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AF1B Break-In


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Good points and my AP, CFII and I are all on the same page with everything.  A preflight meeting to go over all the Lycoming breakin procedures, expectations, etc... I'd go up with both if it weren't for the useful load.  In the end, most important to me is in the event something goes wrong, who is best equipped to help get us back safely... 

The AP and CFII have also done this many times and speak each others language.  

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8 hours ago, mike_elliott said:

In my opinion, The guy you should take on the break in flight is the IA/A&P who hung the engine. Typically they wont know as much about aerodynamics, approaches or stalls as a CFII, but they most likely will know more about breaking in an engine, Oil pressure, and any anomalies that may occur and mitigations. Not all A&P's and CFII's are created equal, however. The guy who hung it should be confident enough in it to fly behind it.

While I suppose you could do that, what is an A&P going to be able to do in flight?  It's pretty obvious when recording all the parameters if there is an anomaly.  I circle the airport up to 4,000 feet, then set up a holding pattern on the Aera 760 or, if a GTN 750 is available, do it on the 750 and fly the hold a couple of miles to the side of the runway.  If there were to be an issue, just circle down and land.  I have done all my break-ins with flight following in combination with traffic and weather on the above avionics.  The spreadsheet goes to the Shop after I land.

 

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One of the questions for the A&P power plant exam is that an overly lean engine runs too hot. think about this. And I would say that half of the people I know that work on airplanes think that the further the  red knob is pulled. the hotter it gets. Those are not people to get advice from.  I’m certain they know how to fix airplanes, but I’m not certain they know the reason why the plane broke in the first place.

Everyone’s different, and a lot of old wives tales exist among pilots, but I would say it may be even more exist among mechanics. Get your break-in  advice from Lycoming who designed and built the engine. And temper that with the advice of the person who is warranting it.  Follow the Lycoming advice, not to be contrary to the advice of the shop who built it. Do they tell you that lean of peak for example, burns valves, and they won’t warranty it after that?  Then you should question the people who built it to begin with. 

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1 hour ago, jetdriven said:

One of the questions for the A&P power plant exam is that an overly lean engine runs too hot. think about this. And I would say that half of the people I know that work on airplanes think that the further the  red knob is pulled. the hotter it gets. Those are not people to get advice from.  I’m certain they know how to fix airplanes, but I’m not certain they know the reason why the plane broke in the first place.

Everyone’s different, and a lot of old wives tales exist among pilots, but I would say it may be even more exist among mechanics. Get your break-in  advice from Lycoming who designed and built the engine. And temper that with the advice of the person who is warranting it.  Follow the Lycoming advice, not to be contrary to the advice of the shop who built it. Do they tell you that lean of peak for example, burns valves, and they won’t warranty it after that?  Then you should question the people who built it to begin with. 

I hear you... I reviewed the lean limits specifically for the AF1B in the Lycoming manual.  It would be an easier chart to follow if it was in a table format of course but I have my cheat sheet ready.  I know some people like LOP but I have no reason to run it that way.  

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14 hours ago, donkaye said:

While I suppose you could do that, what is an A&P going to be able to do in flight?  It's pretty obvious when recording all the parameters if there is an anomaly.  I circle the airport up to 4,000 feet, then set up a holding pattern on the Aera 760 or, if a GTN 750 is available, do it on the 750 and fly the hold a couple of miles to the side of the runway.  If there were to be an issue, just circle down and land.  I have done all my break-ins with flight following in combination with traffic and weather on the above avionics.  The spreadsheet goes to the Shop after I land.

 

Don, your a different CFI that has experience breaking in an engine, as do I. An A&P who knows engines might be able to diagnose an anomaly in flight, something I believe I am capable of and I believe you might be also, but your 737 door seal specialist just might not be or the newly minted time builder would fail at. 

The first time you replaced your Bravo engine, who flew with you if anybody?

 

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12 hours ago, BravoWhiskey said:

  I know some people like LOP but I have no reason to run it that way.  

I could give you four (gallons per hour) reasons why I run LOP. Maybe I’m just a CB. 

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45 minutes ago, PilotX said:

I could give you four (gallons per hour) reasons why I run LOP. Maybe I’m just a CB. 

Fair enough... but i just spent 7 months on an overhaul with everyone in the build pointing to LOP... 

I am cuious though, can you tell me what setting you fly at? Speed, Fuel flow, etc...

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7 hours ago, BravoWhiskey said:

...with everyone in the build pointing to LOP... 

I am cuious though, can you tell me what setting you fly at? Speed, Fuel flow, etc...

Everybody in the build pointing to LOP? Does that mean everybody said the engine needed a rebuild because it was run LOP? 

FF 14.5gph,  2200/34" that is right around 75%, perhaps a tiny bit higher. CHTs below 380. At 12,500 I showed 141 IAS, usually works around to around 170+ True/GS. Flew the same power setting (with equivalent speeds) and FF was 16.6 gph. 

This Bravo can fly LOP, without GAMIs. My suggestion is to fly an LOP profile with somebody who knows what they are doing and/or talking about. The numbers below are based upon the LOPFFvsHP calculator posted elsewhere. Fuel flow  x 14.31 / 270 so here is what I found, again I am flying closer to 77% power at 14.5gph.

Prop/Power (IAS) %pwr FF

22/30” (125) 65% 12.2

22/32” (132) 70% 13.2

22/34” (137) 75% 14.2

 

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1 hour ago, BravoWhiskey said:

Engine ran smooth and cool... but the alternator belt snapping midflight cut the break-in flight a bit short...

 

 

Ouch. Prop need to come off to put new one… was it set too tight ?

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1) LOP can be good for engines…

2) Mis-used LOP can keep that mechanic’s kids going to a low cost school… as well as mis-used ROP…

3) The Bravo’s Log style intake is not as well balanced as curvy equal length intake tubes, making running LOP take more knowledge… and PIC effort.

 

4) Some people enjoy flying their Mooney in flaming dragon mode… Max cruise speed… there is no LOP for that…

5) Lost belt? Check to see if that was re-used from prior, before engine OH… probably not good economics in re-use of old rubber engine parts…

6) If re-used… see what else got re-used… there will be a list of parts you want to be familiar with their total hours… and not assume everything is new…

PP thoughts only, not a mechanic…

Best regards,

-a-

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Well, we don't know how but it looks like something nicked a pulley causing it to cut the belt and it busted.  It could have happened on run up or the initial roll out.  Pulley and some other stuff that the belt ended up hitting had to be fixed/replaced.   Ran the breakin 2.5 yesterday per lycoming and another 2.3 today.  And running smooth and cool.

I'm not comfortable running LOP so I'm not going to try.  Not to say it cant be done, just not for me.  

 

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Great follow-up BW!

Thanks for sharing the detail…

Plenty of time for LOP after the Break-in flights are over…

Break-in is typically full rich for best cylinder cooling and high ICPs…

Running high LOP for cylinder cooling, won’t have the internal pressure you are looking for…

PP thoughts only, not a mechanic…

Best regards,

-a-

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On 9/3/2021 at 6:39 PM, BravoWhiskey said:

@affricate curious how long the overhaul took?  Did you go with new cylinders or nickel?

The whole process took approximately 6 months. Sourcing new cylinders was next to impossible because of supply chain delay secondary to pandemic. We went with nitride barrels. Overall Airmark did a great job and did the best they could. I'm glad I started the process in March, because waiting until late summer would have caused even further delay.

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  • 2 weeks later...

Had some more belt trouble.  The last one flipped over on me.  Troubleshooting leads back to an alternator.  Probably bad bearings.  It would spin freely and charge at times but during last runup the low charge and some squealing suggested it might be getting hung up under load.  It hasnt completely siezed up but something is definitely not right in there... now i am waiting on a new alternator.  

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On 9/26/2021 at 8:32 PM, BravoWhiskey said:

Had some more belt trouble.  The last one flipped over on me.  Troubleshooting leads back to an alternator.  Probably bad bearings.  It would spin freely and charge at times but during last runup the low charge and some squealing suggested it might be getting hung up under load.  It hasnt completely siezed up but something is definitely not right in there... now i am waiting on a new alternator.  

Why a new alternator? While mine was down for a Bravo conversion and I was waiting for cylinders to come back I sent the alternators out to Aero Accessories in Van Nuys, CA for an overhaul (http://aeroacc-vny.com/) They received my two alternators on a Monday and shipped them back out on Wednesday. Great service and they look brand new. Very fair prices (had both of them rebuilt for much less than one new alternator), great communication and excellent service!!!

BEFORE

image.png.7782e0cc98838d90df69baa48a098d70.pngimage.png.c53f95a43b122b8070414e17d36053b7.png

 

 

AFTER

image.png.97ce80ec6998f5787b3a64b4ff4bb019.png

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  • 2 weeks later...
7 hours ago, PilotX said:

Any more flights?

Not yet.  Should be replaced this week and I'll be doing a few test flights afterwards.  There were a few strange things that happened during the breakin that are now all pointing back to the alternator getting hungup.  For example i had big changes in MP and RPM when making small power adjustments.  Even though I had some good breakin progress I think I need to start over with break in procedures.  Just in case the performance and temps were impacted by the alternator getting hing up or causing some unusual resistance, I want to see how she performs fresh.

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On 9/11/2021 at 10:01 PM, affricate said:

The whole process took approximately 6 months. Sourcing new cylinders was next to impossible because of supply chain delay secondary to pandemic. We went with nitride barrels. Overall Airmark did a great job and did the best they could. I'm glad I started the process in March, because waiting until late summer would have caused even further delay.

https://flightaware.com/live/flight/N1085G

Nice to see that you're one step closer to getting N1085G back home.

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