Power settings……..again

[Troy Jordan]

I just purchased a new Acclaim type S with TKS and feel that every time I get a different Mooney I have to go through a dozen different power settings to figure out which one is the perfect ride.  I am a LOP disciple flying at 16-23k, so would you guys mind sharing what you think is the best setting?  MP-RPM-FF-TIT-CHT-TAS

[LANCECASPER]

1 hour ago, Troy Jordan said:

I just purchased a new Acclaim type S with TKS and feel that every time I get a different Mooney I have to go through a dozen different power settings to figure out which one is the perfect ride.  I am a LOP disciple flying at 16-23k, so would you guys mind sharing what you think is the best setting?  MP-RPM-FF-TIT-CHT-TAS

Here's a start:

 

[exM20K]

If you’re flying LOP, then power is a function of fuel flow, so choose your adventure :-)

13.7*GPH is approximately your HP.

Mine is a Platinum Edition TSIO550 (factory balanced injectors and parts), and it runs well lean to 100* or more LOP. 
 

90% of the time I’m at 16,000 or 17,000 at 30.x / 2400 RPM / 16.2-16.5 GPH. TIT will be between 1590 and 1640, higher when hot aloft like yesterday’s ISA +17.  Some prefer lower TIT, but I have two new turbos and want to show them who’s the boss.

 

Your engine has only 1 TIT probe (right side), so I don’t think that’s the best way to lean. I do this:

1. level off and let speed build to cruise IAS or more.
2. boost pump off (on vs off changes fuel flow in unexpected ways)
3. MAP to 30”
4. RPM to 2400
5. BMP to 16 GPH
6. Enrichen to 18 GPH quickly, then further slowly
7. My #3 is richest, so find that peak.
8. Take a picture of Engine Instrument display
9. lean till #3 is 50* LOP
10. confirm the other five are at least 50* LOP.  TIT lean find is about 65* LOP.

CHT’s are never above 360 in cruise, more often 330 ish.

knowing your engine is helped by recording the engine data for some GAMI sweeps so you know what cylinders peak where.  It is very stable in this respect.

Have fun learning this plane.  It is a magnificent traveling machine.

-dan

[Danb]

Just pussing around today my normal cruise at 27.5/2400RPM hottest CHT around 313, TIT 1600, FF 14.5 was just 5000’ and TAS was around 178 knots. My Acclaim can be flown in a number of settings and altitudes allowing 201 type numbers up to TN numbers.  I have the ability to just cruise as low as 150 at under 12 GPH up to 225 and 20 GPH which I don’t do. Most my trips are around 15 GPH with great low temps if that’s a good thing at 190 or so depending on altitude. 

[Danb]

Troy I didn’t actually answer your question but my point is there are a number of realistic settings depending on you mission that day. You like 16-23 LOP A good setting for 16000  I’d use on a trip would be 29/2400 16-17 GPH LOP  depending how far you’d want to go determines your speed and FF.  A lot depends on whether I’m on a 900+ trip or less than 500 on how I’d fly so I wouldn’t have to land for fuel. As mentioned the acclaim yields a lot of realistic options. Mine always runs cool so CHT isn’t an issue. Today’s outside temperature was in the low 90’s and my CHTS were all around 300. Good luck with your new plane you mentioned you’ve got numerous settings from different Mooneys you’ll figure it out it took almost a year for me to get over my Bravo which IMO is the best.

[Troy Jordan]

Thank you very much for the advice!  Mike Bush would say to fly at 31 mp, 2200 rpm, and pull the mixture back until slight loss of power, and just be concerned with cht’s.  But I’m not sure about this particular engine. I basically have been flying the POH with a slightly leaner setting.   28-2350-15.2 seems to be ok, but maybe too conservative?

[JimMardis]

You shouldn’t lean above 30.5MP. Above 3000ft I pull it back to 30.5 and lean for the climb keeping it around 1450 for the climb. The CHTs are usually well below 375 or so. Then at cruise I’ve been using 29.5MP and 2350 RPM. Lean how you like. At 15k to 16k you will get around 205- 210 TAS.


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[LANCECASPER]

42 minutes ago, JimMardis said:

You shouldn’t lean above 30.5MP. Above 3000ft I pull it back to 30.5 and lean for the climb keeping it around 1450 for the climb. The CHTs are usually well below 375 or so. Then at cruise I’ve been using 29.5MP and 2350 RPM. Lean how you like. At 15k to 16k you will get around 205- 210 TAS.
 

In the 6 turbo-charged Mooneys I've owned I have never leaned in the climb. 

For the Acclaim, the POH shows three climb profiles: Cruise Climb, Best Rate and Best Angle. All three show to climb at FULL THROTTLE/FULL RICH

For the Bravo, the POH shows three climb profiles: Cruise Climb, Best Rate and Best Angle. All three show to climb at FULL THROTTLE/FULL RICH

For the M20K (Encore), the POH shows three climb profiles: Cruise Climb, Best Rate and Best Angle. All three show to climb at FULL THROTTLE/FULL RICH

Why not just go by the POH?

[JimMardis]

Well If you keep full power you are not supposed to. But if you pull it back to 30.5MP or less there shouldn’t be any problem doing so as long as temps are in proper range. Do you know of any harm that I am not aware of? I keep the TIT at 1450 or cooler and at 120KIAS the CHTs are below 375?


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[LANCECASPER]

18 minutes ago, JimMardis said:

Well If you keep full power you are not supposed to. But if you pull it back to 30.5MP or less there shouldn’t be any problem doing so as long as temps are in proper range. Do you know of any harm that I am not aware of? I keep the TIT at 1450 or cooler and at 120KIAS the CHTs are below 375?
 

???
The POH in all three climb profiles says full throttle and 2500 RPM.

 

Your engine is rated at full power. Climbing at Full Throttle Full Rich gets you to your cruise altitude sooner where you burn less fuel.

If you had a normally aspirated airplane prior I can see where you might be used to leaning in the climb, however even on the Ovation the POH says Full Rich in the Climb. 

[JimMardis]

I agree with everything you posted there. Not trying to blow this out of proportion. The POH doesn’t publish any reduced power climb power settings. That doesn’t mean that it is a limitation and you must always climb at full power. Folks may want to climb at reduced power for various reasons. All I am just pointing out is that the engine manufacturer and the POH says above 30.5 you have to be full rich. Below 30.5 you can lean. The POH also has a note right below those three published climb profiles that actually says “Leaning may be required during CLIMB depending on atmospheric conditions.

If I’m not heavily loaded and, not going far and I don’t want to run full power above 3000ft agl for whatever reason, there is nothing wrong, that I can think of, to reduce the power to 30.5” and lean to keep the TIT between 1350 to 1450.


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[LANCECASPER]

12 hours ago, JimMardis said:

I agree with everything you posted there. Not trying to blow this out of proportion. The POH doesn’t publish any reduced power climb power settings. That doesn’t mean that it is a limitation and you must always climb at full power. Folks may want to climb at reduced power for various reasons. All I am just pointing out is that the engine manufacturer and the POH says above 30.5 you have to be full rich. Below 30.5 you can lean. The POH also has a note right below those three published climb profiles that actually says “Leaning may be required during CLIMB depending on atmospheric conditions.

If I’m not heavily loaded and, not going far and I don’t want to run full power above 3000ft agl for whatever reason, there is nothing wrong, that I can think of, to reduce the power to 30.5” and lean to keep the TIT between 1350 to 1450.
 

Two points:

So yes the POH allows leaning in the climb  if you need it for the atmospheric conditions, but doesn't recommend it in the three climb profiles.

What I guess I don't understand is, if you don't need it for atmospheric conditions, what your reason would be for leaning in the climb. You're asking the airplane to climb but you're not giving it the recommended power or fuel to do so.

The reason for leaning in the climb can't be to save fuel. If a full power climb at 38 gph gets you to 15,000 in 15 minutes (38 * (15/60) = 9.5 gallons) and a reduced power climb at 30 gph takes 20 minutes to get you to 15,000 (35 * (20/60) = 10 gallons).  (1) you've burned a half gallon gallon more in the 2nd example but (2) even more importantly you've taken longer to get to a more efficient altitude for the airplane. Where this airplane shines is at altitude.

If your reason for leaning in the climb is that you want to be take it easy on the engine, that doesn't compute either. If you wanted to pull the RPM's back, although it's not part of any of the climb profiles in the POH, I could understand that, and that itself would adjust the fuel flow for that new RPM setting. But to then pull further back on fuel, which has been set up carefully to keep the engine happy during climb, does not make sense to me. The fuel flow settings assist in some cooling on the CHTs in the climb. Leaning in the climb is definitely not taking it easy on the engine. However, it seems like a really good way to burn up some exhaust valves. (You mention TIT in climb, but I've never seen that come into play during climb since the climb setting uses enough fuel to make it a non-issue. TIT comes into play when you reach cruise altitude and lean for cruise.)

If I'm missing something let me know. If the Flight Safety training that I took back in 1996 for the Bravo was wrong or the Mooney Factory Acclaim training was wrong or the MAPA Safety Foundation training was wrong I would like to know. Or if other owners with more experience have discovered something I haven't please let me know. 

[JimMardis]

The TIT comes into play when there is too much fuel due to atmospheric conditions. 1350 to 1450. So TITs below 1350 would be a reason to lean in the climb to keep the fuel air mixture in the proper range. Initially I was running things too cool and too rich and had some spark plug fouling. Another operator suggested to lean a little while taxiing before and after landing to help with not fouling the plugs and also suggested the reduced power climb for longevity and to give the ability to lean in the climb keeping in mind the other engine parameters. The drop off in performance was only about 200ft/min. Still able to climb over 1000ft/min. Most of my climbs were to 12,000 ft and below. I just make my first flight at 15,000 the other day come back to FL from KATL to try out this O2 canula thing. I’m used to pressurized aircraft. It wasn’t too uncomfortable. Might use it more often now.

I appreciate your input and effort you have put in to help bring me up to speed. I’m beginning to get the sense that Acclaim pilots enjoy the speed and power and live with the fact that their cylinders typically don’t make TBO, even if they have purchased a factory new engine. Unless they have a great mechanic that properly adjusts the valves. Read that in another post.

My engine has had all the cylinders replace around the 650 mark and 2 more replace since then. On the prebuy they replaced another one for compression, leaking at the valves. Both turbos got replaced at the 600hr mark by a service bulletin. So I guess I was a little predisposed on taking it easy on the motor. But I guess 32”MP and 2500 is taking it easy already on a motor that can run 38”MP and 2700Rpm in other configurations.


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[Schllc]

16 minutes ago, JimMardis said:

I’m beginning to get the sense that Acclaim pilots enjoy the speed and power and live with the fact that their cylinders typically don’t make TBO,

Completely disagree with this notion. 
In my humble opinion there were three things that caused all of these early cylinder failures.  One was the coking issue in the breather tube, which was addressed in two SB’s, the second and probably more important reason is people flying them trying to get 242kts.  
I have close to 1,800 hours behind io550’s and tsio550’s. More that 1200 in the tsio, and I have never replaced a cylinder or had valve work done.  I fly LOP exclusively which this engine really seems to tolerate well.  I also know most of the guys who bought my old planes, who fly them the same way I told them I did, and only one has had valve work on one cylinder with about 1800tt on the engine. 
I firmly believe most people just abuse the engines.  It may not be intentional, but it’s abuse.  If they did nothing but follow the POH, perhaps they were not aware they were abusing them, or they just resigned themselves to doing what they wanted and paying the premium. 
The third factor is lazy, or overzealous, or ignorant mechanics who just change parts until a problem is resolved, this is more prevalent than I ever thought it would be. 
I sold an acclaim ultra a few years ago and at the prebuy the mechanic wanted to change a cylinder because of low compression.  The engine had less than 400 hours and was two years old!  The buyer wanted a credit, and I acquiesced to get the deal done,  but he didn’t change the cylinder and it’s still flying on the same cylinder today. 

I prefer to keep my TIT between 1550 and 1580, I never lean in the climb, and I don’t notice much performance or noise difference at lower rpm’s so I usually fly between 2400 and 2500, and I only fly LOP.  If you want to wring that engine out and fly wide open throttle ROP everywhere, I think your assessment will ring true. If you listen to the guys here who have years of experience and be kind to your engine you won’t be swapping cylinders like underwear. 

[JimMardis]

I have a question regarding the coking issue. My breathing tube was not connected to the exhaust pipe. My mechanic noticed it and connected per a service builten. Did a later service bulletins take it off the exhaust? Or was that improper?


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[Schllc]

5 minutes ago, JimMardis said:

I have a question regarding the coking issue. My breathing tube was not connected to the exhaust pipe. My mechanic noticed it and connected per a service builten. Did a later service bulletins take it off the exhaust? Or was that improper?


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The second SB was a rerouting of the breather tube, which eliminates the periodic inspections. I’ll see if I can find the SB and post it. 

[LANCECASPER]

6 minutes ago, JimMardis said:

I have a question regarding the coking issue. My breathing tube was not connected to the exhaust pipe. My mechanic noticed it and connected per a service builten. Did a later service bulletins take it off the exhaust? Or was that improper?


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This is the first Service Bulletin: https://www.mooney.com/wp-content/uploads/2020/12/SBM20-312.pdf

If your tail pipe still has the connection for the tube the second SB (https://www.mooney.com/wp-content/uploads/2020/12/SBM20-319.pdf) hasn't been done. I'm of the opinion that if the tubes are kept clean (1st SB) then you are better off without the second SB since after it's done you'll have oil on the belly rather than burned by the exhaust. (I have not done the 2nd one and don't intend to, even though I have an exhaust pipe on the shelf for that SB in case I ever decide to do it.)

[JimMardis]

The second SB was a rerouting of the breather tube, which eliminates the periodic inspections. I’ll see if I can find the SB and post it. 

Oh shoot!!! So he put it back into a condition requiring inspections! That wasted some money.


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[JimMardis]

So whoever did the SB before didn’t patch the tailpipe but manufactured a makeshift plug for the exhaust nipple that the hose connected to. That’s what prompted him to think it was installed incorrectly. Which it was because the nipple was supposed to be removed and patched over. SMH


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[LANCECASPER]

That's why you want late-model Mooney specific mechanics working on this airplane.

[Schllc]

19 minutes ago, LANCECASPER said:

That's why you want late-model Mooney specific mechanics working on this airplane.

Brian Kendrick or the Mooney factory. 

[PeteMc]

On 6/23/2024 at 4:12 PM, JimMardis said:

You shouldn’t lean above 30.5MP. Above 3000ft I pull it back to 30.5 and lean for the climb keeping it around 1450 for the climb.

I don't know any of the engine gurus that say to reduce power or lean in the climb UNLESS there are cooling issues.  John Deakin pretty much proved that you want full power up to your intended altitude and then for a few minutes to accelerate to your cruise speed.  The increased climb speed actually decreased the wear on the engine by reducing the time to altitude.  

I guess I need to also say this is for the Turbo, which I think the discussion is about.  In a Non Turbo you should consider leaning A LITTLE to maintain climb power once you're in the higher altitudes.  But you need to really watch the temps.

Edited June 25 by PeteMc

[JimMardis]

https://www.avweb.com/features_old/operating-tips-for-big-bore-continentals/

I think this guru has something to say about leaning in climb. I’m just learning here and trying to take in as much information as I can. Discussion is good and makes us all better.

How does this article fit with the M20TN? Isn’t 30.5” and 2500rpm 75% power? It you run take off power for 2 to 3 mins and then reduce to 75% and you climb and cruise at 75% isn’t that less stress on the engine as long as temps are appropriate?

I know the manufacture has to have a published climb profile and power setting. That’s where you get your performance data from for planning purposes. But you don’t have to always climb at TO power. It’s not a limitation. As long as you are operating the engine within the limitations of the POH and Engine Manufacturer limitations why can you not make adjustments that may increase engine longevity and operational efficiency?

There are many occasions where the aircraft manufacturer and the engine manufacturer don’t see things in the same light. One is trying to meet performance goals against competing manufacturers while the other is trying to reach longevity goals or win a contract for the airframe. It’s hard sorting everything out. But all of this is a great learning experience and I am grateful for the discussion and various points of view.


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[exM20K]

2 hours ago, JimMardis said:

It you run take off power for 2 to 3 mins and then reduce to 75% and you climb and cruise at 75% isn’t that less stress on the engine as long as temps are appropriate?

I suppose you wouldn't hurt anything, but why do this as SOP?

When I'm lazy and TRACON is issuing step climbs in 1-2000' increments, I'll just pitch up at cruise power.  But the climb rate is really poor as compared to 33x2700.  I routinely climb all the way into the high teens at 12-1500 FPM at full power. Turning a 14 minute climb into a 30 minute one doesn't sound appealing to me, and I doubt there will be much (or any) fuel or time savings.

It's just not obvious to me that a full power climb is any more "stress" on the engine than a reduced power climb. 

-dan

[LANCECASPER]

2 hours ago, JimMardis said:

https://www.avweb.com/features_old/operating-tips-for-big-bore-continentals/

I think this guru has something to say about leaning in climb. I’m just learning here and trying to take in as much information as I can. Discussion is good and makes us all better.

How does this article fit with the M20TN? Isn’t 30.5” and 2500rpm 75% power? It you run take off power for 2 to 3 mins and then reduce to 75% and you climb and cruise at 75% isn’t that less stress on the engine as long as temps are appropriate?

I know the manufacture has to have a published climb profile and power setting. That’s where you get your performance data from for planning purposes. But you don’t have to always climb at TO power. It’s not a limitation. As long as you are operating the engine within the limitations of the POH and Engine Manufacturer limitations why can you not make adjustments that may increase engine longevity and operational efficiency?

There are many occasions where the aircraft manufacturer and the engine manufacturer don’t see things in the same light. One is trying to meet performance goals against competing manufacturers while the other is trying to reach longevity goals or win a contract for the airframe. It’s hard sorting everything out. But all of this is a great learning experience and I am grateful for the discussion and various points of view.
 

Jim, no doubt to fly the jets you do you take the annual training that allows you to be insured and keep flying them. They teach specific things to that airframe that you may not get anywhere else, especially if the airframe manufacturer has helped put together the training.

Lycoming used to come to the MAPA homecoming in Kerrville and taught classes on turbo engine management (M20M). They specifically said that leaning in the climb was not recommended.

The Flight Safety course on the Mooney Bravo specifically taught not to lean in the climb - that airplane was set up with fuel flow to cool properly at full power during climb. They gave several reasons why taking more time and cutting back on the fuel needed to cool the CHTs in climb were counterproductive to the goal of engine longevity.

The Mooney course taught by Bob Cabe on the Acclaim with the Continental engine taught the same.

The MAPA Safety Foundation taught the same. At MAPA they even asked for a show of hands on who leans a turbo-charged Mooney during the climb. A couple of guys raised their hands - new owners who didn't know any better, one of whom was a airline pilot. (The guy next to me in class who had attended many of these over the years said, "There's always one or two in every class that raise their hand.") The instructor went on to show why that was doing just the opposite of what they were trying to accomplish.

The people who cook cylinders on the Acclaim fall into the three categories that @Schllc mentioned yesterday, plus one more category that I can think of: the people who, no matter what anyone tells them, are going to go against what is taught by people who know best: (1) the people who designed and test flew the airplane and (2) the pilots in the field who have the most experience flying it

Lean during the climb to your heart's content if you'd like, it's your airplane and your engine. Feel free to go with a 27 year old article that mainly discussed normally aspirated engines. It never mentioned the TSIO-550-G engine that's in your Acclaim. General Aviation has had a lot of old wive's tales that have circulated for years that weren't based on data, but were based on mistakes repeated often enough that they became the "truth". I'm going to stick with what I've been taught in manufacture-endorsed classes over thirty years of flying Turbo Mooneys by the people who know. By the way I've never replaced a cylinder between overhauls on any of the six Turbo Mooneys I've owned. I think what I've been taught is working.