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).
Comparative analysis of big-end bolt area and big-end bearing specifications across different engine models.
| Identifier | ExFiles\Box 114\2\ scan0074 | |
| Date | 1st October 1934 guessed | |
| -2- of section in bolts; alternatively we ought to make the bolts in a better material than the rods. It is quite possible that one of the two Phantom engines which burst on Sinfin Moor broke a big-end bolt, but it is difficult to tell what went first. The ratio big-end bolt area / area of neck of rod for some of our engines is as follows:- Wraith 82% (has a parallel shank to the rod) Bentley. 87.5% (has a taper shank) Kestrel VI. 84%. (curved foot rod) Goshawk. 136% (articulated rod) "R" Engine. 172%.( " " ) The articulated rod bolts on the two latter engines have to sustain the inertia loads of two pistons. Big-end Bearing. Areas of crankpins as a percentage of the piston area are as follows:- Wraith. 39.4% Bentley. 36.1% Kestrel VI. 27.4%. Rubbing velocities in big-ends are:- Wraith 49.1 ft/sec. at 5000 R.P.M. Bentley. 43.6 " " " 5000 R.P.M. Kestrel VI 28.4 " " " 2600 R.P.M. " 39.3 " " " 3600 R.P.M. "R" Engine. 43.0 " " " 3200 R.P.M. Contd: | ||