pkofman

Bravo- summer heat again- question

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Im sure this has been asked a million times but ....

In my Bravo when It is warmer/hot outside I find it is always a choice of power and cowl flaps to get the CHT down to my self prescribed limits

I typically fly at 29/2400 /obviously Cowl Flaps closed. In this condition when it gets warm outside +18C or into th 70's( that's warm to me im in canada ) I find that my cht will rise to just over 400 on some  cylinders 

My limits;   ( perhaps conservative are 1650 tit and 400 CHT,

I try to stay just below those numbers but what I find is that at that power setting and when leaned to 1650 +/- I have to trail the cowl flaps or add fuel rich the mixture (which will be  >19.5)

So maybe this is all normal, and I'm trying to play nice with the engine, but perhaps im being too conservative

Love to hear others experience

Thoughts.   

Pete

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Hi Pete,

I am just into my first summer with my Bravo so I am typing from a limited experience.  I have found LOP to be a great hedge against higher temps.  That said, I do run ROP at 29/2400 from time to time.  I find that my temps stay at about 400 +- 5 CHT for the hottest cylinder and 1605 +- 5 TIT when the FF is set to 19.0 - 19.5.  No cowl flaps in this scenario.  I did recently install new baffle seals but I did not go through a summer with the old ones so I have no basis for comparison.  

LOP is a different story.  the CHT's go down to <375 for the hottest cyliner, the TIT stays at or below 1600 and the fuel flow is about 14 GPH.  I trade 10-15 knots of airspeed for this but in my view it's worth it.  

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46 minutes ago, alextstone said:

Hi Pete,

I am just into my first summer with my Bravo so I am typing from a limited experience.  I have found LOP to be a great hedge against higher temps.  That said, I do run ROP at 29/2400 from time to time.  I find that my temps stay at about 400 +- 5 CHT for the hottest cylinder and 1605 +- 5 TIT when the FF is set to 19.0 - 19.5.  No cowl flaps in this scenario.  I did recently install new baffle seals but I did not go through a summer with the old ones so I have no basis for comparison.  

LOP is a different story.  the CHT's go down to <375 for the hottest cyliner, the TIT stays at or below 1600 and the fuel flow is about 14 GPH.  I trade 10-15 knots of airspeed for this but in my view it's worth it.  

Interesting. i do not run my plane LOP. so that is all new to me.. but i fly pretty consistently at 29/2400 and my tit is higher around 1650 and then i get a range of 390-435 and 19.5 +/- 

but since i don't like anything over 400 i can bring it down with fuel or Cowl flaps. 

I was always under the impression that LOP was not healthy for the bravo  lyc engine


Peter

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3 minutes ago, pkofman said:

I was always under the impression that LOP was not healthy for the bravo  lyc engine

Hmm.  I wonder where that came from?  Why would LOP be unhealthy for a specific engine?  I will say that GAMI injectors are key as well as a proper engine monitor if one wants to run LOP.  Check out Mike Busch's book, "Engines".  It will transform your thinking on how engines are to be run and maintained.  

Alex

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12 minutes ago, pkofman said:

I was always under the impression that LOP was not healthy for the bravo  lyc engine

Haven't heard that it is unhealthy but I have heard that a lot of Bravo owners can't get their Bravo to fly smoothly LOP.  No personal experience but I've heard it many times.  -K

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Haven't heard that it is unhealthy but I have heard that a lot of Bravo owners can't get their Bravo to fly smoothly LOP.  No personal experience but I've heard it many times.  -K
My engine runs smoothly LOP all the way until it dies due to fuel starvation.

Sent from my Pixel 3 XL using Tapatalk

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Generally on trips 30/2300 cht 375-380 tit 1600 or slightly less, cowl flaps closed enroute, in trail 5-10* less minimal loss of speed. When flying around to nowhere 24/2300 150-155 knots   at much lower temps and 13 gph nice trade off of speed to efficiency 

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9 hours ago, Kris_Adams said:

a lot of Bravo owners can't get their Bravo to fly smoothly LOP

Some can, some can’t. 

@donkaye knows all about this. 

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My Bravo would never run LOP and I tried everything possible. I had to run 19.4 GPH in cruise, exactly as identified above.

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11 hours ago, pkofman said:

Im sure this has been asked a million times but ....

In my Bravo when It is warmer/hot outside I find it is always a choice of power and cowl flaps to get the CHT down to my self prescribed limits

I typically fly at 29/2400 /obviously Cowl Flaps closed. In this condition when it gets warm outside +18C or into th 70's( that's warm to me im in canada ) I find that my cht will rise to just over 400 on some  cylinders 

My limits;   ( perhaps conservative are 1650 tit and 400 CHT,

I try to stay just below those numbers but what I find is that at that power setting and when leaned to 1650 +/- I have to trail the cowl flaps or add fuel rich the mixture (which will be  >19.5)

So maybe this is all normal, and I'm trying to play nice with the engine, but perhaps im being too conservative

Love to hear others experience

Thoughts.   

Pete

@donkaye any thoughts on my post above. I was not so much interested in lop just peoples experience on my observations above.  Hope all is well with you. Peter

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@donkaye or @LANCECASPER would know way more than me but my feeling having based my plane in Florida and encountering 80+ degree to 90 degree days all year long tells me you shouldn’t see that much of a difference.  I run at 30/24 about 18-18.5 gph at 1600 egt and 360-390 chts.   My feeling on the temp mainly has to do with the higher altitude flying I do. When I go from 90 degrees at the surface to an IAS only 20 kts or so slower in the teens but significantly cooler my temps stay about the same if not rise slightly.  Obviously this is due to the air density and IAS but it tells me that you won’t see a material difference in your summer flying.

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11 hours ago, pkofman said:

Interesting. i do not run my plane LOP. so that is all new to me.. but i fly pretty consistently at 29/2400 and my tit is higher around 1650 and then i get a range of 390-435 and 19.5 +/- 

but since i don't like anything over 400 i can bring it down with fuel or Cowl flaps. 

I was always under the impression that LOP was not healthy for the bravo  lyc engine


Peter

My first guess would be your engine baffles, but here's what Lycomings Trouble-Shooting Guide says:

92002952_ScreenShot2019-06-10at8_12_53PM.thumb.png.8d27f2232acf9809c15a8d4047da1294.png

 

https://www.lycoming.com/sites/default/files/SSP-475.pdf

 

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My JPI700 is set LOP. I just looked at the last panel pic I had. 26.7”/2225 1530TIT 359CHT in my Bravo. Around 16GPH with closed cowl flaps. Had a nice tailwind too...

Another flight 28.8”/2228 1599TIT 371CHT closed cowl. 

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22 minutes ago, daytonabch04 said:

My JPI700 is set LOP. I just looked at the last panel pic I had. 26.7”/2225 1530TIT 359CHT in my Bravo. Around 16GPH with closed cowl flaps. Had a nice tailwind too...

Another flight 28.8”/2228 1599TIT 371CHT closed cowl. 

It is interesting because i don’t fly with a FMP setting that low. I always fly about the same at 29/2400. But I’ll try lower.   What is the spread across the cylinders 

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On 6/10/2019 at 10:05 AM, pkofman said:

Interesting. i do not run my plane LOP. so that is all new to me.. but i fly pretty consistently at 29/2400 and my tit is higher around 1650 and then i get a range of 390-435 and 19.5 +/- 

but since i don't like anything over 400 i can bring it down with fuel or Cowl flaps. 

I was always under the impression that LOP was not healthy for the bravo  lyc engine


Peter

My typical cruise is 29/24 at about 18 to 18.5 per hour and at that setting my hottest cylinders are about 385-390 and TIT is just below 1600. This is with the cowl flaps closed. My temps were markedly higher at the same setting before I installed the GeeBee baffle seals so I threw gas at it to keep the hottest cylinders below 400 degrees. IMO it is best to keep chts below 400 and TIT below 1600 for optimal service life.

Edited by Bravoman
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Can I ask a big favor?  If someone who previously installed GEE-BEE's kit in their Bravo could take/send several pictures of the post installation that would be appreciated.  While I'm confident my A&P and myself can figure out the exact piece locations it would help to see the completed product from a few different angles.  My baffle is in such bad shape it may even be difficult to match some of them exactly.

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I did not use the GEE-BEE kit.  I ordered everything from Aircraft Spruce and cut the pieces to match so I'm not sure these photos will help...(not sure why these are rotated and I cannot seem to figure out how to fix that)baffle1.thumb.jpg.1dad444cfbb638fb8b1f40004bcb192f.jpgbaffle2.thumb.jpg.cc56ff8f1b91a1ca1d9af97f8ec48461.jpgbaffle3.thumb.jpg.4e947fcd89e1cc18ddea9def2b2400ed.jpgbaffle4.thumb.jpg.eccc8dab7e237de3c4ca85696e827e4b.jpg

 

 

 

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Thanks! I can never seem to figure out the pictures here either.  

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29 minutes ago, LANCECASPER said:

@alextstone it looks like there's at least a partial area to seal up around your starter that will make a substantial difference.

979606778_ScreenShot2019-06-27at5_03_43PM.thumb.png.e843195f7ba9cf8d4b950f50d934bf02.png

Thank you!!!

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On 6/10/2019 at 7:18 PM, Mooney in Oz said:

Some can, some can’t. 

@donkaye knows all about this. 

The last 5 years I flew the Bravo, I would run 1600 TIT, 29" and 2400. CHT's were well below 400, in the 370 top range, 18 GPH. Yes I could run LOP, but the give up was a bunch, and my cht's were in line ROP.  Keeping the TIT at 1600 or below will save the exhaust stacks I am told by those with more in the know than I. 

I never had any issues with cylinders, exhausts or turbos. Thanks Bob Kromer for teaching me how to fly a bravo properly.

 

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I took my plane to Clarence in Waterloo. Ontario.. he reviewed the seals... all looked great but we applied a new tweaks where the seals had puckered. a bit.A slit here and a cut there to ensure all was lined up and voila... I think it made a difference,  I have to say that this community is amazing and is  always adding great content.. Not to sound to squishy, but if you own a Mooney you need to be part of this forum... Tons of experience here!!

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On 6/27/2019 at 7:52 PM, mike_elliott said:

The last 5 years I flew the Bravo, I would run 1600 TIT, 29" and 2400. CHT's were well below 400, in the 370 top range, 18 GPH. Yes I could run LOP, but the give up was a bunch, and my cht's were in line ROP.  Keeping the TIT at 1600 or below will save the exhaust stacks I am told by those with more in the know than I. 

I never had any issues with cylinders, exhausts or turbos. Thanks Bob Kromer for teaching me how to fly a bravo properly.

 

I run mine like @mike_elliott.  Thursday was 29"/2400/1580TIT at 17.8GPH.  My hottest CHT was number 3 at 382.  The others were in the 350s and 360s.  This was about 150 ROP.

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