Inflatable Rotors (Flying Car?)

(sanman) wrote in message . com...
I was reading about inflatable wings:

http://www.spacedaily.com/news/plane...-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

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

(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

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

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

"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

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...-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?

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

"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

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