The evening times. [volume] (Grand Forks, N.D.) 1906-1914, 1912-01-25
APPLYING POWER CORRECTLY
\ LITTLE SECRET OF PRACTICAL MECHANICS EXPLAINED BY
AN ENGLISH ENGINEER

these photographs. On this he calcu-
lated The exact loss of energy entafled
ny the position Of each nan in the
Cambridge boat. This was about three
per cent. quite enough to lose a race.
Inc defect In the Cambridge rowers'
position was that the handles of their
oars were too long. This made them
twist their bodies into an attitude that
prevented them from using the owe
OF more thai one leg. The Oxford
roWers pulled in a direction as nearly
straight as possible, thereby utilizing
the power of both legs.
II told rowing coaches of this" said
Mr.. Brigg. "but 1t took a physical
demonstration to convince them of
their error.
u have a model of a boat attached
10 a Weighing machine which meas
ures the precise power exerted by a
PAR or oars: When the two oars are
the boat and a thirty-two pound
weight is attached to each of them.
the scale registers exactly siXty-four
pounds. When the oars are placed
at an angle Of fifty degrees and the
same weights are attached by cords
running over pulleys so as to maintain
thelr pun at right angles to the oars.
a : 1aI scale registers only fifty pounds.
a loss or fourteen pounds through the
power being applied at an angle.
demonstrates the folly of a
very long stroke in rowing. The
greater the angle the oars make with
the boat the more of the power is lost
ny being .exerted against the water
instead of in a line parallel
20 tnat IN which the boat is to go.
Less W is wasted in a short. swift
stroKe than in a very long one.
Many rapid swimmers also nut this
principle into practice. Poor swine
mers waste a asst amount of effort
IN pushing sideways at the water. They
ougnt 20 know that only the part Of
tneir stroke that is parallel with their
pouies actuaiiy impels them forward.
n the swiftest swimmers keep their
heads immersed most of the time for
tne reason that h horizontal position
enables the swimmer to utilize ali his
strength in driving the BODY forv,ar ri
instead of wasting it in trying to push
n pody out Of the water, which is
Just what he does who swims with
mead up and feet low.
The tendency of every nron.,,.d
body is to lift forward and to denress
at n rear. Weight is always trans.
1erred from front to rear. This Is :
principle OF the mechanics of nro-
puis!on or iocomotfon.. but I have vet
10 ma 1t stated in any text book.
ignorance of it has resulted in
many a railroad wreck and many an
automobiie smash up. Designers of
rapidly moving machine, with rear
oriving wheels. tend to lift it's for
ward end. The shorter the wheel haso
the more pronounced is this tend ency
! nave shown diagrams on which The
exact amount Of this forward lifting
tendency Is calculated to a nicetv to
many automobile manufacturers, but
0nIv Snmo nf tH4,n ,
stood the principle involved.
The long wheel base tends not onlv
to safety because of the greater weight
on the front wheels. but also to great
er speed. For the line in which tho
power Is exerted runs from the point
at which the rear driving wheels touch
the ground to the axle of the front
Wneels' n the farther apart these
points are the smaller is the angle at
which the power is exerted. and.
therefore. the less the loss in irving
to lift the forward end of the car.
What I say about the wheel base
OF motor cars applies equally to rail-
way engines. The tendency always fs
to lift the front wheels from the track.
Going around a curve, If a very SLIGHT
obstruction is encountered. the front
wheels will jump. There is nothing
to keep them in the direction of the
curve. for. as is we'll known, the ten.
dency is to ny on at a tangent. Now.
II the wheels lift till their ianees are
above the top Of the rail these will
probably come down either on the rail
or on the wrong side of Il. Then the
locomotive Is OF the track there
is an accident.
The famous Shrewsbury disaster in
England end the Woodlawn wreck On
the New York Central were, in INV
opinion, due to just this and nothing
And the remedy?" asked the writ.