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Mooney 231 Slow Climbout


natdm
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23 hours ago, 1980Mooney said:

I don't fly a turbo but just looking at your flight history on long flights above 10,000 ft your plane seems slow for a K with waste gate and intercooler.  And is there a typo in your N number in your profile? - are you N226C? 

Do you fly LOP?  Are you sure your engine is making full power?

 

 

N226C is the tail, it's just not carried over the registration yet and might take a good while to, according to the FAA.

I've taken it to the local mechanic and he did notice the magnetos weren't timed right and fuel flow was low, he fixed those (just upped it more before the most recent flights).

 

I do typically try to fly LOP, at like a 75% power setting, 8gph or so. I was flying ROP on the last few trips, yesterday. Do these look better?
https://flightaware.com/live/flight/N226C/history/20220921/1902Z/KIWA/L 31.46883 -103.91790
https://flightaware.com/live/flight/N226C/history/20220921/2250Z

Cruising with 31" MP and 2300RPM.

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1 hour ago, natdm said:

N226C is the tail, it's just not carried over the registration yet and might take a good while to, according to the FAA.

I've taken it to the local mechanic and he did notice the magnetos weren't timed right and fuel flow was low, he fixed those (just upped it more before the most recent flights).

 

I do typically try to fly LOP, at like a 75% power setting, 8gph or so. I was flying ROP on the last few trips, yesterday. Do these look better?
https://flightaware.com/live/flight/N226C/history/20220921/1902Z/KIWA/L 31.46883 -103.91790
https://flightaware.com/live/flight/N226C/history/20220921/2250Z

Cruising with 31" MP and 2300RPM.

Cruising with 31" MP and 2300RPM. - the engine chart shows that would be about 155 HP or 70%.  Those speeds look better.   Was your fuel flow 11.0 - 11.5 gph (best economy)?

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If he was LOP with a fuel flow of 8 GPH he should using the 200 HP lycomings number of 14 hp per gph be making 112 HP, much less than 75%.

Now a turbo should be more efficient than a non turbo so it ought to do better than 14 HP per gl, but I have no idea. I’m not even sure of the 14 HP for NA.

Point is though that unless the charts specify LOP, the % power if run LOP will be lower than a ROP chart will indicate

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Nat,

Lets continue to get a closer look at what you have, and what you are doing…

Something sounds like we are missing something important…

 

the ability to accelerate and climb comes from excess horsepower…

Even the stock early M20Ks come with plenty of HP…

 

There are great book numbers to compare to…

Start with measuring T/O distance.  Then add climb rates…

Both will indicate if your ship is developing the excess HP you are expecting…

 

+1 for knowing what your VSI is actually measuring… does yours have the delay of ordinary VSIs, or do you have the IVSI?

Compare to the Flight aware data for GPS based data…

 

Of all the crummy aviation videos to watch… there is a horrific one where the M20K owner didn’t recognize his ship not developing full power… and proceeded to have a predictable disaster…. Let’s not repeat that…


Getting FF set up on the 231 is probably the most complex Mooney fuel system to get set up… but, the engine manuals and a mechanic should be able to get it set up properly…

Max FF is often compared to max HP…

300 hp typically uses 30gph…. 200hp typically uses 20gph…. Roughly speaking…

We have the intercooler guy around here for additional data… :)

 

For great data collection… there is an app for that… called CloudAhoy… combined with a WAAS source you can measure actual T/O distance and climb rates… with tremendous GPS accuracy… (not airspeed accuracy)

Let’s get the unknowns to be knowns….

 

PP thoughts only, not a mechanic…

Best regards,

-a-

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1 hour ago, A64Pilot said:

Now a turbo should be more efficient than a non turbo so it ought to do better than 14 HP per gl, but I have no idea. I’m not even sure of the 14 HP for NA.

The number for the TSIO-360 seems to be 13.7

 

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3 hours ago, 1980Mooney said:

Cruising with 31" MP and 2300RPM. - the engine chart shows that would be about 155 HP or 70%.  Those speeds look better.   Was your fuel flow 11.0 - 11.5 gph (best economy)?

I keep it a bit higher than that -- further ROP, but I could lower it. Still learning LOP and ROP, so if I do it, I try to stay at the far end of the scale. People say use TIT, vs the highest EGT, etc, I'm still not sure so I just keep fuel flow around 12.5-13gph. TIT is really low though. Am I fine to go far lower than that?

 

36 minutes ago, carusoam said:

Of all the crummy aviation videos to watch… there is a horrific one where the M20K owner didn’t recognize his ship not developing full power… and proceeded to have a predictable disaster…. Let’s not repeat that…

I *always* set an abort point, due to the discussed issue. If I'm not off by 50% of the runway, I abort. 

 

@carusoam I'll take a look at some of your suggestions when I can. Really good inputs. 

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@1980Mooney I've got gami's and the CHT's/EGT's are pretty consistent, from what I can tell. I've followed a few threads on LOP and ROP and how to best use both but there's so many varied opinions, not sure which one to follow (if I'm reading them right). If you have something you'd suggest I try that you think works best for my setup, let me know. 

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17 minutes ago, natdm said:

I keep it a bit higher than that -- further ROP, but I could lower it. Still learning LOP and ROP, so if I do it, I try to stay at the far end of the scale. People say use TIT, vs the highest EGT, etc, I'm still not sure so I just keep fuel flow around 12.5-13gph. TIT is really low though. Am I fine to go far lower than that?

 

I *always* set an abort point, due to the discussed issue. If I'm not off by 50% of the runway, I abort. 

 

@carusoam I'll take a look at some of your suggestions when I can. Really good inputs. 


Thank you for the extra effort…

The first year of ownership comes with a bunch of extra challenges…

The goal is to get past the first year… to start the second year challenges….  :)
 

The video referenced above was a short field T/O… where the abort point was lost to hope….

 

For interesting reading about M20K operations…. Find the writings of one @jlunseth…. He has written a few pages regarding LOP and his M20K… and some other interesting stories….  
 

M20Ks have great capabilities for LOP, M20Ms have limited LOP skills… OK for some, not so much for others….

TIT is the limiting factor…

EGTs are great for diagnosing a particular cylinder… or how well the fuel injectors are working….

 

TC’d planes watch the TIT because above a certain temp… the turbo vanes turn into turbo nubs….  And nobody likes turbo nubs…. :)
 

Leaning into LOP has some challenges… but, once you get to know your engine…. Some people use the big pull method of skipping through peak as quickly as practical… to get to the other side….  It helps to know where peak is first…
 

PP thoughts again….

Best regards,

-a-

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1 hour ago, natdm said:

@1980Mooney I've got gami's and the CHT's/EGT's are pretty consistent, from what I can tell. I've followed a few threads on LOP and ROP and how to best use both but there's so many varied opinions, not sure which one to follow (if I'm reading them right). If you have something you'd suggest I try that you think works best for my setup, let me know. 

Some history about the M20K 231 and 252.  You said you have an intercooler and wastegate modification so you are similar to a 252 (but not exactly the same induction and cooling and other aerodynamic tweeks)

Mooney 231/252 - Aviation Consumer

 

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1 hour ago, natdm said:

@1980Mooney I've got gami's and the CHT's/EGT's are pretty consistent, from what I can tell. I've followed a few threads on LOP and ROP and how to best use both but there's so many varied opinions, not sure which one to follow (if I'm reading them right). If you have something you'd suggest I try that you think works best for my setup, let me know. 

This guy is a real shop pro when it comes to Mooneys.  He has published some great articles. - look at his publication indext

For you:

200001 Operational tips for the M20K (knr-inc.com)

And your A&P:

199905 Adjusting the TSIO-360 (knr-inc.com)

Edited by 1980Mooney
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1 hour ago, natdm said:

@1980Mooney I've got gami's and the CHT's/EGT's are pretty consistent, from what I can tell. I've followed a few threads on LOP and ROP and how to best use both but there's so many varied opinions, not sure which one to follow (if I'm reading them right). If you have something you'd suggest I try that you think works best for my setup, let me know. 

As @carusoam highlighed jlunseth has the same set-up as you (Merlyn and Intercooler) - his advice (and also on page 2):

 

Edited by 1980Mooney
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1 hour ago, natdm said:

@1980Mooney I've got gami's and the CHT's/EGT's are pretty consistent, from what I can tell. I've followed a few threads on LOP and ROP and how to best use both but there's so many varied opinions, not sure which one to follow (if I'm reading them right). If you have something you'd suggest I try that you think works best for my setup, let me know. 

Here is MooneyFlyer's (June 2020) advice on running LOP in a 231.  See page 34.  It is in response to the question from a 231 owner with Merlyn, Intercooler and GAMI injectores just like you.  The article is by Brian Lloyd who flew an M20K around the world.

Present Position (themooneyflyer.com)

“In the last Mooney Flyer issue I read about Brian Lloyd flying around the world in a M20K. In his article he mentions that most of the time he flies LOP (Lean of Peak). “I also have a M20K for over 15 years also with intercooler, Merlin wastegate and Gami injectors -however I always fly it ROP because I hear so many stories about damaging the engine when flying LOP. Therefore, I would like to talk or write to somebody who really has the experience – like Brian –about him flying LOP on the TSIO 360 - and his experience, and which power settings, temperatures he is using.”

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12 hours ago, natdm said:

@1980Mooney I've got gami's and the CHT's/EGT's are pretty consistent, from what I can tell. I've followed a few threads on LOP and ROP and how to best use both but there's so many varied opinions, not sure which one to follow (if I'm reading them right). If you have something you'd suggest I try that you think works best for my setup, let me know. 

To REALLY learn about running LOP, take the APS seminar.  That is from the horse's mouth on LOP operation.

Much of what you read posted is 3rd and 4th hand.   And like anything, the more people it passes through, the more garbled it gets.

https://www.advancedpilot.com/

 

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On 9/20/2022 at 11:22 AM, natdm said:

I've got a Mooney 231 with wastegate/intercooler and am struggling with climb-out. On take-off, I've got MP at 36" (indicated, not adjusted for power settings), full rich, prop forward, trim in the middle, and flaps set for take-off. FF indicates about 22.5-22.9. I've been told that's low, but my mechanic has repeatedly stated it's not low and I might need to be going higher than 36" with power corrections.

I'm in AZ, and the heat is around 85-100f when I fly, depending on time of day. On rotate, it takes a significant amount of time to reach a good climb-out at vy. I'll maintain vy, but be damn near in ground-effect until the end of a 3000ft runway MAYBE maintaining a 200fpm climb. Eventually, the plane tends to shoot up pretty quickly, around 800-1000fpm. 

Load is not the issue. With full tanks and two adults around 180lb, plenty of load left. 

Is this just a characteristic of the plane? If I up the MP to higher than 36-37", it tends to do a little better, but I'm always terrified of running it too rough.

 

My thoughts. From a power standpoint rather than a temperature standpoint the fuel flow is not a concern in your scenario. Since you are rich of peak already, adding more fuel flow is not going to significantly increase power output, because ROP you already are using more fuel than can be burned in the combustion cycle. The POH required fuel flow is 22.5-24.0 and you are in that range. What extra fuel flow will do for you in AZ while ROP is keep your CHT's down and that's it. Increasing MP is what will increase power while ROP. In the 231 there is an interlink between MP and fuel flow, so if you increase MP the fuel flow will increase, the engine tries to maintain a steady air/fuel ratio.

If you look at the STC for the turboplus, there is a chart for determining what MP the mechanic should use for a given OAT when setting the max fuel flow. Generally speaking, it is around 37" and varies by some tenths of an inch with OAT. The 36" max that people tend to use for the intercooled 231 (including me) appears to come from an article in an old Mooney magazine that basically said, if you have the intercooler, use the power settings for the 252. The max power setting for the 252 is 36". In reality, based on the STC, it is 37" for the intercooled 231. There should be no harm in increasing takeoff MP to 37, and that will increase your power somewhat and will allow the fuel flow to go up somewhat. That said, I will generally pull the power back to around 36" once I am off the ground and in the climb.

Another thing to consider is that the better the intercooler is operating the denser will be the intake air, and the more power the engine will make. So in theory, the intercooler is not having much of an effect when you put in takeoff power at the takeoff end of the runway and let go of the brakes. There just is not much air flow over the intercooler and not much cooling effect. It quickly picks up efficiency as you roll down the runway. There will also be a ram air effect, so if you put in 36" at the takeoff end of the runway you are going to see the MP increase from that effect further down the runway. I am not suggesting that you try to vary your MP from, say, 37 or 38 at the takeoff end to, say, 36 at liftoff. There is just too much going on, so best to just set it around 36-37, reduce it a little if it starts going over 37, and otherwise leave it alone. The engine has plenty of power and my plane does not seem to care if takeoff is at 35 or at 37 on the vast majority of runways.

I don't think fuel flow is your issue at all. If you were concerned about high CHT's fuel flow would be the place to look, but you are well ROP and fuel flow is not going to significantly change power. I am wondering what airport you are having this problem at. KIWA, your home base, is not that high, although it certainly can be hot. But it does not have a 3,000 foot runway either. I am wondering if these longer takeoffs are perhaps at a higher altitude airport than KIWA. Your turbocharger will allow you to make full power even up at Leadville (which is just shy of 10,000), but that does not change the fact that the density altitude is quite high there and it will require a higher airspeed for the wing to generate the same lift that it does at sea level.  Most of the high altitude airports out west are significantly longer than what we would see here in the midwest for exactly that reason.

Also, I am wondering when you raise your gear. It should come up when you have a positive rate of climb, and the flaps shortly after. You will have a little nose down movement when the flaps retract so guard against that. Once gear and flaps are up the aircraft will accelerate quickly, in fact it already has been for awhile.

Here is what I do, any airport any season, if it helps. My takeoff is full rich. I start the roll with the MP roughly 50 % in (I do it by feel and don't really look), and after a short while I adjust it to somewhere between 36 and 37. If it goes slightly over 37 I don't worry about it too much. If it gets near 38 I will pull off just a little power. Rotation is 61 KIAS but I am never in a hurry, I let the plane tell me when it is ready to fly. I raise the gear when I have a positive rate on the ASI, and then the flaps. I pitch for 85 KIAS to 1000 feet above the runway. That is neither Vx nor Vy. There is some good research that Vx is too nose high and you will be in jeopardy if you have an engine failure so save Vx for when it is really needed. Vy takes too much distance so by the time you reach the altitude where you could turn back in the event of engine failure (around 1,000) you are too far away to make the airport to make it back. A speed around best glide (my 85 KIAS) is the best middle ground. The plane will be doing quite a bit of accelerating during this climb to 1,000, ram air plus increasing intercooler efficiency. You may need to monitor MP to keep it at or under 37. Somewhere after 1,000 AGL I will then slow the climb rate. I aim for about 120 KIAS true airspeed for the climb to altitude, which continues to be at 36" and full fuel flow, cowl flaps open. That can be all the way to the flight levels. 

Works for me. Then I go LOP for cruise, but that is another story. The engine is at about 400 hours over tbo right now so this does not seem to harm the engine.

3,000 feet seems to me to be a little short for high, hot, out-west operations. Haven't done any calculations, but that seems to me the equivalent of about 2,400 here in the midwest, which is approaching my lower limit unless I am really really in practice with my short field techniques, and I just don't do short field that much. What you are experiencing does not seem that unusual to me if that runway is a high altitude one.

For the other posters, the OP's comment "(indicated, not adjusted for power settings)" just means that he has not run his MP and RPM settings through the Turboplus chart to see what they are equivalent to in an engine without the intercooler. No need to do that for takeoff settings, too much messing around, and in any event during takeoff the effect of the intercooler is constantly changing (increasing).

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On 9/22/2022 at 6:56 PM, Pinecone said:

The number for the TSIO-360 seems to be 13.7

 

That would be about what I would expect, just a little better than the non turbo Lycoming.

So 13.7 is 110 roughly, or 52% power roughly, which would make his cruise speed about right?

I don’t think anything is wrong with this airplane, it’s climbing at over 1000 FPM 400 feet after takeoff, sound prett good to me, 

 

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13.7 is the multiplier to determine output in HP in the TSIO360. %power=fuel flow x 13.7/total rated hp (210 hp)

I use a LOP power setting for cruise most of the time. I don’t like losing speed just to run LOP. You can make a mixture leaner or richer one of two ways, by reducing fuel flow for a given MP which is what most people do, or adding more air for a given fuel flow, which is what I do. I run at 34” MP and a fuel flow of around 11.1 GPH, which works out to about 71% power. I monitor the TIT. If it starts to climb over 1600 I reduce the fuel flow to keep it at or under 1600. The MP and fuel flow controls in the 231, or at least in my aircraft, and not perfectly precise, so these settings have to be monitored and minor adjustments made from time to time. The POH says it is ok to run the turbo hotter than 1600, but I just don’t like to do it. The CHT’s will be quite nice. I have hundreds of hours at this setting. As I mentioned the engine is about 400 hours over tbo and the turbo has over 1600 hours since it was last overhauled. At some altitude between 12 and 16k I won’t be able to keep this going without excessive TIT, it just depends on the day temp. So I will convert to ROP above that point.

The “reduce fuel flow at a given MP” method is what many do because it is an NA technique. Typical NA LOP ops would be to leave the throttle wide open and control power by reducing fuel flow. However, the MP of an NA in that mode is fixed at ambient pressure, or maybe a little more if you have a ram air effect going on, but it is going to be capped at a given altitude. In the turbo we have the luxury of being able to add more air and to run well over ambient pressure, so why not use that to add air to make the mixture leaner? 

Edited by jlunseth
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@jlunseth you gave some good insights. I’m flying tomorrow for a bit then headed to KFKA on Wednesday (maybe Tuesday) so I’ll have some time to try what you said. 
 

my gear is up pretty quickly, at the first sign of positive VS. Flaps are up at 500agl. 
 

I do take off at 36” or a bit lower if it goes too far, and I end up pulling back. It’ll drop to 34” or so at times. 
 

I do fly out at vy, so I’ll try your procedure and see what happens there. You’re a huge help. 

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10 minutes ago, natdm said:

my gear is up pretty quickly, at the first sign of positive VS. Flaps are up at 500agl. 

Flaps shorten the ground roll only.  If you have the runway available you are going to do better leaving them up.  Certainly if you are staying in the white arc for 500’ it is no surprise you have anemic performance.   
 
I would also still get your FF looked at. 

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I use the T/O setting for flaps every time, but I get gear at pos rate and immediately get flaps, while holding the trim switch nose down.

Yes if you have the runway it’s best to not use flaps, but I prefer to use them and get off the runway quicker as I fly off of grass and over time grass isn’t good for a prop I don’t think, plus being on the ground there is some rolling resistance and it’s greater on grass so getting airborne you lose that rolling resistance plus the aerodynamic drag of the gear, so I think it sort of washes out.

 

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Interesting. I guess I never had a reason to hold flaps that long other than being a bit worried about affecting aerodynamics so close to the ground after all the “oh I forgot flaps” deaths in touch and go’s. So the little flaps I have, just put them up when I have positive rate of climb? Right after, or same time as, gear?..

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1 hour ago, M20F said:

Flaps shorten the ground roll only.  If you have the runway available you are going to do better leaving them up.  Certainly if you are staying in the white arc for 500’ it is no surprise you have anemic performance.   
 
I would also still get your FF looked at. 

???? M20K Vy of 96kIAS is in the white arc.

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7 minutes ago, natdm said:

Interesting. I guess I never had a reason to hold flaps that long other than being a bit worried about affecting aerodynamics so close to the ground after all the “oh I forgot flaps” deaths in touch and go’s. So the little flaps I have, just put them up when I have positive rate of climb? Right after, or same time as, gear?..

I’m not aware of any accidents on go around attributed to not having flaps down on a small single engine airplane, of course large Commercial Jets must have flaps and slats down and some have died from not doing so, or retracting them early, but that’s not us. We climb better as in faster with zero flaps

You can leave TO flaps down as long as you want to, but they will reduce climb a little, everything with airplanes comes with a negative, flaps increase lift of course, but they also increase drag so they adversely effect climb some, not a whole lot, just some. It’s not a huge difference, but it is there.

Me personally I get rid of the flaps just after the gear, you can’t do both simultaneously of course, now if I was on a really short field or had had a tree line to cross, I’d probably leave them down, depending on airspeed you may feel the airplane settle a little when you first bring up the flaps, because without them you need a little more speed to climb, so while you will climb better with them up, it’s at a slightly higher airspeed.

Don't pull the aircraft off prematurely which I think you may be doing, hold the nose just a little light, she will fly when she’s ready, don’t pull a lot as she will wallow as she’s pulled off before she’s ready to fly, that’s soft field technique

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