<div class="section abstract"><div class="htmlview paragraph">BORON compounds offer a heat of combustion 40% greater than that of aircraft fuels in current use. Diborane and pentaborane have burned satisfactorily in turbojets, afterburners, and ramjets. But boron compounds leave troublesome deposits and they present supply, storage, and handling problems.</div><div class="htmlview paragraph">This paper describes investigations into the use of boron hydrides as high-energy liquid fuel. Present results indicate that the ultimate fuel will be a boron-hydrogen-carbon compound.</div><div class="htmlview paragraph">The author also discusses other high-energy fuels of magnesium, aluminum, beryllium, and boron. Magnesium has been found to be a top fuel for short-time high-thrust applications, because of its high combustion temperature.</div></div>