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elleryweld(at)aol.com
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 Posted: Mon Nov 28, 2011 4:08 pm Post subject: CHT still high after cowling modification (test flight with |
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I should have added this to my last post
if you have an airplane that has a cowled engine I would not recommend flying it without the cowl
Ellery Batchelder Jr.
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elleryweld(at)aol.com
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| Posted: Mon Nov 28, 2011 4:20 pm Post subject: CHT still high after cowling modification (test flight with |
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there are some Kolb Airplanes with Jabiru 2200 engines on them
and there not a coweled setup just for your information
Ellery Batchelder Jr.
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jose_m_toro(at)yahoo.com
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| Posted: Mon Nov 28, 2011 4:45 pm Post subject: CHT still high after cowling modification (test flight with |
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Ellery:
I know I will go a little out of topic, but there are many Super Cubs in my area used to tow banners that are flown without cowling to keep the 180hp Continental engines cool while flying slow. I agree that I must not (and will not) fly my plane without cowling because of the cooling requirements of the Jabiru, and have not doubt that this is impractical in most cases, but by no means I consider flying an airplane without cowling an absurd idea.
Jose
From: Ellery Batchelder Jr <elleryweld(at)aol.com>
To: jabiruengine-list(at)matronics.com
Sent: Monday, November 28, 2011 7:50 PM
Subject: Re: Re: CHT still high after cowling modification (test flight without cowling?)
I should have added this to my last post
if you have an airplane that has a cowled engine I would not recommend flying it without the cowl
Ellery Batchelder Jr.
--
| | - The Matronics JabiruEngine-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?JabiruEngine-List |
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pete(at)usjabiru.com
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| Posted: Tue Nov 29, 2011 6:47 am Post subject: CHT still high after cowling modification (test flight with |
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Yes, there are Kolbs and Titans and Rans S-12’s flying with uncowled pusher engine that cool just fine. I’ve built three of those Kolbs and about 20 Titans. But think of why they do! All those engines sit on top of the wing (or just behind and above the wing). Air moving over the top of the wing is moving faster as it flows over the top of the wing and then this faster moving air dives under and around the lower half of the engine. Remember Bernoulli’s principle (I don’t know if I spelled that right) that speeding up the flow lowers the pressure. By placing the engine just above the flow off the wing the effect of higher pressure above and lower pressure below is achieved without the use of a cowl.
One can take that Kolb, Titan or Rans and place a ballistic chute or oil cooler just ahead of the engine that diverts the faster flow away from the engine and temps will go up dramatically because the differential of pressure between top and bottom is decreased. I’ve seen many examples of Titans with BRS VLS chutes in front of the engine that exhibit higher than desirable CHTs. Those temps come down when chute is removed.
Pete
From: owner-jabiruengine-list-server(at)matronics.com [mailto:owner-jabiruengine-list-server(at)matronics.com] On Behalf Of Ellery Batchelder Jr
Sent: Monday, November 28, 2011 5:42 PM
To: jabiruengine-list(at)matronics.com
Subject: Re: Re: CHT still high after cowling modification (test flight without cowling?)
there are some Kolb Airplanes with Jabiru 2200 engines on them
and there not a coweled setup just for your information
Ellery Batchelder Jr.
--
| | - The Matronics JabiruEngine-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?JabiruEngine-List |
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jose_m_toro(at)yahoo.com
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| Posted: Tue Nov 29, 2011 7:38 am Post subject: CHT still high after cowling modification (test flight with |
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Pete:
Thanks for this information!
Jose
From: Pete Krotje <pete(at)usjabiru.com>
To: jabiruengine-list(at)matronics.com
Sent: Tuesday, November 29, 2011 10:43 AM
Subject: RE: JabiruEngine-List: Re: CHT still high after cowling modification (test flight without cowling?)
Yes, there are Kolbs and Titans and Rans S-12’s flying with uncowled pusher engine that cool just fine. I’ve built three of those Kolbs and about 20 Titans. But think of why they do! All those engines sit on top of the wing (or just behind and above the wing). Air moving over the top of the wing is moving faster as it flows over the top of the wing and then this faster moving air dives under and around the lower half of the engine. Remember Bernoulli’s principle (I don’t know if I spelled that right) that speeding up the flow lowers the pressure. By placing the engine just above the flow off the wing the effect of higher pressure above and lower pressure below is achieved without the use of a cowl.
One can take that Kolb, Titan or Rans and place a ballistic chute or oil cooler just ahead of the engine that diverts the faster flow away from the engine and temps will go up dramatically because the differential of pressure between top and bottom is decreased. I’ve seen many examples of Titans with BRS VLS chutes in front of the engine that exhibit higher than desirable CHTs. Those temps come down when chute is removed.
Pete
From: owner-jabiruengine-list-server(at)matronics.com [mailto:owner-jabiruengine-list-server(at)matronics.com] On Behalf Of Ellery Batchelder Jr
Sent: Monday, November 28, 2011 5:42 PM
To: jabiruengine-list(at)matronics.com
Subject: Re: JabiruEngine-List: Re: CHT still high after cowling modification (test flight without cowling?)
there are some Kolb Airplanes with Jabiru 2200 engines on them
and there not a coweled setup just for your information
Ellery Batchelder Jr.
--
| | - The Matronics JabiruEngine-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?JabiruEngine-List |
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