William E. Rumberger Jr., 81, longtime Boeing engineer and inventor

William E. Rumberger Jr., 81, of Newtown Square, a mechanical engineer who helped design airplane parts at the Boeing Co. for many years, died Sept. 24, of cancer at Bryn Mawr Hospital.

Mr. Rumberger, who was known to friends as "Bill," was born in Darby Borough to William and Valinda  Rumberger and reared in Essington. The Christian faith he learned from his family was an important guiding principle.

He spent a happy childhood picking wild elderberries on Tinicum Island, catching snapping turtles along the banks of the Darby Creek, and playing with his dog, Buster. He graduated from what was then Lansdowne High School.

While studying mechanical engineering at Drexel University, Mr. Rumberger was an intern at Boeing in Ridley Park.

After graduating, he went on to spend his entire career, beginning in 1959, at Boeing, as a designer and tester of parts used on various aircraft. "The job utilized his genius in lightweight design," his family said in a tribute.

Starting in 1982, Mr. Rumberger filed for and was granted 15 patents for inventions. One 1984 patent was for a system used in helicopters to detect and collect debris in fluid flow and to route the debris to a reservoir while keeping the fluid moving and the aircraft in motion.

Another invention he patented in 1994, along with Wayne S. Steffier, was the stainless-steel Flex Ring, which enabled the V-22 Osprey' wings to be pivoted and stowed when not in use.

The development of the Flex Ring is described in The Dream Machine:The Untold History of the Notorious V-22 Osprey. Author Richard Whittle described Mr. Rumberger as one of Boeing's reliable old-timers — personable, diplomatic, and able to think outside the box.

"By the 1980s, many engineers were known for using computers to design things, but Rumberger wasn't among them," Whittle wrote. "He drafted his designs on paper and then constructed cardboard models to test his theories. He always kept cardboard and a bottle of Elmer's Carpenter's Glue at his desk for that purpose."

Mr. Rumberger's design for the pivoting device was superseded by that of another engineer for a time, but after the latter retired, the flex ring was installed on the Osprey, a propeller plane that doubled as a helicopter.

The day the design was accepted, his buddies at Boeing dubbed Mr. Rumberger "The Lord of the Ring," Whittle wrote. The earlier design "wasted a lot of time," Mr. Rumberger said, shaking his head.

Mr. Rumberger met Bethel Powell through a youth group at Aldan Union Church. They married in 1957 and reared a family, first in Secane, and then Newtown Square, where they lived for the last 50 years.

"They built a life full of work, sacrifice, service, and adventure," their children said.

An important part of Mr. Rumberger's day was practicing his Christian faith.

"Bill was known for making soup and meals for many, many people of all races and religions who were suffering from sickness and hardship. He and his wife opened their home to those in need of a place to stay, sometimes for years at a time," his family said.

In retirement, he volunteered as an engineer through the Water of Life program to help design and install reverse-osmosis clean-water systems for rural medical clinics in Vietnam, Romania, and Nigeria.

He volunteered for decades at the Frederick Douglass Christian School in Chester, improvising costumes and helping the children act out favorite Bible stories. He sang in the choir and served as an elder and board member in various churches throughout his life.

"Bill will be remembered for his generosity, ingenuity, his homemade sticky buns, his delight in his grandchildren, sharing silly humor and dramatic storytelling, and singing hymns with his face tilted toward heaven," his family said.

In addition to his wife, he is survived by children Timothy, Deborah, Lisa Livezey, and Bryan; 13 grandchildren; three great-grandchildren; a brother and sister; and nieces and nephews. A sister died earlier.

A memorial service was held Sept. 30, at Proclamation Presbyterian Church in Bryn Mawr.