[From P. H. SCHWEITZER and E. R. KLINGE, "Oxygen-Boosting of Diesel
Engines for Take-Off," _The Pennsylvania State College Bulletin_ (April
1, 1941), vol. 35, no. 14, p. 25.]
_Practical Conclusions_
Airplanes require about one third more power during the take-off than in
flight. In diesel-engined airplanes the size of the engine could be
reduced by 25 percent by feeding oxygen into the intake air during the
takeoff. Applying the results of the experiments to a transport plane,
Fig. 31 shows the possible weight saving with various oxygen boosts. The
curves are based on 6000 cruising horsepower and an estimated engine
weight of 2 lb per hp.
For the take-off 8000 hp are necessary. To supply the additional 2000
hp, 200 lb of oxygen are fed into the intake air during the take-off.
The volume of 200 lb of liquid oxygen is approximately 20 gal. Standard
liquid air containers of 55 litre capacity weigh 75 lb. Therefore the
weight of the oxygen and container is 350 lb while the possible saving
in engine weight is 4000 lb. The weight per take-off horsepower is
thereby reduced from 2 to 1.54 lb. The calculation is shown in Table 1.
[Illustration: Figure 38.--Effect of Oxygen Boost on Power and Weight.
(Cruising horsepower 6000, takeoff horsepower 8000.)]
Oxygen addition may be used for starting diesel engines. The raising of
the oxygen concentration from the normal 21 per cent to 45 per cent was
found to be equivalent to a raise of approximately 10 cetane numbers as
far as starting is concerned.
Five per cent increase in oxygen concentration eliminated exhaust smoke
completely.