Not just you in the night: Tiny bugs use superpropulsion to eject huge volumes of pee Scientists have discovered that the tiny insects commonly known as sharpshooters use superpropulsion to ensure they can efficiently eject the huge volumes of urine they produce each day. Sharpshooters eat plant sap, which is mostly water and light in nutrients. To consume enough to survive, they might need to emit 300 times …
Be warned that my comment is based upon a limited understanding of liquid fuelled rockets.
Due to the quadratic portion of the E=MV^2 equation, speed is vastly more important than mass. That leads to situations where Hydrogen + Oxygen engines run as hydrogen rich as they can get away with for a desired exhaust velocity because the hydrogen molecules get a lot more speed than the oxygen or water molecules due to their lower mass.
With that in mind, a propulsion system like the one you describe would have to focus on liquids and quantities which have exceptionally high resonant frequencies which I believe means very small amounts of the liquid which, in turn, leads to it being a low thrust, high efficiency engine along the lines of nuclear engines or xenon thrusters. Not useful for leaving a planet but has potential once in orbit.
All that being said, if the engine can be made incredibly tiny, then it's thrust to weight might actually line up well against chemical rockets, just running 10,000 of them rather than 32.
Correcting something I said here.
Chemical engines have a maximum heat that the nozzle is designed to take.
That defines a maximum rate of combustion.
The heavier molecule (e.g. Oxygen) is regulated to manage the rate of combustion.
The lighter molecule (e.g. Hydrogen) is run rich.
Running the lighter molecule too rich means you need more fuel on the rocket and can over-saturate the heat energy provided by combustion.
Running the lighter molecule too lean means you're losing efficiency by putting more heat energy into the M rather than the V^2.
"I'm sure the scales are WAY off for that, but it's an amusing thought."
Upvoted for the idea :-)
But, or should that be butt?, scaling up or down with liquids rarely works well. Just look at the difficulties experienced by modellers in the TV and film industry when it was actual models, not CGI. Scaled down ships could look ok, but the water never quite "worked", even with all their cameras trickery and film playback speed adjustments. Same with fire and explosions. What works on a tiny scale with a miniscule nozzle, a tiny drop of pee and some frequency adjustment isn't likely to translate when trying to eject a football[*] sized "droplet" :-)
The round one, not the faux one that's more sort of ovoid and rarely kicked so not really a "foor"ball :-)
PS. Did these researchers just discover biological inkjet printer nozzles? Didn't Canons Bubblejet technology use piezo crystal to eject the ink droplet? Or was that heat and HP did the piezo thing?
Possibly came to an ink-jet printer near you many years ago. They use drops in the 10pl-or-so range, and it's common to use a waveform which causes resonances in the firing chamber in order to eject drops efficiently. Imagexpert make development equipment for this sort of thing.
Anon as I'm in the industry.
...just for the phrase "Many insect species may be described as ‘frass-shooters,’ ‘butt-flickers,’ and ‘turd-hurlers’ that innovated unusual strategies to launch away both liquid and solid excrements" ('Discussion', about half way in)
Never thought I'd read a science paper that mentions turd-hurling but there we go. Mind you, I think I've worked for one or two turd-hurlers in my time!
sharpshooters temporarily tune the frequency of their "anal stylus" to the frequency of their pee droplets
For some reason I'm now thinking of Stylophones.
I forget where I read this, but someone collected insects in a box and s/he became curious about an occasional ticking noise coming from the box. Upon further investigation it turns out that these creatures fire their feces considerable distance, meaning that their home is clear of muck, but not so good for neighbouring insects. This phenomenon might also involve resonance when considering creature-size and distance flung.
Edit: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8553070/
Edit 2: I see someone else has already mentioned this.
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