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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).
Analysis of high-speed wheel wobble, focusing on gyroscopic effects and tire wear characteristics.

Identifier  ExFiles\Box 29\1\  Scan295
Date  24th February 1926
  
SQUARE TREAD
ROUND-TREAD
VELOCITY OF TIRE
AT POINT A = wR
AT PT. B = wr
Contact Area
1. INSPECTION OF WEAR OF ROUND-TREAD TIRES SHOWS THAT POINT A, HAVING GREATEST CONTACT PRESSURE, FOLLOWS THE ROAD, WHILE POINTS B ARE CONTINUALLY DRAGGED FORWARD ALONG THE ROAD, SCALLOPING AND WEARING THE SIDES OF THE TIRE. AS SHOWN AT C,D
2. WHEN A ROUND-TREAD TIRE IS INCLINED AS SHOWN IT TENDS TO RUN ROUND A POINT E DUE TO VARYING VELOCITIES OF POINTS ON THE TREAD AT THE CONTACT AREA.
3. U.S. TIRES WHICH HAVE NEARLY FLAT TREADS SHOW LESS OF BOTH ABOVE EFFECTS

CONDITIONS OF WOBBLE
CORRESPONDING GYROSCOPIC EFFECTS
SPEED = 60 M.P.H.
w = ROTATION OF WHEEL = 615 R.P.M = 64.6 RADS/SEC
Ω = PRECESSION OF WHEEL (FROM TRACES) = 5.12 RADS/SEC
I = MOM. OF INERTIA OF WL. = 2.73 LBS. FEET² (NEGLECTING BRAKE DRUMS)
VEL 60 M.P.H

GYROSTATIC MOMENT ON FRONT AXLE
I w Ω = 1800 LBS FEET
= 380 LBS AT EACH WHEEL

TITLE BLOCK:
Drawn by: Hogal
Pass by: Sy
Date: FEB 24 '26
ROLLS-ROYCE OF AMERICA, INC.
TITLE: HIGH SPEED WOBBLE
DRAWING NO. I
SEE ALSO THE FOLLOWING OPERATION DRAWINGS
STAMP: FEB 36
  
  


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