[hharney]

The MT STC requires both front and rear must be purchased at the same time. Maybe you should approach them with the idea of amending the STC so that just one engine could be re-propped at a time. I know that this would bring them more business as most folks don't do both engines at the same time and typically at engine change or overhaul is when the props are done. The original STC is from Coastal Planes LLC but I think MT may own the STC now. Aviation Enterprises (Owen Bell & Co) have their own STC for the Continental 550 engine set up so they can do one engine at a time. Something to at least explore and maybe get MT interested in. If the time came that this would happen I would suggest adding the Blended Airfoil design to the STC. Much better blade efficiency.

When Riley developed the Super Skyrocket conversion the STC calls out the TSIO-520 Continental and a Hartzell 3 blade prop. So knowing this Hartzell does have history with the airframe just not the 360 engine in the Skymaster. The engine was used in several other models like the Hawk XP, Cutlass, Seneca and Maule to just name a few.

Robert, What about McCauley? Did you happen to talk to them?