Article: Rajahmundry, Andhra Pradesh, India
Thousand Oaks, California, USA
Dr. Gadicherla V.R. Rao (G. V. R. Rao) (June 24, 1918- May 27, 2005) was a noted American Rocket Scientist and inventor of Rao Nozzle, which is used currently in every rocket, missile, and satellite control system in the world. It is taught in every university in the world that offers Aerospace Engineering (including MIT, CalTech, Georgia Tech, Stanford)
During the Apollo Moon Landing program, while working at Rocketdyne, he invented the Bell Optimum Nozzle for Rockets. It is known as "Rao Nozzle" or "Rao's Nozzle" in the aerospace community.
In his classic textbook, Rocket Propulsion Elements George P. Sutton credits Dr. G.V.R. Rao with working out the mathematics of the optimal Bell nozzle design in 1955, while working at Rocketdyne.
Early life and Education
Rao, as he was known to friends and family, was born June 24, 1918, in Rajahmundry, a small village in the Andhra province of southeastern India. Born into a large Brahmin household, he was the son of the local school headmaster
He is related to Gadicherla Harisarvottama Rao, well known freedom fighter for India's independence.
Rao came to America in the late 1940s for higher studies and earned his doctorate in Aerodynamics at New York University.
He met and married Mary Fabrizio in New York.
Teaching in India
They moved to India, where Rao taught at the Graduate Research Institute in Bangalore
General Electric and Rocketdyne
After the birth of their first son, Raman, Rao and Mary returned to America, where Rao worked for General Electric's jet engines division. After the birth of their second son, Krishna, the family moved to Woodland Hills, CA where Rao worked for Rocketdyne.
It was there that he did his most significant work, most notably, the design of the optimum thrust nozzle. The rocket design, often referred to as the "Rao’s nozzle" is part of the design standard for rocket engines.
Robert Kraemer and Vince Wheelock wrote in their 2005 book ) Rocketdyne: Powering humans into Space“By the mid 1950s large mainframe digital computers became available opening up new thresholds in design techniques. The Advanced Design group hired an expert aerodynamicist G. V. R. Rao to explore nozzle design via computer computation. Rao developed a method for determining the nozzle contour that would produce the maximum thrust for any given nozzle area ratio and length. Expansion efficiency could then be traded with weight to yield an optimum bell nozzle for any given missile application. The optimum turned out to be not only more efficient but also considerably shorter by about 60% than a 15-degree conical nozzle of the same area ratio. Bell nozzles today are still referred to as Rao optimum contours.“
George P. Sutton in his book “History of Liquid Propellant Rocket Engines> wrote, “In 1958 G. V. R. Rao who worked at that time with Dillaway and the Author (George P. Sutton), published the analysis of the optimum curved nozzle-exit contours. He analytically derived that the wall contour of the method of characteristics. This new contour minimizes the losses of internal shock waves in the supersonic flow. The words bell-shaped nozzle were coined at that time. The ideal calculated new bell shape was relatively very long and would be heavy when built, A new shortened bell nozzle shape was also determined by this analysis method; it gave slightly higher losses than a long bell-shaped ideal nozzle, but it had a shorter nozzle length which could be even shorter than an equivalent 15-degree cone. The bell shape or curved exit contour is used almost universally today for nozzles designed since about 1960 for large as well as small thrust chamber nozzles and also for liquid propellant as well as soild-propellent rocket nozzles. Several large Liquid Propellant Rocket Engines which were designed originally with a straight conical nozzle-exit section and had flown, were then modified to have bell-shaped nozzle”
Later years
Rao and Mary moved to Thousand Oaks, CA in 1976. In later years, he worked on aerodynamic and fluid dynamic design projects such as chemical lasers, the space shuttle main engines, wind-powered generators, scramjet and aerospike rocket engines.
Rao was awarded 3 patents for his inventions
In addition to being a distinguished engineer in his field, he was much admired and respected by his coworkers for his wisdom and his wit.
Rao died on Friday, May 27, 2005, at the age of 86. He is survived by his wife, two sons, and four grandchildren.
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