Keith Rider's last design was the R-6, completed in time for the 1938 races. It was entirely covered in plywood, with the exception of the aluminum engine cowling. Like all Rider racers, it had a manually-operated landing gear, similar in design to that on the R-4 and R-5. The aircraft was painted pale blue and had a large "8-Ball" design on the fuselage and upper left wing. Rider hoped to use 8 as the aircraft's race number, but it drew race number 18 at the 1938 Nationals, so this number was painted behind the "8-Ball."
Joe Jacobson piloted the R-6 at the 1938 National Races. He placed third in the Greve race, with a speed of 218.3 mph. (other Rider racers placed first, fourth and sixth in the Greve.) Jacobson also raced to a sixth-place finish in the Thompson race.
In 1939, the R-6 sported a new dusty medium blue paint scheme, retaining race number 18, but with the "8-Ball" markings removed. It also had a Hamilton Standard constant speed propeller. The counterweights on the propeller prohibited the use of a spinner.
George Byars was the pilot for the 1939 races. The R-6 was plagued by engine trouble during the races and failed to start in any event. This was the last year of the National Air Races at Cleveland, and the R-6 was retired after 1939.
The original R-6 is on static display at Planes of Fame Air Museum, restored to its 1938 configuration featuring the "8-Ball" markings.