Yep, I remember them well. A bit vague on the types, one was a red bi-plane like a Pitts, small engine, maybe .020, terrible flier, descended like a streamlined brick when the engine ran out of fuel.
One was like the Wright Flyer, I think the .049, another pig with wings. A yellow T-28, .049, not bad.
The best was a Cox aerobatic .049, big wings with actual airfoil shapes, ribs were externally molded in place. Flew quite well, lasted a long time. 65 years later I still have all of the engines, likely they would still run well if cleaned up and serviced.
They all led to eventual forays into balsa free flight and then RC. I still build free flight scale, great winter activity, then fly them in summer.
Patrick