A New Form Factor for Drones: Vertical and Coaxial
28 comments
·March 21, 2025blutack
rasse
It's not a new form factor for Ascent Aerosystems, either. They did a Kickstarter for a coaxial drone in 2017.
https://www.kickstarter.com/projects/ascentaerosystems/sprit...
alphan0n
> this has been around for donkeys
"What giants?" asked Sancho Panza.
"The ones you can see over there," answered his master, "with the huge arms, some of which are very nearly two leagues long."
"Now look, your grace," said Sancho, "what you see over there aren't giants, but windmills, and what seems to be arms are just their sails, that go around in the wind and turn the millstone."
"Obviously," replied Don Quixote, "you don't know much about adventures."
blutack
Contraction of donkey's years, a common en-GB idiom for a long time. Good reference though!
hengheng
> Stacking the two rotors generates more thrust per unit area
But that's not a thing, and that's also not how that works. Multicopter rotor design is incredibly subtle.
(Two basic ideas for quad copters are that they need to slowly move horizontally for maximum efficiency, and that the vertical stagger between front and rear pair of rotors matters a lot.)
At the end of the day, this design is exactly what it is: Looks like a bottle which might be nice for someone. And the whole general layout thing boils down to flight time, in its weight class, with a given payload weight. There's not much more to it.
impossiblefork
It at least doubles the thrust per swept area area, probably more, due to the counter-rotation and that the second stage rotor experiences a higher airspeed.
This isn't a multicopter. It's a coaxial helicopter. The design parameter most similar to the distance between two rotors on a multicopter is the rotor diameter.
It's obviously going to be less maneuverable though relative to the thrust, due to the cyclic being on only one rotor.
raydiak
Far less than double. Putting one rotor directly in the turbulent wash of another is nowhere near as efficient as two well-separated rotors, for a number of reasons. https://en.wikipedia.org/wiki/Contra-rotating_propellers gives an estimate of "between 6% and 16% more efficient than normal propellers".
impossiblefork
Yes, I don't know why I wrote it, since it's obviously wrong. I assumed mentally that they'd put as much power into the second propeller as into the first and that it'd go into the airflow reasonably effectively, but you don't double the thrust by doing that, you presumably double the power in the airflow, so that its velocity velocity to sqrt(2) times what it was, so you get a momentum increase by sqrt(2) and since force is the derivative of momentum the thrust is increased by sqrt(2), and then you a thrust increase by sqrt(2), and maybe you also get those 6-16% you mention.
impossiblefork
Though, how do they control cyclic?
Is there a swashplate or something that I do not see, or is it as I assume, some kind of mechanism that allows cyclic to be controlled implicitly by motor speed? Edit: The patent apparently says they have a swashplate and cyclic control on the bottom rotor, so it's basically a model helicopter.
They can't patent the coaxial bit just by adding the 'on a UAV', so they patent their way of having the blades collapse.
Zanfa
If you look closely at the 6th picture in the article, the swashplate arms are visible on the bottom rotor.
impossiblefork
Ah, yes. I missed them at first.
blutack
They can't patent the coaxial helicopter UAV bit because there's a huge amount of prior art.
impossiblefork
Yes, that is basically the idea.
jackhalford
> Ascent's Helius may make the quadrotor form obsolete
We didn’t kill all the horses when we invented cars, as always the world just gets more complex. Quadcopters have an edge on this in terms of agility so many use cases will still be served by quadcopters
hashtag-til
I'm sure the community will make an inexpensive Pringles version of it.
out_of_protocol
Standard 4-engine copter is VERY simple hardware wise - 4x blades+engines attached directly to a frame, plus some orientation sensors stolen from a phone. And that's enough to maneuver in any direction with ease, with turning radius of zero. That's why the whole industry is booming
wao0uuno
Half Life 2 predicted this more than 20 years ago. Next step is to make the rotors razor sharp.
05
Just use a 450 class heli instead..
https://www.rcgroups.com/forums/showthread.php?165680-Man-Ki...
https://www.rcgroups.com/forums/showthread.php?1991999-Heli-...
IshKebab
Why though? Seems way more complicated (swashplates!) for little benefit (a bit more compact?)
blutack
Better if you need to send it to Mars and fly it there, otherwise yes which is why these designs aren't particularly widespread.
HPsquared
The key benefit seems to be it's narrower. I suppose it could be an advantage in fitting through narrow spaces, e.g. doorways.
dwighttk
Ugh I hate those videos that each went to full screen and had to be closed for me to continue READING
I don’t even want em to autoplay much less auto-full-screen
d--b
I think the argument that the quad copter looks incredibly cooler than this flying turd is going to matter eventually.
dogman1050
If it falls over while landing, it'll require manual righting. Flat drones don't have this risk.
bluesounddirect
there is something odd about that site . scroll it starts playing a video. scroll past another point it does it again . scammy !
maxldn
I guess they decided that auto play video wasn’t _quite_ irritating enough
Definitely not a new form factor, this has been around for donkeys. I've personally seen them for at least 20 years at various industry shows.
This is presumably a totally uncritical lazy press release copy paste. For goodness sake, NASA's Ingenuity is not exactly a secret and that's only the latest in a very long line of commercial coaxial UAS.
Looks like a perfectly nice coax, but exactly the same tradeoffs of much higher mechanical complexity for a slightly smaller operating footprint which make them less appealing for most use cases. The article completely glosses over the fact that most traditional X/+ designs fold for transport.