United States of America
Dr. Francis Xavier Caradonna, US Army Emeritus Scientist, worked for the US Army for 43 years at the NASA Ames Research Center in flight dynamics as a researcher and mentor to others in the field with numerous scholarly publications on the subject.
Caradonna was born in Worcester, Massachusetts, on Oct. 12, 1941, and grew up with a loving family pursuing his interests of music, science and aviation. In his youth, he was also known to dabble in the fabrication of amateur fireworks, putting what he learned in the local library to good use, sometimes to the chagrin of the local fire department. He received a Bachelor of Mechanical Engineering from Worcester Polytechnic Institute in 1964, a Master of Science in Aeronautics and Astronautics from Stanford University in 1965, and Doctor of Philosophy in Aeronautics and Astronautics from Stanford University in 1978. He joined the US Army Aeroflightdynamics Directorate (AFDD) co-located at the NASA Ames Research Center in June 1970 on military assignment as a captain in the US Army’s Ordnance Corps. Beginning in 1973, he continued in his research role at AFDD as a civilian.
Caradonna conducted computational and experimental studies of helicopter rotor flows. He developed the first computational fluid dynamics (CFD) analyses of transonic rotor flows in the early 1970s. He designed and conducted pressure-instrumented rotor experiments and related computations leading to the first validation of rotor CFD computations. He performed basic studies on the structure of rotor wakes. The first CFD models of hovering rotor wakes were developed by Caradonna. In the 1980s, he jointly developed the first computational coupling of rotor CFD codes with comprehensive analyses. In the 2000s, he designed and conducted experiments for the study of rotor-vortex interactions for use in rotor acoustic analysis. He led a large industry/academic/government study group performing computational validations of blade-vortex interaction computational methods. He advocated for, defined and managed the development of a major facility for the testing of mid-scale model helicopter rotors — aimed at using the NFAC for high-lift and acoustic testing. This facility was used to study hover performance and it enabled the only major tiltrotor descent experiment to be performed in response to the 2000 V-22 accident at Marana, Arizona. Caradonna served as a technical advisor to the subsequent V-22 investigation board. He also guided the development of new small-scale experimental rotor facilities that use a tow-tank.
As an Emeritus, Caradonna remained active in the guidance of rotor free-wake performance computation methods. He advised the design of a new test capability for the study of hover-related blade vortex interactions, and jointly conducted initial tests using this capability. He was an active participant in a joint Army/ NASA study group for the definition of hover test techniques aimed at a new level of basic hover wake and performance understanding.
Caradonna was a recipient of the US Army Research & Development Achievement Award, a VFS Technical Fellow (1990), and author of several VFS technical papers. He was remembered as being an active mentor who always made time to advise younger researchers on technical and professional topics.
Dr. Oliver Wong, the US Army’s Associate Director, Design, Simulation & Experimentation at Ames Research Center recalled: “Frank was a mentor to many of us here. In my case, I met Frank in fall of 1996. He graciously allowed a novice team of GT VLRCOE students to piggyback on his test in the 7-by-10-ft Wind Tunnel to try out a novel diagnostic technique. Frank was always interested in hardcore science. I can remember him always asking ‘What [were] the fundamental physics of the phenomena?’ He embodied and passed down to the current workforce many of the traits that enable us to be world class scientists in our disciplines.”
Dr. Francis Xavier Caradonna passed away peacefully on July 12, 2022, after a brief illness at age 80.
VFS Update: 'In Memoriam,' Vertiflite, September/October 2022