Compressed air aviation?

[obsteve]

Hi there,

 

My first post here

 

Can compressed air be used to direct a helium balloon?

 

I want to make a device that is highly maneuverable.

 

I was thinking some sort of directional nozzles does something like this exist, or is it impractical?

 

Many thanks,

 

Steve

[SH3RL0CK]

Certainly compressed air could be used. I think, however the weight of the storage tank with the compressed air would be too great to be practical. You should look into whatever gives you the greatest energy density (in terms of propellant, however you manage this) per unit weight.

 

I suspect (but do not know) this will be a battery and fan combination attached to your balloon. This is how commercial products are sold, anyway.

 

http://rcvehicles.about.com/od/rcairships/p/rcblimps.htm

 

http://rcvehicles.about.com/gi/dynamic/offsite.htm?zi=1/XJ/Ya&sdn=rcvehicles&zu=http%3A%2F%2Fwww.rcblimp.com%2F

[obsteve]

cheers SH3RLOCK,

 

do you know of any instances of compressed air propulsion that I could investigate for comparison?

[SH3RL0CK]

I've seen compressed air powered model cars, boats and even rockets.

 

See for example http://exploration.grc.nasa.gov/education/rocket/rktstomp.html

http://www.make-digital.com/make/vol15/?pg=105

 

But I've not seen any compressed air powered blimps.

[cameron marical]

I know that torpedos use compressed air for propulsion sometimes.

 

There is also compressed air cars, but they use the compressed air to push their pistons rather than propulsion itself.

 

Compressed air Is usually much heavier than gasoline or electric fans, though I definetly think that It Is possible and that you should build it. Why not.

 

http://en.wikipedia.org/wiki/Compressed_air_vehicle

 

http://www.damninteresting.com/?p=359

 

 

http://exploration.grc.nasa.gov/education/rocket/rktstomp.html

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Damn. Sherlock, you beat me.

Edited May 24, 2009 by cameron marical
Consecutive posts merged.

[obsteve]

Have a look at these things, the movie takes a while to load automatically, and has sound

 

http://www.airstage.de/

 

they are graceful, but I'm looking for something that is a lot sharper on the move. And multidirectional- like one of those bikes, instead of gliding serenely, could suddenly pull a weelie, or go into reverse.

 

Does nothing exist that pushes air through directional nozzle or such like, as propulsion?

 

I don't need to go high up- air hose could be attached.

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Hmmm... Big electric fan might be best way. Thanks for your help, goodnight

[CaptainPanic]

I've seen compressed air powered model cars, boats and even rockets.

 

See for example http://exploration.grc.nasa.gov/education/rocket/rktstomp.html

http://www.make-digital.com/make/vol15/?pg=105

 

But I've not seen any compressed air powered blimps.

 

That is a good keyword to get you started on maneuverable helium devices: blimp.

 

Next thing you need to check is the total stored energy per kilogram of compressed air, and compare that to your other options (if you have any).

 

There is no reason why it does not work - in theory you can just make the blimp bigger or the air cylinders smaller... it will reduce flighttime, but will still work.

[morp]

In calm air It certainly is possible. The only problem is the compressed air container. Y should use a plastic cylinder, not a metal one A metallic container will be too heavy for your helium baloon.

[insane_alien]

ah but a metal cylinder can hold more air and at a much higher pressure without leaking/deforming. quite probably more than enough to compensate for the larger balloon required.

 

if plastic really was a viable option then it would be used in spacecraft gas storage tanks, this is not the case and high tensile metals are used.

[CaptainPanic]

Look up bottle rockets to see the power (and flight time) of compressed air. It's probably as good as it gets for this type of technology. Youtube is full of videos.

[ScienceGuyOrg]

I created this video about water rockets:

http://www.scienceguy.org/Videos/TabId/57/VideoId/10/Water-Rockets-I.aspx

 

And wrote this article:

 

http://www.scienceguy.org/Articles/WaterRockets.aspx

[InigoMontoya]

if plastic really was a viable option then it would be used in spacecraft gas storage tanks, this is not the case and high tensile metals are used.

Keep in mind that the requirements for spacecraft are very different than the requirements for terrestrial systems. Spacecraft are known for experienceing all sorts of extreme conditions (hot/cold/etc.). Also note that there have been ENORMOUS amounts of money spent in recent years to try to get composite structures able to survive space-type environments.

[insane_alien]

yes, but the primary goal is strength to weight ratio as you want your spacecraft as light as physically possible.

[InigoMontoya]

yes, but the primary goal is strength to weight ratio as you want your spacecraft as light as physically possible.

Sure, but there are terrestrial applications wherein similar goals are expressed but the space environment requirements are relaxed or removed. One off the top of my head is the air tanks used by firefighters.... Note that they tend to be of composite construction these days.

[CaptainPanic]

That is because the gas tank that the fire fighters carry around only needs to survive in the range of -50 to +100 degrees C. (The firefighters themselves will not survive anything more extreme, so why would their tanks have to survive).

 

The tanks in space need to survive a much wider range of temperatures, and also radiation.

 

But, we are discussing air powered helium balloons. The main point still stands: the stored energy in a gas tank is low.

Also you have to keep in mind that a balloon has a large surface area - You will require quite a lot of "fuel" (air) to compensate for a little wind.

[Externet]

Think out of the box... No tanks , very lightly and gently compressed air :

 

 

Isn't that beautiful ?

 

Now make yours like a bird...

Edited February 2, 2010 by Externet

[CaptainPanic]

Think out of the box... No tanks , very lightly and gently compressed air :

 

 

Isn't that beautiful ?

 

Now make yours like a bird...

It's a fantastic video.

 

You may be right that the swimming or flying motion is more efficient than a jet of compressed air, in terms of forward motion per energy spent... I am not sure though - and I don't know how to calculate it.

 

But why not? A swimming blimp...

 

It's not gently compressed air though. It's gently compressed helium.

[Externet]

... It's not gently compressed air though. It's gently compressed helium.

 

I meant that for the tail action, veeeery gently compressing (and expanding) the atmosphere air cyclically to propel forward.

 

The helium too. Barely compressed.