I also wondered about a triplane and since there appear to be radiators on the sides of the fuselage, I wondered about a racing triplane.
I know, it sounds stupid, but it turns out there was one - the Curtiss Cactus Kitten:
A bizarre history - started off as a monoplane, then a biplane and finally a tripe!
https://en.wikipedia.org/wiki/Curtiss_Cox_Racer