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).
The properties and testing of Isopropyl Ether blends in aviation fuels.
| Identifier | ExFiles\Box 150\1\ scan0211 | |
| Date | 29th September 1936 guessed | |
| - 5 - although meriting attention under some conditions is not an important handicap to its use in aviation fuels. Another characteristic of major practical importance in determining the acceptability of a fuel is its storage stability. Blends of Isopropyl Ether in aviation gasoline have low gum content by all the usual methods of test. With the addition of 1 to 2 milligrams of gasoline inhibitor per 100 ml., these blends also have satisfactory resistance to oxidation. The induction period determined at 212°F. {Mr Friese} under oxygen pressure of 100 lbs. per sq. in. exceeds seven hours. The best motor gasolines rarely have an induction period exceeding six hours. The gum tests and the oxidation test are usually accepted as measures of the storage stability of a fuel. However, actual storage tests are also being made to confirm the indications of the accelerated tests. Table II shows the preliminary results of storage tests now in progress. After 2-1/2 months at 100°F. {Mr Friese} , the stability of the Isopropyl Ether blends, both leaded and unleaded, appears unimpaired. Table III gives pertinent inspection data on blended fuels containing 3 cc. of tetraethyl lead and meeting 100 octane number specifications. Specifications for the U.S. Army, U.S. Navy, British Air Ministry, Pratt & Whitney, and Wright Aeronautical are shown to allow comparison with fuel inspection. A typical aviation gasoline is also included for comparison. It will be observed from Table III that a 40% blend of Isopropyl Ether in aviation gasoline, with 3 cc. of lead per gallon of blend, meets the specifications set by the U.S. Army, U.S. Navy, British Air Ministry, Pratt & Whitney and Wright Aeronautical Corporation. Figure 3 gives A.S.T.M. distillation for these same blends and the aviation gasoline. Figure 4 shows how various 45% combination blends of technical Iso-Octane and Isopropyl Ether in aviation gasoline can be used to give a distillation very closely approximating the straight aviation gasoline distillation. Figure 5 shows the distillation effect of various percentages of Isopropyl Ether in aviation gasoline and demonstrates that mid range volatility may be varied widely without materially affecting overall boiling range of the gasoline. Octane Numbers A considerable amount of data is available in regard to the octane number and lead susceptibility of blends of Isopropyl Ether by various methods. Summarized data are shown in Tables IV and V and graphically in Figures 6 to 9. A study of these results justifies the following conclusions in regard to performance on single cylinder test engines: | ||