Enemy Fuels Examined, WWII Tactical and Technical Trends, No. 22: April 8, 1943 (Lone Sentry)

Tactical and Technical Trends, No. 20, p. 26, gave an analysis of some samples of gas and oil used in German mechanized vehicles. It is evident from the following report that the enemy continues to maintain a high standard for gasoline and other fuels.

a. Aviation Gasoline

There are still two chief types of fuel in use in the Luftwaffe: viz., B. 4 ("blue," generally used in bombers) and C. 3 ("green," used in fighters).

During the last year, there has been no fundamental change in the quality or method of production of the blue-type fuel. The base spirit is of petroleum origin. If it emanates from current Axis production, it probably comes from Rumania. It is understood, however, that the quantities involved do not preclude the possibility of its derivation from pre-war or captured stocks of American or Venezuelan aviation gas.

It is blended to 90-octane by the addition of mixed high-octane gasolines, aromatics or hydro-gasoline, and T.E.L. (tetra-ethyl-lead). A previous conclusion that usually two of these blending agents (and T.E.L.) are used in conjunction has been confirmed. It has been suggested that the added high-octane gasolines come from captured stocks, and this is a possible explanation of the small concentrations used.

The reason for the continued use of blue fuel is not yet clear. There is no evidence of any increased use of hydro-gas--if anything, the reverse is true.

Evidence strengthens the view that the C. 3 green fuel is capable of giving very high performance, and that it has an exceptionally good rich-mixture performance, considerably better than 100-octane aviation gasoline.

The origin of the aromatics in the green fuel is not certain, but the possibility of making them by the treatment of hydrogenation products from creosote has been established.

The method of preparation which most closely fits the analysis of this green fuel is the blending of a light cut of straight-run petroleum spirit with gasoline or naphtha, produced from creosote by some form of aromatising hydrogenation, and with the addition of high-octane materials.

All German aircraft fuels continue to show the presence of about 5.5 milliliters of T.E.L. per imperial gallon.

b. Motor Fuels

The test results on motor fuels from Europe, as well as other information available, suggest that T.E.L. is not being used, but that alcohol is being employed to a limited extent. A number of samples from the Middle East contained T.E.L.; others contained alcohol. A fair proportion of both sets of samples from Europe and the Middle East contain a high percentage of aromatic hydrocarbons, indicating that there is no general shortage of aromatics in Germany.

Octane numbers vary widely, and from the very low antiknock value of some of the motor gasolines captured in the Middle East, it would appear that local blending with benzol, alcohol, and/or T.E.L. must take place.

c. Other Fuels

The high-speed diesel-fuel samples from Europe are all of low pour-point, some as low as minus 40° C; it is suggested that a number contain Fischer-Tropsch gas oil (probably a special process for mixing gas oil) mixed with creosote. The low pour-point indicates that extensive provision has been made for dewaxing. On the other hand, some high-speed diesel-fuel samples from the Middle East are of much higher pour-point, showing that the enemy may have segregated them according to the type of climate in which they are to be used.

Several fuels appear to be of Rumanian origin, while one may be Persian. For heavy bunker fuels, coal tar products are being used in some cases.