I agree,
I'm building new for SPA for next year but both will be four cycles and switched to TD's.

Anyone who thinks a four cycle can't stay with a piped .61 hasn't been tuning their fourcycles very well nor choosing the 'magic' prop either. Trust me, they've got it without all that infernal screaming.

I guess, while having loved my , Merco's, Tigers (I have a special reverence for Tigers), Webra's Backheads and Speeds ---- even the Dynamix, Kraft's Webra, Ross's and lastly (I hope NEVER to even see ANOTHER) a Rossi .61 on an OPS pipe.

Lots of my fellow competitors swore by their Rossi/OPS set ups. Steve Helms being one, but that set up and I did NOT have a love affair going.
As best I can remember I gave the whole thing (Rossi and OPS pipe) away just to get it out of my sight.

I have good memories of the thousands of flights put in on those two cycles but today I can make the four cycles talk to me ------- and they have a much more pleasant exhaust note.

If there is any lack of performance vs. what you younger folks refer to as ballistic pattern ---- (back then WE did not call it that) you'll have to show me as I can do loops which rocket into (almost) the stratosphere. My current ship (my own desgn CAP) will easily accelerate out of sight vertically ------ except you've got to knock that off to keep orientation.
I started Pattern in the very early sixties when a .45 was considered BIG.

But to each his own ---- it is a hobby to be enjoyed ---- and you place your own definition on that.

Every other two cycle mentioned I could get to eat from my hand ----- the Rossi simply gave me unending grief! They may be great engines ------ but for someone else please!