From: " eanderson@carolina.rr.com" <flyrotary@lancaironline.net>
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To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: N214FL RV-4 First Flight
Date: Sun, 21 Feb 2021 16:49:21 +0000
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Great Going Finn!

If my coolant temps remained below 220F on a Hot day during take off, I=20
felt they were within bounds.  After getting to cruise airspeed coolant=20
temps were around 170 - 180F.  On a cold < 45F day, coolant temps would=20
stay below 180F (no thermostat used in my installation).

Ed

------ Original Message ------
From: "Stephen Izett stephen.izett@gmail.com"=20
<flyrotary@lancaironline.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: 2/21/2021 2:49:18 AM
Subject: [FlyRotary] Re: N214FL RV-4 First Flight

>Hi Finn
>
>I see that I was reading your water temps wrongly. You were a little warme=
r than I first thought.
>
>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 =
Chinese ripoff=E2=80=99s I=E2=80=99m guessing.
>
>I started wiring them directly to the EGT inputs with the dynon providing=
 the 5v supply.
>From 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=
 me some picture of the pressures.
>
>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=
 sheet 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 t=
imes 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.
>
>Either way, they still have given me comparative data which has been very=
 illuminating.
>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 aga=
inst 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 flig=
ht 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 fur=
ther.
>
>Cheers
>
>Steve
>
>
>
>
>>  On 21 Feb 2021, at 11:50 am, David Leonard wdleonard@gmail.com <flyrota=
ry@lancaironline.net> wrote:
>>
>>  Congratulations Finn!
>>  You must be walking on clouds.
>>
>>  I agree that more cooling will make flying more enjoyable for you.  Get=
ting cooling capacity at exactly the optimal level is very tricky.  So I sa=
y error well on the side of excess cooling.  Makes life easier, makes flyin=
g more relaxing, and the loss in performance is practically trivial.
>>
>>  Dave Leonard
>>
>>  On Sat, Feb 20, 2021, 11:25 AM Finn Lassen finn.lassen@verizon.net <fly=
rotary@lancaironline.net> wrote:
>>  N214FL left the ground this morning for an 18 minute flight.
>>
>>  Main concern was engine (water) cooling. As you know, cooling is a comp=
romise between drag from unnecessary air through cowling and adequate cooli=
ng during normal flight conditions. Climbed to 1,500' before pulling back o=
n throttle to see if coolant temp would stop rising. It did. Still, I think =
I erred in too small fluid inlet openings in the A/C evaporator cores I us=
ed for radiators. Some more work in that area is in my future before hot da=
ys arrive.
>>
>>  Cut the flight short due to a bit of smoke (didn't smell anything) brie=
fly observed low in the cockpit at full throttle later in the flight. To be =
investigated.
>>
>>  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.
>>
>>  Engine log attached. Unzip and open with Excel.
>>
>>  WTALR: Water temp after left radiator
>>  WTARR: Water temp after right radiator
>>  Use EGT and CHT Ref to compare to OAT and adjust accordingly.
>>
>>  Finn
>>
>>
>>
>>  This email has been checked for viruses by Avast antivirus software.
>>www.avast.com
>>
>>
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>
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