The story of Curtis D. Summers and Charles Dinn have been intertwined since the two men met in the early 1970's working on projects for Kings Island Amusement Park in Mason, Ohio. Their legacies live on today in one of the most successful wood coaster designers and builders, The Gravity Group, located in Norwood, Ohio.

Curtis D. Summers, Inc.

Curtis D. Summers left the U.S. Navy in 1958, moved to Cincinnati and joined an engineering firm that did design work for Coney Island. When Coney announced plans to build Kings Island in the late 1960’s, Summers was retained to help design many aspects of the park, including the Eiffel Tower.

In 1972, he opened up his own engineering and architectural firm bearing his name at 7800 Laurel Avenue in Loveland, Ohio. Much of the firm’s work involved amusement and water parks but Summers also helped design office buildings, manufacturing plants commercial buildings. Throughout his career, he only designed wood coasters. It was there that Summers met Charles Dinn, who served as the Director of Construction at Kings Island. In 1976, the firm was retained to help design the legendary Beast at Kings Island. In the mid 1980’s, Dinn left Kings Island and formed Dinn Corporation and joined Summers on a number of coaster projects. The duo combined their talent to design and build 10 wood roller coasters across the country. They include:

Georgia Cyclone – Six Flags Over Georgia
Hercules – Dorney Park
Mean Streak – Cedar Point
Predator – Darien Lake
Psyclone – Six Flags Magic Mountain
Raging Wolf Bobs – Geauga Lake
Texas Giant – Six Flags Over Texas
Timber Wolf – Worlds of Fun
Thunder Run – Six Flags Kentucky Kingdom
Wolverine Wildcat – Michigan’s Adventure

In 1992, Summers passed away and his partners ultimately dissolved his company in 1994.

Dinn Corp.

Charles Dinn, served as Kings Island’s Director of Construction, Maintenance and Engineering in the 1970’s. His most notable project was The Beast roller coaster that he managed with an in-house team that included Jim Nickell, Al Collins, and William Reed. With assistance from Philadelphia Toboggan Coaster designer John Allen, The Beast opened to rave reviews in 1979. A few years later, Dinn left Kings Island and opened his own firm, Dinn Corporation and located his headquarters in West Chester, Ohio. For engineering services, he teamed up with Curtis D. Summers, Inc. in nearby Loveland.

From 1983 to 1992, the duo combined their talent to design and build 10 wood roller coasters across the country. They include:
Georgia Cyclone – Six Flags Over Georgia
Hercules – Dorney Park
Mean Streak – Cedar Point
Predator – Darien Lake
Psyclone – Six Flags Magic Mountain
Raging Wolf Bobs – Geauga Lake
Texas Giant – Six Flags Over Texas
Timber Wolf – Worlds of Fun
Thunder Run – Six Flags Kentucky Kingdom
Wolverine Wildcat – Michigan’s Adventure

In 1992, Summers passed away and Dinn retired.

Custom Coasters International, Inc.

Charles Dinn's daughter, Denise Dinn Larrick took over where her father left off and opened Custom Coasters, Inc. along with her husband, Randy Larrick and her brother, Jeff Dinn in 1991.

Based in West Chester, CCI brought along their main designers from Curtis D. Summers, Inc. They included Larry Bill, Chad Miller, Korey Kiepert, and Michael Graham. CCI became the most prolific wood coaster builder during the 1990's. The company closed in July 2002 in the midst of the Dinn's divorce. Denise formed the wood roller coaster division of S&S Sports. Bill, Miller, Kiepert and Graham formed The Gravity Group, LLC.

CCI coasters include:
Boss - Six Flags St. Louis
Boulder Dash - Lake Compounce
Cornball Express - Indiana Beach
Cyclops - Mt. Olympus
Ghostrider - Knott's Berry Farm
Great White - Morey's Piers
Hoosier Hurricane - Indiana Beach
Legend - Holiday World
Lost Coaster of Superstition Mountain - Indiana Beach
Outlaw - Adventureland
Pegasus - Mt. Olympus
Raven - Holiday World
Shivering Timbers - Michigan's Adventure
Sky Princess - Dutch Wonderland
Timber Terror - Silverwood Theme Park
Tremors - Silverwood Theme Park
Twisted Sisters (FN) - Six Flags Kentucky Kingdom
Twisted Twins - Six Flags Kentucky Kingdom
Villain - Geauga Lake
Underground - Adventureland
Zach's Zoomer - Michigan's Adventure
Zeus - Mt. Olympus

The Gravity Group

The design and engineering team of Bill, Miller, Kiepert and Graham got off to a slow start and became consultants on several coasters before building their first one in 2004 at Mt. Olympus and Holiday World.

By November 2004, The Gravity Group had their first contract providing consulting services to Holiday World on two of their wood roller coasters, both of which had been built by CCI. Over the next few months, The Gravity Group picked up 10 additional projects, many of which were not associated with amusement parks.

Today, The Gravity Group serves as one the premire wood coaster design and engineering firms in the country.