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Rate of Climb - Advice Needed From Higher Flyer's


59Moonster

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Trying to spread the wings on this little bird of mine and my fuel burns have been way more than expected. I plugged info into foreflight for my performance profile according to the answers I found. And now for reality.

I flew up to 11,000 started a timer at 2500 and recorded the altitude every minute. I did my best keeping it at 120 IAS and would guess it was there at least 95% of the time. I think I had

I averaged 236 FPM climb rate. Starting at 460FPM  and ending around 160FPM and took me almost 36 minutes and 78 miles to get there. 

My question's are:

1. Am I doing this wrong?

2. Should this be done full rich or leaning? If so, when do you recommend leaning? Certain altitudes?

3.  Any other recommendations?

 

<-------- In that plane (M20A)

Edited by 59Moonster
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Note sure about M20A but best rate of climb ROC speed Vy should be way less than 120ias especially at altitudes? the POH numbers for VY & VX are given are sea level but you expect VX (max angle) to increase and VY (max roc) to decrease as you go higher 

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In your M20A, I'd start at 120 mph, and allow it to decrease as you climb.  120 is good for engine cooling, but at higher (cooler) altitudes and lower power output, you'll do better finishing your climb closer to Vy.  Also, try 2600 rpm or wherever the engine is running smoothly.

You will definitely need to lean the mixture as you climb.  How much is dependent on whether or not you have an engine monitor.  Try a search for "Target EGT".  When you get to an altitude where your engine is only producing 65% power (go by the charts in the POH), you can lean as much as you want without hurting the engine.

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There is no wrong..... sort of.

But, there are better ways to do things...

With the single EGT instrument... you can actually do some decent leaning, properly...

There are two methods of knowing you are developing HP... T/O distance and climb rate...

You want to compare this with other planes that have decent data... the M20C POH May be pretty helpful... as a starting point.

It is important to note OAT, and starting altitude agl...

You only have one CHT... use it to protect your cylinders...

You have one EGT... it can be calibrated to peak EGT... so you can tell if you are operating 100°F ROP...

You are doing a climb rate study for a reason..?

In this case you are doing an ordinary cruise climb, but not supplying important data...

 

It is going to take following the rules of attitude and power, while watching the CHT...

Having the CHT exceed 450 °F is probably pretty easy... In the climb...

 

Do you have any data to share?

Was the engine running?

Was the throttle WOT the whole way?

what MP were you using?

what rpm did you use?

What did you lean to, °F ROP...

 

These are just some of the questions you want to answer for your bird...
 

No reason to do all of this in one experiment... it may be better to figure this out at a casual single altitude first...

These questions are typical for an M20C or Ovation... 70 years later...

No fear... some Os didn’t get any better instrumentation either... single/single...

:)

Best regards,

-a-

 

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Vy on the M20F is 113 - 1mph per 1000ft. I was still making 200fpm when I stopped climbing at FL220 in my naturally aspirated M20F at 2700 RPM. I would lean in the climb. Do you have an engine monitor or EGT?

Edited by FloridaMan
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Good advice above...

What I want to add is that climbing at VY (even adjusted for altitude) is not always your best bet for fuel economy.  Winds can have an effect.  For instance, if you were climbing into the wind, doing a faster climb will to better..  In a tailwind, VX (adjusted for altitude) will be better.

as an example, imagine you look up your Vy and it is 90 knots.  You decide to fly 90 knots and adjust for altitude.  You start your climb into a 90 knot wind.  You would start out at 0 ground speed and as you climbed and reduced that speed to maintain a corrected Vy, you would begin going backwards and would do so at an increasing rate for the entire climb.  this would obviously be a silly way to get where you are going and would take much much longer than going faster, giving up climb rate and penetrating the wind.

  I doubt you will find a large improvement in overall trip fuel burn by changing your climb to a set standard no matter the conditions..  However if you adjust for conditions will will probably see an improvement.

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Yes, wind & wight & altitude (even vertical air movement) do factor into best RoC speed VY, the POH lists only one speed as other variables are hard to quantify but you can go +/-5kts or even up to +/-10kts if you need depending on conditions, but hardly an exact science

Same debate as Vbg speed, if one flies competition gliders they will factor in wind, weight, flaps, water, expected thermal climb/sink strength, cloud base height as well as their risk appetite for landout, in power aircraft unlike a high performance glider when the fan quits, I would rather fly a single POH Vbg and nail it down instead of scrolling polar curve data vs wind/weight :) it will be already +/-10kts around that number just from distraction and adrenaline factors :lol: 

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9 hours ago, Ibra said:

Yes, wind & wight & altitude (even vertical air movement) do factor into best RoC speed VY, the POH lists only one speed as other variables are hard to quantify but you can go +/-5kts or even up to +/-10kts if you need depending on conditions, but hardly an exact science

Same debate as Vbg speed, if one flies competition gliders they will factor in wind, weight, flaps, water, expected thermal climb/sink strength, cloud base height as well as their risk appetite for landout, in power aircraft unlike a high performance glider when the fan quits, I would rather fly a single POH Vbg and nail it down instead of scrolling polar curve data vs wind/weight :) it will be already +/-10kts around that number just from distraction and adrenaline factors :lol: 

Coincidentally, I own a glider and am quite familiar with the things you mention.  And yes, we do factor those things and more into what we do when racing.  In glider racing every last bit of energy management and min /maxing is important.  That being said, races are won by VERY VERY small margins because those things do not make MASSIVE differences.  They make "very very very small" differences that add up to "small" differences over TIME and repetition.  In fact, for them even to matter you have to do all the BASIC stuff correct.  You can undo all th eprogress you made by simply losing 1 thermal (out of a hundred you may work on a course)

Which brings me back to the point I was trying to make Moonster.  That being he will likely not see a drastic change in fuel burn for the trip (he was stating he had higher fuel burns than expected) by trying to nail POH climb speed.  Also, the price for any decrease in overall fuel burn will be longer trip times.  Which, as it happens, is part of the reason the overall trip burn will not be significantly less.  While climbing at 120ias results in a slow climb rate, it results in  a faster ground speed for the duration of the  climb and less time in flight overall.  If he reduces his climb speed to say 90 knots, he will be 30 knots slower for the duration of the climb, and thus have more time in cruise burning fuel for that leg.

in short (too late I know), his best course of action is to learn to lean in the climb, find a speed that keeps the engine nice and cool and let her rip.  I think all of us probably bun more gas than we expected to or than what one or more performance programs have told us... Heck, we even have to set up a Fuel bias in our Arinc performance section for the Gulfstream... and that is some serious software based on very detailed manufacturer spaghetti charts  for an aircraft that carries 43,000 lbs of fuel.  Even then it is not correct and has to have a bias put in with experience to get it closer to reality.  It is typically less than a + or - 3 %... but with the weights and distances we are talking that is a BIG error.

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15 hours ago, FloridaMan said:

Vy on the M20F is 113 - 1mph per 1000ft. I was still making 200fpm when I stopped climbing at FL220 in my naturally aspirated M20F at 2700 RPM. I would lean in the climb. Do you have an engine monitor or EGT?

Yes. EDM 711

I'll test a couple things and see. I did lean a few times. Just shocked to find it took me 36 min over 78 miles  vs 10 min. (As estimated) for a 240 mile flight at 11k. 
 

at least at this point in life I carry extra fuel and smaller kids

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I'm not really a "high flyer," as I prefer to travel between 7-10K. I've timed myself several times, different seasons--2 people, full fuel, C model with 3-blade Hartzell--I can go from turning the key to leveled off, power set, mixture leaned at 7500 msl in 15 minutes or less. But I climb at Vy, which for me is 100 mph - 1 mph per 1000 feet.

I have the O-360-A1D. Not sure what's in an A.

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11 hours ago, Hank said:

I'm not really a "high flyer," as I prefer to travel between 7-10K. I've timed myself several times, different seasons--2 people, full fuel, C model with 3-blade Hartzell--I can go from turning the key to leveled off, power set, mixture leaned at 7500 msl in 15 minutes or less. But I climb at Vy, which for me is 100 mph - 1 mph per 1000 feet.

I have the O-360-A1D. Not sure what's in an A.

Thanks. I've been through the manual and guess I assumed Vy was 120 since the manual says to climb between 115-120 once out of the pattern. It also mentions for "High Altitude Climb" on a hot day with a heavily loaded airplane to climb at 120-125mph.

I've just assumed that was IAS.

On that flight I was showing 120 IAS at 9280' AGL. I was going 158mph ground speed but only climbing at 150fpm. (Had tailwind but didn't record the speed. I think it was 10-15)

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8 minutes ago, 59Moonster said:

Thanks. I've been through the manual and guess I assumed Vy was 120 since the manual says to climb between 115-120 once out of the pattern. It also mentions for "High Altitude Climb" on a hot day with a heavily loaded airplane to climb at 120-125mph.

I've just assumed that was IAS.

On that flight I was showing 120 IAS at 9280' AGL. I was going 158mph ground speed but only climbing at 150fpm. (Had tailwind but didn't record the speed. I think it was 10-15)

Do you have a page like this in your manual(s)? This is for my C.

1719149081_Screenshot_20200701-090723_AdobeAcrobat.thumb.jpg.754f7a7a507b4a73ec02b0075566f986.jpg

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2 hours ago, Hank said:

Do you have a page like this in your manual(s)? This is for my C.

pic removed

My 1959 manual isn't that fancy. I did find a Vy at 105 on the checklist sheet but haven't used it since the manual stated 120 and the previous owner said to use 120. But he never flew much above 4-6k.

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4 minutes ago, 59Moonster said:

My 1959 manual isn't that fancy. I did find a Vy at 105 on the checklist sheet but haven't used it since the manual stated 120 and the previous owner said to use 120. But he never flew much above 4-6k.

Yeah, I have that too, but find Vy works well most of the time; on warm days aloft, I speed up for more cooling air over the engine.

758615468_Screenshot_20200701-115830_AdobeAcrobat.thumb.jpg.bf8f7fb026ab024b22d25bbed66aaee2.jpg

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Just an FYI...  Turns out people smarter than me know about what I have been saying and even have a name for it... Carsons speed

 

TIL  https://www.aopa.org/news-and-media/all-news/2010/december/01/technique-cheap-speed

 

http://www.eaa1000.av.org/technicl/perfspds/perfspds.htm

 

In short, take your best glide speed and multiply it time 1.316

 

 

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27 minutes ago, 59Moonster said:

My 1959 manual isn't that fancy. I did find a Vy at 105 on the checklist sheet but haven't used it since the manual stated 120 and the previous owner said to use 120. But he never flew much above 4-6k.

Do you have a ceiling figure and VS, Vx, Vy for your aircraft? you can use that to extrapolate how Vy and max RoC changes with altitude using linear shape, for weight impact you can just adjust Vy speed by impact on Vs usually 3kts to 6kts? and about 30%-50% of that will be the loss on your max ROC -1kts/-3kts (-100fpm to -200fpm)

For altitude, usually something like add 0.5kts for Vx, take 1kts of Vy for each 1000ft will do the job until they hit each other 

 

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4 minutes ago, Austintatious said:

Just an FYI...  Turns out people smarter than me know about what I have been saying and even have a name for it... Carsons speed

A fuel savvy Mooniac here on MS go for 125ias on the M20J & ROP all the way from takeoff to landing while climbing as much as possible B)

Edited by Ibra
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1 minute ago, Ibra said:

A fuel savvy Mooniac here on MS go for 125ias on the M20J & ROP all the way from takeoff to landing while climbing as much as possible B)

I recently did a trip from FTW to Savannah and back (fuel stops on the way back, fighting headwinds)  We had plenty of time to play with different cruise settings at low altitudes while we stayed below the strong winds.  What I found is that while I could increase speed and reduce flying time by quite a lot, The penalty for doing so in fuel burn was actually pretty low.  I dont remember exactly, but I did decided to leave the power up and shave off the time because it was WELL worth it.  Especially when you factor in the hourly maintenance cost of running the engine.

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