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tracy(at)rotaryaviation.c
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 Posted: Wed Sep 16, 2009 1:10 pm Post subject: Rotary powered RV-8 Cooling test |
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Thanks for all the encouragement guys. Here's an update on the testing.
Been thinking over what to do about the cooling on the 20B rotary powered RV-8. The indications are that I'm getting too much pressure under the cowl but that was only a guess. Without doing a number of time consuming pressure surveys or chopping up the cowl there was no way to be sure it was not something else like too small oil cooler and radiator, inlet diffusers not working as well as I had hoped, inlet shape not right (they had very sharp lips which might be causing separation) or some other unknown.
Time is limited before I leave on vacation and I really needed to know the answer before I do. So, last night I made the decision to fly the -8 one more time - This time Without the cowl on. Wish there was someone around to get a pix, must have looked pretty strange.
Secured anything that might get blown loose with tie wraps and did the deed. Whoo Hoo! Oil temp 147, coolant temp 161. This on a hot day (92 deg OAT). With the cowl on, they never went below 200 and hovered around 210 most of the time at low throttle. They went up rapidly with more throttle.
Obvious conclusion is that I need a better path for the air to leave the cowl. Have read with interest the results of some Lycoming RVs with high oil temps that fixed the problem with louvers (on bottom?) of cowl. Some say they worked great, others had less than good results so not sure that is the answer but ordered a set if nothing else occurs to me.
The airplane felt a little draggier , down about 15 MPH at the low throttle setting I used for test so this should be a worst case test. The wheel pants and main gear intersection fairings are also off. Did some brief full throttle climbs and temps stayed under control, oil never exceeding 160 F. Climb is awesome with a deck angle so high it was uncomfortable. Was looking hard at temps so did not note the ROC but it was more than anything else I've flown. My 13B powered RV-4 goes 2500 FPM on a standard day.
Tracy Crook
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rvhad(at)yahoo.com
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| Posted: Sun Sep 20, 2009 7:15 pm Post subject: Rotary powered RV-8 Cooling test |
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Tracy,
you might want to use a cowl flap to pull more air out...look on the EGG site for specs. the volume of air increased by 80%, brought the numbers down if i recall properly.
cheers,
Had 
From: Tracy Crook <tracy(at)rotaryaviation.com>
To: rv-list(at)matronics.com
Sent: Wednesday, September 16, 2009 3:41:41 PM
Subject: Re: Rotary powered RV-8 Cooling test
Thanks for all the encouragement guys. Here's an update on the testing.
Been thinking over what to do about the cooling on the 20B rotary powered RV-8. The indications are that I'm getting too much pressure under the cowl but that was only a guess. Without doing a number of time consuming pressure surveys or chopping up the cowl there was no way to be sure it was not something else like too small oil cooler and radiator, inlet diffusers not working as well as I had hoped, inlet shape not right (they had very sharp lips which might be causing separation) or some other unknown.
Time is limited before I leave on vacation and I really needed to know the answer before I do. So, last night I made the decision to fly the -8 one more time - This time Without the cowl on. Wish there was someone around to get a pix, must have looked pretty strange.
Secured anything that might get blown loose with tie wraps and did the deed. Whoo Hoo! Oil temp 147, coolant temp 161. This on a hot day (92 deg OAT). With the cowl on, they never went below 200 and hovered around 210 most of the time at low throttle. They went up rapidly with more throttle.
Obvious conclusion is that I need a better path for the air to leave the cowl. Have read with interest the results of some Lycoming RVs with high oil temps that fixed the problem with louvers (on bottom?) of cowl. Some say they worked great, others had less than good results so not sure that is the answer but ordered a set if nothing else occurs to me.
The airplane felt a little draggier , down about 15 MPH at the low throttle setting I used for test so this should be a worst case test. The wheel pants and main gear intersection fairings are also off. Did some brief full throttle climbs and temps stayed under control, oil never exceeding 160 F. Climb is awesome with a deck angle so high it was uncomfortable. Was looking hard at temps so did not note the ROC but it was more than anything else I've flown. My 13B powered RV-4 goes 2500 FPM on a standard day.
Tracy Crook
[quote][b] [quote][b]
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tracy(at)rotaryaviation.c
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| Posted: Mon Sep 21, 2009 9:06 am Post subject: Rotary powered RV-8 Cooling test |
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I have cut out the bottom of the cooling exit ramp, Installed a hinge at forward edge and filled in the sides of the ramp to form a cowl flap. It helped a little but not the final solution. Also tried the VGs on trailing edge of cooling exit but saw very little effect.
Question for you guys who installed the louvers. Did you install them on the bottom of the cooling exit ramp or on either side of it?
Tracy Crook
On Sun, Sep 20, 2009 at 11:14 PM, Hadley Heinrichs <rvhad(at)yahoo.com (rvhad(at)yahoo.com)> wrote:
[quote]Tracy,
you might want to use a cowl flap to pull more air out...look on the EGG site for specs. the volume of air increased by 80%, brought the numbers down if i recall properly.
cheers,
Had [img][/img]
From: Tracy Crook <tracy(at)rotaryaviation.com (tracy(at)rotaryaviation.com)>
To: rv-list(at)matronics.com (rv-list(at)matronics.com)
Sent: Wednesday, September 16, 2009 3:41:41 PM
Subject: Re: Rotary powered RV-8 Cooling test
Thanks for all the encouragement guys. Here's an update on the testing.
Been thinking over what to do about the cooling on the 20B rotary powered RV-8. The indications are that I'm getting too much pressure under the cowl but that was only a guess. Without doing a number of time consuming pressure surveys or chopping up the cowl there was no way to be sure it was not something else like too small oil cooler and radiator, inlet diffusers not working as well as I had hoped, inlet shape not right (they had very sharp lips which might be causing separation) or some other unknown.
Time is limited before I leave on vacation and I really needed to know the answer before I do. So, last night I made the decision to fly the -8 one more time - This time Without the cowl on. Wish there was someone around to get a pix, must have looked pretty strange.
Secured anything that might get blown loose with tie wraps and did the deed. Whoo Hoo! Oil temp 147, coolant temp 161. This on a hot day (92 deg OAT). With the cowl on, they never went below 200 and hovered around 210 most of the time at low throttle. They went up rapidly with more throttle.
Obvious conclusion is that I need a better path for the air to leave the cowl. Have read with interest the results of some Lycoming RVs with high oil temps that fixed the problem with louvers (on bottom?) of cowl. Some say they worked great, others had less than good results so not sure that is the answer but ordered a set if nothing else occurs to me.
The airplane felt a little draggier , down about 15 MPH at the low throttle setting I used for test so this should be a worst case test. The wheel pants and main gear intersection fairings are also off. Did some brief full throttle climbs and temps stayed under control, oil never exceeding 160 F. Climb is awesome with a deck angle so high it was uncomfortable. Was looking hard at temps so did not note the ROC but it was more than anything else I've flown. My 13B powered RV-4 goes 2500 FPM on a standard day.
Tracy Crook
| Quote: |
| Quote: | [b]
t="_blank">http://www.matronics.com/Navigator?RV-List
tp://forums.matronics.com
_blank">http://www.matronics.com/contribution
|
[/b] |
[b]
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rveighta(at)comcast.net
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| Posted: Mon Sep 21, 2009 10:23 am Post subject: Rotary powered RV-8 Cooling test |
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Tracy, I installed my cooling louvers on each side of the exit ramp.
Walt Shipley
From: "Tracy Crook" <tracy(at)rotaryaviation.com>
To: rv-list(at)matronics.com
Sent: Monday, September 21, 2009 1:01:56 PM GMT -05:00 US/Canada Eastern
Subject: Re: Re: Rotary powered RV-8 Cooling test
I have cut out the bottom of the cooling exit ramp, Installed a hinge at forward edge and filled in the sides of the ramp to form a cowl flap. It helped a little but not the final solution. Also tried the VGs on trailing edge of cooling exit but saw very little effect.
Question for you guys who installed the louvers. Did you install them on the bottom of the cooling exit ramp or on either side of it?
Tracy Crook
On Sun, Sep 20, 2009 at 11:14 PM, Hadley Heinrichs <rvhad(at)yahoo.com (rvhad(at)yahoo.com)> wrote:
[quote] Tracy,
you might want to use a cowl flap to pull more air out...look on the EGG site for specs. the volume of air increased by 80%, brought the numbers down if i recall properly.
cheers,
Had [img][/img]
From: Tracy Crook <tracy(at)rotaryaviation.com (tracy(at)rotaryaviation.com)>
To: rv-list(at)matronics.com (rv-list(at)matronics.com)
Sent: Wednesday, September 16, 2009 3:41:41 PM
Subject: Re: Rotary powered RV-8 Cooling test
Thanks for all the encouragement guys. Here's an update on the testing.
Been thinking over what to do about the cooling on the 20B rotary powered RV-8. The indications are that I'm getting too much pressure under the cowl but that was only a guess. Without doing a number of time consuming pressure surveys or chopping up the cowl there was no way to be sure it was not something else like too small oil cooler and radiator, inlet diffusers not working as well as I had hoped, inlet shape not right (they had very sharp lips which might be causing separation) or some other unknown.
Time is limited before I leave on vacation and I really needed to know the answer before I do. So, last night I made the decision to fly the -8 one more time - This time Without the cowl on. Wish there was someone around to get a pix, must have looked pretty strange.
Secured anything that might get blown loose with tie wraps and did the deed. Whoo Hoo! Oil temp 147, coolant temp 161. This on a hot day (92 deg OAT). With the cowl on, they never went below 200 and hovered around 210 most of the time at low throttle. They went up rapidly with more throttle.
Obvious conclusion is that I need a better path for the air to leave the cowl. Have read with interest the results of some Lycoming RVs with high oil temps that fixed the problem with louvers (on bottom?) of cowl. Some say they worked great, others had less than good results so not sure that is the answer but ordered a set if nothing else occurs to me.
The airplane felt a little draggier , down about 15 MPH at the low throttle setting I used for test so this should be a worst case test. The wheel pants and main gear intersection fairings are also off. Did some brief full throttle climbs and temps stayed under control, oil never exceeding 160 F. Climb is awesome with a deck angle so high it was uncomfortable. Was looking hard at temps so did not note the ROC but it was more than anything else I've flown. My 13B powered RV-4 goes 2500 FPM on a standard day.
Tracy Crook
| Quote: |
| Quote: | [b]
t="_blank">http://www.matronics.com/Navigator?RV-List
tp://forums.matronics.com
_blank">http://www.matronics.com/contribution
|
[/b] |
t=_blank>http://www.matronics.com/Navigator?RV-List
p://forums.matronics.com
blank>http://www.matronics.com/contribution
[b]
| | - The Matronics RV-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV-List |
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