Table of calculations for crankshaft stiffness based on a suggested empirical formula, compared with test results.
| Identifier | ExFiles\Box 25\3\ Scan325 | |
| Date | 3rd May 1928 guessed | |
| SUGGESTED EMPIRICAL FORMULA FOR CRANK SHAFT STIFFNESS IN BEARINGS. EQUIVALENT LENGTH FROM A TO B IN TERMS OF JOURNAL SHAFT ℓ = (2b + 0.8h) + 3/4 * (d₁⁴ - δ₁⁴)/(d₂⁴ - δ₂⁴) * a + 3/2 * r * (d₁⁴ - δ₁⁴)/(h * w³) ℓ/d₁ = P + Q + R STIFFNESS FROM A TO B = GJ/ℓ WHERE G = 11.8 x 10⁶ FOR STEEL J = π/32 * (d₁⁴ - δ₁⁴) --- TABLE DATA --- Nº | d₁ | r {Sir Henry Royce} /d₁ | δ₁/d₁ | d₂/d₁ | δ₂/d₁ | b/d₁ | h {Arthur M. Hanbury - Head Complaints} /d₁ | a {Mr Adams} /d₁ | w/d₁ | P | Q | R | ℓ/d₁ | L/d₁ | RATIO: (2b+2k+a)/L | RATIO: CALC. 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. 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 | EXAMPLE GIVEN BY PROF. LEWIS. SOC. NAVAL ARCHITECTS & MARINE ENG. VOL.33. 1925 (NEW YORK) 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 | .857 | .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 | 1.152 | 2.32 | 4.544 | 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 | 1.052 | .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 | 1.65 | 1.647 | 2.678 | 5.975 | 6.75 | .2962 | 1.13 | 1.163 | MOTOR CAR ENGINE. 17C | 1.89 | 1.353 | .423 | .937 | 0 | .544 | .4047 | .2592 | 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. --- DIAGRAM LABELS --- Top Diagram: w, A, B, r, h, a, b, b, d₂, δ₂, d₁, δ₁ Middle Diagram: EQUIVALENT LENGTH ℓ Bottom Diagram: EQUIVALENT LENGTH L FROM TEST --- FOOTER --- ROYAL AIRCRAFT EST: Handwritten note: 204B (next to row 14C) | ||
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).