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Sorry the pictures were not attached - I got distracted - 5 grand kids descended on us for the evening. I'll send the pictures Monday. Your idea for a vertical plate to divert more air from the water and to the oil may be the ticket. Also I'm using about 50% water and antifreeze, I'll change to 10 % antifreeze, 90 % water and a teaspoon to a tablespoon of liquid soap to help lower the water temps more. We have plenty of 95 + degree days here in the summer! Air cooled engines have a big advantage because the cylinders can run 450 deg F and the delta T between the cylinder and fins is much higher. A 10 degree change in max. temp due to ambient temps going up is not nearly as critical for them as compared to us when we are trying to control temps at 200 to 215 deg F. I'm surpassed cowl flaps are not standard issue on rotary A/C. I may have to add them in the future to enhance full power climb cooling.
Dennis H.
Ed Anderson wrote:
Hi Dennis,
It sounds like you have a good handle on the cooling. From what I see in your data, your coolant temps are golden for a 90F OAT day. Your oil on the other hand could stand a bit of improvement. Noticing the configuration of your oil cooler, have you considered dividing your duct into vertical sections such that a bit more air is directed to the oil cooler? I would like to see the oil temps come down to around 200F even if your coolant went up a bit.
Your photo did not come through, so try again. I would like to see the insert.
Ed
----- Original Message ----- From: "Dennis Haverlah" <clouduster@austin.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Sunday, June 10, 2007 6:56 PM
Subject: [FlyRotary] RV-7A cooling - continued
I've improved my cooling quite a bit by installing an insert in the bottom of the cowl to direct air up and into the oil and water radiators. This took the place of the vanes I had installed first. Attached is a picture taken looking into the air inlet duct showing the foam insert in the lower cowl/duct. My last flight at 90 deg. OAT my oil went to 212 and the water went to 199 F. This was at about 5200 rpm, 23 in. mp and 115 kts. My oil pressure was 65 psi. I'm using Castrol Synthetic 10W-30. On start-up my oil will go to 85 psi max. From tests I've run, I now have more flow through the first 40 % of the radiators and less flow through the rear 60 %. I probably need to change the wedge shape to increase flow to the back of the radiators. I'd like to review the document by Kays and London that covers design of a wedge. Does anyone have information on how I can get this document? Also does anyone know if the inner combustion "O" rings used in the Renesis engines are Teflon encapsulated from the factory? I
Thanks,
Dennis H.
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