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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).
Drawing analyzing high-speed wobble, tire wear, and gyroscopic effects on a vehicle's front axle.

Identifier  ExFiles\Box 29\1\  Scan297
Date  24th February 1926
  
SQUARE TREAD
ROUND-TREAD
VELOCITY OF TIRE
AT POINT A = ωR
AT PT B = ωr
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.
ω - ROTATION OF WHEEL = 615 RPM = 64.6 RADS/SEC
Ω - PRECESSION OF WHEEL (FROM TRACK) = 5.12 RADS/SEC
I - MOM. OF INERTIA OF WL = 2.78 LBS FEET² (NEGLECTING BRAKE DRUMS)
VEL 60 M.P.H

GYROSTATIC MOMENT ON FRONT AXLE
IωΩ = 1800 LBS FEET = 380 LBS AT EACH WHEEL

TITLE BLOCK:
Drawn by
Traced by
Checked by
Approved by: Gy
Limits
ROLLS-ROYCE OF AMERICA, INC.
Model
Sec.
Weight
Date: FEB 24/26
TITLE: HIGH SPEED WOBBLE
SCALE
HEAT TREAT
BRINELL
STANTON
DRAWING NO. [BLANK]
SEE ALSO THE FOLLOWING OPERATION DRAWINGS [BLANK]
  
  


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