Rolls-Royce Archives
         « Prev  Box Series  Next »        

Calculations to find the radius of gyration squared for an 11-G-111 landaulet body by swinging.


Identifier  ExFiles\Box 107\4\  scan0083
Date  28th November 1927 guessed
  
X4538

TO FIND K² FOR 11-G-111 BY SWINGING.
(LANDAULET BODY. SPARE WHEEL AT REAR). X5830

Let K²_GT = K² of total car (including axles) about c.g. of total car.

= T² p g / 4 π² - p² ft²

Where p = distance of c.g. from point of support when swinging
= 10.167'

T = 3.9 secs.

Then K²_GT = 22.6 ft².

Weight of total car = 4004 lbs.

∴ I_GT = 4004 X 22.6 = 90,500 lbs.ft².

From this must be subtracted the axle inertias about the same point.

Weights are ( Front 305 lbs. k² = 1² + 6.083²
( Rear 485 lbs. k² = 1² + 4.708²

Inertia for two = 305 (1² + 6.083²) + 485 (1² + 4.708²)
= 22,840 lbs.ft².

∴ I_G = Inertia of sprung part about c.g. of spring + unsprung parts
= 67,660 lbs.ft².

Weight of sprung part = 3214 lbs.

∴ k_G² = 67,660 / 3214 = 21.06 ft².

To find position of c.g. of sprung part.

contd :-
  
  
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).


Copyright Sustain 2026, All Rights Reserved.    whatever is rightly done, however humble, is noble
An unhandled error has occurred. Reload 🗙