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).
Calculations for increasing flywheel inertia by 30% for model crank tests.
| Identifier | ExFiles\Box 63\4\ scan0066 | |
| Date | 12th February 1930 | |
| MODEL CRANK TESTS Increasing Inertia of flywheel by 30% Wt of flywheel = 48 lb. Length of each test wire "l" = 2 ft. Distance between wires "d" = 16.250 = 1.354 ft. Periodic Time "t" = 26/20 = 1.3 secs. t = 2π√(Il/gd²), I = Wt²d² / 16π²l I = (48 x 1.3² x 1.354²) / (16xπ² x 2) = (3 x 1.3² x 1.354²) / (π² x 2) = .4707 (lb ft units) Extra Ring must increase inertia by 30% = .4707 x .3 = .14121 I = M/2(R²+r²) = W/2g(R²+r²) = .1412 R² + r² = (.1412 x 2g) / W W = ((R+r)/2) x 2π x (R-r).h.w = (R²-r²)πhw {h = width of flange} {w = wt/c.ft of cast iron} R⁴ - r⁴ = (.1412 x 64.4) / (π x .156 x 449.2) = .04125 R⁴ = .04125 + r⁴ = .04125 + .2592 = .30045 ∴ R = ⁴√.30045 = .7404' = 8.8848" ∴ Outside diam of Extra Inertia Ring = 17.7696" Side calculations (logs): logs. 3 = 0.4771 1.3² = 0.2278 1.354² = 0.2632 ------- 0.9681 π² = 0.9944 2 = 0.3010 ------- 1.2954 .4707 = overline{1}.6727 .1412 = overline{1}.1498 64.4 = 1.8089 ------- 0.9587 π = 0.4972 .1562 = overline{1}.1937 449.2 = 2.6524 ------- 2.3433 .04125 = overline{2}.6154 r = 8.562 = 0.9326 12 = 1.0792 ------- overline{1}.8534 4 ------- r⁴ = .2592 = overline{1}.4136 .30045 = overline{1}.4778 / 4 .7404' = overline{1}.86945 | ||