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M20E Cowling openings on both sides.


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Hello Mooniacs

I saw this airplane parked on the ramp yesterday, I noticed that cowling has an opened space between cowling and the airframe at the middle part where upper cowling meets lower cowling on both sides as shown on the picture, looks like there's a spacer underneath, does anyone knows why it's like that?

Thanks in advance! 

20210306_134053.jpg

20210306_134045.jpg

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That cowling appears to be installed incorrectly. That U-channel with the cam loc should be on the inside of the firewall flange. That camloc will then go through the firewall flange into the u-channel along with the screw on the upper cowling. 

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Thanks for the solid feed back David..!

Camlocs have their retainers to hold the hardware in place...

Having random openings created by faulty hardware... certainly isn’t going to improve cooling in a way that is helpful all around...

If you look close at the pic... there is a camloc outline behind the machine screw head...

Looks like a temporary fix that isn’t holding...

If this were intentional... the other side would have a matching pair...

If you see the owner.... say hi from MS... :)

PP thoughts only, not a mechanic...

The paint sure looks nice!

Getting camlocs fixed isn’t too big of a challenge... without messing up the paint....

Getting cooling fixed has a bunch of real world practices... including improvements like Sabremech’s cowl...

Best regards,

-a-

 

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5 hours ago, carusoam said:

If this were intentional... the other side would have a matching pair...

That’s my curiosity, too.  Does the other side match?  I wonder what the drag penalty is?  

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7 hours ago, carusoam said:

Thanks for the solid feed back David..!

Camlocs have their retainers to hold the hardware in place...

Having random openings created by faulty hardware... certainly isn’t going to improve cooling in a way that is helpful all around...

If you look close at the pic... there is a camloc outline behind the machine screw head...

Looks like a temporary fix that isn’t holding...

If this were intentional... the other side would have a matching pair...

If you see the owner.... say hi from MS... :)

PP thoughts only, not a mechanic...

The paint sure looks nice!

Getting camlocs fixed isn’t too big of a challenge... without messing up the paint....

Getting cooling fixed has a bunch of real world practices... including improvements like Sabremech’s cowl...

Best regards,

-a-

 

Yes both sides are the same, that's why it caught my attention in 1st place (picture of the right side) 

20210306_134023.jpg

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When you allow pressure to escape from one area...

It affects the flow of air from the usual engineered and tested distribution that took years to get as good as possible...

Just a guess on my part...

Some of our cowls actually use sides slits intentionally...  when trying to cool a TC...

In that case, it is similar to improve outflow at the bottom of the cowling, but organizes airflow close to the red hot TC...

Its not a hard thing to test... the CHTs will either be better or worse...

Chances are... things get worse...

Organized airflow works the best... for cooling.  

the side slits are below the cylinders, so the main airflow is from top to bottom, passing the cooling fins...

In some cases a few mm of a rubber spacer have been used to add space next to cooling fins... to better organize flow...

random changes, like fasteners hanging in the breeze... doesn’t look intentional...

If it works, post the results...   

More information is always better than less...  anything is possible...

Best regards,

-a- 

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12 minutes ago, jamesm said:

How is that? I would think that  you would be allowing more heat to escape and it's above the  wing low pressure area creating a suction.

I can attest to the fact that it won’t help. I installed an exit duct in the cheek panels of one of the cowlings I modified and it made no noticeable difference in CHT’s. 
David

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1 hour ago, Sabremech said:

I can attest to the fact that it won’t help. I installed an exit duct in the cheek panels of one of the cowlings I modified and it made no noticeable difference in CHT’s. 
David

Wow I wished I had asked this question years ago. I had bought a spare left  engine  cowl  and had some slots water jetted in it. Like Cessna 182,210 and some Bonanza  have hoping it would cure my occasional high CHT problem usually on climb out for  cylinders 2 &4  and sometimes cylinder 3.  It sound like you have already tried this.

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1 hour ago, jamesm said:

Wow I wished I had asked this question years ago. I had bought a spare left  engine  cowl  and had some slots water jetted in it. Like Cessna 182,210 and some Bonanza  have hoping it would cure my occasional high CHT problem usually on climb out for  cylinders 2 &4  and sometimes cylinder 3.  It sound like you have already tried this.

Hi Jamesm,

I tried vents or louvers in both of the cheek cowls along with just in front of the nose gear in the center of the bottom cowling with little effect. Seems most of the air wants to be pulled out by the cowl flaps as Mooney designed it to. 
David

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38 minutes ago, Sabremech said:

Hi Jamesm,

I tried vents or louvers in both of the cheek cowls along with just in front of the nose gear in the center of the bottom cowling with little effect. Seems most of the air wants to be pulled out by the cowl flaps as Mooney designed it to. 
David

I  was watching Wasabi Flight Test on  a Lancair . They guy had put a flare at end of the cowl flap. My understanding is that having the flare at end of cowl creates low pressure to get more heat out  cowling.  Unfortunately there isn't a lot material to work with on the Mooney's.

https://www.facebook.com/WasabiAirRacing/posts/hakan-calls-it-a-cowl-flare-but-whatever-you-call-it-i-was-excited-by-the-chance/1715308705299459/

Thank you for saving me the grief.... Are you still making/ selling  sabre cowl(s)?

James '67C

 

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Putting flares flairs  

bending a lip is an aerodynamic way of generating a lower pressure zone to help draw more air out of the cowl...

nothing does this better than opening the cowl flaps way up...

Compare your cowl flaps open, to Wasabi’s lip....

If you are comparing aerodynamic flares, to the square box of the dog house...

There isn’t going to be enough improvement for that....

That’s what makes the Sabremech cowl so interesting...

And how Lopresti was able to sell so many super cowls at much higher prices....

Some planes have to live within a budget...

Some forever-planes... have the laws of finance completely suspended...

Best regards,

-a-

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21 hours ago, Sabremech said:

Hi Jamesm,

I tried vents or louvers in both of the cheek cowls along with just in front of the nose gear in the center of the bottom cowling with little effect. Seems most of the air wants to be pulled out by the cowl flaps as Mooney designed it to. 
David

David,

Isn't this what RayJay Turbo install STS has on M20E and F? I guess they thought that should work. I remember seeing pictures but not sure of exact location of louvers on the Cheek cowl. There are few turbo STC'd owners around hear that could do a proper flight test applying (and removing) Al. speed tape.

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14 minutes ago, Igor_U said:

David,

Isn't this what RayJay Turbo install STS has on M20E and F? I guess they thought that should work. I remember seeing pictures but not sure of exact location of louvers on the Cheek cowl. There are few turbo STC'd owners around hear that could do a proper flight test applying (and removing) Al. speed tape.

Igor_U, 

I don’t know much about the turbo installation. I suspect it could help with cooling the turbo, but is not much help on non turbo aircraft in my opinion. 

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The proximity of the turbo to the cowl sides can brown the paint if airflow isn’t maintained between the turbo and the sheet metal...

A layer of insulation may also help keep the heat from the sheet metal...

Of course, this is for cooling the cowl, not for cooling the cylinders...

There are pics around here of baked paint by new turbo owners...

PP thoughts only, not a mechanic...

Best regards,

-a-

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