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My comment about 'no overlap' assumed
that he was running a Renesis. Everything I've ever read about the
Renesis says there is zero overlap (actually, a 6 degree spread)
between exhaust closing and intake opening on the same rotor.
A P-port intake obviously has the potential to change that, but I
have no idea about whether or how much it does change it.
If it's a 13B, then...never mind. :-)
Charlie
On 10/21/2020 5:14 PM, William Jepson wrjjrs@gmail.com wrote:
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/
> > Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html
> > <split.JPG>--
> > Homepage: http://www.flyrotary.com/
> > Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html
>
>
> --
> Homepage: http://www.flyrotary.com/
> Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html
>
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