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| Charlie,
Flying? No, I don't know of anyone flying a pp Renesis...yet. PL built one that dyno'ed at over 250hp at 6500 rpm. So, it is doable. As I understand it, as hp goes up, efficiency goes down. My fuel burn increased by 2 gph when I switched to p-port. But then I now fly 15 knots faster than with the side port motor, so I get there sooner, so I don't run the engine as long and recoup some of the extra fuel burn. But, with higher airspeed comes higher airframe and cooling drag. In the end, I guess its worth it.
Have you seen the intake that Dennis Haverlah designed for his Renesis? He picked up something like 10 kts on the top end with it. It is based on dynamic tuning. Looks like something off a racing egine. He recently published some pretty impressive performance numbers. But I don't know how those compare to Tracy's numbers.
Mark S. On Sun, Aug 14, 2011 at 12:11 PM, Charlie England <ceengland@bellsouth.net> wrote:
Who's flying one (P-ported *Renesis*), & does it meet *both*
criteria?
On 08/14/2011 10:02 AM, Mark Steitle wrote:
Charlie,
Maybe you meant "...best power of all side ported rotaries".
I'm pretty sure that a p-ported 13B would easily produce more
power than a side port motor, assuming they do a good job on the
intake and exhaust. The nice thing about a p-port motor is the
intake is simpler and easier to build than a side port intake.
Mark S.
On Sun, Aug 14, 2011 at 8:34 AM,
Charlie England <ceengland@bellsouth.net>
wrote:
On the subject of
Renesis intake complexity, take a look at Tracy's intake
(pic from his web site).
http://www.rotaryaviation.com/renesis_engine.htm
Can't get much simpler, & as far as I know, he has the
best power numbers and the best efficiency numbers of
anyone flying. His intake tubes are now longer than in
this shot, but as you can see from the pic, adjusting tube
length (retuning) is pretty straightforward.
Charlie
On 08/14/2011 06:36 AM, Ed Anderson wrote:
Sam, As you find in this "hobby"
there are always trade offs. First, technically
there is no reason you could not do what you propose
- however, you will add weight and complexity. A
poor intake affects both N/A and forced induction -
its just with forced induction you are paying in a
different way to overcome any defficiencies in your
intake.
If going that route, I
personally would prefer the centrifugal type
belt/gear driven blower over the roots type which
has historically had the poorest efficiency. On the
other hand, if you are not going to "boost" above
ambient pressure - then I think I would concentrate
on getting a good N/A intake.
Good luck on your project
whichever decision/approach you take. Super and
Turbo chargers have both been used successfully.
just my $0.02\
Ed
Sent: Sunday, August 14, 2011 1:01 AM
Subject: [FlyRotary] Renesis Question
I think my brain has had a meltdown: I am thinking about
"supernormalizing" the Renesis engine. Is this even
possible. The idea is to use a by-passable positive
displacement type blower (roots type...probably an eaton
m90) fed to an intercooler that then sends air to the
engine. If my thinking is correct, and it probably
isn't, this would eliminate the complex N/A intake,
while not over-boosting the Renesis engine. Also, the
supercharger being a positive displacement blower would
in theory produce more boost than is needed by the
engine at all rpm levels, eliminating the "peeky" torque
of boosted engines. The excess (above standard intake)
pressure would be controlled via an automatic or manual
waste-gate. Please shoot my idea down if it is insane,
but i would like some constructive criticism if it is
available.
Sam
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