engineering vol 72 1901-10-25
TRANSCRIPT
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7/23/2019 Engineering Vol 72 1901-10-25
1/35
OcT 25, rgor.]
E N G I N E E R I N
G.
SLIP\VAY
AT LAS
PALMAS, GRAND CANARY.
(
Fo D
esc1 i
ption
see
Page
679 .)
-
TH E INSI'lTUTION OF MECHAN I CAL
ENGINEERS .
T
H
first
genera
l m
ee t
ing of t
hi
s Institution for
th e
present
season was he
ld at
the Inst
ituti
on
H ouse,
St?re
y
's Gate
,
on Friday eve
nin
g,
October 18,
t
he
.
President,
Mr.
W. H.
M
aw
, occu
pyi
ng the
chair.
After
the us
ual formal bu
s
ine
ss h
ad
been
disp
osed of, the list of
candidates
who
had jus
t been
elected was
read
ou t. The
Pr
esident annou
nc
ed t hat
the number
of
additions
to
t he roll of the
In
s
titution
durin
g the
pr ese
n t
year amounted to
449.
This
was ve
ry considerably
above
t he record for
an
y
previous ye
ar. Mr. Maw thought
that t
he
fact
u l ~ be exceeding
ly grat
ifying
to
memhers, as
sho
wm
g
the
popularity
an
d
continued prosperity of
the
Inst
i t
ut i
on.
GA s-ENGIN
E R ESEARCH.
Th
e chief business of the
meet
ing was the
read
in
g a
nd di
scu
ss
ion
of
t
he
Sec
on
d
Report to
t
he
Gas
Engine Research
Co
mmittee,
which bad
be
en pre
pared by
Professor F. W. Bu r
s
tall,
of
Birmingham.
o
ur
e r s
w i l ~
r
ememher, the first
r epor t
of
th1s
Committee
, whiCh
was
read and
disc
us
se
d on
F e
bru
a
ry 11
a
nd
April
27 , 1898,*
gave an
acco
un
t
of
the
appara
tus and engine
which
were
u
se
d for
the
experiment s, a
nd
of a small
numb
er
of
prelimin
ary experiments
made in o
rder to pave the
w
ay
for a
mo
re
extende
d a
nd
complete
series.
The
present
r
epo
r t we comme
nce
to
print
in full
?n
page
~ 9 2
of _his i
ssue
.
The President, in open
mg the
disc
ussion, remark ed that t
he
pap
er
which
t
hey
had j u
st
h
eard
r
ep
r
esente
d
an
e
norm
ous
amount of conscien t io
us
wo
rk
on the part of the
auth
or
.
Not
o
nly
had
Pr
o
fe
ssor B
urstall
c
ar ried
o
ut
with
great
care a
large number
of
exper
iments ,
but
he
had h
ad to
devi
se
t he
app
lianc
es whi
ch
render
ed
those
exper
ime
nts capab
le
of
affording
u
se
ful d
at a
.
n designing and constructing the
experimental
apparatus
which
he
had employed,
Professor Burstall
had
di
s
played
an
or
ig
inality
a
nd
an
appreciat
ion
of the impo
rtanc
e of po
ints of
de
tail
which
wer
e wor t
hy
of
a
ll
{>raise.
Th
e
pa
per
ap
p
eare
d
to him (the President) to
open o
ut two
distinct
lin es
for discussi
on
, namely, fir
st,
a
cri
t i
cism of
the methods and
devices e
mployed in
t
hese expe
ri men
ta
l
in vest
i
ga t
ion
s;
and, seco
ndly, an
exami
na t
ion
of
the resu lts which those investiga
tions disclosed.
He
h
oped
th
at
t hey wo
ul
d h
ave
a
discussi
on
which wo
uld
do justice
to
b
ot
h th
ese
bran
ches
of
the
subj ec
t.
Th
e fir
st
-n
a
med br
a
nch
was one of
much import
ance, becau
se
it w
as
hoped
53
; . ENGUi EERING, vol. lxv., pages 197, 35 1, 413,
and
'
that t he experim
ents
defcl'ibed in
the present
pap
er wou
ld
on
ly
fo
rm the commencement
of a
l
ong se
ries,
and
it was very des
irable
that
in an
extended
investigation
of this
kind
the modes of
procedure
sho
uld
be
very
carefully consi
de
red so
th
at
they
might
m
ake
no false
step
s.
Before' he
disc
ussi
on ope
ned, he would a
sk
t hem
to
accord
the
author a hear
ty vote of thanks for
t
he
great t
rouble
he
had ta
k
en with
the subj
ec t
, a
nd he
would
then ask
Profe
ssor
Burstall
to
mak
e a few
add
iti
ona
l
re
marks
on ce
rtain
special
points
n
ot
d
ea
l t with
in
t
he
paper
wh ch mig
ht aid in rendering
the s
ubsequen
t
discuss
ion
more usef ul.
n
r
eply to the Pr
es i
dent's request, Pr
ofe ss
or
Burstall
sa
id that, in
additi
on to
the facts
put
fo
rw
a
rd in the
rep
or t ,
the
ex
periments
bad
reyealed so
me matt
e
rs of deta
il which were
imporhant
from a
practical point
of view.
The
first
of these
r el
at e
d
to igni
t ion. For
quite
small engin
es
the
hot tube
was most u
se
ful;
but
f
or la r
ger
powers
elec
trical
ig
niti
on offered
great advantages.
With
the
h
ot tube
th
ere
mig
ht
be some
delay
; but with electricity it
wa
s
hardly
possi
ble
t o
suppose
t here wo
uld
be
r
etardati
on, which would
be
a
se
ri ous mat ter with
eng
ines
d
eve
l
op
ing
high
powers.
He tr
u
ste
d
that
Engli
sh
maker
s wo
uld
follow Cont
inental
practice in
this re
spect, and
adopt
electrical igni
tion
f
or
engines developing over
60
hor
se-power.
He wo
uld dr
a w
attention to
Table VII.
in
the
App
e
ndi
x
to the report,
which
had
b
ee
n
prepared
to
show
the
effect
of the
cha
nge in
co
mpr
ession ;
the
relation bet ween s
uction temperature
and t
he ratio
of air
to
gas , as shown
by diagrams
accompa
nying the
pape r
,
wer
e also
of in t
e
re
st . These were
the first
experim
e
nt
s which
had been mad
e
to
d
etermine
t
he
s
ucti
on
temperature.
H e
considered
that in
de t
er
mining the h
eat
balance
it
was advisable
to have
an 0pen
cycle.
Many,
perhap
s, wo
uld
not
agree
with
him
in
th i
s
re
sp
ect
.,
and
might
think there
sho
uld be
a closed cycle.
Th
e
temperature
te
st
wo
uld
show
what the
indi
cato
r would not
reve
al.
The
combustion appea
red to
be
complete
when t
he
maximum
te
mperatur
e
was
r eache
d,
the charge
appearing to beh
ave
durin
g
expansion as
a
perfect
gas . He had always considered
the temperature of
the whole c
har
ge in the cylinder
to
be un
ifo
rm, and
the result
s o
bt
a
in
ed , showing
mate
ri
al diff
ere
nces
of
tempera
t
ur
e
in
differe
nt parts of
the
vo
lume,
came
so
mewh
at
as a
surprise.
I t sho
uld be
r
eme
mb
er
ed, however, that the
cylinder
was not
a s
ymmetric
al one.
l ie prop
osed
to
go
in
to
t
his
m
atte
r at a
future time, and
wo
uld
hope
to
put
the
re
sults
of
his
investigation
s before the In stitut ion.
Dr. Kennedy said
that as
Chairman
of
the
Gas-
Engine Research Committee he had
occupied an
easy and plea
sant
position, h
aving
simply
to
sit
by
and
give advice,
bu
t
not
being r
equired
to
do any
work.
The plan of
ope
ra
t ions
had
been
to
e
n
dea vour fir
st
to
find
out
t
he
c
ondit
i
ons
of work
ing
of gas
eng
ines,
and then
to
attempt to apply the
in
vest
igations
to
ma
kin
g
impr
ovemen
ts
.
So
far, t hey
h
ad
on
ly pr
oceeded
with the
first
part
of t
heir
pro
g
ramme;
but though
the
work was not co
mpleted,
he thought they had alrea
dy
gone
further
in
inv
es
higatin g the ex
act
working conditions of gas engines
than
had
been done on
any
previous occasion. The
app
lication of the
inf
o
rmatio
n
obtained
to pract
ical
work was y
et
to come.
One
of
th
e
things
they
WE re
mo
st
anx
ious
to do
was
to
test
an
eng
ine
much
nearer
to practice in rega
rd to large
sizes
than had
yet
been poss
ib l
e.
He
was glad
to sa
y
an
engine of t
hi
s
kind
would
be
sh
or t
ly
at the
dtsp?
sa
l
of
the
Oo mmittee
.
The Birmingham
Uni
versity were
about to
acq ui
re
a gas e
ngine
of 160
h o r s e p o ~ v e r an
d this would have a closer bea
ring
pract
iC
al work than the 5 h
orse
-power engine
hither
to
use
d.
There
h
ad
been
at
t
he
di
sc
ussion of a
fo
rm
er r
eport
a good d
ea
l of criticism, which he could
not
he
lp
describing
as cheap, on
the sma
ll
size of
the
eng
ine f
ormerlv
used. The
remark
s were
obvious, a
nd ne
ed not have
been
amplified in t
he
man
ner
they
were.
He
would o
nly po
int o
ut
that
hose who should
ha
ve
been
most interested
in
t
he
work the
O o m m ~ t t e e
a
nd
who would
pr
ofit m
ost
by_ theu
labo
ur
s, n
ot
come fo
rw
a
rd
with he
lp
in
thiS respect. W1th the small e
ngine
, the experi
men
ts
w
ere
n o
ne the
less
tr
ue
and
accur
ate
on
a . c c o of
the
size
of
t
he
machine
tested
. n
any
case, 1t was f
or tunat
e
that th
e
Committee
wo
uld be
able to ca
rry
out
their
inv
es t
igat i
ons in
fu t
ure
on a
la r
ger scale. Dl'.
Ke nn
e
dy
had one fau
lt
to
find
with the report., and he wo
uld get
t h
at
over first.
The auth
or
stated that All vo
lum
es, both air
and ~ a s
have
been
reduced
to
sta.nd
a
t d
co
nditions;
t hat 1s, a temperature of 16 deg. Cent.
and
a
pres
s
:lr
e 760
m i l l i ~ e t r e s
of
mercury
; res
ults
a
re
g
iven
1n t
he
metr1c system,
but
f
or
convenience
of co
mpar
ison a few leading figures have
been
given
in
the
English units also.
H e thought
that if
t
he
author
had rev
ersed
his procedure, and had
sai
d
th
at
he gave a few le
ading
fig
ures
in
the
met ric
system f
or the
he
lp
of a few
stud
ents
at tech
nical
and had
u
sed
in
stea
d
pounds
per
sq
ua
re
Inch for
the bulk
of his
result
s, it wo
uld
been
to
t he
advant
age
of
th
e m
ajo
rity
of
hi
s
readers. Those
who w
ere
in
th
e
habit
of
using the ordinary unitt:J
of
pounds and in ch
es
found a good deal of difficulty
in tra
nspos
ing
them
to
metrical
units. The author
h
ad been
en
deavo
uring
to
get
two
things-the
complete
ana
ly
tical
history
of the gas
durin
g
the
cycle,
and
a com
plete
temperature of
histo
ry also.
The
lat ter was
only complete as
far
as
the
Callender t
herm
om
eter,
which was a deli
ca t
e
in
st r
um
ent, would allow them
to
go.
In
o
rder to
u
se
t
hi
s thermom
eter
t
he
en
gine had to
be running slowly, and o
nly
ex
pl
oding once
in
s
ix
times
or
s
o; as
if
fa
st run
nin
g were
tried,
it would smash t
he
in
strum
e
nt.
I t was with
the
slow experiments only,
th
e
refore
,
that the
temperature
s were
taken,
a
nd in others
they were
arri
ved
at
by calculation. H e wo
uld
ask
what
was
meant by
su
ct
ion
temperature.
Did
it me
an th
e te
mp
e
rature
of
the
charge
when
the
cylinder was completely full 1
[Professor
Bur
st a
ll
assented.] The temperatures in
trials
A, B,
C,
and
D we
re
calculated
on suction tempe
r
atu
res. On
tr
ials
X, Y,
and
Z the
co
rr espondin
g
temperatures,
corr
espondin
g
ly
calculated,
did
not agree with
the
m
easur
ed temperatures,
and
that
led to the
experi
ments on
non
unif
o
rm ity
of t
emperature in the
b
urnin
g mass. I t was
to be
hoped that a met
hod
of meas
uring
a
true mean temperature
would
be
fo
und in the future. In
connection with
the
state
men
t
made
t hat in th e gas
engine
only a
bout
one
third of
t
he
temperature
range
was used, while
in
t
he
steam e
ngine
three
-q
uarters of
the range
was
available,
he would
point out that in
any
he
at
eng
in
e,
wh
ere
the theoretical
effici
enc
y w
as high,
t here was always gr
eate
r difficulty
in
reac
hing
a c o m ~
paratively
good r
esult than in
cases
wher
e t
he
t heoretical efficiency was low.
In
the gas eng
ine,
the
r efore, which had a high theo
retic
al effi
ci
ency,
it was mo
re diffic ult to rea
ch
this
efficiency
than
in
the
stea
m eng
ine. The
a
uthor had
r eferred
to
t
he tr
o
uble arising fr
om moi
st
ure
with
w
et asbestos
,
which wo
uld destroy insulati
on.
The speaker had
u
se
d
the
Ca.llender thermometer
with n:ost
satisfac
tory
r
esul t
s for o
btaining
s
team temperatures
;
but
it was fo
und
necessary to pr
ote
ct it by a t
hin metal
-
7/23/2019 Engineering Vol 72 1901-10-25
2/35
envelope.
T h ~ s
necessarily would give a s
light
lag,
but not
suffictent to be of importance in taking
steam
temperatures.
In taking
the temperatures
of the charge, however, of a gas engine as used
by
the author
the
retardation would be of
import
ance,
and
the metal shield would therefore be
inadmissible.
He
would ask the author if he
thought
that
the
difference
in
temperature
in
the explosive charge was due to
the
rapid suc
cession of explosions. This was a very important
matter. Dr. made, 13 years ago, a
good many expertments 1n gas engines.
In
those
days the present appliances did
not
exist, and the
Callender thermome
te
r
had
not
t
hen
been intro
duced. He had, however, arrived
at
the tempera
tures by means of calculation, and it was with
considerable satisfaction
that he
compared
the
results he
then
obtained on theoretical grounds
with those
that
had been arrived at now by
p r ~ c t i c e , for he found that they aareed very
well. Some of
the
experiments he made
in
1888
(Society of
Arts
Trials) were made upon a Crossley
engine, and he found that comparing these results
with the nearest corresponding results of the
author they agreed very closely. Particulars of
some of these experiments were given by the
speaker
. He had formerly thoug
ht
that combus
tion
was
not
always complete
at
the end of the
stroke; but the full informati
on
conveyed
by
the
Committee's
report
throws
further light
on this
matter
and the
assumption must be rectified. In
regard to
the
effdct of change of compression, he
thought
conclusions
must
n
ot
be
drawn
too ha
st
ily.
Substituting other sets of tria]s for the particular
set chosen
in
Appendix VII. they showed different
results, though no doubt equally correct. Details
in connection with this matter were also given by
the speaker. There might, he said, be a special
explanation of the fact, but he thought that all
circumstances should be
taken into
account. The
figures were, however, so clearly given
that
anyone
could make the comparison for himself.
The President
here said
that
it would
be
convenient
i
Mr. Bryan
Donkin would at this point give some
account of the Mathot continuous-pressure recorder,
examples of which w ~ r e shown at the meeting.
Mr. Bryan Donkin said that before proceeding
to speak of
the
continuous-pressure recorder, he
;vould like to point out, with regard to
the
work of
the Committee and the scale on which the experi
ments had
been
made, that what was true of a
small engine
might
be used
in
deducing
th
e action
of the
larger
motors. They hoped, however, in the
fu t
ure
to have a fair-sized engine
at
their disposal.
The advantage of compression was one of the
chief points
in the
paper, and
in
regard
to
gas
engine trials, misfires should be cuefully avoided,
as they caused changes in
the
conditions. The
temperatures of the different parts of the charge
after
the
explosion was the main and most interest
ing part of
the
report. The maximum was about
2000 deg. Cent. That was a very high temperature,
and
it
was wonderful how well gas engines stood it.
The centre of the gas in the cylinders was found to
be hotter by some 200 deg.
Cent
. than the
part
near
the wall. They m remember, however, that that
was
not
ascertained on full load,
but
only when
working very
light. I t is hoped
that
some improve
ment will
be
made
in
this respect, and that it would
be
possible at some future time to give the tempera
ture
records
at
half
load,
or
even more.
The
platinum
wire used was only about one-hundredth of a milli
metre thick. He would like to have seen attached
to
the
paper a few complete temperature diagrams
for
the
whole cycle. Those shown gave only the tem
peratures on the expansion curves. He would also
like to know the exact position of the thermometer
in the clearance space. As to the e
ntropy
diagram,
he was sorry that
not
even one had
been
given. It
would be noticed
that
the maximum heat efficiency
for horse-power was 23
per
cent. whereas formerly
it had been 21
per
cent. Turning to
Mathot
's con
tinuous-pressure indicator, of which ~ x a m ? l e s w ~ r e
shown
in the
room,
the
speaker descr1bed 1ts actwn
by
means of several wall d i a g ~ a m s .copied from
originals
taken
from. gas and o.ll engines.
~ e n e -
rally,
it
may be satd to .cons1st. of an ordinary
pressure indicator, the pencil of whwh.
c ~ s
on a con
tinuously-moving band of paper unw1ndmg fr
i
m a
drum
and
on a
time
base,
and
driven
by
a clock
inside. In this way a
constant
record of all the
pressures are
taken
viz , explosion, ?ompression,
aspiration, &c., and this for few m n ~ u t e
d
oubt the instrument
did not gtve more 1nformatwn
than
could be deduced from many ordinary indicator
E N G I N E E R I N G.
diagrams, but the records were shown in a very
much more convenient form.
Professor R.
Threlf
all pointed out that on
page 23 of
the
report it was stated that
the
finest
wire employed
in the
platinum resistance thermo
meter had fused after a few explosions. Now the
mel ting point of platinum can hardly lie below
1700 deg. Cent.-a much hi gh
er
temperature than
any recorded. It may be argued t
hat
t he platinum
~ b s o r b s carbon at
the
high temperature to which
it
IS exposed, and that thi s lowers the meltillg point;
but against this view
it
is to be remembered that
the
absorption of ca
rb
on by platinum is
not
instan
t a ~ e o u s ,
nor s the :e
~ n y
evidence that the melting
pmnt of plattnum 1s,
1n
fact, m a ~ e r i a l l y lowered
by
the carbon which
it
may take up.
In
addi t i
on
to this,
the
temperatures measured were found to appear
higher
the
thinner t he wire. Everything seems to
point, therefore, to .the probability of the measured
temperatures being too low. I t is quite evident
that metals with higher melting points than plati
num will have to be used. With regard to the
calculated temperatures,
it
appears from the cal
culations of Le Chatelier
i t s
fiir Physik.
Chem. II. 782, 1888) that in the case of carbon
di.oxide,
at
all events, the high pressure prevents
there being any serious
amount
of dissociation.
The method of calculation adopted appears there
fore to be sound from this
point
of view. Return
ing
to
measurements of high temperatures, Pro
fessor Threlfall po inted
out
that
the
thermo couple,
though electrically less sensitive than the resistance
pyrometer, has
the
great advantage that it can be
much more easily repaired ; and it may be used
exactly as
the
author has used the resistance instru
ment. To do this, all that is necessary is to close
the circuit of the couple through a potentiometer
by means of the rocking key, just as was done
for the resistance instrument. In
order
to
obtain sensitiveness the wire can be used in
the form of thin strip, this being, of course, pro
tected, except
just
where
it
is exposed to t he
temperature in question. Mr. W. H. Steele,
in
a
paper read before
the
Royal Society of Victoria
in
1893, describes some experiments
in
which he had
found large electromotive forces generated in wires
(supposed to be homogeneous) when unequally
heated . The speaker had not had an opportunity
of examining this effect, nor had he seen any corro
boration of Mr. Steele's results by other workers ;
bu t it is a matter which shou]d be considered by
anyone using a couple of
the
kind described.
With
regard
to
the small size of the e xperimental engine,
no apology was needed. In order to thoroughly
elucidate the details of the action of a gas engine,
it
is important to investigate the effect of varying
the relation of
the
volume of
the
active gases to
the area of
the
cooling surfaces to which these
gases are exposed, and this necessitates trials
with at least two engines one large and one small.
I t is also necessary to establish the experimental
methods on a firm basis, and this can be done more
cheaply and quickly in a small engine than in a
large one. I t was to be hoped that when the ex
periments were extended to larger engines these
engines would be really larger, i
e ,
ha
Ye lar
ger
cylinders ; 150 horse-power was t he size mentioned,
and
he hoped
that
this was to be got o
ut
of one
cylinder.
The
author expressed surprise at
the
variable temperatures observed
in the
cylinder.
The
speaker could not see
that
this was a
matter
for surprise:
the
influence of the cylinder walls
must of necessity be felt; but even setting this
aside, there was every reason to suppose that the
gases were in a state of violent motion during the
explosion, anil this motion was turbulent. Conse
quently, the pressures and temperatures would
vary locally throughout the mass. Some very
interest ing high - speed photographs were ob
tained by Von Oettingen
and
V on
Gernet
(Wiedemann's Annalen, 1888) of
the
explosion of a
mixture of oxygen and hydrogen
in
a
tube; the
ex
pl
osion being rendered luminous by
the
addition of
the
dust of copper salts. rhese photographs illus
trated very well
the
complex nature of a gas explo
sion. Referrin g to the indicator diagrams and
the re10ark made as to the desirabili ty of obtaining
entropy diagrams, the speaker pointed out that thi s
would be difficult, seeing how arbitrary the selection
of
the temperature
would be.
Durin
g the discussion on Mr. Humphrey's paper
las tyear (Proceedingsof Mechanical Engineers, 1900,
page 237) the speaker drew
attention
to the curious
increase
in
the work required
to
pump
the
charges
as the velocity of rotation of
the
engine increased.
He suggested that this
might
be due to the gases
becoming hotter
in
the
p a s s ~ g e s
of the admission
valves the fa ste r the engine ran, and consequently
having their viscosities increased. Calculating on
this basis, he concluded that to make
the
e x p l a n ~ -
tion valid, the g3ses would have to be hea ted to
140 deg . at the higher speeds. This calculation,
referring to a la rger engine, cannot, of course, b3
insisted upon, but it is at least curious that the
present trials have given a practically identical
value. The relation of the viscous properties of
gases to the working of the gas engine is a com
parative ly open field, in which research could
hardly
fail to yield results
of
interest.
At this
point
the
President
adjourned the dis
cussion until the evening of Friday, November 1,
when a special general meeting will be held
to
con
clude it.
DIE FORGING. No. IX.
By J
osEPH
Ho: NER.
Tm s article will deal with a few selected examples
illustrative of the classes of work performed in the
wagon and carriage stamping shop
at
Swindon. The
large and varied volume done in this departme
nt
may be inferred from the account given
in
the
previous article on the machines ; but its magnitude
must
be seen to be fully app reciated.
The
photo
graph reproduced in
the
last article (page 470,
Fig. 216), showing die blocks lying
out in the
yard,
will supply
an
object-lesson
in
numbers, while
the
drawings to follow are taken as representative of
many different classes of work.
Spring shoes (Fig. 217, page 569) for open goods
wagons are made at one heat. They are stamped
first to the shape in Fig. 218, in the die, Figs. 219
to 221, by a punch, Figs. 222 and 223 of the same
outline as Fig. 218.
Then
the stamping is laid in
a supplementary block A, bolted on
at
the back of
the die (Figs. 219 and 220), and t he horns
are
turned
over
by
the die B on the horizontal ram.
The die block is furnished with openings at
the
sides, through which the stamping is removed.
The
face of the die is also formed with a steel
plate screwed to the main cast-iron block, the hole
in which (seen dotted in Fig. 220) gives clearance for
the stamping. The punch alone- apart from its
holder (seen in Figs. 222 and 223)- illustrates an
economy in manufacture. It is countersunk in
both faces for the cheese-headed screws that secure
it to
it
s block, so
that
when one face becomes w
or
n
badly, the punch is turned over and the oppos
ite
face
brought
into
service. In addition, a
cut
can be taken
off the faces when they
both
become worn,
and
the
punch is
then
ready for a new lease of life. These
precautions are worth taking, because
the
correct
shaping of the punches is rather an expensive job.
An example of a rapid piece of forging is the
combined brake hanger bracket and safe ty hanger
(Figs. 224 and 225). This is made perfect to shape
and size from a piece of rough plate at one heat
within a
co
uple of minutes. The plate (Fig. 226)
is punched at one blow of the
punch
(Fig. 227) on
the die,
three
views of which are given (Figs. 228
to 230). On the rear face of the main die a sup
plemen
ta
ry bending die A is cast, and the stamping
is laid
in a groove in this,
and
the horns
or
wings of
the hanger bracket are
turned
over
in
pairs by a
die B, attached to the horizontal ram of the forging
press. One pair of horns is done thus,
and
t
hen the
bracket is turned round and the other pair
bent
over,
at one heat. 1
he value of the horizontal ram here
is very apparent, for without i t
the
work would have
to be transferred to another press, or done on the
same press on another block at another hea t.
In Figs. 228 to 230 the body of the die block
is of east iron, and the face is of steel, screwed
upon it. The d
otted
outline seen in plan in Fig 230
is the hole in the casting ; the full line is that in the
steel face, giving, as in the previous example, a
clearance for
the
stamped plate to fall through.
It
is removed through the openings seen
in
Fig. 229.
The punch
in
Fig. 227 is of mild steel secured
in
a holder with screws, and t he holder is bolted to
the T -groovee in the face of the top ram of
the
press. The faces of punch and die are flat. In
some practice the punch face is curved lengthwise,
with a view of giving a detailed or shearing cut,
but
this does
not
seem
to
be necessary.
There
is
no
hardening of the faces dono, but the faces of
punch
and die become so hot that they have to be
swabbed with water
after
each piece is stamped,
and that
in t
ens
ifi
es
the
hardness of
the
steel
in
some degree. The method of attachment of the
-
7/23/2019 Engineering Vol 72 1901-10-25
3/35
OcT. 25, 1901.]
bottom die by the lugs with open slot-holes for bolts is
ado
J?t
ed neal'ly universally,
o t s s a v i n
some tr ou
ble In at tachment by compa
ri
son
wit
h ro
und
holes.
E N G I N E E R I N G.
the corn
er
s, a
nd
bent round, and welded. At Swin
don these are made in three welds in o
ne
heat, one
being that of stem on a flat piece,
th
e lat
te
r
cent re. The blocks us
ed
are shown in Figs. 232
to
242.
Th
e main block A is bol
te
d to the table of the
press, and is recessed at the
to
p
to
receive the
_
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ig
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bridle, the posit ion of which is indicated by the
dotted lines
in
F ig. 23
7. Th
e welding is done by the
pressure of the top block B,
attac
hed to the t op
ra
m
w
it
h t wo bolts, coming do
wn
on the forging
in
block
A ; F ig. 240 is
an in
ver
te
d
pl
an of this showing t he
recess. Block C ca
rri
es thAdr ift D (Figs. 241 and
242), which is inser
te
d
in
the hole d uring th e opera
t ion of welding,
pr
eve
ntin
g dis
to
r t ion, so th
at
th
e
bridle is welded and finished at once to shape . The n
th e horizontal ram is drawn back, and a loose piece
of
bl
ock inser
te
d be
hind
the mand rel, and t
he
hori
zo
n
ta
l rnm moved fo
rward
aga
in
,
pu
shin g
th
e man
drel
out, a
nd
leaving t
he
hole smooth to shape .
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e
.
The spring buckle (Fig. 231, page 570)
is
made
differently
fr
om the usual practice, which is
to
fo
rm
the b
ridl
e in o
ne
t
hickn
ess, drawl\ down,
up
set for
being j ust bent at th e
end
s sligh tly, which piece is
welded all over its
fl
at face to t
he bridl
e proper
bent round and welded underneath at about the
A n
eat li
tt le
jo
b of stamping is seen
in
makin g
th e draw-bar for an open goods wagon,
as
sh
ow
n by
F igs. 243 to 245. One way
by
w
hi
ch to make this
would be that described in previous art icles,
nam
ely,
by drawing do wn a shor t welding length
fr
om a bar
having an o
ri
ginal se
ct
ion about equal
to
t hat of
t
he
boss, and welding
on
the shan
k
of p
lain
ro
un
d rod. At Swind
on
the
met
hod adop
te
d is t o
take a
le
ngth of square bar (seen
dotted
in
F ig. 243
at
A), a
nd
t he long
ba
r B. Bo th pieces
being
bro
ught to a welding heat , A is laid on the
fl
oo
r a
nd
t
he
end of B da
bb
ed
upon it
.
The
ends
ar
e then bent over to the full lines, and
flatte
ned
against B
und
er the
pr
ess. The e
nd
is then p
ut
back i
nto
t
he
furnace,
and
a seco
nd
welding h
ea
t
taken over it , and one squeeze in the dies (
Fi
gs.
244 and 245) finishes the end.
The shoes seen in
Fi
gs. 246
and
247, page 571, in
volve a
numb
er of ope
rati
ons, which
are
illu
st
ra
ted
-
7/23/2019 Engineering Vol 72 1901-10-25
4/35
570
in subsequent figures.
The
square socket is
turned
round and welded at
the
corner Fig . 248),
and
welded to
the
shoe, and
the
entire forging is
then
drifted
and
set
in
separate recesses
in
dies.
The
first operation
after cutting
off is
that
of
bending
the plat
s to
the
sq
uare form for
the
socket
(Fig. 248), which is done
in the
dies shown
by
Fig.
249. One half
the
work is done
in the manner
shown
in that
figure.
The plate
A is bent in
the
b
ot
tom die E
by the
pressure of
the top
die F. I t
is
then
taken
out and
placed in an angular recess
in the bottom die, the long
end
being uppermost,
0.
A mandrel D is inserted
and the top
die
bends
the
free
end
over
the
mandrel,
thu
s forming
the
square.
The next
operation is seen
in Fig
s. 250
and
251,
in
which
the
socket,
after
being
brought
to
a.
weld
ing heat, is laid
in the
die A,
the
doubly
tapered
~ r i f t B inserted,
and the
top die 0
brought
down upon
1t, closing the weld.
The drift
B is
then
pushed,
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A
E N G I N E E R I NG.
and crane hooks.
Formerly both
were made
by
bending, when iron was used for both.
Iron
still
remains in use for
the
crane hooks, but
the
draw
bar hooks
are
made of steel.
The
resulting difference
in
manufacture is
that the
first must generally
be
forged by drawing down
and
bending, while
the
latter ca
.n be stamped from a solid lump.
The
latter are
made
at
Swindon
in
two heats,
under
a
30-ton steam hammer,
thus
:
A lump is drawn down very roughly (Figs. 258
aud 259) thicker than the hook,
but narr
ower,
at
one heat. At another
heat
it is put between a
pair of top
and
bottom roughing dies
under the
steam hammer, which spreads
and thins the
lump
to fill
up the
dies,
but
leaves a fin something like
in. thick
F
ig. 260)
and
of variable width all round.
At th
e same heat
the
forging is driven through a
stripping die (Figs. 261
and
262) which cuts off
the
fin.
Then the
finish is imparted in a p1ir of
dies similar to those used for roughing out.
.. --
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239
t-g
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.
240
8
-
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~ . 2 3 6
I
c
L
f . ~ ~
I
by the
hori
zo
ntal
ram
of
the
machine, through
the
forging, making its interior straig
ht
and smooth.
l he shoe,
bent
from
a.
piece of plate, is now welded
to
the
soc
ket
in
the
pair of dies shown in Figs. 252
to
257. These are but a single pair of dies, each
being shown
in plan and
joint
face views re
spectively.
The
bodies A B are made of
Cc; l.St
iron
faced with steel, C D, screwed to form
the joint
and
working faces of
the
dies. These pieces
\J
D
are
recessed
out
to
take the
rough forging.
The
welding of
the
shoe to
the
socket is performed
while
tha latter
is retained
in the
socketed portion
E.
Afterwards
the
entire forging is placed
in the
recess F,
and set
to correct form between the dies,
and
by
the
aid of a drift inserted and pressed down
by th
e top ram. This
drift
is fastened to
the
top
ram, which withdraws
it
after the
sett
ing is accom
plished.
The
die A (Figs. 252, 263,
and
266) is
the
one which is
bolt
ed to
the
table of
the
press.
The
other, B (Figs. 254- 255,
and 257
) is bo
lted
to
the
hori
zontal
ram of
the
press.
There
is muoh similarity between draw-bar hooks
J
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061, L I
The
draw-bar plates (Fig. 263)
are
made at o
ne
heat in
less
than
a minute. The plate is stamped
with a. punch in a die to the outer shape and
dimensions by the vertical ram of a press.
Then it is picked up
and set
in a plain
die at
the rear
of
the
main
bloc
k,
and
the
hole punched by a single movement of
the
horizontal ram.
The
manger
F
igs. 264
and
265)
4ft.
long, is
an
example of a large piece of deep work stamped
in
three h
elts in three
sepa
rate
sets of dies. A piece
of plate is first
cut
(
Fi
g. 266), with radii struck as
shown, from three centres, for each end, and
this
then
goes through three successive pairs of dies, the
general form of which is shown in Figs. 267 to
269, these figures illu
st
rating
the
finishing die only.
The
difference
in this and the
preliminary forming
pair of dies is
that the
sides
and
ends of
the latt
er
slope
at a.
greater angle, those of
the
ones illustrated
having comparatively
little
slope,
and
those of
the
second pair have a degree of slope
that
is
in t
erme
diate between that of
the
first and
the third
set,
so
that the
plate is dished gradually, to avoid dis
tressing the fibres too much.
The
dies consist of top A
and
bottom B. Lugs
are
cast at
the
sides of each, with holes for
the
insertion of bars for lifting
and
adjusting them by
on
the
table.
The
top die is bolted to
th
e
top
ram by
the slot
holes shown.
The di
es
are
of
cast iron,
and
necessarily very
stout and
mas
sive. Such a piece of work as this manger,
if dish
ed
and flanged by
the
o r d i n a r y methods of
the
plater, would be an expensive job;
and
if cast,
as they usually are, they are also expensive by
reason of
the
size of
the
moulding-box wanted,
and
the
large
quantity
of sand
to
be rammed, while
the
metal cannot
be run
so
thin
as
a.
sh
eet
m
et
al
plat
e,
and i f it
could,
the
mang
er.s
would
be
liable to
fracture. This, therefore, affo
rds an
illustration,
among many others, of o
ne
of
the
economies of
the
practice of di
e-
forging
in
a shop, economies
that result from extensions of the practice into
&
'
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(
A
s itself, and
ib
may be interesting to
recall, for the benefit of Lord George Hamilton and other
critics, what has happened tefore. 'l'he a o tiYity of
1
884-5
,
and the fabulous profits which everyone outside
the trade knows
to
be normal in t he locomotive industry,
induced the formation of a new company with extensive
capital, modernly-planned shops, and expert management.
This c o m p ~ had
its
firsb locomotive on show in the
Edinburgh Exhibition of
1886. In
the course of bhree
years ib had l
osb
the third of ibs capital, was glad to sell
1tself to one of the old firms which was l
oo
king oub for a
new location; and, withoub making any mystery of bhe
matter, is now incorporated with Messrs. Sharp, Stewart,
and Co.
Limited, now
of
Glasgow, then of Manchester.
Mr. Edttor, will you kindly insert the enclosed extracts
from the annual reporb of the locomotive trade, and then
tell the public whab the
India
Office did
to
supporb the
new venture and to keep it in existence. Whab guarante
have the l
oco
motive makers that what happened before
will nob happen again, and who will help them in the
struggle for existence when the inevitable depression
comes round again ? These extracb reports show
that
the locomotive makers have been all along cogn
i
sa
nt
of what would happen when demand should
strengthen from other markets, and the India Office
and Indian officials have alone been blind
bo
the necessities
of the case. All interested, including the presenb
Secretary for
India
and his predecessors in office, had
these annual reports senb to bhem,
but
the warnings did
nob seem to affect them greatly. The present Secretary
means kindlr by the home makers, and bhese latter
appreciate
h1s
courtesies; therefore it will nob, per
be baken amiss if we mildly call attention to his Lord
ship's own period of administration. I believe his
Lordship assumed office in July, 1895 . The trade report
in December of thab year stated thab
the
total publio
demand (nob from India. only hub from the
wh
ole world)
could have been met by the output capacity of two of the
firms. Lord G e o r ~ e s hand, however, could hardly have
been felb by bbat btme; hub perhaps by the end of 8 ~ 7 ,
after yeara of office, we might have looked for better
bhan 'he Indian
State
Railways seem still to be l a g ~ i n g
behind, being responRible fo(somewhere aboub
40
,engmes
only : , a number equal to two to three monbbs oubpub
capacity of a
Ei
ngle shop.
From this
ib
will
be
seen that we have only the three
years
1888-990
to regard as years of aobivity, so far as the
India Office is concerned; and as Indian orders have dur
ing
bhab
time been freely placed abroad, the locomotive
trade does
nob
feel itself under an insupportable load of
gratitude
to
the Indian Government.
After all this has been said, ib may be news to his Lord
ship and the oritios, and it may even interest them to
know, bhat every locomotive shop in the country has
greatly enlarged
its
productive
ca.paoiby
within
the
last
few years, in mosb oases the capital has also been greatly
increased ; and these extensions will in the aggregate
-
7/23/2019 Engineering Vol 72 1901-10-25
23/35
s88
equal ab least bwo new shops of large dimensions. f
loc omo
tive
maker3
are
allowed to
know
th e elements
of
their own business, they may
be
pardoned if
they
feel
somewhat doubtful whether the present temporary spurt
justifies this extra expenditure; and
if
th
ey
consider that
a. pause is desirable until rea
sonable
evidence is forth
coming that
the
shareholders' mo ney has not been re.shly
squandered.
So
far as
the
India Office is con ce rned,
there is nothing
to compel
them in the
future to geb their
wants
supplied
in this c o u n ~ r y . f ib suited
their
book
{or the personal failings or
crotchets
of any of their
officials), they C)uld still go
to
America or Germany; and
British makers will
onJy
eecure the work
wh
en they can
compete
succeEsfully in price
and
time of delivery, and
when
they secure
contracts on
these
terms
only, they
need
not
feel
greatly
beholden
to
the
India.
Office.
Lord George
Hamilton seems
to
imply that the recent
orders
have
been
plac
ed
in Germany
solely
because of the
failure of the
Brit.ish
makers to increase their capacity.
The two have n o bearing on ea-ch
other,
or if
they
have
the obverse is
the
case. British makers, before investing
furth
er
capital in
works
and plant,
have to consider all
possible co
ntingenoies,
and one of th
ese conting
encies
is
the present state
of
trade in
Germany.
Ib is
Germany
's
policy just n
ow,
as ib may be Belgium's
to-morrow,
and
France, Austria, or even
Italy
's
the
next day, to cut
prices for British orders;
and
when these foreigners are
supported as
they are by
th eir fiscal policy, our firms are
helpless
to pr event
them cutting
in.
America's
presence
in our markets
represents competition
(although on
un
fair linea), hub Germany 's present advent
i.1
temporary,
and
due entirely to
extra
neous
ci
rcumstances.
Both
Germany
and America
protect themselves
against
forei g n competition
within their
own borders by
a.
high
customs tariff.
They can thus secure
a. splendid
return from their
own
hom9
requirements,
and
can afford to
dispose of the
balance
of
their
produ
c
tion to outsiders
ab a low,
if
not
even
unremunerative, rate. f by a long continuance of
this
policy: they were to extinguish
the
indust ry
in
this
country, tb does nob require great perspicacity bo see
what a
plight
we wou
ld
be in,
and
how we shou
ld
ulti
mately
have to
pay through the nose for our lo
comoti
ve
power.
Without
waiting for
the
standardising of
the
rolling
stock, if L o
rd
George Hamilton
could
only
see his way
to deal direct
with the maker
s, accepting their reasonable
guarantee for the work, the pr
e
sent total annual
capa-city
of the
shops
in this cou
ntry would,
by that fact,
be
in
creased
sufficiently to
meet
all
his requirements, with
a.
trifle over for the Cape and other quarterP,
I am, &c,
October 2L, 1901. FAIR PLAY.
EXTRACTS
FROM
PUBLIS
HED
.ANNUAL REPOR'lS
OF
THE
LOCOMOTIVE TRA
DE
.
1888.
The Indian market has this year been unusually dull, and manu
facturers have consequl'ntly bad to busy themselves in finding
other markets to take its place. There have only been two or
three orders for Indian State Railways given out for a considerable
time. Such a state of matters is without parallel, and
we
think
thereoan be no question as to the unwiadom of a pause in the
railway development of our grPat Eastern dependency. India has
so far only been touched by railways, and both from a military
and commercial point of view there
is
the greatest desirability, and
even necessity, for a policy
of
progress in laying down lines.
Mr.
Holt Hallett, in an admirable paper, demonstrates the profit to
Ind.ia itsell to be derived from the proper and extensive o p e n i ~ g
up of
India by railways, and the cause
of
the present standsttll
seems to us to be inex.Plir.able. Glasgow
is
now rep resented by
seven Membera of Parhament ; and in view of the importance.of
the Indian market to the West of.Scotland, the lack of enterpnse
in Indian railways might very well form the subject of a question
to the Secretary for India.
1889.
A most remarkable circumstance is that the Government
of
India have failed to take advantage of their opportunity. L -st
year
we
drew attention to the fact that orders for the Indmn
State Railways bad been given out only in such very small quan
tities as would n ot keep their rolling stock up to
a. p r p ~ r
state of
efficiency. This year tt has been even worse; and 1t JS safe to
predict that. the Indian Council will be forced into the market by
preBSure
of ci rcumstances when prices are greatly enhanc
ed
.
They have let slip their opportunity, and the longer they delay
the more they will have to suffer; as will be readily understood by
every one conversant e\en in a very ordinary degree with the
present great demand and
in
crease in prices for all kinds of
and manufactured materials. We can hardly contemJ?late wtth
equanimity the position this c o : l n t ~ y
w o ~ l d be
m, were a
time of war-like emergency to anse
1n
India, nec
ess
1tatmg a large
and speedy supply
of
rolling stock.
1890.
The Indian market has not shown the act ivity whi ch
was
anti
cipated at this time a year ago. Year after year we have bad to
call attention
to
the lack of enercry OJ the Pl;\rt of those. respon
sible for the State Railways in Ind1a. It
JS
so long Since the
Government placed orders, t ~ ~ t their ~ l l i n g stook must now.
be
in a most unsatisfactory oonditton, the year the Indtan
companies have given out orders for 95
enjZmes,
and of t h e e ~ only
30 ordered within the last week have been for Government hoes.
1891.
India, which, with its enormous resources, ought of i t s ~ l f to
keep our locomotive shops fully employed, has b ~ e n praotumlly
non-existent for years past ns a market. for engmes , and year
after year this repo
rt
has had to chromole the enme
stat
e
of
matter
s.
The hopeful view to take
that
since the demand for
locomotive power must come some time, every year that elapses
must bring us nearer to it.
1892.
India has bulked rather more largely than the home market,
and still the State Railwoys' requirements are remarkable by
tbeir absenc
e.
Year after year
we
h Jo
ve
bad
t?
~ r o n i
thesame tbing, and have already
p r o g n o s t 1 c a ~ e d
an
}n
evlt Joble early
floodin g of the market with orders to brmg theJr e.qutpment up
to
normal efficiency ; but every time our prognostJoatJons bav.e
failed and we shall consequently now cease to prophesy unttl
the is realised.
1893. .
As a market for locomotives, India has ag-ain been a failure;
E N G I N E E R I N G.
[OcT. 2 5, 1901.
were practically non-existent. Time after time in this column
we have indicated a great spurt in the locomotive industry in
the following year, due to Indian officials awakening to a sense
of
railway
~ q u i
r e m e n t s but we cease henceforth to prophesy
on Indian ratlway
s.
Probably, when the spurt
come1.1
,
we
may see
it, but meantime matters are
gett
ing wor se from year to year.
Whill' in the case of India, long looking in that direction has
made the heart sick, makers are refreshed when they transfer
the ir vision to China and Japan
to. be very
near
the
ends
.of
the
rails, leav ing o
nly
about
lm . of metal fr om
the
side
of the
hole to end of rail.
The
nexb
two
bolts may
be
wider
sp
a
ced and
smaller
in
diameter.
The bolts near
the
middle of the fishplates
have much more strain
to re
sist than
tbe
other
two;
they
should,
therefore, be stronger, and
be
placed as near
as possible to their mark, which is at the e
nd
of the rail.
No
other eng ine ering
structure
depends so much for
security on
bolts
as rail
joints,
yeb
bolts
~ e n e r a l l y put
in
are much too weak for their w
or
k. 'Vtth good,
sho
rt,
we11
-fitt
ing fishplates
and
large-s
i
r.e
d middle bolts a
strong and durable joint may be madA.
1894.
We ceased last year to
co
unt upon the return to life of the
Indian rail
waJ
s, etating that
we
had prophl'sied
so
long that
we
would
now
haYe to wa tch
a.nd
see
th
e event when it happened.
f the desired improveml'nt has not yet co
mt>,
it seems to be
coming ; and the market in that great dependency shows indica
tions of awakening from its slumbers
of
many years. Fully a third
of
the public con t racts have come from India, and a gratifying
feature
is
that
the
progrl'BB
has been reg
ul
ar and not spasmodic;
in any
c a s ~ : >
makers are looking to that market as their chief
anchor of hope.
E xpamsion. - Rails lAid in summer time
shou
ld
be
laid
close
-butb
to butt; if laid
in winter
1\l in. to a
30 fb.
rail
is
enough space to leave
for
expansion,
which
is
nob
such
an irresistible
force as
is generally
imagined.
Sl
p
rs.- I
ha.ve
Lean surprised
to
find the rails of ter
minal s
tations,
shunting yards, and docks laid
on
sleepers,
as of old, when those
places
where there is n
ob
great s
peed
of train co
uld be
laid with broad-Banged rails placed on to
solid concrete,
and
buried half their
depth
in this same ma
terial. When laid in this way
they a.
re done with ;
ther
e i J
no wood
to
rot
or
swe
lJ
,
or cbaira to trip over
or
be
come
loose. When concrete is a continuous
bearing
under
the
rail, it does not make ba rd running like what the old
atone blocks mad e in the early
day
s of railways. G J ~ g o w
tramway cars run sometimes very quickly, bub always
smoothly, and
th e
rail
s
are
laid di rectly on concrete.
1895.
The amount of work placed through the open market might
well have been undertaken by two of the leading establishments;
and while there was a considerable quant
it
y of work privately
negotiated, still over all the re was not anything like sutfloient
demand to take up half the produ
ct
ive ca
p1
city of the country.
1896.
The Indian market has been specially active during the past
year, and has assumed the importance a m o n g s ~ markets for l
oco
motive wo rk whioh has been conspicuously absent during recent
times. Its importance has almost equalled that
of
the home
market, and the pressure of traffic seems to have been fel t all
over the land.
nter
cour
s of
Officers.-
do not find that there is much
intercourae between the officers of
the different
rail w
ay
a.
They do nob mee t ab abort intervals
to exchange
ideas
and discus3 proposed improvements, like the Mas ter
Mechanics and
Car
-Builders of the U nited
States
. Th ough
there
are many
railway
companies in
thi s
country,
the
island
is
so small
that rail
ways, as far as their ro
lling
stock is concerned, must
be
wo
rked
pretty much as one
concern. I therefore think that instead of working out
ne w i
deas
alone,
the
master
m
echanics
ought to meet
with their fellows of all other railways, tJo reason
tog
e ther
and take counsel.
1897.
Of all the markets whi ch have helped to keep the locomotive
trade in full pressure, probably the most important this year has
been that of India. The State R'lilways seem still to be lagging
behind,
bei
ng responsible for somewhere about forty l n ~ i o e
only, whioh is a small proportion
co
nsidering the mileage of lin
e3
coming under
that
heading.
BRITISH
RAILWAY PRACTICE.
To THE EDITOR oF ENGINEERING.
Sm, - In reading
the addre
l a
that
L ord R )sebery de
livered the other day at
Birmingham, I was
impr
essed
with that part of it
wh
ich treated
of
" the want of inde
pendent thought i n Great Britain."
I am an engineer
who
has lived over forty
yeare abroad.
I came home a
few
months ago on a sho
rt
visit, and
t imed my holiday so
a-s
to enable me to visit the Glasgow
Exhibition, which
includes
an admirable
exhibit of
new
ma
c
hines and
processes.
There
are, however,
many
things,
bo
th
in tJhe Exhibition and oub of it in th is country, th.ab
a little independent thought o u ~ h t
to
have
altered
and
improve d
before
the e
nd
of the nine teenth centu
ry.
As
I
am
connected with
a.
railroad abroad, I will con
fine
my
criticism bo rail road matters,
and
mention
a.
few
thingd
that I,
bei
ng
a stranger, see a
nd
consider de
fects,
which may
not
be
noticed ab all by all
engineers
in
this
co
untry.
In the Glasgow Exhibition are
several
fine in s
ide
cylin
der-c
o
upl
ed locomotives, and all of them-except one
ha ve the outside cou pling-rod cranks shorter than
the
ma in
axle
c
rank.
One
of
them that gives figures on
the
dr aw
ing
exhibited illustr
at ing the
engine, shows
the
inside
cranks to be
13 in . and the outside cranks 9 in.
No
w I
ask- because I do n
ob
know-why is this difference made?
The only excuse that I find for the practice is that it w
as
common forty years ago,
and
it therefore continues almo
st
univeraa.l to day.
Yet it
cauees much more
strain
on the
crankpins, rods,
and
brasses.
and
a
greater
danger of
heated
brasses and waste of oil.
Again, coupling-rod cranks
are put in the driving
wheel opposite
to
the main crank on the axle; I presume
that they were put orieina.lly on the opposite side
to
help
to
balance
the w ~ t g h t
the main crank ~ n d con
necting-rod,
and for thi
s obJect
are
pub
there
still.
But
Mr. Stroud
ley showed, more
than thirty
years ago,
that it
was
bebter to
pub the outside c
ranks on the
same side of
th e
wheel
as the main crank, because the turning of the
leading and trailing wheels
was
then a. di rect push-and
pull from the crank in the driving wheel; whereas the
present
practi
ce requires
that
the force t
-
7/23/2019 Engineering Vol 72 1901-10-25
24/35
very
shorb indeed-the
whole subjecb
was thrashed
out.
Noth
ing was glo3sed over. But
neith
er of th
ese
gentle
men appears
to
be sa.tisfi
3
d. I will therefore make another
at tem
pt.
The engines and screws. and
all
the
rotabing
pa.rbs of
tbe
machinery
in the
Cobra,
we
re
very
beautifully
b:l.la.nced,
as
they are in all of
Parsons'
turbines. Both
s y a t e ~ s we r
e mount.ed in the
same
rigid
fram
e
sec ured to
the a
htp
ab
many pomts. Th
e
shaft
s
had a.
fixed
position
as
re
la tes to ea
cb
other, approximately
parallel. The
weight
of the
two
sy
st e
ms* was
identica
l ; they
were
bobh
su pplied
with steam from
th
e sa
me source
and
both
discharged
their steam
into
the
same c o n d ~ n s e r .
V
~ a . y
therefo
re
infer
that th
ey rotated in opp
>
site
duecttons
at
very nea
rly
the sa
me certainly
within
1
per
ce
nt
.
Suppose
that
the
Cob
ra.
had
b
ee
n
provi
ded wibh
trunnions passing transversely
th r
oug
h
her
cent
re
of
gravity, and
tba.t
she had been mounted on ball
bearings so as to be traiped freely
in
any direct
ion
li k
e a.
gu
.o, and tba.b
the engines
sh
ould be set
in
motion, the
shtp ~ c c u p y i n g a horizontal -position. S uppose now that
we ratSed the bow of
the sh
1p and de-pressed the stern.
One syatem of turbines would ma.ke a. s
hght
effort
to
move
the
stern of th e ship
to
the
right,
and
the
other
wou ld make an effort with exactly equal force to
move it to the left, but as tbe fra me is absolutely
fixed, and as the st ern bearings ca.n neither approach
n )r re cede from each other, this moveme
nt
becomes
im p
ossible. In ord er to develop
any
gyroscopic
restsbance to bhe mo vement of the bow of the ship, either
up or down, ib is necessary for the shafts to throw
them
selves
oub of a parallel p o ~ i t i o n and a.s this is impossible,
th e
engines,
a.
s gyroscopes,
be
cJmes completely impotent,
and offer no
re
sist an
ce
ab
all
; in fact, the ship could be
tilted in
any
dire
ct
ion or rotated on a. vertical axis with
perfect freedom whether the turbines
wore
rotating or
not . Th e rotat ion of the turbines has abJolutely no effect
upon the free movement of the ship in any direction.
I t
is
true
if
we
pl a
ce one spi
nning
gyroscope
in
a.
box
or
frame, and
at t
9mpb to tilt
ib
on a.
hori
zontal axis, the
gyroscope
will of
itself turn on a.
verti
c1l
axis-in
fact,
the management of a
gyroscope
in a. box held loosely in
the hand is
so
mething like
driving
a. pig which h
as
a.
will of it s
own,
and it is this action which has deceived
superficial experimenters.
I f a.
single gy r
os
cope is
mounted in a rigid frame,
ib
offers not one
particle
of
resistance to having
its plane of
rotation
changed in
any direction. This is the poinb tha.b is not undersnood
by engineers. Mr. Cassel,
however.
is nob
satisfied
with
theory;
he wants
figures.
To satisfy
his burning desire
for figures
to
acc
urately
express the
force
mo
ments
due
to gyr
oscop
ic
acti
on in the O
ob
ra., I
eupply
the following
complete
statement
for the four s h a f t ~ looking afb :
Resistance
bo
pi bching . 0 + 0 + 0 + 0
=
0
Transverae couples
du
e
to
pitching
.. . . ..
+
A + B - B - A
=
0
where
A and
Bare
horizo
ntal
static
couples applied
by
the
shafbs,
balanced by equal
and oppos
ite
- B
- A
when
the
vessel is und er
way
.
I f Mr. Se
rrell, in
his experiments which be
s1.ys are
so
"e x tremely
easy, " will
use
two bicycle wheels
instead
of
one,
and rotate th
em
in opposite direction
s ab
equal
velo
cities,
ib
will
do
infini
te
ly
more to enlighten him
on this
subject than anything
tha.b I co
uld write.
I will
admit
tha.b
this
letter co
ntains
no
new ideas, and
tha.b the whole principle of the gyroscopic action on
board the Cobra was fully shown and set forth in my
previous letter.
My
only
excuse
for the great length of
the present letter is that my first letter was not under
sto:>d.
Yours truly,
HIRA M STEVENS J\tlAXIM.
18, Queen's Gate-plac3, London, S.W., October 21, 1901.
To
THE
EDITOR OF ENGINEERING.
Srn - I
hav
e read with great interest
the
letters now
appearing in ENGINEERING, aud should like
to
say, with
ree
rence to
S r Hira.m S. Maxim's
letter
of October 9 on
tl:le above subject, that by
actual
experiment with two
gyrJscopes
of equal weight and
diam
e ter, mounted in a
re
ctangular frame,
both
spinning in op.Posite directionEI,
on turning from the vertical
to
the honzo
nt a
l, bhe r e ~ u l b
is
absolutely
ni l
as regards
any
gyroscopic
effect
trans
mitted
to the
frame.
On spinning
the
gyroscopes
both
in the same
direction,
or either singly, the frame being held by a. strong man,
great diffic
ulty was
experienced in turning. In fa.cb, it
was found alm
os
t im possible,
without
the
ends
of the
fram
e
moving
laterally.
Th i
s would certainly
pub
an additional strain on any
framework of the
ship.
On putting the r
ectangular
frame
bebween lathe cenbres, the
gyroscopes
spinning
with th
eir
axe1
at
right
angles
with the lathe
ce
ntres, both turning
in the same di r
ec t
ion, bhe frame burns on the
centres as
easily
as
when they were nobspinning.
Thu
s s
howing
there can
be
but little
or
no
additi
o
nal
strain
on
the
framework
of the
structure,
assuming it is
well secured.
I
may menti
on the
gyroscopes experimented
with were
6 in. in diameter, and
weigh
ed 6 lb .
eac
h.
Yours faithful1y,
J Al\fES
F.
CARTER.
Experimental Works,
Ba.thea.ston, Oot
obe
r 22, 1901.
To THE
EDITOR oF
ENGINEERING.
Sm,
Mr. Serrell
will
find
tha.b S
ir
Hi
am Maxim's
atatemenb is " in
accordance
with
fact,
" if,
instead
of con
fining his
attention to one
wheel,
he performs his experi-
*
Ib
is
assumed here
that the Cobra.
had one system
of
two screw shafts revolving bo
the right,
and
another
y s b e m
of
bwo
screw shans revolving to the left.
E N G I N E E R I N G.
menb
with
two. I book
two front bicy
c
le wh
eels on
their
bearings oub of
two
bicycles, and rigidly connected the
two axles together l y screwing one
end
of
one
axle
to
the
end of
th
e
other
axle with an ordinary bicycle wheel nub,
so
that the bwo wheels were practically
on one
rigid axle.
I
then
held the two wh
ee
ls by
th
e o uter ends of the now
rigid
axle,
and got a. fri
end
to
start
th
e
wh ee
ls revolving.
When
one
wheel only was
revolving, I
naturally
ex
perienced the " r esistance
to
some
deviati
ons of the
axis," as
mentioned by
Mr. Serrell.
When
both wheels wer
e
revol
'ing in the
same dire
c-
tio
n, this resistanc
e
appeared to
be aboub double; but
when th
e two
whee
ls
were revolving as
near
as
p o
ssible
at
th
e
same
speed in
different direc t
ions,
this
resiRta.n
ce
was practica.lly t
.
That
this result would be attain
ed
is qu1te clear
from
mathemati
cs,
as
may
be seen
if
one
co
mpound
s
th
e
angular momentum
of
b o ~ h
wheels
with
the couple whi
ch is
applied to turn
the syste m
as a. wh
ole.
Yours faithfull
y ,
Norbh Ke n
s
ington, October
23.
G. S. ODLING.
TESTING DOWSON GAS.
To THE EDITOR
OF
ENGINEERING.
Sm , - I should be glad of the assistance of
any
of the
readers of your paper in the following matter :
I
want
a
simple,
but fairly r e l i a b l ~ method of te
sting
the quality
of Dowron ~ a s .
I
am concerned
with a. plant for supplying this gas,
which is used for a variety of heating purposes.
As
a
general rule, satisfactory
re..c:mlts are
obtained, but
every
now and then complaints ar ise from the users of the
gas
that ib nob of good quality . Sometimes the cause of the
complaints can be tra.c:e j
to
carelessness on the
part
of the
stoker, ab other
times
no explanation ca.n be fou
nd,
and no
doubb co
mpl
aints are frequently made when the is
not ab fa.ulb ab all.
Ib
occurred to
me thab some si
mpl
e method of
te3ting
the
in
the
same way
that
boiler flue
gases
are
tested
could
be
devis
e
d,
whe
reby
the
inflammable and h
eat
giving
constituents of the
gas could be
sepa