Hey Bobby, that RANs S21 looks like a nice airplane ... another high-wing (not too many) coming to the Rotary world ...  the rotary should give that decent performance.
Jeff

I used Jet Hot on my first custom manifold. It flaked off within a short period of time. The "professionally" build 321 manifold burned out at the rectangular to round flange transitions. Due to the ceramic coating I decided not to try and weld in a repair. I've decided to not to have any new manifolds treated so they can be repaired if needed. But I could see a benefit for pipes downstream of the manifold.

Bobby

RV10 airframe sold w/ 553 hours. - Rans S21 on order with 16 month lead time. - Rotary FWF development will start in a couple of months.