CAFE EAS 2019 #6 - David Ullman - eSTOL Potential for Urban Air Mobility скачать в хорошем качестве

CAFE EAS 2019 #6 - David Ullman - eSTOL Potential for Urban Air Mobility

David G. Ullman, Principal, Ideal eSTOL EMERGING TECHNOLOGIES PANEL Dr. David G. Ullman, Emeritus Professor of Oregon State University, spoke about the potential of electric STOL (short takeoff and landing) aircraft for Urban Air Mobility. “The goal here is to see if eSTOL can rival VTOL and identify what is unique and its potential,” said Ullman, who explained that there are three ways to shorten take-off distance of an aircraft: • Lower the wing loading (W/A) – low weight big wing. Cruise penalty. • Raise the thrust to weight ratio (T/W) • Raise the take-off lift coefficient Ulman recent research has focused on using distributed electric propulsion (DEP) to create Propulsion-Airframe Interaction (PAI) where air moved by the propulsor gains aerodynamic advantages as it passes over the airplane’s wings, fuselage and other surfaces. One STOL aircraft configuration that Ullman finds quite intriguing was Willard Custard’s channel wing. Other aircraft like NASA’s QSRA (Quiet STOL Research Aircraft, based on a de Havilland Canada DHC-5 Buffalo) and Boeing YC-14 used upper surface blowing (USB) to achieve high lift coefficients. Ullman’s is currently testing a number of different DEP configurations in a homemade wind tunnel and on his own single-engine JabirWatt home-built aircraft that has been modified with four 120-mm electric ducted fans mounted to the wings for USB. The key takeaways of Ullman’s presentation are: • “eSTOL can be designed to give very short take-off distances!” • “VTOLs need 2-5 times the power to take-off!” • “VTOL has nearly half the range of eSTOL.” He believes that eSTOL aircraft could easily operate out of “pocket airports” built on one hectare (2.5 acres) of land featuring 420 ft long runways. Biography Dr. David G. Ullman: Ph.D. Mechanical Engineering, the Ohio State University; B.S. and M.S. Aerospace Engineering; Life Fellow, ASME; Emeritus Professor, Oregon State University; Keynote speaker at the 2018 Sustainable Aviation Symposium, “Electric Air Vehicle Performance Prospects: Comparing eVTOL versus USTOL”; and author of “The Mechanical Design Process”, 6th edition, 2018; “Making Robust Decisions”, 2006; and “What Will your Grandchildren See When They Look Up?”, 2018.