This idea actually came from a poster that was in one of the math classrooms at my high school. You have a colony on the moon. You build a huge dome there and fill it with air. People strap wings to their arms and fly around like birds!
Could this work? Could an adult human of average weight and strength lift one sixth his or her Earth weight this way?
It’s a plot used in many science fiction books, and I believe it is feasible if you have an air filled dome.
I don’t know if it could be done by flapping your arms; but people fly here on Earth using special hyperlight aircraft that are pedal driven (Gossamer Condor). And people can climb in Earth gravity just using their arms, so it’s technically possible to exert enough force through you arms to lift your weight. It’s a question of the inevitable inefficiencies of flapping wings through air.
An excellent treatment of this is given in Heinlein’s short story The Menace from Earth. A collosal underground cavern is pressurized, and the space used for gliding. Do such caverns exist on the Moon? I haven’t the foggiest.
With the proper application of high explosives, they do.
My WAG is either a no, or just barely.
In other words at best you could flap for all you are worth for a very short period of time to fly.
Reason 1
IIRC, you legs can typically put out, give or take, 6? times the power output of your arms.
Reason 2
Human built flying machines with very long efficient (and fragile) wings and efficient propellors jjust BARELY fly with super fit atheletes pedaling like hell.
Reason 3
Flapping is going to be significantly, if not way, less efficient than wings and propellors.
Combine all three and probably no.
The only saving grace might be if the atmosphere was REALLY dense, in which case flapping might work. That would also allow you to build in some balloon type bouancy/floatation.
Just my 2 cents…
Could work, with caveats. You would probably need to carefully design your muscle powered flying device for the average person to manage flight.
Apart from actual flight, which might still be work, and require mechanical devices, if you want to postulate having a long drop at standard Earth pressure, you could probably go skydiving without a real parachute, using only a few small surfaces or even loose clothing. Terminal velocity is proportional to the square root of gravitational acceleration, so I get a terminal velocity on the moon of about 50 mph falling spread-eagled (120 Earth), about 80 limbs pulled in (200 Earth), more if you deliberately fall headfirst. You could still kill yourself if you didn’t know what you were doing, but some small surfaces to slow yourself a bit, maybe a soft landing area or a pool of water, and you would be OK.
I can imagine it being fun to have a “flying squirrel” suit - with membranes that you could deploy by spreading out your arms and legs. Drop from a couple thousand feet up at 1/6 G, and play “Rocky the Flying Squirrel” all the way to the ground.
What about if there were a way to generate updrafts? Could someone then glide with wings spread (or spread-eagled in a squirrel suit) to the top of the cavern, then leave the updraft and glide back down?
ETA: I think updrafts played a part in the flying in The Menace from Earth; I recall that the characters were following an updraft when one of them panicked and inadvertently dove.
I believe there were up- and down-drafts, as well as the dome having higher-than-normal air pressure.
OK, now I’m going to re-read that story (I’ve got the 1962 Signet paperback right here). I don’t recall mention of higher atmospheres, nor if drafts were natural or generated (I think the former).
Creating them sounds challenging - you could certainly blast a big hole with the right kind of explosives, but then you’d have the problem of roofing it over.
And how friendly would the moon’s “geology” (“lunology” ?) be to such a scheme? Is the near-surface rock strongly bound together?
In The Menace From Earth, the dome was a naturally formed volcanic bubble, if I recall correctly. I seem to recall that they didn’t really flap their arms, although they did do some sort of movement that could keep them aloft under their own power. I think they had tail feathers, too, so they could dolphin kick for some additional thrust. It was also mentioned that the tourists got big clumsy wings and mostly just rode the updrafts and glided, while the natives had lighter and more agile sets. I believe our heroine had shoulders like a weightlifter and trained regularly in order to be able to fly.
Power required for flight is proportion to the square root of wingloading (weight / wing area) and inversely proportional to the square root of air density. If gravity is reduced by a factor of six while other things stay the same, the power requirement goes down to around 40% of what it was on earth - very manageable.
But earth-bound manpowered aircraft have to be almost absurdly large and light (and thus fragile) to achieve sufficiently low wingloading. An aircraft of even half the wing area would still be awkward - especially if it had to be powered by flapping.
Given the fact that they CAN do it (see reference to Gossamer Condor) in 1G, I’d guess that it would be about 1/6 as difficult on the moon, meaning that all else being equal, it should be possible, maybe easy, even for us normals. Of course, this dome would have to be miles and miles across for the project to have much meaning.
If the atmosphere is the same density as what we have hear, you’re not flying anywhere by flapping. Imagine jumping on a trampoline to simulate a few seconds of reduced gravity on the way up… are you going to be able to increase the height of your jump with any kind of wing strapped to your arms?
Based on the way our bodies are built, you’d need a denser atmosphere to perform flight anything like a bird (using your own arm power to propel yourself up, not the gliding part). Even then flapping would be a terrible way of moving through the atmoshpere for a human. If you could get enough purchase on the atmosphere to be able to push/pull yourself through it, “flying” would be like moving around completely under water - like a scuba diver. Yes you can propel yourself around using your arms, but you’d get at least 10 times the “lift” by strapping a couple fins to your feet and kicking.
Soaring using thermals works quite well on earth for birds and gliders - no reason it shouldn’t work on the moon. (Though you’d probably want a bit more wing area than a squirrel suit would offer.)
A practical minimum sink speed (for a manned aircraft on the moon, in a space pressurized to 14.7 psi) would probably be around 50 to 60 ft/min (~0.25 m/s). So that’s the minimum updraft velocity needed to stay aloft.
If you change that guess to 1/sqrt(6) you’d be right.
A better simulation would be imagining being tethered to a helium balloon that provides buoyancy equal to 5/6 of your weight. In this case, with some well-designed strap-on wings you no doubt would be able to make a difference.
Maybe an ornithologist could unwind this description into how the wings are built. Note the part about the air pressure @ 17lbs.
ETA: Ha! Here’s the whole short story online.