Sabremech Cowling Mod Testing (Ongoing)

[Sabremech]

Hi Bob,

Here's the Van's air dams for the IO-360 engines. I'll make full size copies for you tomorrow morning and e-mail them to you. I think I'll be installing these on Matt's during his upcoming annual next week. Your cooler temps have me believing too much air is blocked on his. Time for some more testing.

David

 

[Bob_Belville]

1 hour ago, Marauder said:

 

Ok, here are my numbers from today:

 

Flew 5500 @ 75%, leaned to 80° ROP, FF 10.9, MP 23.7, RPM 2530, 155 KTAS

 

 

 

Flew 6500 @ 72%, leaned to 80° ROP, FF 11.0, MP 22.7, RPM 2520, 153 KTAS

 

 

 

Flew 7500 @ 70%, leaned to 80° ROP, FF 11.0, MP 21.7, RPM 2540, 152 KTAS

 

 

 

What I think is strange is that my fuel flow hovered right around 10.9 GPH at the different altitudes.

 

 

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Chris, your temps and speeds are really great. I'm not sure my speeds will beat that by much and I know my temps will be higher. You ought to hang on to that bird.

[Marauder]

3500msl, 40 LOP 

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Time for some CiES fuel senders to get rid of that pesky “fuel mismatch” error message. Fueled up today, JPI showed 0.1 gallons difference between actual and indicated and fuel gauges were smack on.

 

What was your TAS at that LOP setting?

 

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[Marauder]

Climbing at 120 MPH

 

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What altitude? Judging by your MP, I would say you are in the 5.5 to 6.5 k. At that altitude, Vy+10 (110 KIAS) and OAT, I would be in the 340 range max.

 

 

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[Marauder]

Chris, your temps and speeds are really great. I'm not sure my speeds will beat that by much and I know my temps will be higher. You ought to hang on to that bird.

She has always been a solid running plane for me. I remember doing the Lasar cowl mod to help raise temps since I saw some cold winter numbers living in Buffalo.


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[carusoam]

East coast or west coast tonight, Cap’n Marauder?

-a-

[Marauder]

100 ROP. 6500MSL

 

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Looking closer at your numbers. No real difference between MP, I’m running 40 RPM more than you, the OAT is 27°F for me, 12°F for you, cylinders are ~30° hotter on your plane. and a 0.4 GPH higher fuel flow for you. Oil temp in your bird is ~20° warmer.

 

What was your TAS?

 

 

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[Marauder]

And just for the cake on this Mooney pie, I flew with a Piper owner today. First time in a Mooney. He is a prospective Mooney buyer. He kept asking me if he could buy my Mooney. He was commenting how he would be see high 70 knots ground speed with the headwinds we had. I was showing 130.


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[Marauder]

East coast or west coast tonight, Cap’n Marauder?
-a-

East coast. Just did one of those old man nap things most of the evening. You on the other hand!


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[carusoam]

Waiting to see the markets open on the other side of the pond..

Got to figure out a way to keep up in the panel wars... 

GTN, JPI, and other 2020 things... ESI500 just to get ahead...

Enjoying the engineering level discussion in this thread....

reserved the Old man naps for weekdays... after the gym or after the jog... 

You’re going to love retirement!

Best regards,

-a-

 

[Guitarmaster]

 
Looking closer at your numbers. No real difference between MP, I’m running 40 RPM more than you, the OAT is 27°F for me, 12°F for you, cylinders are ~30° hotter on your plane. and a 0.4 GPH higher fuel flow for you. Oil temp in your bird is ~20° warmer.
 
What was your TAS?
 
 
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I didn't do a tas test. I was indicating 143. I'm guessing about 149 or so

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[Guitarmaster]

 
What altitude? Judging by your MP, I would say you are in the 5.5 to 6.5 k. At that altitude, Vy+10 (110 KIAS) and OAT, I would be in the 340 range max.
 
 
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This was towards the end of the climb to 6500

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[Guitarmaster]

 Time for some CiES fuel senders to get rid of that pesky “fuel mismatch” error message. Fueled up today, JPI showed 0.1 gallons difference between actual and indicated and fuel gauges were smack on.
 
What was your TAS at that LOP setting?
 
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I would love to do the new senders, but too many things are pulling at my account right now.
The true airspeed at 3500 feet in this configuration is about 137. That's a calculated speed based on a hundred and thirty-three indicated.

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[Bob_Belville]

7 hours ago, Marauder said:

 

She has always been a solid running plane for me. I remember doing the Lasar cowl mod to help raise temps since I saw some cold winter numbers living in Buffalo.


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Yeah, you certainly could run a lot hotter w/o worry. I am a little puzzled about the EGT peaks. Are the probes 6" below the flange on the exhaust header? Maybe @kortopates can tell us how much variation there is in peak EGTs. My 1500-1525 might be the outlier. 

[Marauder]

1 hour ago, Bob_Belville said:

Yeah, you certainly could run a lot hotter w/o worry. I am a little puzzled about the EGT peaks. Are the probes 6" below the flange on the exhaust header? Maybe @kortopates can tell us how much variation there is in peak EGTs. My 1500-1525 might be the outlier. 

Bob -- mine are around 3 inches below the flange. I think the actual temps will vary a lot and not to take them as absolutes. If your probes are 6 inches down on the tubes, you may be at a hotter point in the exhaust plume.

Edited March 12, 2018 by Marauder

[Marauder]

8 hours ago, carusoam said:

Waiting to see the markets open on the other side of the pond..

Got to figure out a way to keep up in the panel wars... 

GTN, JPI, and other 2020 things... ESI500 just to get ahead...

Enjoying the engineering level discussion in this thread....

reserved the Old man naps for weekdays... after the gym or after the jog... 

You’re going to love retirement!

Best regards,

-a-

 

It's easy. Just give them your wallet, first born and the note on your most expensive car.

[Bob_Belville]

1 hour ago, Marauder said:

Bob -- mine are around 3 inches below the flange. I think the actual temps will vary a lot and not to take them as absolutes. If your probes are 6 inches down on the tubes, you may be at a hotter point in the exhaust plume.

I think that explains the difference. 

[Marauder]

6 minutes ago, Bob_Belville said:

I think that explains the difference. 

Yep. I suspect the temperature leaving the cylinder increases a bit after the flange. How uniform are your EGTs? As you saw from mine, they are close.

Edited March 12, 2018 by Marauder

[Bob_Belville]

1 minute ago, Marauder said:

Yep. I suspect the temperature leaving the cylinder increases a bit after the flange. How uniform are your EGTs?

Very close. JPI manuel calls difference of 70-90 normal, my last flight max EGTs were 1502, 1519, 1494, 1506. Difference 25.

[jetdriven]

38 minutes ago, Bob_Belville said:

I think that explains the difference. 

That fuel line passes less than one inche from the red hot #4 exhaust stack. I pulled mine back and clamped it to the intake tube to keep it away 

Edited March 12, 2018 by jetdriven

[kortopates]

3 hours ago, Bob_Belville said:

Yeah, you certainly could run a lot hotter w/o worry. I am a little puzzled about the EGT peaks. Are the probes 6" below the flange on the exhaust header? Maybe @kortopates can tell us how much variation there is in peak EGTs. My 1500-1525 might be the outlier. 

Honestly we don't even look at or consider actual or absolute values of peak EGT and we only give some attention to the size of the spread. We see spread sizes all over the map, and it varies widely on the same engine based on MAP or throttle setting because this can effect mixture distribution as well. But usually injected engines have a pretty tight spread at cruise power. But if we see a change in spread size then its time to investigate. 

[Marauder]

1 hour ago, jetdriven said:

That fuel line passes less than one inche from the red hot #4 exhaust stack. I pulled mine back and clamped it to the intake tube to keep it away 

Oh no! Clarence has rubbed off on you!  

[Marauder]

1 hour ago, kortopates said:

Honestly we don't even look at or consider actual or absolute values of peak EGT and we only give some attention to the size of the spread. We see spread sizes all over the map, and it varies widely on the same engine based on MAP or throttle setting because this can effect mixture distribution as well. But usually injected engines have a pretty tight spread at cruise power. But if we see a change in spread size then its time to investigate. 

I can tell you one thing... When you had me do those GAMI and mag flight tests, I saw some really HOT EGTs.

[carusoam]

Nice observation on the EGT placement...

High MAP and ROP, the flames will be pretty far down the exhaust tube continuously converting fuel to heat and exhaust getting hotter the whole way...

Balancing the getting hotter the whole way, the exhaust gasses will be expanding rapidly, providing adiabatic cooling...

To Make raw EGT number comparisons useable between engines would require standardizing the exact location of the EGT probes.  

In this case, Each mm counts.

The one place where raw EGT gets used is measuring the turbine inlet temp TIT.  This raw EGT data is in a standardized location.

More challenges for understanding comes with TIT...

• The TIT is further down the exhaust system.
• often reads higher than individual EGTs further up.
• Conversion of fuel is most complete further down.
• combined flow from multiple exhaust streams.
• EGT is an average over time.
• hot exhaust gasses come in waves, as the exhaust valve opens.
• A turbo keeps the exhaust pressure from dropping quickly.  Minimizing the adiabatic cooling effect.

The importance of the raw number here...  protecting the exhaust parts in contact with the waves of very high temps.  

Protecting the tubes and turbine blades from erosion....

For the NA engine... EGTs relative to peak tell 99% of the story in flight.

Other Questions.... what’s causing the stain running down Bob’s #4(?) exhaust tube?

PP thoughts only,

-a-

[Marauder]

1 minute ago, carusoam said:

Other Questions.... what’s causing the stain running down Bob’s #4(?) exhaust tube?

PP thoughts only,

-a-

He has oil on the oil cooler lines as well. The staining on the #4 looks like it is originating from the valve cover gasket. Look under the nut on the flange, looks like the starting point.