Deja Vu - It's summer and #2 is HOT!

[MikeOH]

10 hours ago, Bunti said:

It looks to me that the SB-182 had been installed in this Mooney. 

https://mooney.com/wp-content/uploads/2020/12/SBM20-182.pdf

That includes the pieces of metal in front of cylinder 1 and 2.

@Bunti

What a FIND!

Thank you very much!!  And, to think I was about to try removing that baffle for better cooling!

Now, I need to check if the "exit scoop" is installed.

[MikeOH]

Oddly, this SB is 4 pages, but only 2 pages are on the Mooney website for SB downloads!?!

Initial Googling is not helping....anyone have all four pages of SB 20-182?

[Jblanton]

On 7/16/2022 at 5:46 PM, MikeOH said:

Ok here are pictures of the cowl and baffle:

It might be just the picture angle, but your spinner looks like a larger diameter than stock to me.  

[MikeOH]

1 minute ago, Jblanton said:

It might be just the picture angle, but your spinner looks like a larger diameter than stock to me.  

Thanks for that observation. Something I never would have thought of.

Not too sure how to check that, however. 

[Marauder]

[mention=7883]Bunti[/mention]
What a FIND!
Thank you very much!!  And, to think I was about to try removing that baffle for better cooling!
Now, I need to check if the "exit scoop" is installed.

Mike - Sorry I am late to the show. I have the SB applied on mine and saw what changes happened when I had the Lasar lower cowl mod installed in 1995. Before the lower cowl enclosure, my cylinders ran cooler. The cowl enclosure raised the CHTs about 20° across the board.

I often wondered why they applied two baffles to the #1 cylinder and not a second one to the #2 cylinder. I’ll look at my engine data and see if I have a higher #2 temp but I think I don’t.


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[Shadrach]

56 minutes ago, MikeOH said:

Thanks for that observation. Something I never would have thought of.

Not too sure how to check that, however. 

That looks like a stock F model spinner to me. Seriously doubt that someone fabricated or adapted a larger spinner to your airplane. Big PITA for no obvious benefit.

[Ragsf15e]

3 hours ago, Marauder said:

Mike - Sorry I am late to the show. I have the SB applied on mine and saw what changes happened when I had the Lasar lower cowl mod installed in 1995. Before the lower cowl enclosure, my cylinders ran cooler. The cowl enclosure raised the CHTs about 20° across the board.

I often wondered why they applied two baffles to the #1 cylinder and not a second one to the #2 cylinder. I’ll look at my engine data and see if I have a higher #2 temp but I think I don’t.


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Possibly the SB and STC aren’t compatible.  That wasn’t necessarily tested.  Also, I’d like to see the “air scoop” the SB mentioned and how that interacts with the cowl closure.

[Guest]

The scoop part number still shows on the Mooney website, but no stock at the moment, the complete kit doesn’t show, but the part number may have changed.

Clarence

[MikeOH]

1 hour ago, Ragsf15e said:

Possibly the SB and STC aren’t compatible.  That wasn’t necessarily tested.  Also, I’d like to see the “air scoop” the SB mentioned and how that interacts with the cowl closure.

@Ragsf15e

Very good point! Assuming I could get through to anyone at the factory, I wonder if anyone left would even know?

Here’s what the scoop looks like, and what is actually on my plane. As you can see the scoop was replaced with the unpainted aluminum plate. Seems like this is a problem!

 

[MikeOH]

And, here’s what it is supposed to look like:

 

[Ragsf15e]

52 minutes ago, MikeOH said:

And, here’s what it is supposed to look like:

 

Well at least you know what’s going on now.  You could probably go either way. Delete the SB or fix the scoop.

Does @Marauder have the scoop from the SB?

[Marauder]

And, here’s what it is supposed to look like:
 

Mike - mine definitely has this scoop. It looks like there is just a flat piece of metal in your first picture.


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[MikeOH]

26 minutes ago, Marauder said:

Mike - mine definitely has this scoop. It looks like there is just a flat piece of metal in your first picture.


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That's exactly right; I just have a flat piece of metal.  With the gear up ALL airflow has to exit the cowl flaps.

I need to go back to the logs and look at dates, but the plane had a gear up back in the last millennium.  My guess is that the scoop got trashed and some repair genius just fabbed that flat plate and didn't even bother to paint it!

[Marauder]

That's exactly right; I just have a flat piece of metal.  With the gear up ALL airflow has to exit the cowl flaps.
I need to go back to the logs and look at dates, but the plane had a gear up back in the last millennium.  My guess is that the scoop got trashed and some repair genius just fabbed that flat plate and didn't even bother to paint it!

I’m sure that scoop can be made by anyone with limited sheet metal skills. If it will help you, I can take measurements of mine if you don’t have access to one.


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[MikeOH]

12 minutes ago, Marauder said:

I’m sure that scoop can be made by anyone with limited sheet metal skills. If it will help you, I can take measurements of mine if you don’t have access to one.


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@Marauder

That is very kind of you!

However, I just found the dimensions in a post from 2019 by @Yetti:

 

left to right

5 3/8 wide by 2 3/8 tall Plus thickness of material   Mine is factory.  so no riveting it on

3 `1/4 wide by 2" tall plus thickness of material.   5 rivets.  5/8 spacing Start first hole 3/8 from side

piece 2 and 3 are duplicates

Scoop

10 1/2"  overall wide.  3/4" side flanges

6" long.  1" and 3/4 drop on back of scoop   minus thickness of material

12 rivets on front

5 on side

[Bunti]

On  our M20F, we installed only parts of the kit (https://mooney.com/wp-content/uploads/2020/12/SBM20-182.pdf).

A  Mooney Service Center installed the metal pieces in front of the cylinders but not the lower air scoop. After some flights, it was adjusted again and the metal piece in front of cylinder 2 was removed  because we did not like the CHT 2 temp. Without the piece the CHT was a little lower. 

We have the Lasar cowl enclosure installed and the oil cooler relocated behind cylinder 4 instead of the front cowling. The Mooney kit 182 was designed somehow for the original big mouth without any enclosure and the standard front oil cooler. So the airstream and cooling efficiency with the complete kit installed is for sure different than originally anticipated.

Our cruise CHTs are ok now. During LOP cruise we see CHT 2 and 3 at 327 F and CHT 4 at 306F and CHT1 at 302F. ROP cruise temps are up to 30 degrees higher.

In my opinion, there is room for improvement in our oil temperature. It is climbing fast to 205F or so and wants to stay there. Also during taxi it is increasing fast.   We changed the Vernatherm and overhauled the cooler. But I would like to see it a little lower. LOP cruise  brings it a few degrees down, on longer flights to about 185F to 195F. Also a reduction in RPM helps when flying ROP. Mechanics and other pilots told me that the oil temps are normal in our hot Florida weather.  

On the ground, our hottest CHT is number 3, about 20F more than number 2. Typical values prior takeoff are: CHT3: 320 CHT2: 300, CHT1: 280  CHT4: 300 In flight, usually CHT 2  is a little hotter than number 3.