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Flexible monocopter drone can be completely rolled up

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Re: Flexible monocopter drone can be completely rolled up

#23
post #14

It folds into a small storage tube, is lightweight, has good autonomy, makes little noise, and safely autogyrates to the ground on failure. If you could somehow add a camera and stabilise it, it could make an excellent search drone for search / rescue / military ops.

What would be the advantage over existing drone technologies? Look at these autonomous drones [0]that can fly through the forest at high speeds. High speed, highly maneuverable and can hold other equipment like a camera. [0] https://electronics360.globalspec.com/article/17357/video-fl...

And there are already relatively cheap commercial offerings with very impressive collision avoidance and path planning (www.skydio.com)

Re: Flexible monocopter drone can be completely rolled up

#26

I wonder if it could be even better and lighter with carbon fiber instead of basla wood.

Carbon fiber is much more difficult to iterate on though. Using accessible and cheap materials is beneficial for adoption by hobbyists or other researcher.

Re: Flexible monocopter drone can be completely rolled up

#28

I tried to do a similar thing with a single actuator frisbee. The goal would be a frisbee with a single fin could fly anywhere when launched out of some high power launcher. The goal was to make a single-use aircraft which could go anywhere in a city for under $1. By making the aircraft unpowered and under 250g, lots of regulations no longer apply, and it becomes practical to use them to deliver small items. The fin…

Sounds like something the military would like. Cheap way to see if anyone is behind a barrier in front of you.

Re: Flexible monocopter drone can be completely rolled up

#29

I tried to do a similar thing with a single actuator frisbee. The goal would be a frisbee with a single fin could fly anywhere when launched out of some high power launcher. The goal was to make a single-use aircraft which could go anywhere in a city for under $1. By making the aircraft unpowered and under 250g, lots of regulations no longer apply, and it becomes practical to use them to deliver small items. The fin…

If by vertical you mean that the frisbee has rotated so the disc is perpendicular to the ground, that effect is actually aerodynamic, not gyroscopic. It comes from imbalance of lift due to two halves of the disc see different relative airspeeds.

In competitive disc sports this is usually mitigated by adding more spin (to add more moment of inertia in the spin axis to gyroscopically resist the turn), and by releasing the disc with the advancing edge pointed down to extend the period before it over rotates.

If this is what you were talking about, then you should be able to just make the disc more edge heavy to try to counter act that. Or maybe you can try to someone add more drag to the forward spinning edge. Presumably if you have a single fin, that fin will usually be at the 6 o'clock position (from top view). Assuming we have a forward moving disc rotating clock wise (from top view), and the fin is at 6 oclock, then the forward rotating edge would be at 9 oclock. If you had a second fin (or some other type of feature) basically mounted at 9 oclock (so at 90 degrees relative to your main steering fin), then it should always spoil that air... might be able to use that to somewhat counter act the rotation.

However, if you were actually talking about the gyroscopic effect (trying to rotate a spinning disc along it's axis pointing in the forward direction should cause a torque in its pitch axis)... I don't really know how to deal with that.

Re: Flexible monocopter drone can be completely rolled up

#30

I tried to do a similar thing with a single actuator frisbee. The goal would be a frisbee with a single fin could fly anywhere when launched out of some high power launcher. The goal was to make a single-use aircraft which could go anywhere in a city for under $1. By making the aircraft unpowered and under 250g, lots of regulations no longer apply, and it becomes practical to use them to deliver small items. The fin…

If by vertical you mean that the frisbee has rotated so the disc is perpendicular to the ground, that effect is actually aerodynamic, not gyroscopic. It comes from imbalance of lift due to two halves of the disc see different relative airspeeds. In competitive disc sports this is usually mitigated by adding more spin (to add more moment of inertia in the spin axis to gyroscopically resist the turn), and by releasing…

I was talking about the fact that the center of lift is ahead of the center of mass of a circularly symmetric wing with positive lift. [1]

That force would normally cause an aircraft to 'pitch up' (and hence planes have tail's and carefully balanced weight to stop this happening). In a frisbee, the gyroscopic effect means that this 'pitch up' force actually translates into a 'roll right' motion. By making the rim heavier, you can make this happen slower, but as far as I can see, you can never eliminate it entirely.

My fin is on the outer edge of the disc, spinning with it, so it can oscillate at ~50Hz to get independant roll and pitch control, while also being able to trade off loss of angular momentum vs lift. It also has the benefit that it can be made from cardboard in a single pressing with the disc with no glue or assembly labor.

[1]: http://ffden-2.phys.uaf.edu/645fall2003_web.dir/Mike_Abrams/...

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