Correct! A radial engine will make the plane fly a slow, very slow, lazy turn in one direction because the engine is turning over in the other direction, but when the engine is a rotary, it tries to make the airplane do a barrel roll! Could be fun until it happens when you let go of the controls!

Because of this, radial engines were considered much safer and the airplane would remain relatively stable in flight on it's own. I worked on a couple desigs of rortary diesels when I was an engineer for Chrysler. These had advantages we now attribute to the two stroke, capable of starting up easily with maximum power output very fast! The rotary was however incredibly expensive to build and maintain, so the radial was adopted. The rotary was most often used in cooling systems where immdiate refrigeration was required and land based and was experimental in getting big loads moving fast, like a tanker truck filled with water used by firefighters!