From: "Marc Wiese cardmarc@charter.net" <flyrotary@lancaironline.net>
Received-SPF: pass
 receiver=logan.com; client-ip=47.43.20.30; envelope-from=cardmarc@charter.net
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
Mime-Version: 1.0 (1.0)
Subject: Re: [FlyRotary] diffuser re-shaping?
Date: Sun, 21 Feb 2021 12:15:45 -0600
Message-Id: <0C00E114-7DA0-4C8F-85BB-A45B0EF5472B@charter.net>
References: <list-1240823@logan.com>
In-Reply-To: <list-1240823@logan.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>

Steve,
Any before and after pictures?
M

Sent from my iPad

> On Feb 21, 2021, at 1:49 AM, Stephen Izett stephen.izett@gmail.com <flyrot=
ary@lancaironline.net> wrote:
>=20
> =EF=BB=BFHi Finn
>=20
> I see that I was reading your water temps wrongly. You were a little warme=
r than I first thought.
>=20
> The pressure transducers I am using are MPX10=E2=80=99s. I=E2=80=99m using=
 5 that I purchased on eBay. They are probably not true Freescale units but C=
hinese ripoff=E2=80=99s I=E2=80=99m guessing.
>=20
> I started wiring them directly to the EGT inputs with the dynon providing t=
he 5v supply.
> =46rom memory Ive now added 1K in each leg.
> I just used Cat 5 twisted pair cable so the signals are noisy but readable=
.
> Engine Monitor is in the cockpit while box of stacked transducers are unde=
r the cowl in the heat.
> I=E2=80=99m using them with the differential inputs across the face 4 inch=
es in from each corner and one in the middle of the core.
> Wish I had a bunch more for higher resolution of the face, but this gives m=
e some picture of the pressures.
>=20
> A couple of issues:
> 1. When I tried to calibrate them with a water manometer to read inches of=
 water on the Dynon they max=E2=80=99d out at about 6 inches H2O. The data s=
heet says 1.45 psi which I thought was 40 inches of H2O.
> I=E2=80=99m just not sure what the EGT input circuitry thinks of the trans=
ducers output impedance etc. or the temp compensation.
> 2. Ive had issues with a couple of the transducers now in flight. As in th=
e data going haywire. Sometimes providing constant data but then at other ti=
mes all over the shop.
> I thought it was temp related, however I=E2=80=99m beginning to suspect th=
at there is substantial turbulence inside my diffuser.
>=20
> Either way, they still have given me comparative data which has been very i=
lluminating.
> On the last test after squeezing the wedge end really tight the upper back=
 transducer reported very low pressure (As in, the diffuser wall is now agai=
nst the radiator face and there is now basically zero flow to that 4 x 4=E2=80=
=9D section - perhaps larger).
> Having changed the shape of the diffuser, the flow through the front of th=
e Rad has improved enormously. The result better cooling than previous fligh=
t data ever with that back corner section not flowing any air!
> So I=E2=80=99m going to sand off some of the foam in the diffuser and open=
 up the end of the wedge slightly, and hope to improve the cooling even furt=
her.
>=20
> Cheers
>=20
> Steve
>=20
>=20
>=20
>=20
>> On 21 Feb 2021, at 11:50 am, David Leonard wdleonard@gmail.com <flyrotary=
@lancaironline.net> wrote:
>>=20
>> Congratulations Finn!
>> You must be walking on clouds.
>>=20
>> I agree that more cooling will make flying more enjoyable for you.  Getti=
ng cooling capacity at exactly the optimal level is very tricky.  So I say e=
rror well on the side of excess cooling.  Makes life easier, makes flying mo=
re relaxing, and the loss in performance is practically trivial.
>>=20
>> Dave Leonard
>>=20
>> On Sat, Feb 20, 2021, 11:25 AM Finn Lassen finn.lassen@verizon.net <flyro=
tary@lancaironline.net> wrote:
>> N214FL left the ground this morning for an 18 minute flight.
>>=20
>> Main concern was engine (water) cooling. As you know, cooling is a compro=
mise between drag from unnecessary air through cowling and adequate cooling d=
uring normal flight conditions. Climbed to 1,500' before pulling back on thr=
ottle to see if coolant temp would stop rising. It did. Still, I think I err=
ed in too small fluid inlet openings in the A/C evaporator cores I used for r=
adiators. Some more work in that area is in my future before hot days arrive=
.
>>=20
>> Cut the flight short due to a bit of smoke (didn't smell anything) briefl=
y observed low in the cockpit at full throttle later in the flight. To be in=
vestigated.=20
>>=20
>> Van's RV-4 with Mazda 13-B Renesis (RX-8) stock engine.
>> RWS 2.87:1 Propeller Speed Reduction Unit
>> RWS Engine Controller and Monitor (modified)
>> Performance Propeller 76x88
>> Empty Gross: Approx 926 lbs.
>>=20
>> Engine log attached. Unzip and open with Excel.
>>=20
>> WTALR: Water temp after left radiator
>> WTARR: Water temp after right radiator
>> Use EGT and CHT Ref to compare to OAT and adjust accordingly.
>>=20
>> Finn
>>=20
>>=20
>>=20
>>   =20
>> This email has been checked for viruses by Avast antivirus software.=20
>> www.avast.com
>>=20
>>=20
>> --
>> Homepage:  http://www.flyrotary.com/
>> Archive and UnSub:   http://mail.lancaironline.net:81/lists/flyrotary/Lis=
t.html
>=20
>=20
> --
> Homepage:  http://www.flyrotary.com/
> Archive and UnSub:   http://mail.lancaironline.net:81/lists/flyrotary/List=
.html