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Old 07-24-2019, 02:00 PM
crabandy crabandy is offline
Join Date: Jan 2010
Location: Ottawa, Ks
Posts: 2,167

I did some flying today and got some intial numbers. I used stabilized cruise with realitively smooth air and utilizing the autopilot, I recorded 5 minute averages for speed, temps and pressures twice open and twice closed. Lower cowling pressures were obtained with a single picollo tube place vertically at the bottom of the lower cowling attached to the lower engine mount with the manometer plumber to the static system and CHTís and TAS from the EFIS.

Opening the oil door drops the lower cowling pressure approximately 60%, .65 in H2O @110 KIAS and .85 in H2O at 146 KIAS.
LOP cruise was 161 KTAS with the door open and 164 KTAS with it closed.
Very little change in CHTís, avgerage was 3-5 degrees cooler with the door open. Oil temp was about 1-2 degrees cooler.

Iíll need a lot more flights to try and filter any cooler climb out data. I need to check the pressure directly underneath the cylinders to see if it changes as much as the rest of the lower cowling does.
I did do 2 hot quick turns giving rides today without a single hiccup during ground ops, it was only 88* though.
RV 7 400 hours and counting
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Old 09-20-2019, 11:23 PM
crabandy crabandy is offline
Join Date: Jan 2010
Location: Ottawa, Ks
Posts: 2,167

Iíve put 20+!hours on the oil door/cowl flap, the small CHT/Oil Temp differences remain but Iíve stopped measuring them. I do like the slightly lower temps on climb but Love the RPM/Speed increase when I close the flap.
Since the addition of the cowl flap Iíve only had 1 battery over-temp alert, I was heading home after my third hot quick turn at 90+* (giving rides) after I leveled off and closed the cowl flap. Low level and hot the alert didnít turn off on my short 15 min return flight after I re-opened the cowl flap. Needs more time and or cooler air.
Fuel boiling in the carb has been reduced significantly. With the cowl flap open on the landing checklist, lean mixture and using a higher idle of 1000 RPM Iíve been able to quick turn/hot start and taxi with minimal ďchugging.Ē
Iím making progress!
RV 7 400 hours and counting
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Old 09-21-2019, 08:07 AM
BillL BillL is offline
Join Date: Sep 2007
Location: Central IL
Posts: 5,380

Excellent thread progression, Andy. The CHT/oil temps might have a larger delta on a max angle of climb at full throttle. At cruise and steady speeds I have similar results to you (for changes), a shallow slope effect on CHT.

You can cut out the core and back fill with flox for your pivot anchor. That will restore the glass stiffness around the bracket connection. Maybe I missed it and you did that already.

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