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 of the coefficient of friction and efficiency for a '1940 Worm No.2' component under various conditions.
| Identifier | ExFiles\Box 67\4\ scan0373 | |
| Date | 22th August 1927 | |
| '940 WORM NO.2. MOTORINE C. 22/8/27. CALC. OF COEFF. OF FRICTION AND EFFICIENCY. (SEE FIG.1.) a) (PARKING). T/W = (11.4 x 20) / 1000 ; tan(θ+γ) = 228 / 700 = .326. (θ+γ) = 18° 3' θ = 12° 4' γ = 5° 59' | μ = .1047 EFFICIENCY = .2138 / .326 = 65.6% b) T/W = (10 x 20) / 1000 ; tan(θ+γ) = 200 / 700 = .286 (θ+γ) = 15° 58' γ = 3° 54' μ = .0682 EFFICIENCY = .2138 / .286 = 78%. c) (JOGGLES): T/W = (5.4 x 20) / 1000 ; Tan(θ-γ) = 108 / 700 = .154 (θ-γ) = 8° 45' γ = 3° 19' | μ = .0579 EFFICIENCY = .154 / .2138 = 72.2%. d) T/W = (3.5 x 20) / 1000 ; tan(θ-γ) = 70 / 700 = .100 (θ-γ) = 5° 43' γ = 6° 21' | μ = .1113 EFFICIENCY = .100 / .2138 = 46.7%. | ||