Page 295 - Robots Androids and Animatrons : 12 Incredible Projects You Can Build

building. If a ballast system is too difficult to implement, neutrally
buoyant robot blimps can be positioned on each floor. Operators
would simply switch to an unused telepresence robot held on a
requested floor when wanting to change floors.
Because of the low weight of blimps, they have physical restric-
tions. For instance, a blimp would not be able to push open a door.
Buildings would need to be modified so that doors and elevators
could be operated electronically using remote control signals
emitted from the blimp.

The blimp kit
The blimp we will construct is made of a tough Mylar material. The
material can be heat sealed using a household iron. There are
many different styles of blimps one may build: a flying-saucer
shaped, delta-wing-glider shaped, or a typical “Goodyear” blimp. I
recommend the simplest one of all, a pillow-shaped blimp.
Making a pillow-shaped blimp is easy. Fold the sheet of Mylar mate-
rial in half (shiny side out). Heat seal the three open sides closed,
leaving a little space that isn’t heat sealed for a fill tube at the bottom,
and you’re finished.
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Helium

Helium is sold in canisters from many party stores to fill balloons.
The canisters resemble those used to hold propane gas. If you
don’t have a local party goods store, look under helium or gas in
the yellow pages to find a supplier.

Helium versus hydrogen

When I first began this project, I thought about using hydrogen
instead of helium, reasoning that because hydrogen weighs about
half of what helium weighs, I could increase my lift by a factor of 2.
Right? Wrong!

While I was correct in my assumption that hydrogen weighs about
half of what helium weighs (see Table 14.1), I was incorrect in cal-
culating the lift. Here’s why. Lift is generated by the amount of air
displaced by the helium (or hydrogen), just like an air bubble in
water. Let’s use this analogy. The air is less dense than the sur-
rounding water, so the air bubble rises to the surface. Likewise,
helium is less dense than the surrounding air; therefore, it rises
also. Think of the rising helium or hydrogen as floating on top of a
much denser gas we call air (see Table 14.1).

Team LRN
Chapter fourteen