Raymond John Koester Jr.

Koester, Raymond “Ray”, age 96 of Centerville, passed away on Tuesday, June 30, 2026. He was born in Dayton, Ohio to the late Raymond and Della (Phillips) Koester. Also preceding him in death are his first wife, Catherine (Corbett) Koester; sisters Dorothy Koester and Marilyn Cogan, and daughter Virginia (Ginny) Zahora.

Ray is survived by his wife Elaine Slack. Also, sons David (Maryjane) Koester and Anthony (Ollie) Koester; daughter Angela (Joe) Plumlee; grandchildren Kevin (Stephanie) Zahora, Kristy (Michael) Worden, Amy Zahora, and Andrew (Jordyn) Plumlee; great-grandchildren Grant and Grady Zahora, Landen and Ella Worden, along with many other relatives and friends. Ray was a loving husband, father, grandfather, and great-grandfather. He enjoyed the frequent family get-togethers with the Cogans and Corbetts. Always surrounded by family he was blessed and lived a full life. Ray studied at the University of Dayton, where he received his Bachelor of Science degree (B.S.) in Engineering in 1954 and his Master’s degree (M.S.) in Engineering in 1972. He was a member of the American Society of Mechanical Engineering (ASME) and the Ohio Society of Professional Engineers (OSPE). Ray worked as a civilian engineer in the Air Force Research Lab at WPAFB. He contributed to many different programs over the years such as the early space program called the DynaSoar, C5 Galaxy, air launched cruise missile, and several drone programs. Ray was considered a stealth pioneer stemming from his early and lasting contributions to Have Blue (the first stealth plane), the B-2 and F-117 stealth planes. Ray was a long-time member of St. Helen Parish and had recently joined the Knights of Columbus. In his earlier years he was an avid runner, completing two Marine Corps Marathons in Washington, D.C. He was also a member of Eastview Recreation Center, where he enjoyed playing tennis and volleyball during the summer months.

A visitation will be held from 4 pm – 6 pm on Wednesday, July 8, 2026, at the Tobias Funeral Home – Beavercreek Chapel. Another visitation will be held on Thursday, July 9, 2026, from 10 am - 11 am at the St. Leonard Chapel, 8100 Clyo Rd., Centerville, OH. A Mass of Christian Burial will follow at 11 am with Fr. Jerry Haemmerle, Celebrant. Graveside services will follow at Calvary Cemetery. In lieu of flowers memorial contributions may be made to Ohio’s Hospice of Dayton, https://www.ohioshospice.org/give/ or mail contributions to Ohio’s Hospice Foundation, 7575 Paragon Rd., Dayton, OH 45459