I'd like to know more about the glider on the March 1984 cover, and

Why, that's the Rutan Solitaire, of course, winner of SSA's homebuilt
motorglider design contest. I'm too lazy to dig up my hardcopy, but it's
likely astronaut Mike Melvill on board. Or perhaps NASA test pilots
Enevoldson and Meyer whose data argued that canards aren't ideal for
sailplanes.