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I think that everyone should remember that ALL of our typical engines have overlap.
Pistons included.
This is always mentioned as the reason rotaries won't idle. Not true! The highest output engines have always been P-port in and out. I am showing you video of a 200 HP rotary idling at 1100 engine RPM solidly. Something else to consider is if you are making an aircraft rotary you don't need to make huge intakes like a Le Mans racer. The 200 HP engine I mentioned has 1 5/8 I.D. intakes. 41mm round intakes at the standard position perpendicular to Trochoid face. Overlap itself isn't the biggest culprit. if you have radical port timing or huge intakes designed for 10,000 RPM of course it's not going to idle! Here is a link to check out. excellent reduction drive as well. I have looked at reproducing that but it would be very difficult to break even in the current market. Here is the link to the engine running on the aircraft dyno. Note that the max RPM was 6,500. this is a very quiet muffler. With a flowmaster duplicated in stainless it was a bit louder and made 200 HP!
battery ignition, aircraft fuel injection. nothing fancy! KISS design rules. Bill Jepson Charlie : Seems to me you got us all. There is no shortage of unanswered questions in this rotary world. Hope i am on the right track with a 13 B p- ported with 44 mm intakes to reduce the overlapp between the intake and exaust ports.Just want the intake flow a little bit better than standard ports on the intakes. My side sump is almost complete will post some photos soon. Hope to develope 180 Hp on “full power” or thats my goal.
Regards Sent from my iPhone Le Roux Breytenbach Conventional measurement technique is to measure water temp leaving the engine, and oil temp after the oil cooler (before entering the engine). What's the temp look like after your oil cooler?
Almost all water cooled conversions seem to have more cooling drag *initially*, because we're all having to experiment with getting cooling optimized in an airframe not designed for liquid cooling, in contrast with the 'cookie cutter' installations of traditional air cooled engines.
What airframe?
10-12 kts isn't a huge difference. Are all your fairings in place?
RVs typically see 12-15 kts increase when the wheel pants & leg fairings are installed.
What RPM and what MAP (is it wide open throttle) to get the 168 kts?
Is the 18 gph figure leaned to best power, or full rich? If running fairly rich (.55-.6 lbs/hp/hr), that would be somewhere between 180 & 200 HP, assuming everything is optimized; intake, exhaust, timing, even mixture between rotors, etc etc. Intake runner length? Exhaust configuration? Supposedly, the Renesis is insensitive to exhaust tuning (due to zero intake/exhaust overlap), but still fairly sensitive to back pressure. Did P-porting the intake create any intake/exhaust overlap, which could affect tuning?
Charlie
Steve, what are your temps? In Florida, with outside being 90-95F I can taxi all day long without overheating. On takeoff, I have to throttle back after 1 to 1.5mins because my oil pan gets to 230F. Coolant out is around 215F. Cruising around at ~3000ft, 80F OAT @ 2250prop rpm. Oil settles to 215-220F, coolant 185-190F. Maybe 140kts. My plane is slower and eats more gas to a comparable lycoming. Usually they cruise at 180kts @ 8gph. I'm sitting at 168kts @ 18gph (not verified yet). Haven't been past 5000ft yet to see the performance numbers. I know my cowl needs a good redesign, intake probably doesn't flow the best, oil cooler is too small, prop may be off. But so far, not too impressed with the engine. I highly doubt the P-Port intake RX8 is anywhere near 250hp like Paul said. I'll have pics/videos soon (this weekend) of plane and flight data, so you'll see what I'm dealing with.
Thanks Lyn
So PP’ing a Renesis 4 port provide significantly better breathing.
Is there a porting option for the Renesis 4 port that yields significant improvement, say 10% hp or is there too little material to play with?
Cheers
Steve Izett
> On 21 Oct 2020, at 9:35 am, lehanover lehanover@aol.com <flyrotary@lancaironline.net> wrote:
>
> A Periphery ported side exhaust is better than both intake and exhaust being periphery ported. Neither the intake or exhaust port ever closes. So, there is exhaust dilution of the intake flow based on the amount of exhaust back pressure. Up to the point where RPMs do not allow enough time for this to occur.Then it sort of steps up on the cam and the power comes on as if by an electric switch. The full periphery engine tunes like a dirt bike. The intake length and diameter and the exhaust length and diameter tune like a trombone.
> A periphery ported 12-A can do 310 HP at 10,000 RPM. A 13-B can do 330 HP at 10,000 RPM. We have to be under 105Db at 50 feet at full throttle. The Renesis has zero overlap. But it had a Micky Mouse intake with 2 different tuned lengths.
> There was a builder at Sun&Fun years ago who had a RX-7 transmission for speed reduction. It worked fine. Later he had the idle too slow and it shook the gears of of 2nd gear. I forgot his name but he died of cancer.
> LEH
> In a message dated 10/20/2020 5:35:49 PM Atlantic Standard Time, flyrotary@lancaironline.net writes:
>
> Mat,
>
> It will only idle hot at that rpm. (1800). Cold it is 2000 plus. Yes P ported and the advance seems to vary little from 20 degrees. Running Fueltech ECU. And running cheapest gas.
>
> Neil.
>
>
> From: Rotary motors in aircraft <flyrotary@lancaironline.net>
> Sent: Wednesday, October 21, 2020 1:38 AM
> To: Rotary motors in aircraft <flyrotary@lancaironline.net>
> Subject: [FlyRotary] Re: Tuning
>
>
> Steve = Using Megasquirt for ECU. How is your flight testing going?
>
> Jeff = I meant prop rpm. Using Neil's PSRU, which is 3.17. I just bumped up my idle to around 800prop (2500engine). I forgot to add, I am P-Port which causes a need for higher idle.
>
> Lynn = Idle can be that high? Usually I see rotary idle around the 10-18 range, but that is for a car. Little different with a prop on 100% of the time.
>
>
> Neil = That is a nice idle. I forget, are you P-Port? What is your timing at?
>
> Dave = 35 all time? Doesn't that seem really high for rotary. Pump gas? Lynn was saying 24 degrees for 87 octane.
>
>
> - Matt Boiteau
>
>
>
> On Mon, Oct 19, 2020 at 12:11 AM Stephen Izett stephen.izett@gmail.com <flyrotary@lancaironline.net> wrote:
>
> Hi there Matt and all
>
> What computer is controlling your fuel and spark Matt?
>
> Ive left the timing of the EC2 on the Renesis 4 port at Tracy’s default and haven’t changed it but was wanting to do some experimenting.
> I take it that the timing setting in the EC2/3 will vary the whole timing curve over the rpm/load envelope.
>
> Cheers
>
> Steve Izett
> Renesis 4 port EC2 EM3 RD1-C
>
>
>
>
> > On 19 Oct 2020, at 10:21 am, Matt Boiteau mattboiteau@gmail.com <flyrotary@lancaironline.net> wrote:
> >
> > Split table.
> >
> > - Matt Boiteau
> >
> >
> > On Sun, Oct 18, 2020 at 10:17 PM Matt Boiteau mattboiteau@gmail.com <flyrotary@lancaironline.net> wrote:
> >
> > What AFR and timing are people running for idle, taxi, takeoff, climb, cruise, descent?
> >
> > idle = 11afr, 20 timing
> > I seem to have to be around 11afr for it to stay alive. Still trying to get it to idle around 600rpm, maybe bump it up to 700rpm to be smoother without dieing and shaking apart.
> >
> > taxi / takeoff / climb = 13.2afr, 28 timing
> >
> > cruise - not sure aft, 28 timing
> >
> > decent - not sure aft, 32 timing
> > Not sure what the plane likes. I tried 14afr, but the MAP really get's low and engine shakes. Guessing it should be more rich?
> >
> > I attached the timing table and split rotary table (second email). Not sure how to tune timing, I just want safe values for now.
> >
> >
> > - Matt Boiteau
> > --
> > Homepage: http://www.flyrotary.com/
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> > <split.JPG>--
> > Homepage: http://www.flyrotary.com/
> > Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html
>
>
> --
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