Rino, any comments on the Griffin oil cooler location and inlet ducting Vs the RX7 oil cooler location and ducting?

If oil flow was not the problem it must have been air flow.

Jeff

----- Original Message -----

From: Al Gietzen

To: Rotary motors in aircraft

Sent: Friday, October 30, 2009 3:50 AM

Subject: [FlyRotary] Cooling report - was Tracy RV8

 

Rino;

 

It seems very peculiar that you get better oil cooling with the stock RX7 oil cooler than the Griffin with more than twice the core volume. Given the low exit air temp with the Griffin cooler, one would conclude something wrong on the oil side - flow was seriously limited; air trapped in the cooler, maybe very poor flow distribution; something.  What is the core configuration of the Griffin – fin density, tube configuration?

 

Al  

 

Tracy,

 

The following info. might be of interest to you, it has to do with my latest cooling system experience.

 

I ordered 2 Griffin radiators and installed that, had to modify the air ducts

A water radiator: no: GRI-2-58185-X

CROSSFLOW - DUAL ROW  1-1/4" tubes

core 18" X 13" X 2.75"    234 sq. in.     643 cu. in.

 

A custom made oil radiator no: CX-27256-01

core 18" X 7.5" X 2.75"  135 sq. in.     371 cu. in.

added a spall 10" fan (15 amp.) to the oil radiator

 

Still not enough cooling, could not climb at full power for more than a few minutes before the oil reached 220 deg. F.

I had nore than eough water cooling, so I Built a oil/water heat exchanger and added that in series with the Griffin oil rad.

That did not work too well, not enough cooling.

Removed the Griffin oil rad. and the fan.

Replaced it with the original RX7 oil radiator

core 17.5" X 4.5" X 2"      78 sq. in.      157 cu. in.

Kept the oil/water heat exchanger in series with the oil rad.

 

Air flow;

Water rad air in 84 sq. in.      air out 180 sq. in.

Oil rad air in 40 sq. in.     air out 54 sq. in.

 

I think this last system works --- finally

 

The outside air temp is presently between 30 and 40 deg. F. so it is hard for me to tell how it will work in the summer but the indications are good.   I had to plaster the front of the water rad. with duct tape to raise the engine temp. and block the oil rad. air exit to reduce air flow.  The oil rad. air flow is reduced to 12 sq. in. at the moment and not much air is flowing through the water rad.

 

I have no water thermostat and no oil thermostat so I have to control the temp with the air flow.

I need to build vanes to control the air flow, that is what I am working on at the moment.

 

I consider this installation much simpler and easier to maintain.  The reason I figured that the griffin oil cooler was not working properly, the air flow behind the rad. was not getting higher than abour 85 deg. F even when the oil was at 220 de. F  On the other hand the griffin water rad. seems to work fine.  Now the air flow temp behind both rads. goes to about 130+ deg. F

 

A photo of the present installation.

 

Rino Lacombe

Renesis powered Glass Goose

----- Original Message -----

From: Tracy Crook

To: Rotary motors in aircraft

Sent: Thursday, October 29, 2009 1:19 AM

Subject: [FlyRotary] Re: Tracy RV8

 

Cooler weather is helping now but still a work in progress.  I'll write up a report when the problem is fully solved.

Tracy

On Wed, Oct 28, 2009 at 6:56 PM, <stevei@carey.asn.au> wrote:

Hi Tracy

Are you in a position to give us a further update on the cooling of the RV8.


Thanks

Steve Izett
Perth Australia

---

The contents of this email are confidential and intended only for the named recipients of this e-mail. If you have received this e-mail in error, you are hereby notified that any use, reproduction, disclosure or distribution or the information contained in this e-mail is prohibited. Please notify the sender immediately and then delete/destroy the e-mail and any printed copies. All liability for viruses is excluded to the fullest extent of the law.