The annual Reno National Championship Air Races, featuring racing planes of vintage stock refurbished for contempo speed, provide the basis for the spare and less-than-thrilling “Air Racers 3D,” which surprisingly under-exploits the subject’s rich Imax 3D possibilities. Narrated by Paul Walker in the style of surf docs of yore, pic provides a fun time for flying and air-warfare enthusiasts, but fails to effectively place the viewer in the cockpit for dazzling pilot p.o.v. shots. Item will serve as useful program filler on busy spring-summer Imax calendars.

A too-brief opening sequence (with co-helmer Christian Fry acting as one of the pilots) stages a WWII dogfight, serving up the film’s best 3D shots and placing the Reno airshow in its historical context. Many of the racing planes in Reno — reaching speeds of 500 mph, and at dangerously low elevation — are refashioned from vintage wartime craft, such as the P-51 Mustang piloted by the 2009 race’s winner, Steve Hinton Jr. Camera placements and telephoto shots rob the pic of giantscreen 3D impact; Douglas Sirk’s staging of a similar race in “The Tarnished Angels” was more viscerally exciting than anything here.