollenbaugh
AnyBody43 wrote in message
>...
>Mark Hickey > wrote in message
>...
>> (sanman) wrote:
>>
>> >I was reading about inflatable wings:
>> <snip>
>> >So you'd be riding a sort of lightweight automotive vehicle along the
>> >road, and you could switch to helicopter mode, with inflatable rotors
>> >popping out on the top of your vehicle. Your engine would then power
>> >the rotors, and you'd fly away. Once you landed again, the deflated
>> >rotors would be tucked back into whatever compartment they'd popped
>> >out from.
>> >
>> >Cmon, there are all kinds of wierd-looking lightweight concept cars
>> >out there, so why not this? What would be the main difficulties with a
>> >concept like this?
>
>Given that centrifugal force keeps the rotors from folding upwards
>anyway it seems a relatively small change in the principles of operation
>to have such a mechanism.
>
>If inflatible was no good how about folding/telescopic . . .
>or just ribbon/strip with a weight on the end.
>
>
>## Miniature emergency parachute hat ##
>
>Since the "wing" area of a helicopter is much less than that of
>a parachute, and that a helicopter CAN land softly without an engine
>why not have a small device that:-
>
>Is an auto gyro that infates out of a bag
>Uses gas jets to accelerate the blades to operating speed
> lowering the wearer safely to the ground.
>Would be smaller and lighter than a conventional parachute?
>Maybe a pyrotechic charge could be used as a gas source?
>
>Perhaps a small hand grenade would be enough to get it going:)

[Christopher]

There was a design for an inflatable car years ago it was quit good.
"Ken Sandyeggo" > wrote in message
om...
> (sanman) wrote in message
>...
> > I was reading about inflatable wings:
> >
> > http://www.spacedaily.com/news/plane-inflatable-wing-01a.html
> > http://www.ilcdover.com/EngineeredInfl/inflatwing.pdf
> >
> > and I wondered why these couldn't be implemented as rotor
> > configuration, for a
> > "flying car" type of vehicle -- ie. a car that could instantly convert
> > to helicopter flight.
> >
> > If you look back at those older Hiller helicopters, they had big,
> > thick, rigid aluminum rotors:
> >
> > http://avia.russian.ee/vertigo/hiller_x-2-235-r.html
> > http://avia.russian.ee/vertigo/hiller_xh-44-r.html
> >
> > An inflatable equivalent might be somewhat thicker and yet not be so
> > rigid, and would not have the high mass penalty.
> >
> > So you'd be riding a sort of lightweight automotive vehicle along the
> > road, and you could switch to helicopter mode, with inflatable rotors
> > popping out on the top of your vehicle. Your engine would then power
> > the rotors, and you'd fly away. Once you landed again, the deflated
> > rotors would be tucked back into whatever compartment they'd popped
> > out from.
> >
> > Cmon, there are all kinds of wierd-looking lightweight concept cars
> > out there, so why not this? What would be the main difficulties with a
> > concept like this?
>
> Getting anyone to stop laughing long enough to think about it. Are
> you related to Moller?
>
> KJSDCAUSA

[Ken Sandyeggo]

"Christopher" > wrote in message >...
> There was a design for an inflatable car years ago it was quit good.

If it was only "moderately good," the way we buy junk, it'd be on the
market. "Quite good" would make it an overwhelming success. If it's
not on the market at all, it was "quite" junk. Maybe had a couple
good features, but not enough that people would buy it, or we'd see
them all over the place.

KJSDCAUSA



> "Ken Sandyeggo" > wrote in message
> om...
> > (sanman) wrote in message
> >...
> > > I was reading about inflatable wings:
> > >
> > > http://www.spacedaily.com/news/plane-inflatable-wing-01a.html
> > > http://www.ilcdover.com/EngineeredInfl/inflatwing.pdf
> > >
> > > and I wondered why these couldn't be implemented as rotor
> > > configuration, for a
> > > "flying car" type of vehicle -- ie. a car that could instantly convert
> > > to helicopter flight.
> > >
> > > If you look back at those older Hiller helicopters, they had big,
> > > thick, rigid aluminum rotors:
> > >
> > > http://avia.russian.ee/vertigo/hiller_x-2-235-r.html
> > > http://avia.russian.ee/vertigo/hiller_xh-44-r.html
> > >
> > > An inflatable equivalent might be somewhat thicker and yet not be so
> > > rigid, and would not have the high mass penalty.
> > >
> > > So you'd be riding a sort of lightweight automotive vehicle along the
> > > road, and you could switch to helicopter mode, with inflatable rotors
> > > popping out on the top of your vehicle. Your engine would then power
> > > the rotors, and you'd fly away. Once you landed again, the deflated
> > > rotors would be tucked back into whatever compartment they'd popped
> > > out from.
> > >
> > > Cmon, there are all kinds of wierd-looking lightweight concept cars
> > > out there, so why not this? What would be the main difficulties with a
> > > concept like this?
> >
> > Getting anyone to stop laughing long enough to think about it. Are
> > you related to Moller?
> >
> > KJSDCAUSA