Staying with 2 1/4" in & out.  I think this is enough for 300 HP.  Bigger than that would be like putting those silly 4" tailpipes on Honda Civics : )

 

I was amazed at the results of the engine stand tests we did last year at the RR fly-in.  When we tried that tiny 1" outlet reducer on Monty's muffler, the engine only lost 200 rpm (6500 down to 6300).  It was very quiet as well.  Wouldn't want to go to that extream but based on evidence like this & other experiments, I think we've been way high on our estimates of exhaust diameter requirements.  

 

Tracy  (getting ready for Tail of the Dragon trip)

 

On 11/3/07, Kelly Troyer <keltro@att.net> wrote:

 

Tracy,

   Curious as to the inlet/outlet diameter of the Hushpower II you

ordered for the 20B.........Somewhat larger I would presume........

--
Kelly Troyer
"Dyke Delta"_13B ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil Manifold



 

-------------- Original message from "Tracy Crook" < tracy@rotaryaviation.com>: --------------

Max static rpm on the 20B with 72 x 104" 3 blade prop is ~ 6000 rpm.  I think the peak rpm on the day of the video was 5970.  The sound of the engine, prop and windblast in the cockpit (canopy not on) is unbearable without the hearing protectors I was wearing.  Ordering a HushPower II muffler for it this week.  No muffler was installed during the video.

 

Thanks for posting the video Bob.

 

Tracy