I know these pipes are the oil cooler, but the S-6B is what made me think to look for a racing triplane.
While looking for a suitable picture, I stumbled on this amazing website:
https://johnkshelton.********.com/20...mitchells.html
Since PPRuNe hates this particular domain for some unknown reason, here's a workaround:
https://tinyurl.com/56496vf2
I love Mitchell's description of the S-6 as a "flying radiator".