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Do I really need a radiator under the belly?

26 posts in this topic

Posted (edited)

I know, kind of like asking "How long is a piece of string?"

If the 582 was designed to be cooled  by the two radiators in the cowling, I'd really like to be rid of the one hanging out in the weeds creating drag.

I've built a couple corvettes over the years, and the secret to getting the C3's to cool well was to seal all around the radiator with foam to close off any "leaks" and force all the incoming air through the rad.

Is sealing around the cheek rads enough to cool the 583 Mod 90 sans belly rad?  If so, is there a proper way/style to approach this?

 

 

Edited by Knuckledragger

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Posted (edited)

I think that there are a couple of 582s with the Cheek rads only.   Also a couple of Soobs cooling with Cheek rads only.

Better sealing means better cooling - I think inlet to outlet is about  1:4 or 1:5 ratio for good cooling.

Some pilots went to the belly rad to put the weight farther back for better CG.

EDMO

Edited by EDMO
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Posted

I think that there are a couple of 582s with the Cheek rads only.   Also a couple of Soobs cooling with Cheek rads only.

Better sealing means better cooling - I think inlet to outlet is about  1:4 or 1:5 ratio for good cooling.

Some pilots went to the belly rad to put the weight farther back for better CG.

EDMO

This site wont let you add or edit more than once.    I think most use silicone cowl seal rubber around the rads.

EDMO

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Posted

What is "silicone cowl seal rubber"?  

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Posted

What is "silicone cowl seal rubber"?  

Look in Spruce catalog - its just a piece of rubber strap 2 or 3 inches wide and maybe 1/8 to 1/4 inch thick that they use for baffle seals and cowl seals on the "Real Aircraft"...

EDMO

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Posted

My Avid only has cheek radiators, and I haven't had any cooling issues - in fact it tends to run too cool.  I'll see what it is like when I get it to Florida.

Mark

 

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Posted

Mark,  I'm in FL.  When are you coming and where will you be?  I fly out of 3FD4.

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Posted

North of you, 15FL.  I wander down to Tavares every so often for a seaplane fix until I get my Avid to Florida and get the floats under it.

Mark

 

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Posted

Hi!

the two cheek radiators will work fine. I flew my 582 MKIV with the two radiators for over 1200 hours in all temps including in excess of 100 degrees.

The secret is to seal the radiators at the cowl inlets so air must go through them, AND to have a good lip at the bottom of the cowl and a large open area in combination with the lip to pull air through the radiators from the bottom. All of the sealing you do to the radiators at the cowl will not do anything without a BUNCH of air being sucked out the bottom of the cowl. There needs to be a negative pressure inside the cowl and that is created by the opening and the lip at the bottom in order for air to go thru the radiators. Thinking of it as air must be sucked through the radiators rather than being forced into them will get you thinking right about what needs to happen. There is enough radiator there to cool the engine.

In the summer I also went to a 10% dexcool / distilled water mix to enhance heat transfer.

 I do not think you need belly radiator.

Chris

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Posted

This makes perfect sense Chris.  Do you have a picture of your suck it out lip under the cowl?

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Posted

What is "silicone cowl seal rubber"?  

If you need some silicone material,  I've got tons of it I bought from AS in bulk I'll and never use.  Hit me up. 

I went with the belly radiator for (a) the reason Ed stated above (b) I couldn't source any appropriately fitting cheek ones at a reasonable price and (c) it was just easier at the time to put the belly one on that I sourced reasonably from akflyer.

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Posted

If you need some silicone material,  I've got tons of it I bought from AS in bulk I'll and never use.  Hit me up. 

I went with the belly radiator for (a) the reason Ed stated above (b) I couldn't source any appropriately fitting cheek ones at a reasonable price and (c) it was just easier at the time to put the belly one on that I sourced reasonably from akflyer.

So are you saying you have a belly instead of cheeks?

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Posted

I put this in another post - Kitfox makes a horizontal pan for the belly rad.  

EdMO

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Posted

If you need some silicone material,  I've got tons of it I bought from AS in bulk I'll and never use.  Hit me up. 

I went with the belly radiator for (a) the reason Ed stated above (b) I couldn't source any appropriately fitting cheek ones at a reasonable price and (c) it was just easier at the time to put the belly one on that I sourced reasonably from akflyer.

So are you saying you have a belly instead of cheeks?

Yes, I have a genuine Kitfox belly rad.  They look small but they're a double row.

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Posted

I sold my MKIV and don't have a good picture. I am working on a Fat Avid which is based on a MKIV. The Fat Avid I am working on is 912 powered, but the same rules apply with regard to developing a negative pressure within the engine compartment. I used a MKIV cowl and modified the lip to assure air will be sucked out the bottom. I extended the lip and made sure of a good sized open at the bottom of the cowl. The lip extends a bit below the bottom of the fuselage to enhance the suction even more. haven't flown this one yet, but do not anticipate any cooling issues. Here are a couple photos. 

Chris

IMG_0744.JPG

IMG_0745.JPG

IMG_0695.JPG

IMG_0743.JPG

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Posted

Kayak hauler is looking good Chris - Guess yours will be flying before mine.

EdMO

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Posted

Thanks for the pics Chris. Your plane is looking good. Do you plan to keep the little wheel up front?  

I'll finally be reunited with my plane this weekend. Lockwood had it an entire month, the jones was damn near unbearable.  

Then I 'll take pics and do some testing, post the results here. I'm encouraged by the comments here that I can lose the belly rad.  As I recall there is a pretty big lip under the cowl to create the low pressure in the engine area. 

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Posted (edited)

Thanks for the pics Chris. Your plane is looking good. Do you plan to keep the little wheel up front?  

I'll finally be reunited with my plane this weekend. Lockwood had it an entire month, the jones was damn near unbearable.  

Then I 'll take pics and do some testing, post the results here. I'm encouraged by the comments here that I can lose the belly rad.  As I recall there is a pretty big lip under the cowl to create the low pressure in the engine area. 

It's very hard to haul Kayaks with a taildragger - At least Chris has an excuse for the training wheel - Maybe I need to buy a Kayak for mine?  But, I cant swim !!!

EdmO

Edited by EDMO

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Posted

Thanks for the pics Chris. Your plane is looking good. Do you plan to keep the little wheel up front?  

I'll finally be reunited with my plane this weekend. Lockwood had it an entire month, the jones was damn near unbearable.  

Then I 'll take pics and do some testing, post the results here. I'm encouraged by the comments here that I can lose the belly rad.  As I recall there is a pretty big lip under the cowl to create the low pressure in the engine area. 

It's very hard to haul Kayaks with a taildragger - At least Chris has an excuse for the training wheel - Maybe I need to buy a Kayak for mine?

EdmO

ahh!  I hadn't thought of it like that. :)

seems like a set of floats might be an option?

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Posted (edited)

Thanks for the pics Chris. Your plane is looking good. Do you plan to keep the little wheel up front?  

I'll finally be reunited with my plane this weekend. Lockwood had it an entire month, the jones was damn near unbearable.  

Then I 'll take pics and do some testing, post the results here. I'm encouraged by the comments here that I can lose the belly rad.  As I recall there is a pretty big lip under the cowl to create the low pressure in the engine area. 

It's very hard to haul Kayaks with a taildragger - At least Chris has an excuse for the training wheel - Maybe I need to buy a Kayak for mine?

EdmO

ahh!  I hadn't thought of it like that. :)

seems like a set of floats might be an option?

Floats AND Kayak might just be too much drag , and you've got all that rigging in the way - They would have to be amphibious to take off on land....I don't think he would want to take the plane where he goes with the Kayak - Look at his Avatar!

EDMO

Edited by EDMO
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Posted

You can do it either way trigear or taildragger:

IMGP2944.jpg

IMGP2947.jpg

IMGP0590.jpg

boat plane3.jpg

boatplane4.jpg

Pict0579.jpg

N842RSs.JPG

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Posted

Sweet pics! 

I had issues with the cheek radiators cooling on mine when I got it so I pulled them and went to the belly radiator.  When I got the MK IV cowling and actual MK IV radiators I put them on and got rid of the belly radiator.  I did use the silicon baffle to seal up the radiator to cowling and increased the lip on the bottom as Chris suggested to get more air pulled through.

In the winter time I put the radiator scoop on he back of  one radiator to help out my heat muff to really get the cabin toasty.  In the summer I have to pull the scoop or I have over heating issues, but I don't want the extra heat in the summer anyway!

 

:BC:

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Posted

Weather is cooling off a bit here.  Temps dropped all the way into the 60's a couple mornings this week and the 582 would barely make 140 water temp.  I took the belly rad out of the circuit and flew on just the cheeks.  Now temps are 150-180 all day long.  And I still need to install the rubber seals around the cheek rads. 

Now I can just remove the belly rad and all that extra plumbing - woo hoo - free weight and drag loss!

I also removed the "cabin heat" hose from the right rad, it was not doing anything.  Sooo, if anyone has a good idea for adding cabin heat via the muffler....

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Posted

Here are a few pics of a heat muff I built for the MK IV with a 582.  It worked okey like this, but better when I plumbed in a scoop behind the radiator for the inlet heat.  This would probably be all you would need down south, I fly all winter in northern Mn.  Jim Chuk

firewall muffler mt + heat muff 012 (Large).jpg

firewall muffler mt + heat muff 005 (Large).jpg

firewall muffler mt + heat muff 007 (Large).jpg

firewall muffler mt + heat muff 009 (Large).jpg

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Posted

Here is an update on the belly radiator removal.  To review, I had a belly rad plumbed in with the two cheek rads.

On TO the temp climbs to about 175-180, sometimes 185 for a moment or two.  I keep an eye on it and dip the nose a bit when it creeps past 180 and the temp quickly responds.  Cruise is 140-160.  Ambient air temp is about 65-75 during this period,

  • I haven't added anything like water wetter type stuff.  
  • Coolant is still 50/50. I plan to make it more like 80/20, water/coolant  
  • I haven't fitted seals around the cheek rads yet.
  • The baffle at the bottom of the cowl used to draw air into the cowling is minimal and could be extended and/or angled to provide greater drag induced vacuum.

I figure with the above bullets implemented I should not need the belly rad anymore unless I move back to AZ.

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