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Calculations comparing two design variants (Fig A and Fig B) of a mechanical component, including dimensions, inertia, and weight.


Identifier  ExFiles\Box 130\3\  scan0125
Date  28th February 1940
  
Top Section (Fig A):
Diagram Dimensions: 1.850, .650, .525, .650, 14.5, 14.15 (circled), .205, .015, 11.9, 10.725, .895, 12.125.
Diagram Labels: A, B, C, D, E, F, Fig A. {Mr Adams}
Annotation: if 14.05, I=623, W=13.25

Calculations for Inertia (I):
Column Headers: d, d⁴-d₂, w, (πx.283)/32, I
A: d(19.95, 14.5), d⁴-d₂(50000, 44200, 5800), w(x .650/2), calc(x .02777 = 52.4)
B: d(14.5, 14.15), d⁴-d₂(44200, 40000, 4200), w(x 1.850), I(= 216)
C: d(14.15, 12.125), d⁴-d₂(40000, 21600, 18400), w(x .525), I(= 268.5)
D: d(12.125, 11.9), d⁴-d₂(21600, 20050, 1550), w(x .280), I(= 12.)
E: d(11.9, 10.725), d⁴-d₂(20050, 13250, 6800), w(x .205), I(= 38.7)
Total I: 587.6

Calculations for Weight (W):
Column Headers: area, in³, W LBS
A: area(175.5, 165, 10.5), calc(x .65/2 = 3.41)
B: area(165, 157.3, 7.7), calc(x 1.85 = 14.25)
C: area(157.3, 115.5, 41.8), calc(x .525 = 21.95)
D: area(115.5, 111.2, 4.3), calc(x .28 = 1.2)
E: area(111.2, 90.5, 20.7), calc(x .205 = 4.24)
Total Area: 45.05
Total W: x .283 = 12.75

Bottom Section (Fig B):
Diagram Dimensions: .200, .975, 14.50, 13.80, 11.9, 12.125, 12.400.
Diagram Labels: A, B, C, D, E, F, x, Fig B.
Annotation: x Extra cost machining not justified WRP

Calculations for Inertia (I):
(Carried over value: 52.4)
A: d(14.5), d⁴-d₂(44200, 36200, 8000), w(x 1.85), calc(x .02777 = 41.1)
B: d(13.8), d⁴-d₂(36200, 23600, 12600), w(x .2), I(= 70)
C: d(12.4), d⁴-d₂(23600, 21600, 2000), w(x .525), I(= 29.1)
D: d(12.4, 12.125), d⁴-d₂(21600, 20050, 1550), w(x .28), I(= 12)
E: d(11.9, 10.725), d⁴-d₂(20050, 13250, 6800), w(x .205), I(= 38.7)
Total I: 613.2

Calculations for Weight (W):
(Carried over value: 3.41)
A: area(165, 150, 15), calc(x 1.85 = 27.75)
B: area(150, 121, 29), calc(x .2 = 5.8)
C: area(121, 115.5, 5.5), calc(x .525 = 2.89)
D: area(115.5, 111.2, 4.3), calc(.28 = 1.2)
E: area(111.2, 90.5, 20.7), calc(.205 = 4.24)
Total Area: 45.29
Total W: x .283 = 12.8
  
  
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).


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