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).
Technical note with a diagram explaining the relationship between effective pressure, load, and gaps in a piston system.
| Identifier | ExFiles\Box 66a\4\ scan0118 | |
| Date | 16th February 1926 guessed | |
| contd :- -7- The load was further reduced, and at each reduction the pressure piston rose until with 40 lbs. load it has moved through 85% of the distance it would have traversed with no resistance to overcome. From this it appears that the effective pressure P. varies with the size of the cut off gap G.{Mr Griffiths - Chief Accountant / Mr Gnapp} owing to the leak L. being of necessity of appreciable proportions. In effect when cut off, gap G.{Mr Griffiths - Chief Accountant / Mr Gnapp} is the same size as leak L., the effective pressure P. is nothing with an oil of low viscosity. LEAK L. CUT OFF GAP G.{Mr Griffiths - Chief Accountant / Mr Gnapp} EFFECTIVE PRESSURE P. Therefore under appreciable loads, the large piston does not closely follow the movement of the small piston as sufficient effective pressure P. cannot be built up to deal with the load unless cut off gap G.{Mr Griffiths - Chief Accountant / Mr Gnapp} is considerable. When we are working near the limit of the oil relay as we are trying to do with the reduced contd :- | ||