Friday, November 30, 2007

Not Just a Gasbag

Art, Garett108, asks what is the difference between a Blimp and a Zeppelin.

A Blimp is limp. It is a bag of air with a helium balloon inside.  The Blimp has an air scoop to keep it filled with air when it is flying.  When it is parked it needs a blower to keep it inflated. It has no framework to hold its shape.

A Zeppelin is a dirigible, having a rigid frame to hold the covering. Inside the Zeppelin are bags of hydrogen.

The Blimp goes up and down by changing the air pressure inside the bag of air.  If it increases the air pressure, it squeezes the helium into a smaller space and makes it less buoyant, and the Blimp goes down.  If it decreases the air pressure, the helium expands, become more buoyant and the Blimp goes up.

The Zeppelin goes up by dropping ballast, usually water, and becoming lighter than air.  I don't know how it comes down.  It is a good thing I am not driving a Zeppelin because we would have to stay up there.  Maybe they valve off hydrogen, it is cheaper than helium.

You didn't ask, but a hot air balloon is an airbag too, like a Blimp, using a blower to get filled up.  Then a propane burner heats the air and it becomes more buoyant and rises.  As the air cools the balloon comes down and the burner is lit to warm the air and keep the balloon up.  If you were taught not to play with fire, you wouldn't like flying a hot air balloon.  You cant steer a hot air balloon and you go where it wants to go which is whichever way the wind is blowing. I rode in a hot air balloon once but it was securely tethered to a winch which kept us from blowing away and and which brought us safely back to earth at the same spot from which we started.

I think soaring would be the most fun of all.  In soaring you use rising air currents to  keep you aloft.  I have flown a sail plane for about fifteen minutes.  We used a tow plane to tow us into the air, then we cut loose and glided.  It was quiet and smooth and fun. We had no air currents to keep us aloft so we merely glided back to airport and landed.

Birds fly because they have hollow bones and feathers. We could probably fly too if we had hollow bones.

Bees are aerodynamically incapable of flight, but they don't know that, so they keep flying anyway.

I hope I have answered your question.



garnett109 said...

yep thanks chuck!

plittle said...

Bees are *not* aerodynamically incapable of flight. We know this because...well, because we see bees fly. Obviously, they are capable of flight. For many years, scientists were unable to understand the mechanism behind bees' flight, but our failure to understand something does not make it impossible, or miraculous. It simply means we need to work harder to study it. In the case of bees, the advent of extremely high-speed photography and sophisticated computer modelling software has led scientists to an understanding of exactly how bees fly, so there's one more of the world's great mysteries solved.

jckfrstross said...

great info Chuck thank you


valphish said...

Interesting.   I have always wanted to fly.  I do in my dreams.  So, I just need hollow bones, huh?  LOL  xox