Veteran California race plane builder Keith Rider built two new racers for the 1936 season that were essentially identical, the R-4 and the R-5. Even though the R-4 had a more successful career, the R-5 is a treasured racer because it represents the technology of the state of the art of the smaller class racers of 1936. It was sold to Dave Elmendorf who raced it at the 1936 Nationals at Los Angeles as the Elmendorf Special and it was registered by the FAA as the Elmendorf A-1