Efficiency!

[MBDiagMan]

Was doing some flying today and the instructor in the right seat started playing with engine settings and using the Lean Find feature on the JPI.  I’m not a big fan of LOP, but I didn’t mind him doing so since it’s not regular practice and was a fun and enlightening experiment.  We were cruising at 8,000 feet.  He leaned it out and had it at 59% power and 7.3GPH I think.  I know it was seven something and believe it was 7.3.  It was cruising straight and level in pretty smooth air.  The only time we were in smooth air I think.  Once he had that done he used the 430 to determine TAS and it was 152 knots.  The engine wasn’t running smooth, but the cylinders were running nice and cool.

Now this is some efficiency folks.  I won’t be repeating that very much, but it really says something about Al’s work.  BTW, this is a ‘67 F with all the J mods to include nose, windshield and the normal gap seal and tail mods.  It had pretty full tanks and about 400 pounds of pilot, copilot and baggage.

[MIm20c]

Probably need to do some more flight testing. I have no doubt your F can do 152kts but most likely not on 7 gph without a tailwind.  My 6.5-7 gph speeds in a short body are around 145-150 mph.  Going to 9.5 gph ish changes the mph into kts. 

[MBDiagMan]

My C turned in better numbers than yours but it had all the speed mods except for a J cowl.

I am under the impression that air speed is not headwind or tailwind dependent.  

Aerodynamically my F is effectively a J.

Edited June 29, 2020 by MBDiagMan

[gsxrpilot]

1 hour ago, MBDiagMan said:

Now this is some efficiency folks.  I won’t be repeating that very much, but it really says something about Al’s work.  BTW, this is a ‘67 F with all the J mods to include nose, windshield and the normal gap seal and tail mods.  It had pretty full tanks and about 400 pounds of pilot, copilot and baggage.

You should fly that way as often as you can. Your engine will thank you by living to a very ripe old age. 

Your wallet will thank you as well with many more miles per gallon.

[carusoam]

Numbers like these... make you want to check...

• the JPI numbers often
• look forward to getting balanced fuel injectors
• and dynamically balancing one’s prop...

 

Mooney ownership 102...   

Great Nmpg numbers!

Best regards,

-a-

[MikeOH]

Please describe how the 430 was used to determine TAS.

[MBDiagMan]

I’ve seen it done twice Mike, but don’t remember how to do it.  It’s not as if there is a button you push for a TAS readout.  There is just a screen where it knows some of the factors in the equation and you twist in one or two others.  It is in the Flight Planning menu.  A fancy calculator.  It’s in the manual.

I darn sure didn’t pay close attention to the process on this flight.  I was flying on instruments the whole trip with nothing but a Britain wing leveler to help.  When he did it we were at altitude in smooth air.  Most of the trip was bouncing my butt off while keeping the top side up with instruments.

Edited June 29, 2020 by MBDiagMan

[Hank]

6 hours ago, MikeOH said:

Please describe how the 430 was used to determine TAS.

Several clicks of the big knob. Enter OAT and altimeter setting, it shows TAS, wind speed and direction.

Edited June 29, 2020 by Hank

[MBDiagMan]

9 hours ago, gsxrpilot said:

You should fly that way as often as you can. Your engine will thank you by living to a very ripe old age. 

Your wallet will thank you as well with many more miles per gallon.

I completely believe that you are correct Paul, but I have gotten the impression that the success of LOP is in the hands of the person adjusting the mixture control.  Someone like yourself and several other folks I know will have/are having great success with it.  It is not a process to be approached casually without attention to detail.

I have observed a few planes get cylinders all too often.  These planes are flown by great folks, but not someone who understands everything involved and don’t apply adequate care and attention when setting it up.

I’ve also heard from several knowledgeable A&P’s that the engine shops can look at a cylinder and piston set and tell you if it’s been running LOP.  I expect that what they are seeing are cylinders that were run LOP by someone who did not have a good working knowledge of the process.

I am still a rookie pilot, although a very old one.  If I EVER get a decent autopilot where I can climb out and then be able to Take the time to carefully and accurately lean it, I believe there will be a time when I can have the same success with it that you do.  Until that point I’ll be burning extra gas.

[Nukemzzz]

6 hours ago, MikeOH said:

Please describe how the 430 was used to determine TAS.

I was thinking the same things as you maybe:  "This must be a misunderstanding and the instructor called out ground speed from GPS".  

[MIm20c]

14 minutes ago, Nukemzzz said:

I was thinking the same things as you maybe:  "This must be a misunderstanding and the instructor called out ground speed from GPS".  

I believe the instructor was trying to be helpful. This utility screen does make a rough estimate of TAS. However, the errors involved can be substantial for CAS etc. A better way would be a couple three way gps calculations averaged out. 

[David Lloyd]

Don't know about the 430, but the newer radios can calculate the true airspeed.  The Garmin 375 in mine, I have to enter the temp, pressure altitude and IAS.  If connected to something like a G5 with a temperature sensor, the 375 would give true airspeed without entering anything else.  Of course, a G5 with a temp sensor would also give TAS.

One problem with any calculation is in my Mooney according to the POH, IAS is about 4 mph higher than calibrated airspeed where any correct calculation should start.  And then there is instrument error.  And installation errors.  Anyone ever check and verify the accuracy of their airspeed indicator?

[Jerry 5TJ]

3 minutes ago, David Lloyd said:

Don't know about the 430, but the newer radios can calculate the true airspeed. 

 As can an E6B.  
 

[David Lloyd]

I can still work a whiz wheel on a dark bumpy night with one eye shut.

[MBDiagMan]

OAT on my 430 comes from the JPI. 
 

Yes David, if I had been doing the calculation I would have done it with a Whiz Wheel.

[MBDiagMan]

1 hour ago, Nukemzzz said:

I was thinking the same things as you maybe:  "This must be a misunderstanding and the instructor called out ground speed from GPS".  

No he used the 430 to calculate TAS.  He showed me the resulting 152 knots TAS.  Refer to Hanks 430 picture to see where TAS is indicated.  This is a really savvy guy.  I have seen the 430 used as a TAS calculator on the ground.  I wish now I would have asked him to take a picture of the 430 screen, the JPI screen and the ASI.  I had no idea that on a Mooney forum there would be people skeptical of such efficiency.

I’m not sure why this seems impossible from a Mooney with the J mods that make it aerodynamically a J.

Edited June 29, 2020 by MBDiagMan

[gsxrpilot]

2 hours ago, MBDiagMan said:

I completely believe that you are correct Paul, but I have gotten the impression that the success of LOP is in the hands of the person adjusting the mixture control.  Someone like yourself and several other folks I know will have/are having great success with it.  It is not a process to be approached casually without attention to detail.

I have observed a few planes get cylinders all too often.  These planes are flown by great folks, but not someone who understands everything involved and don’t apply adequate care and attention when setting it up.

I’ve also heard from several knowledgeable A&P’s that the engine shops can look at a cylinder and piston set and tell you if it’s been running LOP.  I expect that what they are seeing are cylinders that were run LOP by someone who did not have a good working knowledge of the process.

I am still a rookie pilot, although a very old one.  If I EVER get a decent autopilot where I can climb out and then be able to Take the time to carefully and accurately lean it, I believe there will be a time when I can have the same success with it that you do.  Until that point I’ll be burning extra gas

I love the video clip. Solid IMC and none of the needles are moving. Nicely done!

I agree with you on not wanting to hurt the engine while learning LOP operations. One thing I learned is that once I'm down around 65% power, there isn't anything I can do to hurt the engine. The power is just too low to hurt anything. Even running right at peak won't matter. So what I did was to figure out at what altitude, was I down to 65% or less power, while still WOT. Then once at that altitude, I'd play with the mixture, the lean find, etc, to get comfortable with LOP and learn EGT numbers, FF numbers, how lean can it go, where is peak, etc. All confident that since I'm below 65% power anyway, I can't hurt anything and I can practice, experiment, and learn. 

Even today with hundreds of hours of LOP opps, I still don't fly LOP above 65% power. I'm just more comfortable knowing that nothing I can do will hurt the engine.

[MIm20c]

56 minutes ago, MBDiagMan said:

I’m not sure why this seems impossible from a Mooney with the J mods that make it aerodynamically a J.

I’m not trying to pick on your F. I’m sure it’s one of the nicest around. I’d welcome any long term J owner to comment if they can run 7.3 gph at 8k and get over 150kts TAS. I’m genuinely curious. 

[cliffy]

2 hours ago, David Lloyd said:

I can still work a whiz wheel on a dark bumpy night with one eye shut.

Used to carry it in the Boeing and Airbus and still do in the Mooney I can use it one handed too!

Got a few quizzical looks from young whipper-snapper copilots - you know- the touch screen troubadours 

[MBDiagMan]

2 minutes ago, MIm20c said:

I’m not trying to pick on your F. I’m sure it’s one of the nicest around. I’d welcome any long term J owner to comment if they can run 7.3 gph at 8k and get over 150kts TAS. I’m genuinely curious. 

I too am anxious to hear from a savvy J pilot.

[MBDiagMan]

2 hours ago, gsxrpilot said:

I love the video clip. Solid IMC and none of the needles are moving. Nicely done!

I agree with you on not wanting to hurt the engine while learning LOP operations. One thing I learned is that once I'm down around 65% power, there isn't anything I can do to hurt the engine. The power is just too low to hurt anything. Even running right at peak won't matter. So what I did was to figure out at what altitude, was I down to 65% or less power, while still WOT. Then once at that altitude, I'd play with the mixture, the lean find, etc, to get comfortable with LOP and learn EGT numbers, FF numbers, how lean can it go, where is peak, etc. All confident that since I'm below 65% power anyway, I can't hurt anything and I can practice, experiment, and learn. 

Even today with hundreds of hours of LOP opps, I still don't fly LOP above 65% power. I'm just more comfortable knowing that nothing I can do will hurt the engine.

You’re repeating much of what my instructor was saying.  He said below 65% power LOP would be fine.  I also never mentioned that once leaned out and stabilized the CHT’ were ice cube cold at lower temps than I am accustomed to seeing.  Now that I no longer have a hot cylinder my CHT’s typically run in the 390’s.  When he had this all set up and stabilized they were like 350 and 360.  If I had it to do over again I would have asked him to take pictures of the ASI, JPI and 430, if for no other reason beyond analysis at a later time.

 

BTW Paul, thanks for the complements on my flying.  Now if this old boondocks pilot could learn to talk on the radio I could be a REAL instrument pilot.

Edited June 29, 2020 by MBDiagMan

[MIm20c]

Next time you go flying just for fun try and lean quickly to 8ish gph. Then you can play around with different settings to find out what gives you the most speed and smoothness. The reason engine builders can easily spot a LOP run engine is how clean everything looks around the cylinder heads/valves. There are many benefits to LOP operations but I agree with GXSR that 65% power or less operation makes the whole process less stressful. 

[MBDiagMan]

After looking at J performance charts, 59% power and 152 knots doesn’t look far fetched at all.  I was below max gross.  The J shows one 8000 ft. entry of 55% and 150 knots lightly loaded and 55% and 145 Knots at max gross.  That was for a factory J so there were no gap seals tail mods and other tweaks.

Edited June 29, 2020 by MBDiagMan

[Ragsf15e]

6 hours ago, David Lloyd said:

Don't know about the 430, but the newer radios can calculate the true airspeed.  The Garmin 375 in mine, I have to enter the temp, pressure altitude and IAS.  If connected to something like a G5 with a temperature sensor, the 375 would give true airspeed without entering anything else.  Of course, a G5 with a temp sensor would also give TAS.

One problem with any calculation is in my Mooney according to the POH, IAS is about 4 mph higher than calibrated airspeed where any correct calculation should start.  And then there is instrument error.  And installation errors.  Anyone ever check and verify the accuracy of their airspeed indicator?

I’ve done a bunch of 3 and 4 way speed runs using ground speed to solve for TAS. I was curious about my asi as well because I would also use my 430 from time to time just like the OP if I wanted a quick check and it seemed high.

So I took careful data at a couple of altitudes and solved back for IAS and found the asi was indicating about 4kts fast at about 130kts indicated. Not terrible, but that’s why I dont trust anyone just showing their TAS on an Aspen or G5 when we all debate who’s is faster.  It’s a garbage in/garbage out or “close enough for government work” type of thing.  If you want exact, you gotta do the 3 way speed tests.

[MBDiagMan]

Don’t know if it makes any difference, but my ASI was certified for IFR flight not long ago.

I do indeed understand and agree with what you’re saying.  I did a two way speed run with it not long ago, just fooling around, not scientific.  It was at low altitude.  I will go look up the data to make sure I don’t incorrectly state it here.

I went back and looked at my two way unscientific speed run and made a swag on temp and density altitude.  It came in within one knot of what the model J performance table indicated for those conditions.

Edited June 29, 2020 by MBDiagMan