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From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Sequence of events and forces involved when a road wheel suspension encounters a bump.

Identifier  WestWitteringFiles\O\2April1926-June1926\  Scan144
Date  20th May 1926
  
Contd.
-3-
HS{Lord Ernest Hives - Chair}/ACL/T20.5.26.

The results obtained are given in the sequence
that would occur supposing the road wheel to encounter a
bump, the complete cycle which could be represented by :-

(1) Upward deflec. of wheel from its mean
riding position.
(2) Return to its mean position.
(3) Rebound past mean position.
(4) Upward return to its mean position.

(1) RESISTANCE TO UPWARD DEFLECTION CAUSED BY A BUMP.

The piston would be working in the large bore
of the cylinder with the light flap valve open permitting
comparative free flow of oil through it as well as past the
sides. The radial clearance of the piston in this bore
is .017".

Curve No.1 of this appended graph shews how the
resistance to motion in this direction varies with the speed
of deflection.

In order to get a rough idea of the amount of
damping we should obtain we will assume the spring to be
passing through its mean position at the same speed as it
would do if vibrating freely under the weight of the car with
an amplitude of 2" or deflection of 1". The velocity
would be approx. 35 ft/min. resultingin a maximum resistance
of 60 lbs. In practice when under the action of the
"damper" the amplitude would have to be greater to result
in the above velocity.

Contd.
  
  


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