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S5 912S overheating - cowling?

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skyring

Joined: 01 Nov 2006
Posts: 32

Posted: Fri May 25, 2007 10:49 pm Post subject: S5 912S overheating - cowling?

Our S5 912ULS has about 10 hours flying on it now. Temperatures last week 

were around 32 Cdegrees and during some short flights the CHT and Oil temp 

started reached the limits. They were ok in the cooler months.



We have the standard firewall forward set up from Sky Star with the smooth 

cowl. I've always thought the air outlet on the bottom cowl was small in 

comparison to the inlets at the front. Has anyone experienced overheating 

with this set up? Has anyone tried enlarging the opening at the rear of the 

cowl? Any experience based on a similar set up would be greatly appreciated.



Kerry

(builders helper)



 	  Quote: 	
		  



Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=114681#114681






	


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tstaley(at)centurytel.net
Guest

Posted: Sat May 26, 2007 2:07 am Post subject: S5 912S overheating - cowling?

Kerry,

The 5 I have had a heating problem at first. The builder lowered the

radiator 3 inches and it fixed the problem.

Hope this helps.

LeRoy

rjdaugh

Joined: 30 Aug 2006
Posts: 195

Posted: Sat May 26, 2007 5:47 am Post subject: S5 912S overheating - cowling?

Kerry,

I didn't have any cooling issues once I added the oil cooler.  In fact, I am

seriously considering the oil cooler from Lockwood to keep the oil warmer.  



I think my air outlet is plenty big.  Do you have some obstructions?  How

big is your opening?



Randy Daughenbaugh,  N10NH

Black Hills of South Dakota, - Near Mount Rushmore

Home Strip, Grass   Room in Hangar for visitors

Series 5/7 (7 Firewall Forward) 912S, Warp Drive Taper Tip

Gross Weight 1320 lbs, Flying since November 2004  

--

_________________
Randy
Kitfox 5/7 912S
Black Hills, South Dakota

davestapa

Joined: 13 Mar 2007
Posts: 30
Location: Woodstock, GA

Posted: Sat May 26, 2007 7:29 am Post subject: S5 912S overheating - cowling?

Kerry, I've got the same set-up and have the same problem. In fact infact

I think our planes first flights were the same day. I have 6 flights but

only a little over 3 hours. I moved some oil lines that were close to

exhaust. Then attacked the out flow. I had some 1/2 material that was in

the airflow out on the sides. 90 deg to airflow. I removed it then cut

the trailing edge of the cowling out flow by 1/2 inch. This reduced my

temps. by about 25 deg F. It still is higher than I would like so today

I'm going to cut another 1/2 inch and see what happens. It's fiberglas

,so I can always add back. By the way my oil cooler is standard Earls

that came with the kit back then and is right behind the prop below the

spinner.

C. David Estapa

Woodstock, GA

S5 TD N97DE 912ULS

On Sat, 26 May 2007 08:48:09 +0200 "Kerry Skyring"

<kerryskyring(at)hotmail.com> writes:

 	  Quote: 	

 <kerryskyring(at)hotmail.com>

 Our S5 912ULS has about 10 hours flying on it now. Temperatures last 

 week 

 were around 32 Cdegrees and during some short flights the CHT and 

 Oil temp 

 started reached the limits. They were ok in the cooler months.

 We have the standard firewall forward set up from Sky Star with the 

 smooth 

 cowl. I've always thought the air outlet on the bottom cowl was 

 small in 

 comparison to the inlets at the front. Has anyone experienced 

 overheating 

 with this set up? Has anyone tried enlarging the opening at the rear 

 of the 

 cowl? Any experience based on a similar set up would be greatly 

 appreciated.

 Kerry

 (builders helper)

 >

 >

 >Read this topic online here:

 >

 >http://forums.matronics.com/viewtopic.php?p=114681#114681

 >

 >

 >

 >

 >

 >

 >

 >

 >

 >

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 Express yourself instantly with MSN Messenger! Download today it's 

 FREE!

_________________
C. David Estapa
Woodstock, GA
S5TD N97DE

fredshiple(at)sbcglobal.n
Guest

Posted: Sat May 26, 2007 8:56 am Post subject: S5 912S overheating - cowling?

When I went to floats in my S6 with 912S I had to add Lockwood's large oil cooler and remove a 3/8" lip at the lower rear outlet on the smooth cowl to get temps down in 85+F temps.

  Fred



Kerry Skyring <kerryskyring(at)hotmail.com> wrote:

  [quote]--> Kitfox-List message posted by: "Kerry Skyring" 



Our S5 912ULS has about 10 hours flying on it now. Temperatures last week 

were around 32 Cdegrees and during some short flights the CHT and Oil temp 

started reached the limits. They were ok in the cooler months.



We have the standard firewall forward set up from Sky Star with the smooth 

cowl. I've always thought the air outlet on the bottom cowl was small in 

comparison to the inlets at the front. Has anyone experienced overheating 

with this set up? Has anyone tried [quote][b]

skyring

Joined: 01 Nov 2006
Posts: 32

Posted: Sat May 26, 2007 9:45 pm Post subject: Re: S5 912S overheating - cowling?

David, Leroy and Fred, thanks for the quick responses. It looks like we need to remove some material from the bottom cowling and enlarge that outlet. David your set up sounds exactly like ours. 



We have the small oil cooler right up against the front of the cowl and eventually may have to go to larger. Some oil lines are also very close to the exhaust. But I reckon getting some more air through will help. We've installed probes for temperature of the air at the back of the cowl (carburettor inlet) so will be able to monitor changes quite accurately. I'll report back and will also post those performance figures. 

Kerry.

Joel

Joined: 06 Oct 2006
Posts: 57
Location: Bremerton, WA USA

Posted: Tue May 29, 2007 9:56 pm Post subject: Re: S5 912S overheating - cowling?

My model 5 with 7 fwf 912uls is running very warm now that summer is arriving. How successful has opening the cowl exit been at lowering your temps? Do you have any overlap between the bottom of the cowl and the lower edge of the firewall?  I fabricated a heat sink for the oil tank in an attempt to cool it down a little, but only saw a few degree difference.

_________________
Joel Mapes Kitfox 5 912 ULS Aerocomp amphibs

skyring

Joined: 01 Nov 2006
Posts: 32

Posted: Tue May 29, 2007 11:35 pm Post subject: Re: S5 912S overheating - cowling?

Hi Joel, We are still working on the cowl and the weather has turned foul so no test results yet. We have cut about an inch from the rear edge of the lower cowl. This still leaves a bit of an overlap with the bottom of the fuselage so the opening is not that much greater but at least we have got rid of the upturned lip. 



We are also enlarging the opening under the spinner that feeds air to the oil cooler. This was smaller than the oil cooler so we are making it a perfect match so the entire radiator gets direct air. A bit of work in this as it has to faired in. 



I'm hoping for some photos from Kem, who is also on the list. He had similar problems and solved them mainly by opening up the bottom cowl. He says the outlet should be 4 times the inlet - others suggest 3 to 1. In any case the standard smooth cowl is nowhere near this. Will keep you informed. 



Kerry

rjdaugh

Joined: 30 Aug 2006
Posts: 195

Posted: Wed May 30, 2007 5:50 am Post subject: S5 912S overheating - cowling?

Joel,

Do you have an oil cooler?  I had temp problems until I added the oil

cooler.  Now it runs cool even in the 90's F.  Too cool in the winter.

Randy Daughenbaugh,  N10NH

Black Hills of South Dakota, - Near Mount Rushmore

Home Strip, Grass   Room in Hangar for visitors

Series 5/7 (7 Firewall Forward) 912S, Warp Drive Taper Tip

Gross Weight 1320 lbs, Flying since November 2004  

--

_________________
Randy
Kitfox 5/7 912S
Black Hills, South Dakota

Joel

Joined: 06 Oct 2006
Posts: 57
Location: Bremerton, WA USA

Posted: Wed May 30, 2007 6:03 am Post subject: Re: S5 912S overheating - cowling?

Hi Randy,



Yes, I have the lockwood aluminum oil cooler mounted at the front of the engine. My cowling is closer than most as I trimmed the firewall edge by about 2 inches. I'm thinking about removing 3/4 to an inch from the bottom of the cowl to increase the exit area and wondered if any model 5 with 7 fwf have had success with that approach.

do not archive

_________________
Joel Mapes Kitfox 5 912 ULS Aerocomp amphibs

rjdaugh

Joined: 30 Aug 2006
Posts: 195

Posted: Wed May 30, 2007 8:42 am Post subject: S5 912S overheating - cowling?

Joel,

A little "trip" edge along the bottom can help too.  I think I would add a

strip of aluminum with about 1" sticking down into the airflow below the

bottom of the cowl across the full width of the cowl - about a 45 degree

angle.  This creates a low pressure zone at the outlet of the cowl to help

pull air out of the cowl.  This is easy to do even on a temprorary basis -

just rivet it on and go fly to see if it helped.  If it works well, you can

cut it to 3/4" and test again.  Then to 1/2".   Then add back a quarter

inch.     It sounds like you may have removed this from the original

cowl.



I understand what you did.  It makes sense.  You probably don't need the

prop extension like I did.



Randy



Randy Daughenbaugh,  N10NH

Black Hills of South Dakota, - Near Mount Rushmore

Home Strip, Grass   Room in Hangar for visitors

Series 5/7 (7 Firewall Forward) 912S, Warp Drive Taper Tip

Gross Weight 1320 lbs, Flying since November 2004



--

_________________
Randy
Kitfox 5/7 912S
Black Hills, South Dakota

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