Sluggish climb

[philiplane]

1 hour ago, Ragsf15e said:

I’m a terrible mechanic, so humor my question since I don’t understand the intricacies of the governor, prop stops, tach, etc.... if you run it up to full power on the ground with a constant speed prop, you should see max rpm, right?  If power output was low, doesn’t the governor just lower the pitch to get to it’s max rpm setting anyway?  Or is that where the minimum pitch stops come in?

A properly adjusted governor will keep the engine at 40-50 RPM below the max RPM during a full power run up. The engine will reach max RPM on the takeoff roll above 40 knots. 

[PT20J]

2 hours ago, Ragsf15e said:

I’m a terrible mechanic, so humor my question since I don’t understand the intricacies of the governor, prop stops, tach, etc.... if you run it up to full power on the ground with a constant speed prop, you should see max rpm, right?  If power output was low, doesn’t the governor just lower the pitch to get to it’s max rpm setting anyway?  Or is that where the minimum pitch stops come in?

It's the low pitch stops. Here's a description from mcCauley...

General Calibration Procedures Following Installation of McCauley Constant Speed Governors.docx

[Ragsf15e]

 

It's the low pitch stops. Here's a description from mcCauley...

General Calibration Procedures Following Installation of McCauley Constant Speed Governors.docx 18.98 kB · 3 downloads

Thanks, that makes sense.

Seems like the OP could just do the full power static run and quickly determine whether or not the engine was developing rated power or not then?

[WaynePierce]

ukrsindicate, you have mentioned fuel mixture a couple of times, and that may be part of the issue. Mooney's don't do well, in my reading and experience, at full rich. Play with it and see where the leanest to taxi is, enrichen a tad and taxi out with that setting then enrichen a bit when you do the runup and definitely have it richer for takeoff but still probably not full rich. My J likes to be out almost an inch.

I, too, think you have more going on though. 2,000 foot takeoff roll and I'd be aborting the takeoff.

 

I too am just a private pilot with only a year Mooney experience so I don't know what I don't know.

[Bob - S50]

1 hour ago, Ragsf15e said:

Thanks, that makes sense.

Seems like the OP could just do the full power static run and quickly determine whether or not the engine was developing rated power or not then?

I would think that just because an engine with a constant speed prop makes 2700 RPM, it doesn't mean it's making 200 HP.

[PT20J]

1 hour ago, Bob - S50 said:

I would think that just because an engine with a constant speed prop makes 2700 RPM, it doesn't mean it's making 200 HP.

The low pitch stop sets the blade angle to absorb rated power at nearly red line rpm. It’s a fixed pitch prop until it gets some airspeed and the governor kicks in to prevent overspeed. 

Skip

[PT20J]

1 hour ago, WaynePierce said:

ukrsindicate, you have mentioned fuel mixture a couple of times, and that may be part of the issue. Mooney's don't do well, in my reading and experience, at full rich. Play with it and see where the leanest to taxi is, enrichen a tad and taxi out with that setting then enrichen a bit when you do the runup and definitely have it richer for takeoff but still probably not full rich. My J likes to be out almost an inch.

I, too, think you have more going on though. 2,000 foot takeoff roll and I'd be aborting the takeoff.

 

I too am just a private pilot with only a year Mooney experience so I don't know what I don't know.

Definitely a good idea to ground lean as higher combustion temps prevent lead fouling plugs and lead deposits on valve stems.

Not sure why you would need to lean for takeoff at low density altitudes. Does it run rough at full rich? What’s your takeoff fuel flow? Most people report between 17 and 18 gph. The IO-360 is pretty tough, but leaning at high power increases CHTs and reduces detonation margin. 
 

Skip

[Marauder]

Hello, esteemed board. I looked around, but couldn't seem to find the answer.
Today,  my CFI and I finally flew my new(to me) 1967 M20F on its maiden flight and it felt good.   However, we did noted that the climb rate was fairly sluggish. My CFI noted that the engine was giving up some vibration.
My IA said that it is possible that we have fouled spark plugs, we will take a look tomorrow. It's possible that we ran the engine too rich on the ground and in the air for a little too long.
What is the usual rate of climb do you usually get? It seems that my POH suggest that I should be around 1100 and 1300 feet per minute.

I realize you have limited experience in the plane and no engine monitor. I think you should probably try to repeat your flights taking careful note of airspeed and what vertical speed you are obtaining. These planes are pretty predictable and if something is different, something is going on (hence where an engine analyzer can help).

As a long time owner of an F model (working on year 30), you get to know what sounds and feels right and more importantly what performance you should be getting. You will also learn that sometimes Mother Nature will lay waste to your optimistic plans. Last night I went out on a flight and decided to climb up to 9,500. The OAT was in the low 80s and I normally expect 800 FPM at 115 KIAS. As with any NA engine, your performance drops off with altitude. Past 7,500 (density altitude), I expected to see 700 FPM at 105 KIAS. This is where Momma Nature came out to play. Instead of getting 700 FPM, I would periodically see my vertical speed drop below 400 FPM. When I feel these, it’s clearly an atmospheric phenomenon I am dealing with and not an engine issue.



Now for a twist to the story. Last year I was on a trip to upstate New York. On my return flight, it was a hot day (upper 80s) and I noticed on my climb out that I was not getting the 800 FPM at 115 KIAS I always would get. I was seeing 800 FPM at 100 KIAS that pretty quickly eroded to 500 FPM at 90 KIAS approaching my assigned altitude of 9000’.

The weird part everything looked fine on the JPI. Oil temp, oil pressure, fuel flow, CHT, EGT all were within a few degrees of what I would expect. Once I leveled, it seemed longer to reach my normal TAS for 9000’ but I did achieve it. My first denial thought was that I had climbed through a major area of downdrafts. Yeah right.

After this trip, my next trip was over to the MSC for her annual. Again, slightly anemic climb but without any obvious signs.

A few days later comes the call. “We found your #1 cylinder was at 50 on the compression test and no matter what we did, it isn’t getting any better”. It was leaking past the valve and rings. New cylinder and she is back to her old speeds.

Let us know what you find.


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[EricJ]

1 hour ago, Bob - S50 said:

I would think that just because an engine with a constant speed prop makes 2700 RPM, it doesn't mean it's making 200 HP.

Static runup is the standard basic test for making power.   If the low pitch stop is set correctly (which it will be unlikely that it's not), it will prevent the engine from turning above redline on takeoff at rated power.   Basically, if the engine can get it to redline or within 50 rpm or so static and on takeoff roll, it's making sufficient power.

[Bob - S50]

2 hours ago, PT20J said:

Definitely a good idea to ground lean as higher combustion temps prevent lead fouling plugs and lead deposits on valve stems.

Not sure why you would need to lean for takeoff at low density altitudes. Does it run rough at full rich? What’s your takeoff fuel flow? Most people report between 17 and 18 gph. The IO-360 is pretty tough, but leaning at high power increases CHTs and reduces detonation margin. 
 

Skip

 

2 hours ago, EricJ said:

Static runup is the standard basic test for making power.   If the low pitch stop is set correctly (which it will be unlikely that it's not), it will prevent the engine from turning above redline on takeoff at rated power.   Basically, if the engine can get it to redline or within 50 rpm or so static and on takeoff roll, it's making sufficient power.

I understand that the pitch changes to prevent overspeed. But are both of you telling me I cannot get 2700 RPM on the ground with less than full power? Seems to me that as power is increased the RPM goes up just like it does for the magneto check. When there is enough power to rotate the engine at 2700 RPM, adding more power will result in higher pitch to prevent overspeed. In my mind, a constant speed prop is a fixed pitch prop until RPM reaches that selected by the prop control. I can see why a ground static run would indicate power for a fixed pitch prop, but not for a constant speed prop.

I guess I don't understand how our props work.

Edit:

I think I now understand what you are saying.  You are saying that the flat pitch angle is set such that it will in fact require full power to get to 2700 RPM during a static run.  As speed increases, the pitch increases to maintain that RPM.

Edited June 26, 2020 by Bob - S50
Add more to the post.

[carusoam]

The gov can hide some performance issues... but...

Full MP may be difficult to tell... Atmospheric pressure, minus losses in the intake, inaccuracy of the gauge... 
What does the book give for its highest MP?

Full RPM may be difficult to get until moving down the runway...

FF is really easy to read on a gauge...

Some people like to confirm MP, RPM, FF, prior to airspeed alive... it takes practice... don’t being looking inside while going 50kias..
 

Always confirm performance to a reference... knowing altitude and temperature is always going to be important...

PP thoughts only, not a CFI...

Best regards,

-a-

[N9201A]

If it took 2000' to get airborne then you are not making full power.
Could be low RPM, low MP, incorrect mixture, or incorrect magneto timing.

Too many pilots never look at how much runway they’ll actually need. The result is often seen when they try to horse their bird into ground effect at the end of a runway or run off the end of the runway trying to stop, with predictable results.

If one isn’t within 10-20% of what one has calculated, abort the takeoff and peek under the hood. I’ve had two occasions where an engine ran up fine but wasn’t producing full power, evidenced by using >120% of what it should have been.

[bradp]

Learn your roll. 
 

For me SL hot summer day to the gills is 1300 ft. I know that by heart.  It’s my go/nogo decision on the runway.  Not off by 1700 feet something is wrong. Stop.  
 

Also you are going to want to download the engine RPM app. That will tell you your takeoff roll RPM within a couple 10s of accurate.  It’s $8 and worth it. 
 

Finally budget for an engine monitor.  It’s the most valuable piece of equipment you can put in a panel besides a backup AI.  
 

Baby bottle test 

Mag timing 

You Borsescoped those cylinders when the plugs were off, right? 

[Shadrach]

On 6/23/2020 at 12:55 AM, ukrsindicat@yahoo.com said:

Hello, esteemed board. I looked around, but couldn't seem to find the answer.

Today,  my CFI and I finally flew my new(to me) 1967 M20F on its maiden flight and it felt good.   However, we did noted that the climb rate was fairly sluggish. My CFI noted that the engine was giving up some vibration.

My IA said that it is possible that we have fouled spark plugs, we will take a look tomorrow. It's possible that we ran the engine too rich on the ground and in the air for a little too long.

What is the usual rate of climb do you usually get? It seems that my POH suggest that I should be around 1100 and 1300 feet per minute.

 

On 6/23/2020 at 9:04 AM, ukrsindicat@yahoo.com said:

Guys, sorry for the rookie post. Definitely, I omitted some key questions in the original post. I will do better next time.

 

Unfortunately, I don’t have an engine monitor. This is something, that I am definitely considering to invest in in the short term. At least JPI700 to get my detailed EGTs and CHTs.

 

My rate of climb was about 250 immediately and 300-350 with the gear up.  We didn’t see 500fpm until we were about 1000agl.

DA = 1600 

I was at Sea Level (Florida). 

Alt 30.08 

Gross Weight: 2280 lbs 

Fuel: 15gal(L) 25gal(R)

OAT: 85F

Light Wind.

I was at full power 

 

Based POH chart I should have been around 1200-1300 fpm.

 

What are your thoughts on this?

That's not great.  I too have a 67F.  I would be concerned with that ROC.  Even with the heat you should have been at 1000fpm once on speed.  I was out under similar conditions last week. I was probably a few 100lbs  lighter but the DA was higher.  Does the engine data plate list the ignition timing as 20° or 25°?

As an aside, one of the things I was doing last week was testing the popular theory that Mooneys won't climb with gear and flaps out.  My  bird had no problems holding 900-1000fpm fully dirty (gear out, full flaps) but i had to climb slow (85mias).  If I can hold 1000fpm fully dirty out of a 701ft field with a DA nearing 3000, you should be able to do better cleaned up for climb.

Edited June 27, 2020 by Shadrach

[Ibra]

High unlikely aerodymanics IMO, but you can check "wing aerodynamics" on power off descent, cut power and look at ROD on various ASI readings on half useful weight, get some ratios and check against your best glide (900fpm at 90kts is 1:10, 1400fpm at 70kts is 1:5) on clean/dirty config if you see something fishy check your aircraft surfaces rigging, also the chance to check your ASI & VSI against GPS ground speed and altimeter descent over long period, second, for delivered power you can check engine & dynamic prop settings against straight & level POH cruise ROP performance (IAS = power) and takeoff distance performane (ground roll = power) this may show some issues with "prop aerodynamics" at fine pitch and high power settings, note that takeoff ground roll is less sensitive to "wing aerodynamics"

Dirty wing or config will not have much meaningful impact on best ROC performance near best climb VY speed but they do matter a lot at high/slow VFE/VSO speeds (but always good to check that your Mooney does not fly like STOL Cub with engine off), once you rulled aerodynamics out, the last thing to check is static prop mechanical loads on breaks & initial roll (max MP & max RPM) but without an engine instrumentation (e.g. EGT or FF) there is no way to guess what is the real power output: you have no thermal load indication and fuel mixture setting can be all over the place, so there is no way to figure out if you engine delivers max rated power (unless your prop has the right size, weight and number of blades and it is well balanced and rigged on the flat pitch stop), obviously with engine monitors issues tend to will be well visible in the data, especially if it is on one of the cylinders....

[irishpilot]

I also highly recommend a JPI. My engine was not rigged properly by PO, and we found it via the numbers.

Agree on aggressive elwan while taxiing. Do static run-up, then note exact numbers on rotate, liftoff, engine parameters, VVI. After that, if you still have low numbers, get the engine compression checked and possibly borescoped.

My guess is you have a cylinder that has low compression but still making power.

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[Mooney-Shiner]

Gents! Thank you for such awesome feedback! I will definitely incorporate all the suggestions. Please let me know if you can think of something else. 

I need to check on ignition and mag timing.  I believe that it is 25 deg. It's marked 25 on the starter gear ring. 

I definitely agree about JPI engine monitor. I'm looking into options now.

I will boroscope the cylinders next week to see the valves. They do have good compression (77-78/80). 

Once everything done, we will do another test flight in the similar conditions here in Florida. 

I will be sure to do more aggressive leaning on the mixture.

I will collect more data and report back to provide more detailed breakdown. 

Thank you, guys. Lots to chew on.

P.S. All this will done, once I will move my prop from being living room furniture status (wifey not loving it). Replacing starting ring due to lost teeth (posted a separate post on this earlier).  

 

[ArtVandelay]

P.S. All this will done, once I will move my prop from being living room furniture status (wifey not loving it).

Just be glad it was only a 2 blade prop. :-)

[Shadrach]

1 hour ago, ukrsindicat@yahoo.com said:

Gents! Thank you for such awesome feedback! I will definitely incorporate all the suggestions. Please let me know if you can think of something else. 

I need to check on ignition and mag timing.  I believe that it is 25 deg. It's marked 25 on the starter gear ring. 

I definitely agree about JPI engine monitor. I'm looking into options now.

I will boroscope the cylinders next week to see the valves. They do have good compression (77-78/80). 

Once everything done, we will do another test flight in the similar conditions here in Florida. 

I will be sure to do more aggressive leaning on the mixture.

I will collect more data and report back to provide more detailed breakdown. 

Thank you, guys. Lots to chew on.

P.S. All this will done, once I will move my prop from being living room furniture status (wifey not loving it). Replacing starting ring due to lost teeth (posted a separate post on this earlier).  

 

Incidentally, our airplanes are just three serial numbers apart. That’s the closest I’ve seen yet.

 

[takair]

20 hours ago, ukrsindicat@yahoo.com said:

Gents! Thank you for such awesome feedback! I will definitely incorporate all the suggestions. Please let me know if you can think of something else. 

I need to check on ignition and mag timing.  I believe that it is 25 deg. It's marked 25 on the starter gear ring. 

I definitely agree about JPI engine monitor. I'm looking into options now.

I will boroscope the cylinders next week to see the valves. They do have good compression (77-78/80). 

Once everything done, we will do another test flight in the similar conditions here in Florida. 

I will be sure to do more aggressive leaning on the mixture.

I will collect more data and report back to provide more detailed breakdown. 

Thank you, guys. Lots to chew on.

P.S. All this will done, once I will move my prop from being living room furniture status (wifey not loving it). Replacing starting ring due to lost teeth (posted a separate post on this earlier).  

 

Just move it up to the wall, it then becomes art.  

[Ibra]

1 hour ago, takair said:

Just move it up to the wall, it then becomes art.

They have lot of success with interior decorators But broken ones 

I don’t want a 3blades heavy one on top of my head when sleeping (always treat it as live prop )

Edited June 28, 2020 by Ibra

[Mooney-Shiner]

OK, some update. 

We were still getting a rough running engine with marginal( but acceptable) mag drops.  So my A&P and I decided inspect all injectors.  Result: found the #2 injector was completely clogged with zero daylight. Same cyl with the greasy spark plug.  All other injectors were clear.  Soaked it in Hoppes 9 bore cleaner and cleaned it up.  Re-install everything and got the aircraft running like a champ.  The mag drops exactly where they should be.  The roughness went away.  Max static RPM is in 2500 zone (its was 2450 before). 

I'm not sure how long it been clogged.  My A&P did a pre-buy in Morristown, TN and saw no issues.  Couple of months later, the seller delivered the  aircraft to me and I began noticing the roughness. If the seller flown from TN to Tampa on 3 cylinders, then he possessed a solid pair of brass ones.  Maybe related: I'm also seeing a slow leak (1 gal a week) on my left tank and wondering if I some of the tank sealant came apart and found its way all the way to my #2 injector? Perhaps, I should inspect the fuel strainer on the belly?

 

 

[carusoam]

Ukrs,

Got any JPI engine monitor to look at?
 

We can look at the data and see exactly when the injector was starting to see a blockage...

Often sellers do a disservice, by erasing all the database in the entire plane....

Some people selling used machinery have large brass orbs... its probably a requirement for the job... 

 

There are so many screens and filters from the tanks to the injectors... it is unlikely that tank sealant can get that far...

Check the status of your sealant first... see if it is stuffing off...

Next visit the tank selector valve screen...

 

Did you collect the crud and take a picture of it?  We can probably make an educated guess from those parts...

There are some simple tests to perform to know how well your fuel is being delivered... we can talk about that next...

The good news... often the blockage in a FI... is made up of lead deposits from the fuel... hence the Hoppes gun barrel cleaner... it dissolves... Pb... Plumbum... aka lead...

 

Work on the JPI download... we can look for a few other things...

PP thoughts only, not a mechanic...

Best regards,

-a-

[Mooney-Shiner]

2 minutes ago, carusoam said:

Ukrs,

Got any JPI engine monitor to look at?
-a-

A,

My JPI install is still aspiration/future project. I'm definitely sold on idea, just slow on getting probes to connect and fully install my 700.

If "stuffing off" means coming off in chunks, then I didn't see it.  We are planning to do a patch inside the tank and will take a closer look once we remove top inspection panels.  

My A&P was cleaning an injector and I don't remember if he ID'd the composition of the crud.

[carusoam]

Ooops, Siri mispell....

Sluffing...  the act of material coming off the surface, in layers....

The result... a visit to the stripper and resealer...

Often, fuel leaks are more simple than that... single rivets, or inspection panel screws... find the blue stain... it has to show up...

For any oddity you come across in the future... pics are an easy way to get everyone on the same page...

My mechanic knows I’m going to ask and share what I have found...

Sorry, I didn’t catch the siri-ism... 

Best regards,

-a-