totm apr 2025 Propeller Flight Not Found In Nature... What If It Was? Would It Compete Well With Wings Or Not?

[Spacescifi]

So we all know propeller or rotor based flight is not a thing in the animal world. They all use wings

 

Would there be an advantage at all for bird like creatures to have biological rotor based flight or perhaps a mix of wings and propellers?

 

Right away I think wings allows for more simplicity (less moving parts that might break), so from a survival POV just plain flapping wings are better so long you're light enough and eat often enough.

[Lisias]

As a matter of fact, there's some microbial life with rotors!

At that minuscule scale, the simplicity of the solution outweighs the drawbacks.

[AckSed]

We also can't forget the plant kingdom has had autorotating airfoils for as long as trees have been around e.g. maple, sycamore and ash.

Any evolutionary path that evolved wings might solve for these kinds of mass-efficiencies if there was pressure to reach the ground safely. I could imagine a lichen, parasitic on a tree insect, that grew a propeller as a prelude to jumping to the ground where it could infect insects climbing up to feed on the tree's leaves.

[darthgently]

2 hours ago, Lisias said:

As a matter of fact, there's some microbial life with rotors!

At that minuscule scale, the simplicity of the solution outweighs the drawbacks.

Was going to bring this up.  Truly amazing stuff

[Nuke]

i dont think its possible for larger organisms to have rotors because of all the various systems the body has, eg nerves, blood vessels, the lymphatic system, etc. you need to solve all these and have some kind of bearing to reduce friction, otherwise the organism cooks itself on the friction heat alone.

id figure rocket propulsion would be easier to accomplish. bombardier beetles can do hypergolics. you can use a bone or horn structure in the shape of a combustion chamber and nozzle. continuous operation would have heating problems but perhaps a pulse jet could function without cooking the organism. genetic engineering required. though octopuses and squids have water jet propulsion.

fortunately life forms can flap wings quite well. going the other way though, ornithopters have proven to be a tough nut to crack.

Edited March 28 by Nuke

[GluttonyReaper]

Even if it was practical, there just aren't that many niches that a propellor could fill - the two places they really shine are for quick acceleration, and for high-speed efficiency. As is, flying animals tend not really to rely on thrust-based acceleration for hunting, instead utilizing stalking and dive tactics to quickly catch prey without burning too much energy, and only really use speed as an escape mechanism to quickly get away from land-based threats. As for high-speed efficiency... there just isn't much need? Being able to move from place to place quickly isn't something animals really value consistently, with making best use of natural air currents and the life seeming to be preferable. The key problem, I think, is that wings are just practically quite versatile.

[darthgently]

8 hours ago, Nuke said:

i dont think its possible for larger organisms to have rotors because of all the various systems the body has, eg nerves, blood vessels, the lymphatic system, etc. you need to solve all these and have some kind of bearing to reduce friction, otherwise the organism cooks itself on the friction heat alone.

id figure rocket propulsion would be easier to accomplish. bombardier beetles can do hypergolics. you can use a bone or horn structure in the shape of a combustion chamber and nozzle. continuous operation would have heating problems but perhaps a pulse jet could function without cooking the organism. genetic engineering required. though octopuses and squids have water jet propulsion.

fortunately life forms can flap wings quite well. going the other way though, ornithopters have proven to be a tough nut to crack.

I’ve thought about this before, out loud in these forums iirc, and pondered that for larger organisms the separate rotor and stator “parts” would need to be separate organisms in a symbiotic relationship.  Not likely to happen naturally but plausible as an engineered organism maybe.  Not that that should be done.  That is beyond my philosophical and ethical pay grade, perhaps.  Not sure honestly

[Nuke]

22 minutes ago, darthgently said:

I’ve thought about this before, out loud in these forums iirc, and pondered that for larger organisms the separate rotor and stator “parts” would need to be separate organisms in a symbiotic relationship.  Not likely to happen naturally but plausible as an engineered organism maybe.  Not that that should be done.  That is beyond my philosophical and ethical pay grade, perhaps.  Not sure honestly

usually when a machine needs to move power or fluids across rotating joints they use a device known as a slip ring. nerves are really the only thing not compatible with such a concept. but if you take a page from the book of octopus, you just have a separate nervous system in the rotating part, much like an octopus has a brain in each tentacle. it may be able to control pressure in a sense channel to relay information to the primary brain. defects or injury to  the bearing surfaces could cause the organism to "bleed out", so these would have to be very precisely grown. alternatively the rotating part could have its own  cardio-pulmonary system as well.

additional pondering, while petting a cat, made me think of how they whip their tails around. helicopters use cyclic pitch control to enable their maneuverability. then you have organisms like cobras that can flatten their heads out into a hood for their warning display. so imagine a cat tail with a structure on the end which can deform to form an airfoil in various directions. because the tail segments are bony they roll as the tail is whipped around so it would need to constantly transform itself through the entire rotation cycle. this might allow flight (eg within a dense titan-like atmosphere).

Edited March 28 by Nuke

[darthgently]

3 hours ago, Nuke said:

but if you take a page from the book of octopus, you just have a separate nervous system in the rotating part, much like an octopus has a brain in each tentacle. it may be able to control pressure in a sense channel to relay information to the primary brain.

If you are going with an octopus as an example then neural signals could be transferred optically s as they can both detect and effect colors at the skin, right?

3 hours ago, Nuke said:

additional pondering, while petting a cat, made me think of how they whip their tails around. helicopters use cyclic pitch control to enable their maneuverability. then you have organisms like cobras that can flatten their heads out into a hood for their warning display. so imagine a cat tail with a structure on the end which can deform to form an airfoil in various directions. because the tail segments are bony they roll as the tail is whipped around so it would need to constantly transform itself through the entire rotation cycle. this might allow flight (eg within a dense titan-like atmosphere)

What is that vid game character that flies spinning its tail?  Bandicoot?  No, it was Tails the Fox from the Sonic the Hedgehog game (thx grok3)

Edited March 28 by darthgently

[Nuke]

while i never played a sonic game in my life, i did watch the old cartoon show. so im familiar with tails. but cats made me remember that. i got one on the back of my chair whacking me in the face with its tail as i type this. however two tails complicates things.

[StrandedonEarth]

15 minutes ago, Nuke said:

however two tails complicates things.

Counter-rotating tails for extra maneuverability!

[Nuke]

Just now, StrandedonEarth said:

Counter-rotating tails for extra maneuverability!

until they get tangled or collide with eachother anyway.  though some helicopters have inter-meshing twin rotors.

[Codraroll]

The simple fact that propellers are not found in nature but wings are abundant, clearly suggests not. We literally have the data here. Propellers can't compete, otherwise you'd see them everywhere.

[darthgently]

4 hours ago, Codraroll said:

The simple fact that propellers are not found in nature but wings are abundant, clearly suggests not. We literally have the data here. Propellers can't compete, otherwise you'd see them everywhere.

Agreed.  The reason we don’t see flapping wings on aircraft is more related to the infancy of our materials science combined with the fact that you won’t likely ever see a flapper flying as fast as a prop plane much less supersonic.  There is a speed threshold where rotary jet or rocket engines would completely outpace.  Then there is surface to weight ratio and ambient air pressure.  Flappers would be limited in size to probably about the same neighborhood as the most massive flying organisms.  Consider that when pterodons were a thing, iirc, ambient air pressure is thought to have been a bit higher

[magnemoe]

6 hours ago, darthgently said:

Agreed.  The reason we don’t see flapping wings on aircraft is more related to the infancy of our materials science combined with the fact that you won’t likely ever see a flapper flying as fast as a prop plane much less supersonic.  There is a speed threshold where rotary jet or rocket engines would completely outpace.  Then there is surface to weight ratio and ambient air pressure.  Flappers would be limited in size to probably about the same neighborhood as the most massive flying organisms.  Consider that when pterodons were a thing, iirc, ambient air pressure is thought to have been a bit higher

Flapping wings is much more mechanical complex. An propeller is an axis and an bearing, you also need an engine but you need that anyway, they have made flapping wing drones. Might be useful as probably silent and can easy be mistaken for birds. 
Also agree on your size restrains, largest flying dinosaur had an 10-11 meter wingspan and is estimated weighted 200 kg and an top speed of 130 km/h. 
https://www.sciencefocus.com/nature/whats-the-largest-flying-animal
Scaling it up to a ton would be hard, same with speed. 
Now large winged birds has an excellent loiter time, assume as they is mostly gliders. 

For nature, an rotating joint could be useful but as other say how to keep the rotating part alive. Now you could have two animals say female with an male propeller and the female feed the male then not rotating you still has the issue of stability and friction, last how to evolve it.