The Appeal. [volume] (Saint Paul, Minn. ;) 1889-19??, 1906-03-31

Every schoolboy knows what a PIN
wheel is and how by blowing he can
spin, yet there are few educated men
outside the ranks of engineers who
have any but the vaguest idea of
what turbine is. Therefore, it may
astonish many people to know that a
turbine IS nothing but series of pin
wheels, one behind the other, fixed
to shaft which turns with them.
For the breath with which the boy
blows the paper pinwheel a jet of
steam is substituted, and fixed to the
inside of the cylinder in which the
pinwheels revolve is a series of sta
Eionary blades projecting into the
space between each wheel and set at
such an angle that they will defect
the stream Of steam to strike the pin
wheels at the angle which will give
the most force. y .
There is the simplest description of
/ turbine ever written.
w. Owen Williams, member of the
Institution Of Engineers and Ship
builders in Scotland, and a famous
naval architect, in the introduction to
ais book on turbine Steamers:
THE Parsons turbine consists Of
cylindrical case with numerous rings
Of inwardly projecting blades. Within
this cylinder, which is of variable in
ternal diameter, is a. shaft or spindle,
and on this spindle are mounted
blades. The diameter of the spindle
is less than the internal diameter of
the cylinder, and thus an annular
space is left between the two. This
space is occupied by the blades, and it
is through these the steam flows. The
steam enters the cylinder by means
Of an annular port at the forward
end; 1t meets a ring of fixed guide
blades which defects it so that it
strikes the adjoining ring of moving
blades at such an angle that it exerts
on them rotary impulse. When the
steam leaves these blades it has nat
urally been detected. The second
ring OF fixed blades is therefore inter-
posed and these direct the steam on
70 the second ring of rotating blades
The same thing occurs with succeed
ing rings of guide and moving blades
until the steam escapes at the ex-
haust passage"
Any boy of average intelligence can
make turbine that will run a good
sized boat, but unless he has had
some experience in the use of tools
and solder he will do we'll to employ
tinsmith to help him. The model
turbine illustrated here was made of
tin, and the picture shows the princi-
pie upon which it works, the upper
half of the cylinder having been re-
moved
This little machine is exactly the
same in principle as that which drives
the giant Cunard steamer Carmania
across the Atlantic. But these differ
ences must be noted: Where the mod
ell has only five rings of eight blades
each the turbine Of steamer has
perhaps hundred rings, each COM
posed Of many hundreds of blades, as
may be seen in the upper picture; and
the stationary blades on the inside of
the cylinder are equally numerous.
This is the only essential difference,
and it is one of proportion, and not of
principle.
To make a model such as this, buy
a square steel shaft one-eighth of an
inch in diameter and five inches long;
turn it round in a lathe, or have it
turned if you possess no lathe, for
three-eighths of an inch at each end,
Get tinsmith to stamp five circles of
thin tin, each one inch in diameter,