From: "Stephen Izett stephen.izett@gmail.com" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] Re: Dyno Sheet
Date: Fri, 7 Aug 2020 22:00:38 +0800
References: <list-613460@logan.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
In-Reply-To: <list-613460@logan.com>
Message-Id: <E82C542D-6B7E-42E2-9843-0F747E7D471C@gmail.com>

Hi Guys.

Today we did some engine data analysis at 9500, 7500, 6000 and 4500 feet =
agl.
WOT with constant best power mixture of 0.9 Lambda.
We looked at Fuel Flow and IAS at 5500,5750,6000,6250,6500,6750 & =
7000rpm.
The data revealed a very slight peak in both IAS and Fuel Flow at the =
6750rpm point at basically all altitudes.
I think what this is suggesting is that increasing rpm beyond 6750 is =
only increasing wear and has no benefit given the current intake/exhaust =
configuration.

With the current Prop Fine Pitch Limit, on initial WOT at Takeoff the =
engine consistently hits 6900rpm within ~6 seconds and 7000rpm by =
liftoff at 70 KIAS.
It then generally builds to 7400rpm (With no pitch adjustment - We =
presently don't have a Constant Speed Controller) before throttling back =
as we turn downwind.

I think this would suggest we ought adjust the props fine limit =
marginally so that takeoff WOT yields approx 6700rpm and keeping the rpm =
as close to 6750rpm as=20
possible when seeking maximum power by manual prop pitch adjustment.
A Constant Speed Controller would be nice!

I=E2=80=99m now thinking we have enough data to tune the Mixture =
Correction Table of the EC2=E2=80=99s computers for climbing at 6750rpm =
and as Bill suggested cruising at 6000rpm.

Next step in tuning in the Glasair Super IIRG will be playing with the =
cowl flaps and cooling drag. Presently the flaps are wide open and =
draggy.
I=E2=80=99m in the process of completing a little box of 5 differential =
pressure transducers (MPX10DP=E2=80=99s) mounted under the cowl.
I worked out that they interface quite nicely without any other =
circuitry with the Dynon Skyview's surplus EGT inputs via a new =
Polynomial in the sensor config settings.
So hoping in the next few weeks to ascertain how the inlets, diffusers =
and outlets are functioning or not.
What I like about the MPX10 interface with the Skyview EFIS is the =
simplicity of displaying the pressure data inflight while its all logged =
along with engine and flight data=20
for analysis on the ground.

I=E2=80=99ve got 7 more hours of Phase #1 testing.
So far both aircraft and engine are really great.

My friend and test pilot Dawie also demonstrated at the end of todays =
flight - a Lazy Eight, a Roll and Wingover.=20
I felt sick for the next 3 hours. I don't think aerobatics will be in my =
future.

Thanks for all the help you guys.

Steve Izett
Perth Western Australia
Glasair Super IIRG Renesis 4 port RD1C EC2 EM3


> On 7 Aug 2020, at 2:25 pm, William Jepson wrjjrs@gmail.com =
<flyrotary@lancaironline.net> wrote:
>=20
> Stephen,=20
> The answer to one of your questions is easy. A fast cruise RPM should =
be 6000. Mazda did many instrumented runs and found that 6000 rpm was a =
sweet spot where the dynamics balanced perfectly. At 6000 there is =
almost no load on the bearings. The rotary would run at that RPM =
indefinitely. If you have more power at higher speeds you can use that =
for maximum speed. Those RPMs are eshaft RPMs not propeller.
> Bill
>=20
> On Thu, Aug 6, 2020 at 4:15 PM Stephen Izett stephen.izett@gmail.com =
<flyrotary@lancaironline.net> wrote:
> Hi Guys
>=20
> Thanks for all the feedback.
> I think I didn=E2=80=99t explain my objective clearly enough.
>=20
> Some questions:
> 1. Given I have variable pitch, what combination of MAP and RPM should =
I climb or cruise at? With fixed pitch I dont suppose you think in these =
terms.
> So should I be Climbings at WOT & 7000rpm OR WOT & 6300rpm Best Power =
Mixture.
>=20
> I think Lynn best understood my intention of trying to use the flight =
as a dyne - I didn=E2=80=99t realise the complexity of the relationship =
of mixture and timing at various settings, thanks Lynn.
> I thought by keeping WOT and mixture constant I might ascertain a =
maximum efficiency combination for MAP/RPM.
>=20
> I=E2=80=99d like a combination for max power. I=E2=80=99m thinking =
identified by higher fuel burn and IAS for the climb, and=20
> a max efficiency/ecconomy combination for cruise identified by best =
miles per gallon.
>=20
> I thought our Renesis with our modified OEM (shortened) manifold but =
no variable intake valves etc. would have a distinctive peak at =
~6400-6600rpm.
>=20
> 2. I=E2=80=99m finding tuning the EC2 (objective being EC provides =
constant mixture across the flight envelope) is dependant on the =
combination I choose to tune it at.=20
> Eg. Tune EC2 MCT for one MAP/RPM combination, say a cruise of 18=E2=80=9D=
 AND 5000 rpm, then the EC will not be able to provide a constant =
mixture if I then choose 18=E2=80=9D at 6000rpm.
> My EC2 has Tracy=E2=80=99s 8 table setup but fueling requirements =
given the extra permutations provided by the variable pitch prop =
(climbing that hill - which gear should I use - 3rd 4th or 5th??)=20
> appears to stretch its inherent capabilities. So I want a plan for =
what MAP/RPM I will use and then adjust/tune the EC MCT for that =
combination.
>=20
> Thanks again guys.
>=20
> Steve Izett
>=20
>=20
>  all is nice if you fly that combination. If I then choose ab
>=20
> > On 7 Aug 2020, at 6:16 am, lehanover lehanover@aol.com =
<flyrotary@lancaironline.net> wrote:
> >=20
> > Your thinking is correct. Control full throttle RPM with load. Then =
experiment always at that particular RPM until you have whatever data =
point you were after. Everything affects everything so it may be that =
(for example) advancing ignition timing at one RPM adds power but at =
another RPM reduces power. A rich mixture at one RPM may increase power =
but reduce power at another RPM. To recover even similar data on =
consecutive days is difficult. The SAE has some charts that produce a =
multiplier to account for density temperature and so on. Required to =
compare results day to day. It takes a long time to collect good =
data..........
> >=20
> > Lynn E. Hanover =20
> >=20
> >=20
> >=20
> > =
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>=20
>=20
> --
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