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Sluggish climb


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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.

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Ukr,

Time to get real....  :)

0) Do you have an engine monitor?

1) You know climb rate is based on excess power...

2) the more excess power you have, the faster you will climb...

3) weight takes away from climb rate, the more weight you are carrying, the slower you will climb.

4) Technique is key... use the right technique, you will climb really fast, at the cost of some excessive CHTs....

5) What’s excessive to you, when it comes to CHTs?
 

6) excess power is really cool to have... there are many ways to get more...

7) There are plenty of ways to have less too...

8) Having High DA at time of rotation is a bad time to look at what the OAT is...

9) So Briefly, because this is important....

  • What was the DA when you were flying?
  • Do you remember the OAT?

10) it’s a good chance It was a crummy day to be measuring performance... without using data that is readily available...

11) Compare your numbers to the POH...they should be pretty close...

12) What did the POH say it should be?

13) Many MSers use 120ias for cruise climb... it is a compromise of good speed over the ground and good climb rate...  Vx, Vy, and cruise climb should be part of your conversation...

Consider these notes from a friend... you left out so many important technical details... what you have may be a good number... how would we know?   Let’s share the numbers...

You have learned an important lesson... before the trees arrived to teach you something interesting....

You aren’t the first, you won’t be the last...  we have Patrick that is our reminder of the effects of DA... :)

PP thoughts only, not a CFI...
 

Best regards,

-a-

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One other question:  how were you climbing? Full throttle / 2700 (hopefully)? Or did you reduce power to some magic number and climb at 2600 or even 2500? Reducing power any at all will reduce your climb rate. Also, what was your actual "sluggish" climb rate?

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7 hours ago, carusoam said:

 

image.thumb.png.eb0cfa83195042b5b73b20a2bbf1a6e6.png

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?

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9 minutes ago, ukrsindicat@yahoo.com said:

image.thumb.png.eb0cfa83195042b5b73b20a2bbf1a6e6.png

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?

what air speed are you climbing at? 

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What's the indicated airspeed? Is it correct?

What's your AI showing for attitude?

Is your vsi correct? Xcheck with an iPad/watch the altimeter

Is your gear coming all the way up? Check on jacks and indicators

Are your flaps or ailerons drooping? Get some boards and check rigging

Is the ball centered?

What's your MP and RPM. Is your tach right? Is your prop governor set right? Use a digital tach

Are you making full static RPM on the ground?

 

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High humidity is going to rob you of power/performance, as well as high temperatures. I read an article/paper that said high humidity will reduce HP by as much as 10%. Florida has both.

Since DA is takes atmosphere pressure and temperature in account, but not humidity, I would not expect book performance.

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Heat and humidity here in Florida will cut the book number almost in half. You saw it in takeoff and climb. The hot runway makes the density altitude higher, which is why initial climb is slow. It improves as you get further from the hot airport environment. Your actual density altitude on the runway was probably 2200-2600 feet. I have an air data computer that I monitor on takeoff and it will show the actual conditions on the runway, not what is recorded on an ATIS, or observed in the cooler grassy area that an ASOS sees. 

After factoring for the atmospheric conditions, you'll need to verify that the airspeed indicator is correct. There is no requirement for them to be tested or calibrated, so you'd have to ask an avionics shop to check it when they do the 91.411/91.413 24 month certifications. If it's OK, then you start with mechanical issues that affect performance. Ignition timing, alternate air system, exhaust system, camshaft condition, max RPM verification (tach reading correctly).

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My 1968 F generally climbs out at ~700fpm around 110-120mph when loaded with 2 adults.  My DA is usually around 2-4,000.

Everything noted above is valid for what might be causing the issues, but I think if you saw less than 500fpm, you have something amiss.  I don’t think you’ll see over 1,000fpm unless on a cold morning by yourself.

Climb may be more sensitive to power but if you’re out flying, so a speed check.  Fly a leg N, E, S, W, let it stabilize at each heading and note the groundspeed.  Average the 4 numbers.  That’s a very close approximation of your TAS. TAS should be about 145ish Rich of peak, full power, 2500rpm at say 6-10,000’ density alt.  If you get 135, something is definitely wrong.

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One way to determine if the power plant is generating power...

1) The run-up checks all spark plugs... and both mags...

2) Without an engine monitor, it will be hard to know if you have a weak plug... or timing difference...

3) Weak plugs are often marked with the word Champion on their side...

4) Weak plugs can be measured for their resistance...

5) A real good measurement of your Take/off HP is to measure your T/O distance....

6) If you have a WAAS source on your ADSB-in device CloudAhoy app to automatically measure your T/O run...
 

7) If your T/O is long, and your climb rate is slow, you have two pieces of data pointing to something being amiss...

8) Check with your CfI, carefully... he may be a highly dense person, all muscle, appears to be slim, but weighs a lot....  :)

9) Your T/O performance really relies on that excess power discussed earlier... as you get towards MGTW.... your excess power starts heading towards zero... (figuratively speaking)

PP thoughts only, not a CFI...

Best regards,

-a-

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First thing I would do is repeat the experiment to verify the results.  Could possibly be you flew into a temperature inversion. Had that happen once and was like flying up into a giant marshmallow.  In our C With full fuel and two on board even in hot weather not ever below 500fpm at cruise climb of 120mph in stable air.  Don't know  if you get downdrafts in clear weather in Florida but very common flying out west. Your performance should be better than our C so try it again see if it still climbs so poorly before you start searching for mechanics that may be the issue. Good luck

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On 6/23/2020 at 9:21 AM, smwash02 said:

What's the indicated airspeed? Is it correct?

What's your AI showing for attitude?

Is your vsi correct? Xcheck with an iPad/watch the altimeter

Is your gear coming all the way up? Check on jacks and indicators

Are your flaps or ailerons drooping? Get some boards and check rigging

Is the ball centered?

What's your MP and RPM. Is your tach right? Is your prop governor set right? Use a digital tach

Are you making full static RPM on the ground?

 

image.thumb.png.418d1de9dcd27f0e94db45b6aa8a3775.pngSM, you asked quite a bit of good questions and I will do more digging trying to find the answers. My gear has only two position lights "Unlocked"(red) and "Locked down" (green). During the our flight the gear was in "Unlocked" up position.  

Turn indicator ball was centered. 

We seemed to be making a full RPM power on the ground. 

On take off, we are thinking that we were airborne just under 2,000 feet.

I don't have a reason to think that the speed reading was incorrect, but worth of checking during next flight.

Thank you for all of your input guess. This helps us learn!

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On 6/23/2020 at 7:07 AM, Hank said:

One other question:  how were you climbing? Full throttle / 2700 (hopefully)? Or did you reduce power to some magic number and climb at 2600 or even 2500? Reducing power any at all will reduce your climb rate. Also, what was your actual "sluggish" climb rate?

I pretty sure that we were full power, unless it backed off while I was manipulating manual gear. 

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49 minutes ago, ukrsindicat@yahoo.com said:

image.thumb.png.418d1de9dcd27f0e94db45b6aa8a3775.pngSM, you asked quite a bit of good questions and I will do more digging trying to find the answers. My gear has only two position lights "Unlocked"(red) and "Locked down" (green). During the our flight the gear was in "Unlocked" up position.  

Turn indicator ball was centered. 

We seemed to be making a full RPM power on the ground. 

On take off, we are thinking that we were airborne just under 2,000 feet.

I don't have a reason to think that the speed reading was incorrect, but worth of checking during next flight.

Thank you for all of your input guess. This helps us learn!

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.

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Definitely use your math and reading skills...

What does the POH say your T/O run should have been at the given DA...

How much weight in people and fuel are you carrying?

If two people and full fuel has you filled to MGTW, the POH is your friend...

If the POH says it takes 2k’ for T/O, you are good...

If the POH says it takes 1200’ for T/O, and you used 2k’... some digging needs to take place...

1) MP gauge...Check what it says while the engine is not running. What does it say while idling?

2) RPM gauge... what does it say at max?  Check with a phone app... the phones can hear rpm...

3) Go any FF data?

4) MP and RPM will give you a decent power indication... FF will supply a good back-up to the first two...

Sounds like one of these details is not working the way you are expecting...

Best regards,

-a-

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On 6/23/2020 at 5:46 PM, carusoam said:

One way to determine if the power plant is generating power...

1) The run-up checks all spark plugs... and both mags...

2) Without an engine monitor, it will be hard to know if you have a weak plug... or timing difference...

3) Weak plugs are often marked with the word Champion on their side...

4) Weak plugs can be measured for their resistance...

5) A real good measurement of your Take/off HP is to measure your T/O distance....

6) If you have a WAAS source on your ADSB-in device CloudAhoy app to automatically measure your T/O run...
 

7) If your T/O is long, and your climb rate is slow, you have two pieces of data pointing to something being amiss...

8) Check with your CfI, carefully... he may be a highly dense person, all muscle, appears to be slim, but weighs a lot....  :)

9) Your T/O performance really relies on that excess power discussed earlier... as you get towards MGTW.... your excess power starts heading towards zero... (figuratively speaking)

PP thoughts only, not a CFI...

Best regards,

-a-

We pulled the plugs, they looked good except Cyl#2. Both plugs were wet. Cyl#2  has a good compression and not metal in filter. My A&P thinks that we have foiled with rich mixture. 

We will check the mag-timing.  We will also do another T/O to check out distance and report back.

"Check with your CfI, carefully... he may be a highly dense person, all muscle, appears to be slim, but weighs a lot" -- :D:D

Thank you for your help! 

 

Yuriy

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IMG_9146.jpg

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11 hours ago, PT20J said:

Fuel evaporates pretty quickly and it takes time to remove cowling and the plugs.

A cylinder that is oily can have good compression since oil can seal the rings.

Easiest power check is static rpm at sea level DA.

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?

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15 hours ago, Bob - S50 said:

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.

Quite possibly true but only if you were making every effort to rotate at earliest opportunity.  Depending on conditions naturally but it depends on when you decide to rotate so this number is a variable.  

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8 minutes ago, bonal said:

Quite possibly true but only if you were making every effort to rotate at earliest opportunity.  Depending on conditions naturally but it depends on when you decide to rotate so this number is a variable.  

I'm almost always int he air in 1000' or so, even when loaded up to travel.

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30 minutes ago, Hank said:

I'm almost always int he air in 1000' or so, even when loaded up to travel.

Quite true, same for us but I'm sure as you apply power you confirm all is correct and rotate at within a few knots every time.  Perhaps a little later in high crosswind and I know it would be difficult to keep it down for an additional thousand feet my point is it can vary depending on conditions and pilot inputs.  How quickly you add power for example.  We don't know the specifics regarding OP's problematic flight.

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