Our knowledge of physics tells us that we do require air (or "fluid" as they say in physics) to fly drones.
But what if it was possible to take a drone's air with it into outer space ? How ? By fitting an air-tight enclosure around the drone.
Ok ... wait ... physics will have something to say about that too! ... it won't fly! ... Net zero force
Newton's 3rd law will prohibit it ... and yes that is true ... if we constrain our minds with current flight machines designs.
... ok explain ...
What if it was possible to come up with a new drone propulsion design ... one that bend (or curve) the ejected propeller air, all the time!
Would that imply that the ejected air will never form a jet stream and will lose it's kinetic energy quickly ?
Ok, say that could work, but how would the re-action forces on the drone be used so that the drone can move in a pre-determined direction ( be controlled ) ?
The answer for that is also given by physics ... vectors with a resultant vector.
Ok, surely you will need more than vectors ?
Yes, add some some Arduino wizardry - 1 or 2 very unique algorithms - together with an IMU ( like a Bosch BNO055), plus a few other parts ...
and you have an outward spinning drone! What is an outward spinning drone ?
The Droverbot
Propelling any vehicle in a pre-determined direction while the entire vehicle continues to rotate (outward spinning) is a groundbreaking innovation in propulsion.
With current mainstream propulsion vehicles, the engines (or motors) provide thrust via the axle in a hub,
e.g. car wheels with an axle at the centre, for propellers with an axle at the centre.
But with the experimental drone above, the thrusters are located on the spokes and rim of the octagon frame.
This propulsion system have distinct characteristics that can be exploited, with huge potential as explored in this post.
Ok, but the droverbot drone is not flying as shown above. Why ?
There are several reasons why I chosed to propel the experimental drone horizontal and not vertical, but it is a story for another time.
But just to indicate how vertical flight might work, please click the link below for another video, it is an early 2D simulation I’ve build a few years
ago which shows just that
Vertical Flight Simulation
The 2D simulator software I used, only had rocket thrusters for propulsion, which would've been a limiting factor if
this simulation had to be build in the real world, with the forces shown in the simulation.
However, it does illustrate how an outward spinning object perform vertical flight.
The Droverbot (shown in the first video) method of propulsion is far more matured, versatile and capable of vertical flight as shown in this early simulation.
(See the Whitepaper in the link, further down below to understand the drone’s method of propulsion.)
Key aspects of this experimental drone (or “droverbot”) that set it apart.
- This drone has the ability to propel in a straight line in a predetermined direction while the entire drone (including its thrusters) is rotating continuously.
- The continuous rotation of the entire drone creates an interesting phenomenon where the air is distributed once it leaves the propeller blades,
resulting from the entire drone's rotating motion. - Powered by 8 brushless motors and propellers, this drone exhibits both linear and rotational motion.
Four motors managing linear motion and four rotational motion. - Modular in design, this drone can be scaled up by adding more drones to a common platform, creating larger drones that can be further scaled,
only limited by practicality.
The central hub of the drone (centroid) allows for an axle to be fitted, providing the flexibility and versatility to scale.
Key Properties
- The reaction forces generated by the motor-propellers on the drone due to ejected air (action forces) are harnessed as vectors in
such a way that they cause a consistent resultant vector. The resultant vector (direction and force) can be chosen and adjusted as needed. - Since air is distributed behind motor-propellers continuously, it is not reinforced with additional ejected air,
leading to quicker weakening of the kinetic energy of the ejected air compared to other propulsion systems
where ejected air is continuously reinforced (e.g. jet streams behind an airplane’s propellers). - This experimental drone, as shown in the video, can propel along a horizontal plane.
With further development, the drone can be orientated vertically and should be able to propel upward into the atmosphere.
Each drone is capable of propelling along one plane, and when multiple drones are combined, they can move in any direction in three-dimensional space.
Individual drones can be connected modularly to a common frame by attaching an axle to each drone hub at its centroid.
Implications
- The drone's resultant vector can be directed to any degree within 360 degrees. Direction and force can be adjusted as needed.
In a multi-drone vehicle, the combined vectors of the drones enable flexible manoeuvring in three-dimensional space. - Since there is no reinforced ejected jet stream (as mentioned earlier) and weak kinetic energy that dissipate rapidly when air molecules collide
with other air molecules at rest, it is feasible to assume that an enclosure (with a sufficient air cushion between propellers and wall) can
be added around the drone.
Adding an enclosure will have several key implications:
- Below follow a few implications when propelling earth-based:
- An enclosure will solve the problem of dust and debris kicking up from propeller-engines at low altitudes.
- Unlike rockets with fixed cylinder shapes, an enclosed vehicle with rapid directional changes and
flexible design shapes will not be limited by high-altitude winds, ensuring flights are not cancelled. - The risk of objects (or debris) colliding with propellers will be eliminated with an enclosure.
- An enclosure will significantly reduce noise pollution caused by conventional airplane propellers.
- The risk of losing parts will also be eliminated by an enclosure.
- Taking all of the above into account, the automotive industry should be able to build "real" – flying cars.
- An air-tight enclosure will enable drones to fly in outer space without requiring an atmosphere.
- An air-tight enclosure will ensure that all propellant (air) is re-used. Since air does not contain energy,
the energy source when earth-based, can be battery powered.
When in outer space, the energy source could be a small nuclear reactor (e.g. “Kilopower” reactor as build by NASA).
This have the potential to reduce the mass to 10% or less of the vehicle's total mass compared to rockets where
propellant (with integrated chemical energy source) is over 90% of the vehicle’s total mass.
With unlimited propellant (re-usable) and long-term energy sources like nuclear re-actors, long-term trips in the solar system and potentially,
even interstellar travel to neighboring stars becomes feasible from a propulsion system point of view.
You might wonder if Newton's third law will be upheld when a drone is enclosed.
With conventional propeller-engine thrusters, this is impossible due to the reinforced ejected jet stream (action force) that is equal
in strength to the reaction force on the vehicle, in the opposite direction. This results in a net zero force.
However, with this experimental drone, there is no reinforced, ejected jet stream in the opposite direction.
Instead, due to its continuous rotation, the ejected air is not reinforced by more air, but is distributed.
So, how does Newton's third law apply then?
At a moment (fraction of a second) of air ejection, Newton's third law is applicable, but since the ejected air is not reinforced by the next moment of air ejection
(which is ejected at a different degree as the drone rotates), no ejected air jet stream is created (in the opposite direction) as with conventional aircraft.
However, the sum of the distributed air (action force) still equals the sum of the reaction force on the vehicle. Newton's third law is upheld.
Since multiple drones can be attached to a large platform, which can take any shape (limited only by practicality), various types of vehicles can be built.
This is not limited to vehicles but could result in large upper atmospheric platforms (even in the atmospheres of other planets) or even platforms in space.
- Below follow a few implications when propelling earth-based:
Resources
Check out the link below for more in-depth technical details on the drone's construction, functionality, experimental results, and potential applications.
Droverbot - Whitepaper
Explore further by accessing the source code for the drone and additional materials through the provided link below.
The-Droverbot at GitHub
To delve deeper into the details of the drone's design, discover the 3D models available at the following link.
FPVWorkBenchV42.zip (Microsoft 3D Builder)
Next steps
This experimental drone is the starting point, marking the transition from zero to one, for a new type of vehicle. Alot of work will still need to be done
to make this a reality.
To unlock its full potential, it will require a collective effort from a community. This could be a revolutionary innovative project if a community decides so.
My hope is that a community will come together around this project to build upon this effort
Please leave a comment below on your thoughts.
Here is a preliminary high-level plan of the next steps that are needed.
High-Level Action Plan
1. Redesign Drone Frame
The current octagon drone frame requires an overhaul, as it was originally designed to host 16 motors for testing various permutations.
The focus should be on creating a lightweight octagon shape frame that is both structurally reinforced and sized appropriately to withstand forces at play.
2. The source code
The source code needs tidying up and rewriting to accommodate improved algorithms for linear and rotational motion,
as well as integrating the list of permutations to control propulsion in different directions.
This also includes expanding the list of permutations on how the 8 motors can be applied together for vertical flight, and multi-vehicle drone configurations.
As development advances, the codebase have the potential to expand to cater for multi-drones, underwater propulsion, space flight, acceleration and
deceleration in different mediums, and much more.
3. Electronic Components
The drone is constructed using consumer-grade electronics on top of the Arduino platform. Each component requires review and replacement if a better component
can be found that will enhance its versatility in creating a more advanced drone.
For example, the current IMU (Bosch BNO055) has limitations with its magnetometer. Additionally, a GPS should be added and better remote-control radio for starters.
4.Multi-drone
Once vertical tests flights are successful, several drones can then be attached to a central frame, and a single flight control computer will manage them all together.
This will enable the vehicle to move in any direction in 3D space.
5. Enclosure
At the same time (or afterward), a super lightweight, air-tight enclosure will be built to fit around individual drones or the multi-drone vehicle.
When this test succeeds, space travel will become a reality for drones. Enclosed air (as a propellant) will be reused with only the energy source that could deplete.
This will result in the ultimate reusable vehicle. This have the potential to revolutionize transportation and spaceflight forever.
6. Undersea Maneuvers
By modifying the existing design for submerged propulsion, trials can be performed below the surface, replacing air (a fluid) with water.
In Conclusion
I've been working on this project in my spare time for a very long time, and it's now at a stage where I believe the fundamental technology has been develop that can be built upon.
With a community involved, progress can be faster and who knows where this effort can go!
I want to thank God Almighty for carrying me over the years to continue, for my family supporting me.
It would have been impossible to get to this point without them.
Please leave your comments below.
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