A number of drone assembly and development projects are available for student projects. This page is dedicated to a project based on aerial vehicle design (3D-printing), assembly, and testing. This project initiation includes: 1) Flight Theory, 2) Project Scope, 3) The Sky is the Limit, 4) Improving the Basic Quadcopter, 5) Tiltwing Technology, and 6) Advanced projects.
Here, flight theory is reduced to rules of thumb ("heuristics") to allow people of diverse backgrounds to make significant progress on drone design. There are a number of inaccurate presentation of flight theory, the persistence of those inaccurate theories (muddied waters, impact on commercialization) presents unique opportunities to make great advances.
To create efficient aerodynamic lift from motors/engines, three processes must occur:
Flight of standard quadcopters are controlled by the speeds of four electric motors to control altitude, roll (sideways/lateral levelness), pitch (front-back/longitudinal levelness), and yaw (orientation relative to north, south, east, and west). The pitch sets forward or reverse velocities.
Normally, there is a limited extent to which the fuselage shape impacts performance once a reasonable design (which does not block propeller air flow too much) is reached. One degree of freedom is the tilt of the propellers where racing drones have a tilt-forward orientation.
The passively-adjusting tiltwing adds a significant degree (of freedom) on the ability of the fuselage/wing design to impact performance. These additional degrees of freedom in design include: shape, span dimension, chord dimension, thickness dimension, location of center of gravity, maximum upward angle, and span of angle tilting (to forward orientation), and shape of vehicle fuselage. Wings extending laterally from the fuselage may also be added to supplement lift with associated design degrees of freedom.
The passively-adjusting tiltwing addition to a quadcopter transforms the body/wing design of a quadcopter from what is primarily cosmetic, to a challenging engineering problem that illustrates many aspects of physics and flight theory. 3D-printing and its enabling software allow rapid and exciting progress to be made on this design/project for enthusiasts at all levels (student through professional).
The standard (metric) of a good aerial vehicle (for present purposes) is a high lift-to-drag ratio (L:D).
For jets, lift corresponds to vehicle weight and drag corresponds to fuel consumption. Therefore higher L:D correspond to less fuel consumption per passenger on an airliner. A good L:D for a jet is 18:1.
For helicopters (quadcopters, tricopters ...), the propeller(s) push air downward, pressures push/pull the propeller(s) upward, and the propeller shaft pulls upward on the fuselage. A helicopter has a L:D near 4:1.
For rockets, burning fuel increases temperature which causes high pressures to develop in the combustion chamber. Gases are directed downward through a nozzle surrounded by a "bell" where forces push upward on the bell resultant of the air accelerating downward though the bell's open end. The net result is an upward pressure on the bell; the bell transfers the force to the rocket body.
Examples of devices used to preserve desired pressures include: 1) wider wingspans, 2) optimal curvature of propellers, and 3) the use of a "bell" on a rocket as opposed to a simple hole for the nozzle.
An effective quadcopter or tricopter technology that offers both vertical takeoff/landing and cruising at speeds/efficiencies of airline aircraft will be transformative. Airline aircraft are among the most energy efficient transportation option (at about 53 passenger mpg).
The standard quadcopter suffers from three design approach flaws which will tend to keep these "standard" quadcopters in novelty/toy applications rather than expanding to major passenger, parcel, and IT (information) applications.
i) Firstly, quadcopters rely on propellers to provide lift rather than wings or lifting bodies resulting in maximum L:D ratios near 4:1 (cruising). ii) Secondly, the discs (circle of propeller rotations) are relatively small resulting in lower efficiency than helicopters. iii) Thirdly, when cruising, the fuselage pushes/pulls air upward due to its nose-down orientation (further reducing the L:D). The bottom line is that standard quadcopters are both inefficient and relatively slow; significantly limiting their use beyond novelty applications.
An advantage of the quadcopter is its simple electronics and control logic where four motor speed provide a wide range of maneuverability.
To make the quadcopter and tricopter viable contenders for major commerce markets, three features need to be implemented: i) it must transition to wing/fuselage-based lift rather than propeller-based lift, ii) the fuselage/body must be nose-up and incorporate lifting body design with lots of surfaces at 1 to 4 degrees from horizontal, and iii) simple controls/hardware must be preserved.
5) Tiltwing Technology & Advanced Projects:
The design goal of passively-adjusting tiltwing technology is a passive design feature where:
- increasing forward velocity moves two (or one for a tricopter) propellers into an increasingly-forward pitch to allow higher velocities and fuselage-generated lift at highly-desirable pitches (1-8 degrees, more preferably 1-4 degrees) to generate aerodynamic lift.
- as the propeller tilts forward, the wing component of the fuselage becomes effective in generating lift to supplement the fuselage's lift.
6) Advanced projects:
Significant challenges and opportunities exist with projects focusing only on 3D printing and incorporating non-electrical components of a passively-adjusting tiltwing equipped quadcopter. Advanced projects could address control software to further enhance capabilities.
The passively-adjusting tiltwing technology has a patent-pending status. The inventor's (Professor Galen Suppes) position on this patent-pending status is that student projects and internally-funded research are allowed for patent-pending technology. What is not allowed under possible infringement penalties (unless licensed) is: 1) selling of manufactured passively-adjusting tiltwing components (or designs therefore) or drones and 2) research funded from government or competitive private sources which uses or advances the passively-adjusting tiltwing technology.
HS-Drone is a start-up company product. The R&D company is Homeland Technologies, LLC. Technology is patent-pending and available for licensing.
Current R&D is a progression of technology demonstrations emphasizing 3D-Printed fuselages with a standard controller and electronics. The current goal is to attain a 75% transition from hover to cruise (prop-based lift to body/wing lift) having 2X the efficiency of other quadcopters (when cruising) while only controlling four motor speeds.
Next will be controller card programming to allow 100% transition to body/wing lift and 4X the fuel economy of quadcopters. For this, 3 motor speeds and 3 other actuators will be needed.
It could easily be the single-greatest impacting technology to reduce greenhouse gas emissions this century. Contact at: firstname.lastname@example.org