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).
Confirmation of a telephone message regarding issues and improvements for the Peregrine & Bensport engine head joint.
| Identifier | ExFiles\Box 179b\1\ img086 | |
| Date | 26th September 1932 | |
| HS.{Lord Ernest Hives - Chair} } FROM R.{Sir Henry Royce} B. } C. to SO. WOR.{Arthur Wormald - General Works Manager} BY.{R.W. Bailey - Chief Engineer} CONFIRMATION OF TELEPHONE MESSAGE. PEREGRINE & BENSPORT. ENGINE HEAD JOINT. X4027 X4553' (1) The first thing that we notice is that there are signs of pre-ignitions being partly (at least) the cause of the trouble. (2) No doubt we must increase the size of the studs to 5/16", and get this point beyond doubt. If, when using this size of stud, the casting (jacket) seems too weak, we should lengthen the engine by .125" between the centres - 4 X .125 = .5". (3) The joints might stand better with a spigot on the liner so as to be like the aero engines, and perhaps the joint made with narrow rings, and the water with copper asbestos or rubber. (4) The alternate head - 6 exhausts - may suit the above suggestion better than the original Peregrine head, and also may reduce the exhaust valve trouble. (5) Perhaps we cannot bear quite so high a compression ratio with so high a boost at low speed. (6) If detonations enter into the fault we shall be less efficient than the G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 1. type of engine, but we must struggle hard not to need such an engine now, as our time is gone. (7) Would it be worth while trying an aluminium bronze head, firstly for better heat conductivity, and also for better valve seats. (8) Regarding the blower, it looks as if the No. 10. Powerplus is as large as we ought to use, and that this type of blower really gives too much boost at low speed (bad for detonations), whereas a centrifugal or even a Roots type blower increases in boost more quickly with speed. The same blower (No. 10.) might give more HP. with longer duration inlet valve opening, which at present seems to close too early, but the exhaust opening should not be early because of the higher pressure and heat. (1) | ||