Part II : 1950 -1957
Advanced Propulsion Concepts
 Dryden's request to Myers was typical of NACA's conservative approach in entering a new field-solicit opinions and build a broad base of national support so that it would appear the agency was practically pushed into the new work. This process continued when Myers, at the May 1956 meeting of the rocket subcommittee, asked the members for suggestions for rocket research for the next 10 to 15 years. By the fall of 1956, the responses were grouped into five discussion topics, one of which was high-energy propellants, but without specific reference to liquid hydrogen.* In discussions of these topics in meetings the following year, evaluation of high-energy propellants  was of first-order importance, but again no specific propellant combinations were singled out.31 The NACA-Lewis rocket group, however, was still greatly interested in liquid hydrogen and believed that they had the support of the rocket subcommittee.
In mid-1957, at the invitation of the chairman of the NACA subcommittee on aircraft fuels, Richard Canright (who had left JPL for Douglas Aircraft in 1953) submitted a paper on rocket propellants as viewed by an airframe manufacturer. Canright had a long interest in rocket propellants and his employer, Douglas Aircraft, had development contracts involving both solid and liquid rocket engines. From this viewpoint, he dismissed the application of air-breathing engines for missiles as "extremely limited if not completely non-existent." After discussing the relative advantages of solid and liquid rocket propellants, Canright gave his views on liquid hydrogen:
This is, of course, the non-carbonaceous fuel that offers the highest performance of any fuel. However, because of its low density, it is useful only in certain extreme applications. Hydrogen offers excellent combustion characteristics, both in the gas generator and in the main motors, and good heat transfer characteristics in the supercritical regime; on the other hand, it is hazardous to handle and there is no large engine experience with this fuel to date.32
Except for the mention of combustion and heat transfer characteristics, Canright offered little more on liquid hydrogen than Tsiolkovskiy 30 years earlier, an indication of the continuing gap between what was known about liquid hydrogen and its practical application.
When asked to summarize the contributions of the rocket subcommittee in its five years of existence, Canright replied:
He added, however, that NACA interest in high-energy propellants was praiseworthy and that the subcommittee supported it.
* The others; nonconventional rocket propulsion, such as solar energy, ions, electrons, charged particles, and free radicals; nuclear energy; comparison of nuclear and non-nuclear propulsion: and summary of the other topics form the viewpoint of applications and military requirements.