Many people of a certain age remember Mazda Motor Corp.'s catchy ads from the 1970s. "Piston engines go boing-boing," they said. "Mazda goes hummmm." The voice-over sang: "There's nothing like it on the road today; the rotary engine is here to stay."

Wrong.

The last Mazda using the rotary, which won fans with its ability to generate more power than traditional power plants of the same size, will roll off the assembly line this month in Hiroshima.