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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).
Empirical formula and data for crankshaft stiffness in bearings.

Identifier  ExFiles\Box 65\4\  scan0209
Date  23th November 1927
  
SUGGESTED EMPIRICAL FORMULA FOR CRANK SHAFT STIFFNESS IN BEARINGS

EQUIVALENT LENGTH FROM A TO B IN TERMS OF JOURNAL SHAFT = l = (2b + .8h) + 3/4 * ((d₁⁴ - δ₁⁴)/(d₂⁴ - δ₂⁴)) * a + 3r/2 * ((d₁⁴ - δ₁⁴)/hw³)

l/d₁ = P + Q + R

STIFFNESS FROM A TO B = G J / l
WHERE G = 11.8 x 10⁶ FOR STEEL
J = π/32 (d₁⁴ - δ₁⁴)

--- TABLE DATA ---

Nº | d₁ | r/d₁ | δ₁/d₁ | d₂/d₁ | δ₂/d₁ | b/d₁ | h/d₁ | a/d₁ | w/d₁ | P | Q | R | e/d₁ | L/d₁ | (2b+2h+a)/L | RATIO:- CAL.{Mr Calvert}STIFF/TEST.STIFF | TEST STIFFNESS LBS.INS./RAD x 10⁶ | REMARKS
1M | 1.656 | .868 | .49 | 1.0 | .49 | .529 | .49 | 1.13 | 1.51 | 1.448 | .854 | .727 | 3.03 | 3.194 | .992 | 1.054 | 1.55 | SCALE MODEL OF A MARINE ENGINE SHAFT. EXAMPLE GIVEN BY PROF: LEWIS SOC: NAVAL ARCHITECTS & MARINE ENG.S VOL.33.1925 (NEW YORK)
2M | 9.453 | .876 | .456 | 1.0 | .456 | .521 | .458 | 1.167 | 1.655 | 1.407 | .875 | .602 | 2.88 | 3.12 | 1.0 | 1.082 | 300 | SCALE MODEL OF A MARINE ENGINE SHAFT
3M | 1.5 | .896 | .541 | 1.0 | .541 | .5055 | .489 | 1.01 | 1.33 | 1.402 | .758 | 1.057 | 3.22 | 3.104 | .967 | .964 | 1.15 | SCALE MODEL OF A MARINE ENGINE SHAFT
4M | 11.22 | .931 | .461 | 1.0 | .461 | .5065 | .457 | 1.126 | 1.648 | 1.38 | .845 | .653 | 2.88 | 3.05 | 1.0 | 1.059 | 512 | EXAMPLE GIVEN BY PROF: LEWIS
5M | 7.0 | 1.0 | .464 | 1.0 | .464 | .5715 | .571 | 1.14 | 1.571 | 1.6 | .897 | .672 | 3.13 | 2.93 | 1.17 | .936 | 129.4 | EXAMPLE GIVEN BY PROF: LEWIS
6A | 2.875 | .826 | .587 | .933 | .652 | .163 | .424 | .892 | 1.022 | .664 | 1.044 | 2.425 | 4.13 | 4.33 | .477 | 1.048 | 5.6 | AIRCRAFT ENGINE
7A | 2.324 | 1.1 | .645 | .848 | .538 | .406 | .322 | 1.015 | 1.22 | 1.072 | 1.452 | 2.32 | 4.844 | 4.34 | .592 | .898 | 2.76 | AIRCRAFT ENGINE
8A | 5.0 | 1.2 | .65 | .85 | .5 | .3 | .32 | .66 | 1.19 | .857 | .884 | 2.742 | 4.48 | 4.175 | .455 | .932 | 28.5 | AIRCRAFT ENGINE
9A | 2.92 | 1.28 | .714 | .99 | .754 | .341 | .3 | 1.01 | 1.145 | .922 | .88 | 3.152 | 4.954 | 5.08 | .452 | 1.025 | 4.2 | AIRCRAFT ENGINE
10A | 2.625 | 1.33 | .524 | .905 | .477 | .381 | .382 | .952 | 1.262 | 1.068 | 1.062 | 2.43 | 4.56 | | | | | AIRCRAFT ENGINE
11A | 5.15 | 1.528 | .687 | 1.032 | .687 | .428 | .419 | 1.01 | 1.298 | 1.19 | .647 | 1.943 | 3.78 | 4.07 | .664 | 1.075 | 30.25 | AIRCRAFT ENGINE
13C | 2.625 | 1.047 | .5714 | .8095 | .4285 | .2857 | .4095 | .7047 | 1.152 | .899 | 1.193 | 2.245 | 4.337 | 4.5 | .466 | 1.038 | 4.17 | MOTOR CAR ENGINE
14C | 2.0 | 1.125 | .625 | .75 | .375 | .2625 | .4 | .75 | 1.1 | .845 | 1.605 | 2.681 | 5.131 | 5.5 | .377 | 1.07 | 1.425 | MOTOR CAR ENGINE
15C | 2.125 | 1.058 | .5882 | .7059 | .3529 | .2353 | .4235 | .6353 | 1.094 | .81 | 1.803 | 2.526 | 5.139 | 5.7 | .343 | 1.108 | 1.718 | MOTOR CAR ENGINE
16C | 2.0 | 1.125 | .625 | .75 | .4375 | .2625 | .375 | .725 | 1.125 | 1.05 | 1.647 | 2.678 | 5.375 | 6.75 | .2962 | 1.13 | 1.163 | MOTOR CAR ENGINE
17C | 1.89 | 1.353 | .423 | .937 | 0 | .544 | .4047 | 2.592 | 1.248 | 1.41 | 2.432 | 2.522 | 6.364 | 5.78 | .776 | .91 | 1.307 | " " " SPECIAL CASE 6 CRANKS 4 BEARINGS CALCULATION APPLIED TO CRANKS IN PAIRS.
18C | 2.6245 | 1.047 | .6675 | .714 | .429 | .2857 | .373 | .7625 | 1.219 | .871 | 2.025 | 1.863 | 4.765 | 4.830 | .5360 | 1.015 | 3.485 | SPORTS PHANTON E.76546.
19C | 2.125 | 1.058 | .648 | .707 | .4115 | .2705 | .343 | .706 | 1.270 | .8175 | 1.99 | 1.86 | 4.615 | | | | | INDIA TB LEC 2480 CALC. STIFF: 1.985 x 10⁶ PER CRANK

--- STAMP ---
ROLLS-ROYCE LIMITED
A.D.D.
23 NOV 1927
  
  


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