Miss D. and I are both reading an on-line version of the long-out-of-print classic science book "Ignition! An Informal History of Liquid Rocket Propellants" (link is to an Adobe Acrobat document in .PDF format) by John D. Clark. Neither she nor I are scientists, but we enjoy science as a subject - and when a scientist author is rib-ticklingly funny about his subject, that's a bonus!
It seems that the history of rocket propellants has been fraught with discovery. The first two photographs in the book bear this out, showing first a successful rocket test (left, complete with so-called 'mach diamonds' in the exhaust), and then - on the right, in the same test bay (or what used to be the same test bay) - the results of an unsuccessful one.
Looks like that second one was a bad hair day all round!
I'm particularly enjoying Dr. Clark's account of early experiments, which were very much a matter of trial and (mostly) error. One particular test (described on pp. 28-29) sounds like it was 'interesting', in the military sense of the word!
The simplest tester consisted of an eyedropper, a small beaker, and a finely calibrated eyeball — and the most complicated was practically a small rocket motor setup. And there was everything in between. One of the fancier rigs was conceived by my immediate boss, Paul Terlizzi, at NARTS [the Naval Air Rocket Test Center at Dover, NJ]. He wanted to take high-speed Schlieren (shadow) movies of the ignition process. (What information he thought they would provide escaped me at the time, and still does.) There was a small ignition chamber, with high-speed valves and injectors for the propellants under investigation. Viewing ports, a high-speed Fastex camera, and about forty pounds of lenses, prisms, and what not, most of them salvaged from German submarine periscopes, completed the setup. Dr. Milton Scheer (Uncle Milty) labored over the thing for weeks, getting all the optics lined up and focused.
Came the day of the first trial. The propellants were hydrazine and WFNA. We were all gathered around waiting for the balloon to go up, when Uncle Milty warned, "Hold it — the acid valve is leaking!"
"Go ahead — fire anyway!" Paul ordered.
I looked around and signaled to my own gang, and we started backing gently away, like so many cats with wet feet. Howard Streim opened his mouth to protest, but as he said later, "I saw that dogeating grin on Doc's face and shut it again," and somebody pushed the button. There was a little flicker of yellow flame, and then a brilliant blue-white flash and an ear-splitting crack. The lid to the chamber went through the ceiling (we found it in the attic some weeks later), the viewports vanished, and some forty pounds of high-grade optical glass was reduced to a fine powder before I could blink.
I clasped both hands over my mouth and staggered out of the lab, to collapse on the lawn and laugh myself sick, and Paul stalked out in a huff. When I tottered weakly back into the lab some hours later I found that my gang had sawed out, carried away, and carefully lost, some four feet from the middle of the table on which the gadget had rested, so that Paul's STIDA could never, never, never be reassembled, in our lab.
There's also the time they tested an . . . er . . . unusually fragrant fuel (p. 31).
[Mike] Pino, in 1949, made a discovery that can fairly be described as revolting. He discovered that butyl mercaptan was very rapidly hypergolic with mixed acid. This naturally delighted Standard of California [today part of Chevron Corp.], whose crudes contained large quantities of mercaptans and sulfides which had to be removed in order to make their gasoline socially acceptable. So they had drums and drums of mixed butyl mercaptans, and no use for it. If they could only sell it for rocket fuel life would indeed be beautiful.
Well, it had two virtues, or maybe three. It was hypergolic with mixed acid, and it had a rather high density for a fuel. And it wasn't corrosive. But its performance was below that of a straight hydrocarbon, and its odor — ! Well, its odor was something to consider. Intense, pervasive and penetrating, and resembling the stink of an enraged skunk, but surpassing, by far, the best efforts of the most vigorous specimen of Mephitis mephitis. It also clings to the clothes and the skin. But rocketeers are a hardy breed, and the stuff was duly and successfully fired, although it is rumored that certain rocket mechanics were excluded from their car pools and had to run behind. Ten years after it was fired at the Naval Air Rocket Test Station — NARTS — the odor was still noticeable around the test areas.
I'm glad I wasn't there for that test! I'm also glad they never got around to using butyl mercaptan in the liquid-fueled rockets that powered the American space program. Can you imagine the (literal and figurative) stink (you should pardon the expression) if Apollo 11 had risen to the moon smelling like a fugitive skunk? "High" flight, indeed!