Yep. I was trying to be conservative in my napkin math. It’s probably not quite as bad in practice.
Of course, if one is really designing for space from scratch, a gas gun might be a better fit. Helium gas guns can reach very high velocities, and will get colder as you use them, not warmer. Maybe one can have both types mounted side by side, alternating shots to maintain an even temperature.
i was just throwing stuff out there.
Math - Advn Calc - Diff Eq and the like are why I abandoned my engineering pursuits after a couple of years. Also I spel to gud tu b n engineer.
I saw James Bond use a rocket pistol.
Or engineering.
Definitely in engineering: Shoving “bad” guys into the intake can’t be good for the inner workings.
Darn.
It is in my memory (that is, I have no cite) that one factor that helped the Soviets when the Nazi’s attacked the USSR, is that the German machine guns didn’t work reliably in the cold due to lubrication. The Soviet guns worked just fine, because they knew (being cold weather trained) to thin out the oil with a few drops of gasoline.
I do know from a particularly cold morning rabbit hunting that a Remington Model 12 .22 will lock up after 1 shot until the temperature of all the workings equalizes a bit. It took maybe 5 or 10 minutes or so. I think it was the case that was heated and expanded, not the steel workings of the gun itself. Hot brass is hot.
Not to hijack, but I seem to recall an SF novel from the 50s that had the people outside the spaceship use pistols to maneuver (instead of some type of thruster). The recoil would provide a significant thrust in the opposite direction. A character expressed concern about bullets possibly damaging another ship, but it was explained to him that the chance of a bullet hitting a ship were infinitesimal (unless one aimed directly AT a ship). It was also explained that this was more practical than using compressed gas cylinders or fuel-based units…just load up a pouch with a bunch of cartridges and you’d be set to go.
Mention of the Mk.19 (automatic grenade launcher) suggests the relatively easy way not to worry about cook off, in space or on earth: it fires from an open bolt (ie the bolt stops in the open position when you let up off the trigger). Rounds can cook off in the Browning M2 machine gun, but basically can’t in a Mk.19, and various other automatic weapon designs. There are offsetting advantages and disadvantages to open/closed bolt firing but open bolt solves cook off. However if the barrel gets hot enough the metal weakens enough for the rifling to get damaged or the barrel to burst, so open bolt firing doesn’t mean no design worries about heat.
It’s early and I’m only half way through my first cup, but doesn’t the M2 use an open bolt as well? My memory might be off.
Wasn’t the 'match" made with an oxidizer too?
The classic Browning machine gun design is closed bolt. Originally it was designed as a universal machine gun and in the WWI era when designed, a/c guns were usually synchronized to fire through the prop of a plane which is difficult to do with open bolt because of the relatively long delay, in terms of a prop blade’s travel, between pulling the trigger and the gun firing. Some companies have produced open bolt conversion kits for M2 HB’s in recent decades, and the US military also uses the GAU-21 machine gun (for helicopter door guns, and the mg in the Avenger AA system), a relative of the M2 which fires from an open bolt (it’s a Browning M3 a/c machine gun re-engineered by FN of Belgium).
It was and is, nitrates some of which can also be used to make gunpowder, such as potassium nitrate in which case the oxygen liberated from the nitrate definitely does substitute for atmospheric oxygen. But my understanding is that the actual reaction in slow match is for the nitrate to slow the reaction of atmospheric oxygen with the organic material of the match rather than wholly provide the oxygen by its decomposition.
That said, hard to find a source absolutely 100% saying it would go out in a vacuum. Here’s an experiment from an old chemistry book though implying it would burn brighter in oxygen than air. ‘Does it burn more brightly in oxygen?’ (I’m guessing the answer must be yes)
Cool, my bad
I, for one, was impressed at the advances turbine blade materials had made in 500 years. “You say you were brought down by a goose? Watch dis!”
Based on their chosen landing sites and the geometry of the intakes, cows must have been a notable intake hazard. I’m sure the Serenity has the rough landing package with reinforced blades and a large object diverter.