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On December 4, 2018, PhD candidate Stephen Conyers successfully defended his dissertation proposal entitled “Empirical Evaluation of Ground, Ceiling, and Wall Effect for Small-Scale Rotorcraft”
The abstract is:
Ground effect refers to the apparent increase in lift that an aircraft experiences when it flies close to the ground. For helicopters, this effect has been modeled since the 1950’s based on the work of Cheeseman and Bennett, perhaps the most common method for predicting hover performance due to ground effect. This model, however, is based on assumptions that are often not realistic for small-scale rotorcraft because it was developed specifically for conventional helicopters. It is clear that the Cheeseman-Bennett model cannot be applied to today’s multirotor UAVs. Experimental findings suggest that some of the conventional thinking surrounding helicopters cannot be applied directly to rotorcraft using fixed propellers at variable speeds (e.g. multirotors), and it is necessary to adjust the helicopter models to better reflect the differences in such aircraft.
Likewise, ceiling effect refers to the apparent increase in lift that a rotorcraft experiences when flying close to a ceiling or any similar surface that is present above the rotor(s).Ceiling effect is similar in principle to ground effect, and can be explained using a similar equation. Ceiling effect, however, was never explored in detail for conventional helicopters because large manned aircraft do not operate in enclosed spaces.
Wall effect is the phenomena that occurs when a rotorcraft flies near a vertical wall, and has the tendency to pitch towards the wall and be drawn into it. Wall effect is the least-understood of these three areas of interest. Wall effect has not been explored in great detail for any aircraft, and is addressed in detail in this dissertation.
The recent widespread use of small-scale UAVs and the demand for increased autonomy when flying in enclosed environments has created a need for detailed studies of ground effect, ceiling effect and wall effect. Ultimately, this work provides foundations for the development of an improved UAV flight controller that can accurately account for various aerodynamic disturbances that occur near surfaces and structures to improve flight stability.
Welcome to the University of Denver (DU) Unmanned Systems Research Institute (DU2SRI).
The Institute was launched in November of 2012 to:
- Serve as the focal point for basic, applied research and development activities in unmanned systems in general, and Unmanned Aircraft Systems (UAS) in particular in the State of Colorado
- Conduct, coordinate and promote research in building the next generation of UAS that will be used for a wide spectrum of civil/public domain applications
- Educate students, scientists, engineers and practitioners who are interested in learning about Unmanned Aircraft Systems (UAS), Unmanned Ground Vehicles (UGVs), Unmanned Aerial Vehicles (UAVs), and Unmanned Underwater Vehicles (UUVs)
- Serve as the organization to facilitate gradual integration of UAS into the National Airspace System (NAS) assisting third parties to obtain Certificates of Authorization (COA) from the Federal aviation Administration (FAA)
- Participate in State-wide UAS research and development initiatives offering its know-how and expertise
- Assist in economic development and creation of new jobs by graduating the next generation of highly skilled scientists and engineers, ready to compete in a very demanding global market
- Serve as a demo site for unmanned vehicles
- Provide the foundation for technology transfer to the private sector
- Bridge the gap between military and civilian application domains