Mineral Point tribune. (Mineral Point, Wis.) 1869-1938, 1890-12-11

power on the same design he would probab-
ly have obtained much lower weight per
horse power.
COMBINATION PROPELLER WHEELS
One horse power is equal to $50 foot
pounds per second. Five of Dr. Freninges'
propeller wheels driven by Mr.. String
fellow motor at fifty-two revolutions per
second, will give a total thrust or lifting
power of thirty pounds and absorb 500
foot pounds, leaving the remaining fifty
foot pounds to overcome friction By con-
Meeting the motor and the FIVE propeller
wheels on a light frame by suit bic gear
ing a machine would be constructed that
would evidently be capable of flight. This
might have been done with Mr.. Stringfel-
low motor but he would not trust it in
the machine available at the time, lest it
might lie broken and a suitable one was
never built.
WHAT HAS BEEN DONE.
Many years ago very interesting ex-
pertinent was made at the Novelty iron
works. The machine employed supported
itself In the air, but its action was un.
steady because the power developed by the
boiler was irregular owing to the employ
mentof coal for fuel Every time the furnace
door was opened the steam pressure drop
ped. Had the experimenters known how
to use the petroleum fuel perfectly steady
and much higher pressure might have
been maintained automatically and the
conclusion then reached that with the
means available flight was impracticable"
would have been very different.
OF the source of devices either built or
proposed there are very few besides those
mentioned that manifest on the part of
their designers more than a remote con-
ception of the difficulties to be overcome
or even a reasonably sensible attempt at
success. Most experimentcrs favored the
combinations of screws or wings with
seroplans, and they depended on their own
muscular strength for motive power. The
more modem of these should have known
that the feat was utterly impossible, but
with the same invariable enthusiasm and
lack of ordinary knowledge they persisted
anu failed, some Of them even loseing
their lives.
Man can never attain flight by his unaid-
ed strength For anything beyond few
minutes work he can exert but one-ffth of
one horse power. Surprising the expert
menter's weight be 100 pounds, and that
his apparatus weighs 60 pounds; total 220
pounds. Every 50 pounds in this 900
pounds requires one horse power to lift it.
Therefore 200 pounds will require four
horse power to lift it, and as a man can
exert but one-hfthy horse power it follows
that he can lift but onetwentieth of his
own weight, and no imaginable device can
help him to do much better.
Instead of discussing theories of wing
action and efficiency, only what has been
demonstrated experimentally and with pro-
peler wheels need be considered. Flight
by means of wings operated by power is
probably more economical and simple,
but as that has not yet been demonstrated
we shall not adopt it in our proposed full
size machine
MATHEMATICS OF THE SUBJECT.
The speed of revolution in the small two
wheeled machine mentioned above, 50 per
seconds, 1919 per minute would be quite
impracticable in larger one. to carry
10000 pounds. 1t must be reduced to what
is attaina bic by steam engines connected
directly to the crank shafts, say about four
hundred and fifty revolutions per minute.
To keep within reasonable limits in this
sketch only the method of determining
the particulars can be given, and even then
only roughly. -----...-----.-----
Remembering that lifting power is pro-
portioned to the square of the speed of rev.
olution and to the fourth power OF the
diameter at the same speed of revolution
it will be found that the small two wheeled
machine can lift only .748 pounds al $50
revolutions per minute, and that the two
wheels of machine to lift 10000 pounds
must each be IL feet 6 inches in diameter
If they be made to revolve at the same
speed.
Only the minimum lifting power of Sc
pounds per horse power, the Aeronauti
cal Societys standard, has been taken so
far.
In experiments made in September,
October and November, 1887, by Messrs
Danistrom and Lehman, engineers, Copen-
hagen, an air propeller applied to a boat
gave 10 pounds thrust per 100 foot pounds
effort, equal to 55pounds thrust or lifting
power per horse power. On this basis two
Ii foot inch wheels, revolving $50 times
per minute, will lift 1920 pounds and
require 27S horse power.
Allowing | 4 pounds of oil for fuel per
horse power per hour Git has been done for
l pound per horse power 347 pounds of oil
will be required per hour.
Changing the pitch employed by DR..
Freninges to 30, reducing the surface and
slightly increasing the diameter, and also
allowing fully one-third for slip, the speed
will be from 60 to 70 miles per hour, with
about the same carrying capacity.
MINIMUM.
S.44 hours X60 miles per h'r= 506 miles
S.44 hours X78 miles per h'r= 65S miles
PROBABLE RANGE.
%. 6 hours X60 miles per h'r=1 ,4l6 miles
236 hours ks miles per h'r=l $40 miles
WHAT MAY BE DONE.
Full details of the design and methods
of operation cannot be given until patents
are secured. The whole machine might
be made very much lighter, as no ingenu-
ity has be,n exercised in saving weight,
but it would be more costly. We have
seen that the power and weight of both
motors and propelers have been ascertain
ed by competent persons. and the eXpendi-
lures of small sum of money to test the
truth of their assertions would put doubts
forever out of the question. A boiler and
engine need not be built for this purpOse