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).
Laboratory test report on the foaming properties of various oil mixtures.
| Identifier | ExFiles\Box 28\1\ Scan119 | |
| Date | 26th March 1928 guessed | |
| RESULT OF LABORATORY TEST ROLLS-ROYCE OF AMERICA, INC. Test No. Date Sheet No. 2 Oils Used: 50% Castor Oil, 50% De. Alcohol First Indications: Started foaming at once 5 Min Stirring: Large bubbles 1/2" from edge 15 min. stirring: No increase in foaming Final Appearance: Large foaming bubbles on outside Foam lasted: 3 min. Of the oils considered, Lovejoy was slightly better than Mobiloil E.{Mr Elliott - Chief Engineer} The addition of glycerine to Mobiloil E, tended to produce much larger air bubbles, so would be a less suitable mixture. A light paraffine base oil showed no better than a light asphaltum oil but would not stand low temperatures without thickening considerably or even setting and becoming solid. Lard oil would be very good from the standpoint of foaming, but its tendency to become rancid after a period of time would exclude it from use in this particular case. Castor oil and its mixtures seem to offer the best possibility. With pure castor oil, altho the very fine bubbles foam slowly, they increase with the period of stirring so that after 15 minutes time, there is quite a turbid solution which takes about 1-1/2 hours to get back to normal again. A mixture of castor oil with 50% of denatured alcohol foams as much as the other oil mixtures, so is not any more suitable. The mixture of 80% Castor oil and 20% denatured alcohol seems to be the best, as the few fine bubbles that foam at first, grow less as the period of time increases and after fifteen minutes stirring, there is an almost clear solution again. If this mixture is of the right viscosity, it should eliminate most of the trouble from foaming. | ||