Garmin Pilot M20M performance profile?

[Rick Junkin]

Has anyone taken the time to build a Garmin Pilot performance table for the M20M? And are you willing to share your work?

Almost everything in my panel (and on my wrist) is now a Garmin product and I'm in the process of making the move from Foreflight to Garmin Pilot for reasons of synergy. I'm not liking the change so much, but then I've been a Foreflight devotee since version 1. The more I experiment with Garmin Pilot the more I understand how it does most of the same things as Foreflight but in a different way, and some things much less elegantly. But I digress.

Back to my ask - GP appears to have performance tables for every Mooney model except the M20M. I initially built my own for Foreflight, and can do it again for Garmin Pilot, but if someone has already done the work I humbly request to share in the fruits of your labor. I've put together something that will work for my primary flight profile but would like to have the data for multiple power settings for more robust planning options.

Thanks in advance.

Cheers,
Rick

[Patrick Horan]

I'm looking aswell!

I believe fltplan has M20M profile. I use Fltplan for my filing in the M20C since it's extremely accurate. But I might be purchasing a bravo soon!

Edited December 31, 2023 by Patrick Horan

[DavePage]

Has there been any progress in this subject?  Rick or Patrick, have  you done one for your Bravo?  I'm facing the same delima w/ GP, no M20M listed for aircraft.

[Patrick Horan]

16 minutes ago, DavePage said:

Has there been any progress in this subject?  Rick or Patrick, have  you done one for your Bravo?  I'm facing the same delima w/ GP, no M20M listed for aircraft.

I just manipulated an acclaim profile. I might reach out to Garmin and see if they can create one

[dkkim73]

2 hours ago, Patrick Horan said:

I just manipulated an acclaim profile. I might reach out to Garmin and see if they can create one

@Patrick Horan, did you find a good Acclaim profile for GP? Detailed flight planning performance data is one of the things that I've been lacking in using GP more. 

[Rick Junkin]

3 hours ago, DavePage said:

Has there been any progress in this subject?  Rick or Patrick, have  you done one for your Bravo?  I'm facing the same delima w/ GP, no M20M listed for aircraft.

@DavePage @Patrick Horan Short answer is yes. Longer answer is what I’ve done may not be useful to you. I’m happy to share it with the understanding you’ll assume it is inaccurate until you personally verify it’s accuracy for your airplane.

I spent about 20 hours over the past two days tabulating data from the M20M POH performance section graphs and entering them into the Garmin Pilot tables. I only went up to 20,000’ with the data, as I’m seldom above 16,000. Unfortunately I’ve only verified the tailored data for my normal ops, which is 30/2200 LOP, that I was able to compare against the Foreflight profile I’ve been using successfully. I did input the peak TIT data for 27/2200 and 24/2200 with the intent of adjusting them to LOP values once I gather some empirical data for validation. However, I built a separate calculated “Best Power ROP” table for 100º ROP ops. I extracted initial values from my previous engine data files and extrapolated the rest of the table (very roughly, I must add) using the peak TIT values for 24/2200, 27/2200, and 30/2200 at ISA+/-20ºC as a basis and fixed fuel flow values of 13, 15, and 17GPH respectively. This table is also unverified and is my starting point for refinement. I haven’t had a chance to run the Best Power GP table against my Foreflight profiles for more than just a quick look, but the GP output was within about 2% of the Foreflight output for one ROP scenario so I think it’s a good start. I won’t be using it for any critical planning without carrying lots of extra gas until I’m able to collect some flight data for validation.

39 minutes ago, dkkim73 said:

@Patrick Horan, did you find a good Acclaim profile for GP? Detailed flight planning performance data is one of the things that I've been lacking in using GP more. 

@dkkim73 Garmin Pilot has a performance profile for the M20TN, but I can’t speak to its veracity. The profiles they provide are proprietary and there’s no way to see what’s in them without loading them up and using them. Perhaps there is someone here who is already using it and can speak to that. You could do the same thing I did and subscribe to both GP and FF and then compare the GP flight plan output with your current trusted data. If you have a larger iPad with the latest iOS you can run both apps side by side in landscape. It’s a great way to compare them and help inform your decision on which way to go.

As for reaching out to Garmin, I asked if they would add an M20M profile and got a quick reply asking me for a copy of the POH. I sent it to them but haven’t heard or seen anything since then. That was at the end of last summer.

 

[Rick Junkin]

On 12/30/2023 at 8:19 PM, Patrick Horan said:

I'm looking aswell!

I believe fltplan has M20M profile. I use Fltplan for my filing in the M20C since it's extremely accurate. But I might be purchasing a bravo soon!

Quoting an old post - DON’T USE THE FLTPLAN.COM M20M PROFILE! It’s a single cruise profile and I’m pretty sure its based on the 34/2400 best power data in the POH. Definitely not what you want to use.

[Rick Junkin]

Closing the loop on this, or at least my part of it. I put the Garmin Pilot advanced profile I built for my M20M in the downloads section.

Don't use the output from this profile until you have validated it for your specific application.

The output from the profile checks well against the Foreflight profile I have trusted for years, as well as against my historical empirical flight data. I only validated it at my SOP cruise setting of 30/2200, 13.2GPH LOP. The data basis is the POH, so the profile should be accurate enough for planning purposes at other cruise settings.

But don't get too excited if you're looking for a comprehensive profile that will work for any power setting, 'cause this isn't it. It's pretty much the same as the Foreflight M20M profile in that it only has performance data for the RPM/MP combinations in the POH, and I only entered airspeed data for ISA +/- 20ºC up to 20,000'. So if you cruise at 2200RPM between 24 and 30", or at 2400RPM between 32 and 34", you're in luck. If you're running 29/2400, which I believe a lot of people use, this profile doesn't have data to support that planning. It's a fairly easy but tedious task to add your empirical 29/2400 performance data to the profile table, but it may be easier to just enter a single basic set of cruise parameters (TAS and FF) and accept the variability in accuracy with altitude and temperature changes.

I entered the peak TIT data directly from the Section 5 charts into the Garmin Pilot advanced performance table to set the ground truth model. Nobody flies like that, but those are the only numbers in the book. Fortunately GP has a function called "Cruise Modifiers" that allows you to apply an adjustment to the values in the table to match your empirical performance. It works by applying a % increase or decrease to MP, TAS and FF from the performance table. Each parameter is independent and can have its own adjustment up or down. I put in a selectable modifier for 35º LOP TAS (-4%) and FF (-8%), and another one for 100º ROP TAS (+3%) and FF (+19%). I came up with the adjustment factors by comparing the GP output for a flight plan with the Foreflight output for the same flight plan at several altitudes and then picked the "best fit" adjustment factor. I also compared adjusted GP output to flight data for validation. All of this can be modified by the user to fit your specific application. If you run 150º ROP you can adjust the ROP modifier up to accurately reflect your increased FF and TAS.

I also derived specific LOP and ROP tables external to GP as a part of this exercise. I originally had entered them into GP (780 data entries... ) but realized it would be easier in actual use to employ the Cruise Modifier function with only the peak TIT numbers entered. At least I have all that tabulated data now. Oh boy.

If anyone has or finds something better please let me know. I'd like to say building this was a fun task, but...