452 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1947 



is found to be low. The extremely high climbing speeds should be 

 taken into consideration in tactical operations. 



The rocket airplane shows amazing rates of climb at all altitudes, 

 varying from 28,500 feet per minute at sea level to 66,500 feet per 

 minute at 60,000 feet, where it runs out of fuel. This airplane will 

 coast to about 75,000 feet. Rate of climb reduces considerably al 

 35,000 feet, because of the reduced speed for best climb, resulting in 

 less thrust horsepower available at constant thrust. As climbing 

 speeds approach and exceed M = 1.0, these powers become extremely 

 large. For instance, 57,000 feet and 600 miles per hour in climb 

 represents 16,000 thrust horsepower. Climb performance has been 



FiGUKE 19. — Maximum rate of climb. 



integrated and weight variation accounted for, including that required 

 for linear acceleration along the flight path. 



Time to climb and absolute ceiling may be compared in the follow- 

 ing table, where the rocket ceiling is given as that altitude at which 

 fuel is exhausted. 



Time to climb, and ceiling 



