Do you know when the pic was shot of the Keith Rider, second from last? The chopper in the background and what appears to be an Army Queen Air would seem to place this pic in the 1950s at least.

Race plane designer Keith Rider built two new racers for the 1936 competitions, the R-4 and R-5, the latter had a 2 ft (0.61 m) longer wing. The R-5 was bought by Dave Elmendorf, and listed as Racer number "22", he raced it at the 1936 Nationals as the Elmendorf Special, qualifying as third with 224.551 mph (361.380 kmh). The aircraft was sold to the Marcoux-Bromberg team who raced it in the 1938 Nationals, named Jackrabbit.
The aircraft was withdrawn from racing, and was even used as a billboard. In 1963 it was registered to James Garvin of Walnut Creek, California. In 1966 he put the aircraft on long term loan to the EEA Museum, later it was registered to Morton Lester who donated it to the EEA Museum in 1980. It was registered to the museum on July 19, 1983.
http://1000aircraftphotos.com/Contribut ... J/7488.htm
The R-4 exists with Planes of Fame, but it had been parted out post-war with the wings going into some kind of glider used at airshows. I think that Ed Maloney had recovered the wings from the glider and they were mated to the fuselage once again.