Wednesday, October 7, 2009


Vol. 13, No. 10

Babbitt Bearings.
I note on page 665, issue of December 30, 1903, an article on "White Metal Bearings,"
by J. S. V. Bickford. He says it "hardly ever requires adjusting." My experience
is that it does need adjusting, but perhaps not so often as some other materials,
and constant adjusting where there is much duty. A bearing that could not
be adjusted would certainly be a failure on any well made machine. His assertion "All
you have to do is to wrap the bearing in asbestos twine, rubbed with lamp clay, and
warm it up until the metal runs, when you have a bearing as good as new," is certainly
a new one to me, and I would like to have Mr. Bickford explain the seemingly simple
operation more fully. When we have a babbitt bearing that is too bad to fill and
scrape to a fit we have to remove all babbit and repour.

Mr. Bickford says "this joint is used in Pratt & Whitney lathe head stocks, etc.,"
but my information is to the effect that it is poured, well hammered or rolled in the
boxes and then bored the same as any other bearing. I have never been able to pour
babbitt that would be tight in the boxes after it cooled, although the boxes were
heated before pouring, and I can vouch for the tightness of the babbitt in the Pratt &
Whitney head stock.

Gyrostatic Action.
I was interested in the editorial in your issue of March 2 on the gyrostatic action
of the flywheel as related to the strength of parts in an automobile, as I have been
working in that line for some time. I do not think that Mr. Ward has as yet presented
the matter in all its aspects. There is no doubt but that the flywheel very
strongly resists a force tending to change its plane of rotation under some circumstances,
but there is also another effect that I think must be taken into account.
When a force is exerted tending to change the plane of rotation, there is a strong
force created thereby at right angles to the first named force, and the parts should
be designed to resist this latter force. The parts may, I think, be so constructed that
there will be no gyrostatic resistance to the first named force, but they cannot be so
constructed that the latter shall not be exerted.

Professor Perry in his "Spinning Tops" (I think) observes that some locomotives
are not so fast as others of the same power, and he seems to attribute this to
such inertia effects, and Mr. Clough in a recent article remarks that the heavy
automobiles frequently take as little power to drive them at a certain speed as
do the light runabouts. It is quite possible that this may be due to the same or
related causes.

I have examined a number of works on mechanics with the hope of finding an
accessible treatment of the subject. The problem seems, however, to be
 treated from a theoretical standpoint, as investigating the very remarkable action of the
gyrostat in the familiar form of a toy, and is either too involved, mathematically, for
ready comprehension, or is not adapted to practical engineering conditions. For instance,
the mathematical expression for the time of nutation of the toy is curious, but
I do not at present see its practical application in automobile engineering.

I have worked out a formula which is sufficiently simple and rational in its derivation,
and have submitted it to some expert mathematicians, who have not as yet
found any error in it. I have designed an apparatus for experimental investigation of
the subject, and hope to have it constructed soon. I hope by this to prove my reasoning
either right or wrong.

Roller Bearings for Qasoline Engines.
Can you tell me whether roller bearings are practical for crank shaft bearings of
two or four cycle gasoline motors or not? I am not sure whether the impulse of explosion
would tend to crack the rollers or not.

[Undoubtedly roller bearings could be made to withstand the shock of explosion
in an engine, but they are not used by any of the well known automobile and engine
builders, probably because they would need to be considerably larger in size than
plain bearings.—ED.]

Gas Engine Oils.
Kindly advise me in your next issue what a first class oil should consist of for a water
cooled motor. Should it be the product of a straight crude petroleum or should
it be of the material of a high grade cylinder oil, which I believe has more or less
fatty matter in it?

Kindly advise me who, in your opinion, makes the highest grade motor oil.

[Gas engine oil differs from the ordinary steam engine cylinder oil in that it is
wholly, or almost wholly, of mineral origin—a product of crude petroleum—whereas
the so called "cylinder oil" is largely composed of animal matter. The gas engine
oil is much thinner, has a higher fire test and does not soot the internal working
parts in the same degree as "cylinder oil" would. The gas engine oil is specially
adapted for cylinder lubrication, and should be used in the crank case if splash lubrication
alone is depended upon for oiling the cylinder. It may also be employed for all
of the bearings if it is considered an advantage to use only a single grade of oil.
Otherwise ordinary machine oil is very satisfactory for bearings. We cannot inform
you who makes the highest grade of cylinder oil.—ED.]

Explosion Engine Queries.
What should be the size of inlet and exhaust valves, also diameter and weight of
rim of flywheel, for a 5x6 inch cylinder gasoline engine, running from 700 to 750
revolutions per minute, compression 60 pounds gauge? Also, if possible, please
give formula for calculating the same.

[A clear diameter of 1¾ inches will be sufficient for both the inlet and the exhaust
valve. It is usual to make the clear diameter of the valves about one-third the diameter
of the cylinder. A proper size for the flywheel would be 22 inches in diameter,
with a rim section 2 inches deep by 2½ inches wide. Such a flywheel would
weigh a little over 100 pounds. A considerable range in the weight of the flywheel
is allowable, as a larger flywheel than that specified above would allow the engine to
run at a lower minimum speed under full load and would prevent it from being pulled
down in speed so much when short, heavy obstructions are encountered.—ED.]

The writer would like to have your opinion on a two cylinder opposed motor. We
now have a single cylinder engine 5x6 inches, which develops fully 7 horse power.
We should like to know, if we hitch two of these cylinders together on an opposed
type, what horse power we would obtain. Should it give 14, more or less?

[A two cylinder engine should give approximately twice the power as a single
cylinder of the same cylinder dimensions. It might give even slightly more than
double the power, as the friction on the crank shaft and cam gear will most likely
not be twice as great as in the single cylinder machine, but, on the other hand, it
is somewhat difficult to perfectly attune the two cylinders so that each shall give its
maximum power at the same spark setting, which would probably counterbalance the
above advantage.—ED.]


The grievances of British motorists are to be tabulated by the Motor Union, says
the Daily Mail, and Parliamentary candidates will be asked for their opinions

In an article by Claude Johnson in the Badminton Magazine on "The Magnificent
Mercedes, the Rich Man's Motor Car," the tire cost per mile is estimated at 19.5
cents, or $975 for 5,000 miles, and the rest of the annual expense on the basis of
15,000 miles running is given as $3,375. including $1,000 for the hire of a driver.

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