| Lynn,
You’ve probably forgotten more about engines that I will ever know!
I've forgotten more than I knew..........you could catch me...........
Based on your quote above (I’m probably dangerous w/ a die grinder), but the kind of mods you are suggesting seem pretty straight forward. (besides, if I screw it up, it only costs me a rotor housing ;)
My questions are:
Q1. If you start to reshape intake ports on a Renesis, how much can you do before you get into the water jacket?
Thats why its called a program. You start off with a junk engine or two, so anything you do will cost nothing. Get the same year and model as your finished engine, as there may be big changes year to year. One of the items will be to drill many holes through the port areas, and measure thickness with a wire with a hook on one end. Make a map with the depths marked on it. Or, band saw the port areas out of the irons and section them about evey 1/4 inch outside to inside. Mark each piece on a paper map.
Lay out a duplicate of the map on your practice iron and grind out your port. Now you can look at a segment of the sectioned iron and see how deep you can go in each location.
Q2. In a well-engineered aircraft installation, how much HP is a Renesis making? In and RX-8 they are supposed to make about 225 HP. Are aircraft installations getting that much?
Any RV- would look like a rocket with a real 225 HP engine. Since most rotaries go about as fast as 160 HP "airplane engined" RVs, they probably put out about 155 to 170 HP. A periphery port engine could be puting out 200 to 210 or a bit more if in top tune.
Q3. If mods that you suggest above are made to get intake/exhaust overlap, how much increase in HP can be expected in an aircraft installation?
Just a SWAG, but say we did the port job and added a real header, guess 190-195 HP. Cooling loads go up, but if you can cool it reliability would not be a factor. Although we use carbon apex seals, reliabilty is not a factor at 9,600 RPM. But our "flights are onlt 45 minutes long and 8 or 9 per year.
I would use older 13B rotors and counter weights, then if you're not happy with the power, you can go back in and do a really well thought out periphery port and get well over 200 HP. Use 3MM ceramic seals.
The engine would look new inside for 10 years of flying. Ceramic and carbon seals are very easy on the chrome. Run the OMP wide open and feed it a name brand 2 cycle oil.
Porting is used to change the timing, like installing a camshaft with more valve timing. Very little (If any) is removed from the runners. The highest possible velocity at the port opening is what you want.
Thanks for sharing your expertise
Jeff Luckey
Many porting pictures and explanations on the "Nopistons" web site. Free sign up.
Any question anytime.
Lynn E. Hanover
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