Thanks.
Actually looks like I pulled back on the throttle before 700' when
water temp reached 200F. Yes very conservative. Wanted to see if
water temp would stop rising.
Max RPM 5713 (2000 prop RPM). Yes definitely a cruise prop. Note
that I never got above 117 mph with full throttle (climbing). Oil
temp not an issue at all. Plan was to go faster once I'd make sure
the water temp was under control, but then saw the smoke. Still
not sure about the source of the smoke. Have a bit of oil leak
around oil filter adapter plate. Oil film on bottom of fuselage.
Best guess that got oil on exhaust pipe that got hotter as I added
throttle to climb again and the smoke got sucked into the cockpit
via wing roots.
Climbing at a higher airspeed and lower rate would probably have
been better.
Able to maintain altitude at about 3700 RPM and climb at 4100 RPM.
Exit area about 42 sq in (not counting the cowl cheeks ballooning
out a bit).
Don't have a way to measure cowl pressure. Perhaps instead of
adding current sensors I should use the unused EGT and/or CHT
channels for pressure sensors. Steve, I need to locate your post
about that.
The evap cores I use have very small inlets and outlets. Instead
of going into ends of tanks they go into sides of tanks. Perhaps
squeezing down to smaller than 0.25"x0.5". Inlet tubes were 1/2"
(3/8" to 7/16" ID) and outlet tubes 5/8" (1/2" to 9/16" ID). Two
in parallel but still less than Lynn's 5/8" restrictor. Most
obvious solution is to have tube elbows welded to the tank end
plates. I'll probably end up paying a welder more than I paid for
the new cores ($34 shipped for two back in September 2019): New
A/C Evaporator Core 1220174 - 000067B10A6P B2200 B2600 B2000...
Similar to this:
Finn
On 2/20/2021 6:18 PM, Stephen Izett
stephen.izett@gmail.com wrote:
Congratulations Finn.
Some reflection from the data:
RPM’s only get to ~5650rpm - Is it over propped?
You appear to have been quite conservative when you pulled the power back with Eng temps being well below 200.
You were probably maybe making ~150hp depending on your intake length etc. The OT being quite low.
Looks like you need to collect some more data.
What is the exit area and can you measure the cowl pressures?
We are continuing to fine tuning our cooling.
Changes to our diffuser wedge shape has made some significant improvements.
We mechanised our right hand (bottom rear) cowl flap and flew the Glasair last week to test.
Closing the one cowl flap at 140 KTAS yielded a 5 KTAS increase and 2 deg C rise in H2o & Oil temps.
Based on this data we’ll now mechanise the left hand cowl flap and test.
Our experience is without doing the science and measuring pressures across the radiator cores we are just spitting in the dark.
Again, congratulations and thanks for your help.
Cheers
Steve Izett
Perth Western Australia
Renesis 4 port, RD1-C EC2 EM3 variable pitch Prop
On 21 Feb 2021, at 3:25 am, Finn Lassen finn.lassen@verizon.net <flyrotary@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 compromise between drag from unnecessary air through cowling and adequate cooling during normal flight conditions. Climbed to 1,500' before pulling back on 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 used for radiators. Some more work in that area is in my future before hot days arrive.
Cut the flight short due to a bit of smoke (didn't smell anything) briefly 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
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