5.  The aero drag on Spintech was costing me more than the 3 - 4 mph that I had estimated.  It was less aero drag that attracted me to the Hushpower II to begin with. 

6.  The airplane is frighteningly fast due to 4 & 5.  Could not do an all out top speed run due to airframe concerns.  I backed off when airspeed exceeded Vne by 10 mph. 

 

So with the Renesis engine, you'll be running the race at half throttle & Vne :-)   

I'm hoping that my Spintech will be far enough forward to keep the 200 mph wind from hitting the front of the muffler.  I may have to extent the bottom cowl back just a bit to make sure, though that's waaaaaaaaaay down on the list of priorities at this point.  

Cheers,

Rusty

PS- my entire exhaust weighs 25 lbs.