Mooney bravo data actuals

[pkofman]

I was able to run a few tests today to check out the 98 mooney bravo and get some metrics

I was curious. There is a spread on a few of the cylinders. The  range on the egt's of about 50f 

The range on the cht's is more significant from 344>424

Maybe it is all normal

Here is the data, colms below are cylinder , egt,cht,tit ( leaned to tit at 1625)

thoughts.

 

	Mooney Bravo tls 98 data
	Temp	68f
	Altitude 7500
	cowl flaps closed
	Power	mp 29.1	rpm 2400	Tit 1625	Fuel flow 19.2
1	1487	386	1625
2	1539	420	1625
3	1442	404	1625
4	1510	344	1625
5	1503	373	1625
6	1523	352	1625

 

 

m20mdatacompsjun22017.xlsx

[carusoam]

PK,

344 - 420 looks like a pretty wide spread...

Do you know if you have any ring type TCs mixed in because the ship's CHT thermocouple may be sitting in the only cylinder hole.  The JPI often gets a lousy substitute and can be 50°F high.

It helps to say with certainty, what TCs are on each cylinder for this type of problem.

Best regards,

-a-

[LANCECASPER]

I would definitely do what it takes to keep your CHT's below 400 - whether that means partially opening the cowl flaps or adding fuel. If not you'll be buying cylinders prematurely.

Most likely if you look at your baffle material it is probably blowing back and letting air escape at the top of the cowling rather than forcing it over the cylinders for cooling. If that's the case, the Gee Bee Baffle kit for the M20M will do a great job.

 

[carusoam]

Are you able to run a GAMI spread with your engine?

That may deliver better info than just the raw EGTs.

The highest CHT happens to also be the highest EGT.

Ordinary PP knowledge... not a Bravo owner...

Best regards,

-a-

[pkofman]

I have no idea how to do a gami spread

also 

Is it possible that the hottest Cyclinder could be because of location on the engine  would that make a difference? 

Do these numbers look generally in the correct range  for a bravo

 

[carusoam]

CHTs <380°F are best for metallurgy of cylinders.  Pretty much a general Mooney guidance...

cylinder location is often a concern. The front ones will see different cooling than the back ones. The cylinder numbers run backwards to Continental numbers. Good seals/baffled are better than old ones... Guy from GB has posted some pictures of new seals that his company builds...

Await some Bravo owner specific guidance for better details.

The Gami spread is a test we use to determine if the fuel injectors are all delivering fuel the same way at the same time. A speck of dirt in a fuel injector can be problematic.  The gami spread is the simple pilot's test to determine fuel injector balance.

Other topics of interest...

LOP with the bravo...

magneto testing at altitude. There is probably a name for this too...

Sorry I don't have much detail to offer,

-a-

Edited June 4, 2017 by carusoam

[LANCECASPER]

5 minutes ago, pkofman said:

I have no idea how to do a gami spread

also 

Is it possible that the hottest Cyclinder could be because of location on the engine  would that make a difference? 

Do these numbers look generally in the correct range  for a bravo

 

Sure, your front two cylinders are usually the coolest, but I would still do what it takes to keep all CHT's under 400. Until you check and possibly replace the baffling material I would keep the cowl flaps open a couple bars on your indicator at cruise. (Of course, full open position on climb)

[DVA]

I'd be investigating a few things here, some of which others have pointed out.

1) Make sure your soft baffling is sealing properly and the inter-cylinder baffles are installed properly (and as odd this seems, also actually there)

2) Fly a test profile per SAVVY's instructions to do both an injector flow test (GAMI spread) and an in-flight lean Mag check. You can get the instructions to do that http://content.savvyanalysis.com/static/pdf/SavvyAnalysisFlightTestProfiles.pdf here. If you can, upload the results from your EDM to Savvy (it's free) and share the results to us.

2a) Confirm that at full throttle / full mixture during the ground roll you are making no more than 36-37" of MP, 2575ish RPM, and at least 30 GPH of fuel flow. Never lean this engine in the climb. You should be flowing at least 25 GPH as you ascent in a power climb.

3) I would not be concerned about going a bit over 400 on an occasional basis, such as during a climb. Do however have full throttle and open cowl flaps when doing it. What you want to watch for in CHT are quick and continually rising temps above 400. So if you get to say 410-420 in the climb and it settles there, no big deal. There is no absolute magic about the number "400" verses 410 or 402. The CHT temp guidance is based on some factual metallurgy centered around a half-way point in the specific yield strength of aluminum vs temp and it is good guidance. It is not however, exact guidance.

4) Please consider not arbitrarily setting TIT. 1625 may be correct, but prove it. TIT varies with a number of factors, altitude, fuel flow, MP, RPM, Trump, (there I go again!) etc. Without GAMI injectors, you should use run this engine ROP at 100 dF rich side of TIT. I would not trust Peak TIT without GAMIs or evidence that my individual EGTs are all peaking together as peak TIT can easily place some cylinders in a detonation zone at higher power settings. (28" MP and above)

5) After you confirm those things (others here may suggest more) fly it per the POH power settings and see if it makes the book numbers for speed? If it does, you're in fine shape. (Deduct a full 8-10 knots off book if you have TKS)

Let us know what you find.
Dave

[jlunseth]

The lean test is at http://www.gami.com/gamijectors/leantest.php .  If that doesn't work, go to gami.com, click on Gaminjectors, click on Lean Test.

I agree you should try to keep CHT's under 400 except for certain circumstances such as a climb where it is sometimes not avoidable.  The lean test will tell you, but I agree that yours is probably an airflow problem.  Yes, the highest EGT correlates to the highest CHT, but the lowest EGT correlates to the next highest CHT.  The numbers don't look way out of line to me.  Airflow makes a big difference.  Also, where is your turbo?  The cylinder it sits under might get quite alot of radiant heat from it.

[pkofman]

15 minutes ago, DVA said:

I'd be investigating a few things here, some of which others have pointed out.

1) Make sure your soft baffling is sealing properly and the inter-cylinder baffles are installed properly (and as odd this seems, also actually there)

2) Fly a test profile per SAVVY's instructions to do both an injector flow test (GAMI spread) and an in-flight lean Mag check. You can get the instructions to do that http://content.savvyanalysis.com/static/pdf/SavvyAnalysisFlightTestProfiles.pdf here. If you can, upload the results from your EDM to Savvy (it's free) and share the results to us.

PK  

Pretty complex and i run ROP.. I will work through this one.

2a) Confirm that at full throttle / full mixture during the ground roll you are making no more than 36-37" of MP, 2575ish RPM, and at least 30 GPH of fuel flow. Never lean this engine in the climb. You should be flowing at least 25 GPH as you ascent in a power climb.

PK

 I am 36>37 , full power on the roll. I see very close to 30gph CF = full open and i do not lean until altitude

 Typical climb fuel flows are higher than 25 and i climb at 34/2400 no leaning ..CF = open

3) I would not be concerned about going a bit over 400 on an occasional basis, such as during a climb. Do however have full throttle and open cowl flaps when doing it. What you want to watch for in CHT are quick and continually rising temps above 400. So if you get to say 410-420 in the climb and it settles there, no big deal. There is no absolute magic about the number "400" verses 410 or 402. The CHT temp guidance is based on some factual metallurgy centered around a half-way point in the specific yield strength of aluminum vs temp and it is good guidance. It is not however, exact guidance.

PK :

The numbers i posted yesterday were level flight and the reason i posted was the 400"s  on a few cylinders at 1600 and 19.5 gph

I was expecting yesterday a lower gph , CF = closed . ambient outdoor temps were only about 68F . 

But i probably did not really did not lean to the 1600 to see if that is in fact the actual proper lean tit. Ill check that

Interestingly the poh says the cht can range up to 500 but i have learned from the forum to keep it at 400 or below

4) Please consider not arbitrarily setting TIT. 1625 may be correct, but prove it. TIT varies with a number of factors, altitude, fuel flow, MP, RPM, Trump, (there I go again!) etc. Without GAMI injectors, you should use run this engine ROP at 100 dF rich side of TIT. I would not trust Peak TIT without GAMIs or evidence that my individual EGTs are all peaking together as peak TIT can easily place some cylinders in a detonation zone at higher power settings. (28" MP and above)

PK  I need to do this properly rather than just use a value and i do always run this rop.

5) After you confirm those things (others here may suggest more) fly it per the POH power settings and see if it makes the book numbers for speed? If it does, you're in fine shape. (Deduct a full 8-10 knots off book if you have TKS)

PK:

I do have tks but did not know it would reduce speed that much. ( actually i fine with that no big deal for me ) and the POH shows that i should be getting lower fuel flows give the above

This is fantastic info 

My biggest problem with the airplane is simply understanding what is normal so the more info on peoples actual experience the better.

Let us know what you find.
Dave

I inserted a few answer above. thank you for the great information

Pete

[pkofman]

20 minutes ago, jlunseth said:

The lean test is at http://www.gami.com/gamijectors/leantest.php .  If that doesn't work, go to gami.com, click on Gaminjectors, click on Lean Test.

I agree you should try to keep CHT's under 400 except for certain circumstances such as a climb where it is sometimes not avoidable.  The lean test will tell you, but I agree that yours is probably an airflow problem.  Yes, the highest EGT correlates to the highest CHT, but the lowest EGT correlates to the next highest CHT.  The numbers don't look way out of line to me.  Airflow makes a big difference.  Also, where is your turbo?  The cylinder it sits under might get quite alot of radiant heat from it.

I have no idea where the turbo sits ,

First thing im going to do is check the baffling that seems pretty easy for the shop to do and might yield some answers.

What surprised me was it was  really NOT very hot outside yesterday so when we get to summer im going to be flying with the CF's open to keep chts in the proper range

Good to have this conversation now before summer.

Edited June 4, 2017 by pkofman
mistake

[Danb]

PK going back a few months ago it appears an MCS installed the top cowling on  not noticing the front right baffling was folded down, it took a couple flights to realize the baffling was shot, the temps actually changed by 10-25 degrees, I changed the two pieces and presto ok. Now my back top right baffling seems flimsy, I looked after a 5 hour cross country depicted the rear temps went from about 385 to 400-410. I'm going to replace that section during my upcoming oil change , I'll report findings In a darkened hanger I stuck a flashlight in the cowl flaps to see where light my shine through.

[pkofman]

Any ideas on what would cause the number 2 cylinder to be the hottest cht and egt.  I understand it is at the front and we checked the injector today and baffles and they are perfect

[LANCECASPER]

I was gonna say partially blocked fuel injector, but it looks like you checked that. Maybe pull a plug and borescope the cylinder to see what it looks like.

[pkofman]

20 hours ago, LANCECASPER said:

I was gonna say partially blocked fuel injector, but it looks like you checked that. Maybe pull a plug and borescope the cylinder to see what it looks like.

Thanks . Injector looks good , Maybe this is just normal give the conditions on a given day, Sometime i feel like i might chase things that are not a problem just becuase i do not know it well enough   . Im going to go though the exact same little test again to see what happens

[PaulM]

You might try swapping the CHT probe (2 to 4) and see if the problem follows the probe or stays with the cylinder. 

I had EGT #2 + #6 go bad last month... and #2 die again after 4 hours (infant mortality)  but those failed low (as you would expect in a TC short down the probe)   .   Also CHT #5 failed during the annual, which they said went high then off the chart and XXX etc..   I also saw a CHT probe in a Seneca indicate way hot 800+  which seems to be a similar failure. 

On my Bravo #2 is the coolest and #1 and #3 are the hottest and your test was at a lower MP (29.1)?    I don't think I can break 400 at that MP... it has to be cowls closed > 32" to generate that heat. 

Running the peak lean test will also tell you if an injector is blocked.. since it would peak well before the others.   When EGT#2 went bad (read 100F lower than all of the other EGT's)  I didn't know at first if it was a probe or a blocked injector, but during lean it peaked right along with all of the other EGT's.. showing that it was a relative problem and probably a probe issue.   

To answer a previous question the turbo sits below Cyl#6.. here is the parts book. https://www.lycoming.com/Content/parts-catalog-tio-540-af1a-af1b

Could you have a blocked exhaust valve oil port?  I had #2 and #4 leak this last winter.

 

[pkofman]

8 hours ago, pkofman said:

Thanks . Injector looks good , Maybe this is just normal give the conditions on a given day, Sometime i feel like i might chase things that are not a problem just becuase i do not know it well enough   . Im going to go though the exact same little test again to see what happens

 

Very important

So today i went out to plane and started it . Everything seemed perfect until  I did my run up... all seemed good. But then the engine just  quit. I put the boost pump on and the engine restarted. The it quit again....!

If the engine did not stop i would never have known that i had a problem

I stopped the plane to find out that fuel was pouring out the cowl flap. I would not have seen that or even known about that if i was in sitting in the plane.

Now under another thread last week i asked about a flickering low fuel pressure gauge .

Maybe that  was the start of the problem or the first indication.

And i suppose we all have different experiences but this  is one i do not wish to repeat. But i actually dont know how you could know you had this problem

I got out of the plane to find the gas flowing out of the cowling.

I got the  plane was operating I have no idea whether this plane would have had the power to take off  with a failed engine driven fuel pump or  if i would have  hit the high boost while "on the roll"/ would it have had the power to take off 

I just dont know if i missed an indication of  pending doom or not.

last week i reported a very tiny ficker in the  fuel gauge needle and discussed it here . Most thought it was normal.

I had no fuel stain on the ground  when i pulled the plane from the hangar and i did not have any hint of this issue.

The mechanic pulled the cowling and confirmed that fuel was flowing from the engine driven fuel pump and the feeling is that when the fuel pump fails that it will just spit out gas and even more gas if  you turn on the high boost pump

Thank goodness i caught this on the ground. I had no indication and the only way i would know if i had a problem was if i saw fuel leaking ( not possible I'm in the plane ) or a zero fuel indication. 

Very scary 

Thoughts.   Peter

[LANCECASPER]

1 hour ago, pkofman said:

 

Very important

So today i went out to plane and started it . Everything seemed perfect until  I did my run up... all seemed good. But then the engine just  quit. I put the boost pump on and the engine restarted. The it quit again....!

If the engine did not stop i would never have known that i had a problem

I stopped the plane to find out that fuel was pouring out the cowl flap. I would not have seen that or even known about that if i was in sitting in the plane.

Now under another thread last week i asked about a flickering low fuel pressure gauge .

Maybe that  was the start of the problem or the first indication.

And i suppose we all have different experiences but this  is one i do not wish to repeat. But i actually dont know how you could know you had this problem

I got out of the plane to find the gas flowing out of the cowling.

I got the  plane was operating I have no idea whether this plane would have had the power to take off  with a failed engine driven fuel pump or  if i would have  hit the high boost while "on the roll"/ would it have had the power to take off 

I just dont know if i missed an indication of  pending doom or not.

last week i reported a very tiny ficker in the  fuel gauge needle and discussed it here . Most thought it was normal.

I had no fuel stain on the ground  when i pulled the plane from the hangar and i did not have any hint of this issue.

The mechanic pulled the cowling and confirmed that fuel was flowing from the engine driven fuel pump and the feeling is that when the fuel pump fails that it will just spit out gas and even more gas if  you turn on the high boost pump

Thank goodness i caught this on the ground. I had no indication and the only way i would know if i had a problem was if i saw fuel leaking ( not possible I'm in the plane ) or a zero fuel indication. 

Very scary 

Thoughts.   Peter

It's good to put these post under the Bravo specific forum so in the future Bravo owners can reference them.

 

This post in the Bravo section may shed some light:

 

[pkofman]

Just now, LANCECASPER said:

It's good to put these post under the Bravo specific forum so in the future Bravo owners can reference them.

 

This post in the Bravo section may shed some light:

Im sorry I did not even realize there was a specific bravo section  . Thank you I will do that.

Im not exactly sure i know the numbers but the needle had been running  right at the bottom of the green /top of the yellow . i dont know the numbers exactly. When i turn on the boost it goes to the top of the green

Peter