Full Power Climb M20K 231 '84 with Marlin

[gabez]

Hello, 

I did some research last night and trying to get some more guidance around full power climb. When I had by V tail the manual asked for reduce power during climb but everyone said to go full power (which indeed kept the engine cooler)

I read through this forum that the message is the same, basically in the 80s they had a different idea round engine management and as long as the CHT are below 400-380 full power climb is okay. 

My question is that on the Marlin supplement I think it says Full power only for 5 minutes. Any suggestions and/or thoughts? I usually take off 40' and 2700 and then back it to 33' 2600. 

 

Thank you

[LANCECASPER]

3 hours ago, gabez said:

Hello, 

I did some research last night and trying to get some more guidance around full power climb. When I had by V tail the manual asked for reduce power during climb but everyone said to go full power (which indeed kept the engine cooler)

I read through this forum that the message is the same, basically in the 80s they had a different idea round engine management and as long as the CHT are below 400-380 full power climb is okay. 

My question is that on the Marlin supplement I think it says Full power only for 5 minutes. Any suggestions and/or thoughts? I usually take off 40' and 2700 and then back it to 33' 2600. 

 

Thank you

Are you referring to the Merlyn Black Magic Automatic Wastegate Controller?    https://www.merlynproducts.com/blackmagicmots.html

[gabez]

4 minutes ago, LANCECASPER said:

Are you referring to the Merlyn Black Magic Automatic Wastegate Controller?    https://www.merlynproducts.com/blackmagicmots.html

yes.

[LANCECASPER]

4 hours ago, gabez said:

My question is that on the Marlin supplement I think it says Full power only for 5 minutes. Any suggestions and/or thoughts? I usually take off 40' and 2700 and then back it to 33' 2600. 

First thing I would do is make sure it says that.

If it does say that, which I doubt that it does, the only reason I can think of would be Cylinder Head Temperature since the TSIO-360-GB (and LB) engines run hot. 

Here's one example of an owner's checklist where they pull back to 35/2500 at 500'. (Not sure why they wait that long to retract flaps or if they have a Merlyn controller)     http://dezkk.de/CHECKLIST_V2.pdf

[kortopates]

It says no such thing. The engine is rated for continuous full HP. Full power climb is cooler for the engine but be sure to pitch for Vy+10-20 kts. if the fuel flow is set up properly it will climb cooler that way all the way to the flight levels.

you may have been thinking of the TSIO-520 with 5 min limit at full power.

Sent from my iPhone using Tapatalk

[gabez]

1 hour ago, LANCECASPER said:

First thing I would do is make sure it says that.

If it does say that, which I doubt that it does, the only reason I can think of would be Cylinder Head Temperature since the TSIO-360-GB (and LB) engines run hot. 

Here's one example of an owner's checklist where they pull back to 35/2500 at 500'. (Not sure why they wait that long to retract flaps or if they have a Merlyn controller)     http://dezkk.de/CHECKLIST_V2.pdf

I'll check tonight but I do remember seeing full power continue rated for 5M but again I will double check.

Why does this checklist says 39' instead of 40'? 

[LANCECASPER]

25 minutes ago, gabez said:

I'll check tonight but I do remember seeing full power continue rated for 5M but again I will double check.

Why does this checklist says 39' instead of 40'? 

Again it's an example of an owner's checklist found on the internet, not the POH.

[Crawfish]

Also have a 231, no Merlyn though. Full power climb and pitch for 115-120IAS cowl flaps full open. 
 

Keeps temps cooler than pulling the power back. 

[gabez]

1 minute ago, Crawfish said:

Also have a 231, no Merlyn though. Full power climb and pitch for 115-120IAS cowl flaps full open. 
 

Keeps temps cooler than pulling the power back. 

thank you sir. 

[PeteMc]

6 hours ago, gabez said:

I read through this forum that the message is the same, basically in the 80s they had a different idea round engine management and as long as the CHT are below 400-380 full power climb is okay. 

My question is that on the Marlin supplement I think it says Full power only for 5 minutes. Any suggestions and/or thoughts? I usually take off 40' and 2700 and then back it to 33' 2600. 

I also have a 231 with the Merlyn, no such limitation of full power. 

As for climbing with full power or pulling back to "square" which I learned in a non Merlyn Arrow years ago (24/2400 I think) was just "the thing to do" and so that's what everyone was taught.  Then I guess it was prob. back in the 80s on AVSIG, John Deakin, George Braly and others got into the discussion of time in the climb and was it better to pull back to "square" or go full throttle until altitude.  I remember John coming back after some test flights saying he had (obviously) better performance at full power, but that yielded not only getting to Alt quicker, but he did not really burn any more fuel based on the climb time being shorter.  Again, just a climb, not a full flight at full throttle and this may have been based on what he was flying and what he normally climbed at, but his new practice was to climb wide open. 

Another comment John had that stuck with me (possibly a different discussion) was that most people are taught to pull the power back as soon as you level off and start trimming the plane.   And we all know you have to keep trimming for a while.   He was the first one to comment on keeping the climb power in for a couple of minutes until the plane reached whatever your normal cruise speed was, then reduce to your cruise power and trim.  Much less chasing the trim as the plane slooowwwlly sped up.

(But I digress, so I'll keep quite now. )

 

[jrwilson]

12 hours ago, gabez said:

Hello, 

I did some research last night and trying to get some more guidance around full power climb. When I had by V tail the manual asked for reduce power during climb but everyone said to go full power (which indeed kept the engine cooler)

I read through this forum that the message is the same, basically in the 80s they had a different idea round engine management and as long as the CHT are below 400-380 full power climb is okay. 

My question is that on the Marlin supplement I think it says Full power only for 5 minutes. Any suggestions and/or thoughts? I usually take off 40' and 2700 and then back it to 33' 2600. 

 

Thank you

Do you have an intercooler?  If so, you should dial that take-off MP down a bit.  If no intercooler, disregard.  

[gabez]

okay so there is a restriction as per the pic attached. it is on the RPM, does anybody do this or just keep it at 2700? 

Edited January 3, 2024 by gabez

[milotron]

That is for the -KB variant used in Seneca 3 and 4. I don't think these were ever used in Mooneys.

[gabez]

4 minutes ago, milotron said:

That is for the -KB variant used in Seneca 3 and 4. I don't think these were ever used in Mooneys.

Shut, you are right. well can't wait to go fly next so I can enjoy my 1000 FPM all the way up 

[milotron]

That extra 200 rpm netted another 20HP. I'd rather get it like the -SB with a bit more boost. 2800rpm must be screaming!

Edited January 3, 2024 by milotron

[PeteMc]

3 hours ago, gabez said:

okay so there is a restriction as per the pic attached. it is on the RPM, does anybody do this or just keep it at 2700? 

Something seems off with that STC.  N57227, S/N 25-0794 does come back to a M20K.  But I didn't think any of the Mooneys had a TSIO-360-KB engine.  Aren't those only in the Senecas?

[Z W]

231 with a TSIO-360-MB here.  Full power climb, 2700 RPM and 36" MP, at 120+ KIAS leads to lower CHTs, lower TIT, quicker climb to altitude, less fuel burned overall, and shorter trip time overall compared to "cruise climb" which is in the POH and was formerly taught to be 2500 RPM and 32" MP. 

I no longer use "cruise climb" settings on initial climb out.  I will use it if I need to go up 3-4 thousand feet in cruise for some reason just to avoid major configuration changes.

In noise sensitive areas, decreasing RPM to 2500 supposedly reduces 90% or more of the noise your plane is putting out, so there's one reason to pull it back shortly after takeoff.

I've also heard it said that RPM = wear, and so running lower RPM in the climb is better for your engine.  That makes some sense to me.  But, in my particular plane, I do not believe the decrease in revolutions is enough to offset the increased temperatures and additional minutes added to the trip that result from reducing RPM for the climb.

[gabez]

5 hours ago, PeteMc said:

Something seems off with that STC.  N57227, S/N 25-0794 does come back to a M20K.  But I didn't think any of the Mooneys had a TSIO-360-KB engine.  Aren't those only in the Senecas?

there is another page in the STC did I didn't post that has the Mooney part of it. The second page I learned is for the piper(s)

[gabez]

1 hour ago, Z W said:

231 with a TSIO-360-MB here.  Full power climb, 2700 RPM and 36" MP, at 120+ KIAS leads to lower CHTs, lower TIT, quicker climb to altitude, less fuel burned overall, and shorter trip time overall compared to "cruise climb" which is in the POH and was formerly taught to be 2500 RPM and 32" MP. 

I no longer use "cruise climb" settings on initial climb out.  I will use it if I need to go up 3-4 thousand feet in cruise for some reason just to avoid major configuration changes.

In noise sensitive areas, decreasing RPM to 2500 supposedly reduces 90% or more of the noise your plane is putting out, so there's one reason to pull it back shortly after takeoff.

I've also heard it said that RPM = wear, and so running lower RPM in the climb is better for your engine.  That makes some sense to me.  But, in my particular plane, I do not believe the decrease in revolutions is enough to offset the increased temperatures and additional minutes added to the trip that result from reducing RPM for the climb.

wouldn't full power be 40' 2700? 

Edited January 3, 2024 by gabez

[A64Pilot]

9 hours ago, milotron said:

That extra 200 rpm netted another 20HP. I'd rather get it like the -SB with a bit more boost. 2800rpm must be screaming!

The IO-520 non turbo in a Cessna 210 turned 2850 from memory and made 300 HP doing so, but had a 5 min limit, at 5 min you had to reduce RPM I think maybe to 2700? Anyway to 285 HP.

I was told by a Continental rep it was due to engine temps, not necessarily cyl head temps, but the engine core I guess you would call it. I reduced RPM anyway right after gear and flaps up anyway as it was noisy if you didn’t, by noisy I mean to people on the ground, I didn’t want to be that noisy airplane.

I can remember pilots arguing reduced power climb at the airport in 1968 when I flew with my Father, it’s been argued forever and will continue I’m sure.

Even the P&W R-1340 should be operated full power in climb, it’s carburetor as many do has an “ecenomizer” which means at reduced power it leans out significantly even with the mixture set full rich, so it will run hotter at reduced power due to the leaner mixture, and that’s a 99 yr old engine design.

Best thing I think is to follow the POH, what’s true in one aircraft may not be with another, even if they have the identical engines. The POH should reflect that engine in that aircraft.

The older V tails in particular had cooling problems, with STC’s to address that and some Bo drivers will go to high boost for extra rich to keep temps down.

[Z W]

1 hour ago, gabez said:

wouldn't full power be 40' 2700? 

The different TSIO-360 models in Mooneys have different max RPM and MP limits.

Mine is a TSIO-360-MB, used in most 252's, and so it's 36" and 2700.

I believe most TSIO-360-LB and TSIO-360-GB engines used in 231 models used 2700 and 40", maybe modified to 38 or 36" with the installation of an intercooler.  I don't fly those so am not as familiar but there will probably be a more knowledgeable person along shortly.  My plane came from the factory with one of these, but got an MB engine via STC.

The latest K models, the 252 Encores, got a TSIO-360-SB that uses 39" MP and 2600 RPM to produce 10 more horsepower.  Some earlier 252's were converted to this engine via STC.

It would be wise to consult the POH for the plane you're flying, and any supplements associated with intercooler or wastegate STC's, to verify your maximum rated power settings.  I do not believe I've ever seen any limitations on duration for max power in a K model Mooney.

[Pinecone]

6 minutes ago, Z W said:

The different TSIO-360 models in Mooneys have different max RPM and MP limits.

Mine is a TSIO-360-MB, used in most 252's, and so it's 36" and 2700.

The latest K models, the 252 Encores, got a TSIO-360-SB that uses 39" MP and 2600 RPM to produce 10 more horsepower.  Some earlier 252's were converted to this engine via STC.

The Encore is not a 252.  It is an M20K Encore.   Some people refer to their airplane as a 252/Encore to denote it was built as a 252, but converted to Encore (more than just the engine).  This is how I refer to mine.

The TSIO-360-SB is 39 inches, 2700 RPM, and makes 220 HP, as you said.  The only difference between the -MB and the -SB are the waste gate and prop governor for the new limits.  You can covert a 252 to a -SB without removing the engine from the plane.

The TSIO-360-MB in a 252 is converted to an -SB, not by STC, but by a shop drawing, as both the 252 and Encore are M20K are the "same" airplane by type certificate.

The 231 to -MB is an STC.  And no, you cannot convert a 231 with a -MB to an Encore the same was as you can with a 252.

To convert a 252 to an Encore also includes going to the dual puck brakes from a long body (requires some new gear doors) and replacing all the balance weights.  The big gain is a 230-pound increase in max gross weight.

[LANCECASPER]

The Encore is not a 252.  It is an M20K Encore.   Some people refer to their airplane as a 252/Encore to denote it was built as a 252, but converted to Encore (more than just the engine).  This is how I refer to mine.

Not to split hairs, but the first 12 Encores back in 1997 actually were certified as 252s since Mooney still held that Type Certificate and could manufacture that airplane without any additional certification from the FAA. Then once the Encore was certified they came back to the factory and were converted to Encores. (I believe serial numbers 13-36 left the factory as Encores)
The one I owned (serial #12) got its Airworthiness Certificate on 10/23/1997 and then was converted to an Encore on 11/10/1997. Here are the logbook entries :
 
 













Here’s an excerpt from a June 1997 article in Flying by Richard Collins (https://books.google.com/books?id=0iNHz-kt9n0C&printsec=frontcover#v=onepage&q&f=false) :

[gabez]

thanks for the info....I have a 231 with an encore interior 

[kortopates]

13 hours ago, gabez said:

okay so there is a restriction as per the pic attached. it is on the RPM, does anybody do this or just keep it at 2700? 

I am pretty sure everyone flying a -KB follows this, but you're flying a -GB or -LB.