Robert Hutchings Goddard

“ Inasmuch as designs and theories alone can hardly carry conviction, certain experiments were desirable in order that any doubtful points might be settled. I first found that the efficiency of an ordinary rocket is remarkably small; namely, less than two per cent. Even the one-pound Coston ship rocket, which I found to have a range of a quarter of a mile, has an efficiency of but little over two per cent; the average velocity of ejection of the gases being about 1000 ft/sec. ”

“ Regarding the heights that could be reached by the above method; I have applied the theory already mentioned to cases which my experiments show must be realizable in practice, and I find that a mass of one pound could be elevated to altltudes of 35, 72, and 232 miles; by employing initial masses of from 3.6 to 13.6, from 5.1 to 24.3, and from 9.8 to 89.6 lbs., respectively. If a device of the Coston ship-rocket type were used instead, the initial masses would be of the order of magnitude of those above, raised to the 27-th power. ”

“ My next experiments were performed with steel chambers, of the form shown in Fig. 1, with the object of increasing the efficiency of the device, as a heat engine; and of therefore obtaining as high a velocity of ejection as possible. Some of these chambers were made of soft tool-steel, and others of tough nickel steel. ”