More Power Through More Surface Area; Pneumatic Functional Models; Catapult; Sliding Door - fischertechnik Profi Pneumatic II Manual De Instrucciones

2.7 More power through more surface area

Exercise:
Try to find out with what weight the lifting platform can be loaded
so that the weight can just barely be lifted.
How can you lift even heavier weights?
Lifting Platform Experiment 7
(see Construction Manual p. 10):
You will utilize a second pneumatic cylinder for lifting heavier
weights. As illustrated in the Construction Manual, install the second
cylinder in the lifting platform, and connect it in accordance with the
Tubing Plan illustrated there.
Exercise:
Why is the weight which you can lift about twice as much as with
one cylinder?
Answer:
F
Based on our formula p =
A
the formula F = p • A
through conversion. The force which one is able to exert is therefore
dependent on pressure and on the area which the pressure affects.
The pressure which the compressor generates is always constant. If
we utilize two cylinders instead of one cylinder, the area which the
pressure affects is twice as large. As a result, the force as well as the
weight which one can lift are doubled.
Too complicated? It doesn't matter. Jut remember: If the power of one
cylinder is not enough, add a second cylinder.
And with that we are at the end of our introductory chapter. As you can
see, the science of pneumatics is actually quite challenging. But it is also
incredibly exciting. That's why we will immediately turn to the construction
kit's other models. Lots of fun!
3. Pneumatic play models
In this chapter we want to deal with a few other functions which are often
pneumatically-conducted in the "right technique". We will also build
ourselves a model of each specific function in order to better understand
how everything functions.

3.1 Catapult

In the first chapter it was mentioned that the Greek Ctesibios constructed
the first compressed air cannons as early as 260 B.C. We have long since
been able to do what he could. Do you have any idea how this was able
to function? Then try to build a model without any instructions. Otherwise,
you attain
you'll find our
proposal in the
Construction
Manual on
p. 13.
In our model the compressed air is generated by means
of the compressor. Before you operate the catapult for
the first time, you have to wait ca. 15 seconds until the
air chamber is full and the full pressure is available to
you. Then you can simply hurl a black module (15) throughout the area.
Exercise:
Hopefully the catapult functions well. But now try to propel the
module block even further. Think about what the various possibilities
are. What functions best?
Possibilities:
Instead of the compressor, utilize the hand pump, and pump the
x
air chamber full with that. Then open the hand valve and observe
how far the module block flies.
Hand pump
12 cm
Connect the hand pump, without air chamber, directly
x
to the middle Connection P of the hand valve.
15 cm
P
Open the valve so that the catapult's cylinder can extended, and
thereafter press the hand pump's piston rod downward as quickly
as you can.
With what did you achieve the best result?

3.2 Sliding door

Certainly you have also walked through a sliding door quite often. These
doors are either electrically or pneumatically operated. For instance, the
doors in public transportation buses are frequently opened and closed
with compressed air. You can even hear the typical "hissing" when the
compressed air escapes. No you will also build a sliding door, which
will be initially opened and closed by means of a valve. You will find the
instructions for this on page 17 of the Construction Manual.
15 cm
12 cm
6 cm
Cylinder for catapult
12 cm
6 cm
GB+USA
13