Ovations Needed for Savvy Analysis!

[ArtVandelay]

Is the EDM/GTN communication 2 way? I don't see any evidence that the GTN gets info from either the EDM or the PFD consequently I don't think the GTN knows IAS, OAT, or even BARO/Altitude. It knows GPS speed (GS) and GPS altitude. But I'd love to be wrong, there's a lot of stuff that I don't know and some of the stuff I do know ain't so.

Sent from my XT1254 using Tapatalk

If you go to your fuel planning page, it should be populated from the fuel flow data from the JPI, a protocol I believe developed by shadin fuel flow boxes, since they did not have OAT, it's not included in the data sent to the gtn. The gtn does have gps altitude but you're right, it's missing IAS.

[kortopates]

10 hours ago, Bob_Belville said:

Paul, I cannot imagine that ground speed is very meaningful when comparing performance. Without knowing the wind how can we compare flights? FWIW, my EDM 930 does not display GS and the value that it stores is nonsensical. I've discussed that issue with JPI and Garmin several times but have not been able to get to the bottom of it. JPI says their box records the GS as received from the Garmin (via RS232) but what gets stored  is very different from what the 750 displays. .   

The Aspen PFD 1000 Pro seems to calculate TAS and the wind vector from the air data (IAS) and heading, probably using OAT and Baro as well - E6-B stuff. I don't think the 750 does the same, does it? It does not display TAS or wind. Does it know OAT, Baro, IAS?

Actually ground speed is not that far off. Mike did a webinar where he talked about "Big Data" and a study Chris did on this very topic. They looked at Groundspeed vs TAS and showed that groundspeed was a bit slower on average from TAS because as I am sure you understand headwinds and tail winds don't average out or cancel each other out, Then they showed on average to wind that for any heading to the relative wind, about 200+ degrees out of the 360 is actually a headwind leaving only less than 160 degrees in the headwind component. They also covered some other interesting aspects. But in the end on average over lost of flights groundspeed was proportionately related to TAS i.e., It all averages out with lots of flight data.

Yes, the GTN750 accepts airdata input and will calculate the the wind vector, density alt, TAS etc for you using sensor airdata (and of course manually too). Airdata includes much more than OAT and baro, also requires pitot-static data. I don't know if there is provisions to pass airdata from the Aspen to the GTN - good question.  

However, recognize EDM relies on a specific fuel interface to talk to the GPS's as @teejayevans was saying. The fuel interface was engineered to allow the GPS to do fuel planning and allow the EDM to display fuel remaining at your destination (or next waypoint) that's the main reason why groundspeed is going back to the EDM. The Garmin serial port configuration may be setup incorrectly or to what the EDM is configured to expect for the GTN to EDM fuel interface. The JPI web site explains the specifics of what the settings are and might help you correct the ground speed issue you're experiencing on the EDM data. It was the fuel interface that was so handy in allowing pilots to climb to altitude and then just lean till they had the desired range at their destination to increase range safely for long cross countries - assuming you had a good handle on how much fuel you really had in the tanks.

Edited September 3, 2017 by kortopates

[Bob_Belville]

8 hours ago, kortopates said:

Actually ground speed is not that far off. Mike did a webinar where he talked about "Big Data" and a study Chris did on this very topic. They looked at Groundspeed vs TAS and showed that groundspeed was a bit slower on average from TAS because as I am sure you understand headwinds and tail winds don't average out or cancel each other out, Then they showed on average to wind that for any heading to the relative wind, about 200+ degrees out of the 360 is actually a headwind leaving only less than 160 degrees in the headwind component. They also covered some other interesting aspects. But in the end on average over lost of flights groundspeed was proportionately related to TAS i.e., It all averages out with lots of flight data.

Yes, the GTN750 accepts airdata input and will calculate the the wind vector, density alt, TAS etc for you using sensor airdata (and of course manually too). Airdata includes much more than OAT and baro, also requires pitot-static data. I don't know if there is provisions to pass airdata from the Aspen to the GTN - good question.  

However, recognize EDM relies on a specific fuel interface to talk to the GPS's as @teejayevans was saying. The fuel interface was engineered to allow the GPS to do fuel planning and allow the EDM to display fuel remaining at your destination (or next waypoint) that's the main reason why groundspeed is going back to the EDM. The Garmin serial port configuration may be setup incorrectly or to what the EDM is configured to expect for the GTN to EDM fuel interface. The JPI web site explains the specifics of what the settings are and might help you correct the ground speed issue you're experiencing on the EDM data. It was the fuel interface that was so handy in allowing pilots to climb to altitude and then just lean till they had the desired range at their destination to increase range safely for long cross countries - assuming you had a good handle on how much fuel you really had in the tanks.

Thanks! I'll have to dig deeper into the bowels of all 3 of my smart boxes.

[kortopates]

Chris has added support for the M20E model now too - go for it @Bob_Belville

[Bob_Belville]

Just now, kortopates said:

Chris has added support for the M20E model now too - go for it @Bob_Belville

Paul, I received an email a little while ago and have already reviewed both the report and the trends. Nice. (At this point the Es are in a cohort with the several O360, 180 HP models - Cs, Gs, etc.. I suspect there are a lot more Cs in there than Es.) But the info is very interesting. 

[kortopates]

9 minutes ago, Bob_Belville said:

Paul, I received an email a little while ago and have already reviewed both the report and the trends. Nice. (At this point the Es are in a cohort with the several O360, 180 HP models - Cs, Gs, etc.. I suspect there are a lot more Cs in there than Es.) But the info is very interesting. 

I see what you mean (running with your N number) , I am checking on that. In other communications I got the below implying a separate cohort so I'll report back after I verify with Chris:

M20E / IO-360
M20 (A,B,C,D,E,G) / O-360
M20 (S/R) / IO-550

 

[gsxrpilot]

I'm a subscriber and am looking forward to the K's being added.

[kortopates]

On 9/4/2017 at 7:05 PM, kortopates said:

I see what you mean (running with your N number) , I am checking on that. In other communications I got the below implying a separate cohort so I'll report back after I verify with Chris:

M20E / IO-360
M20 (A,B,C,D,E,G) / O-360
M20 (S/R) / IO-550

 

Hi @Bob_Belville  and our other M20E clients such as @HRM

Sorry but good news. Its not at all clear, but E model's reporting cohort is truly only E models. We have one Savvy aircraft model for all Vintage short bodies that includes A,B,C,D,E & G. But we derive 2 different reporting cohorts from it, i) 0-360 180 HP powered and ii) IO-360 200 HP powered. Thus the latter cohort is only E models and the former group is all the A,B,C,D,&G. See a follow on post with an example.  

Still on the list are the K,  M and & TN models.

On 9/4/2017 at 7:16 PM, gsxrpilot said:

I'm a subscriber and am looking forward to the K's being added.

Agreed, if it was my choice, the K's would have been first out!  

Edited September 6, 2017 by kortopates
Corrected E model cohort

[carusoam]

Paul,

Remind the team...

Start planning to add a spot for variations in engine ignition timing for those that have selected 20 vs 25° BTDC or electronic ignition...

Some interesting ideas will probably become available from the data...

Best regards,

-a-

[kortopates]

Since the cohort is confusing, due to some early choices we made in grouping similar models into Savvy Aircraft models I'll try to clear up this up with an example.

Here is an example, generating a report card on Bob's E model.

When a Vintage Mooney user enters their N number into the drop list, it will display the Savvy Aircraft model that is shown right after the N number below in the report header. However, although the E model, are combined in the Savvy Aircraft Model M20A/B/C/D/E/G, the reports are based on a unique cohort that uses both Aircraft model and Engine model. In this example the aircraft model includes only two engine type i) all O-360 180 HP, and ii) all IO-360 200 HP. You can think of the cohort as the intersection of aircraft models with the specific engine - in this example the IO-360 i only a match for the E model and eliminates everything else. (its not intended to read as all the A/B/C/D/E/G use an io-360!) And in this examples, Bob's E model is being reported on along with 31 other E models. The second cohort, with the O-360 engine, includes all the carbureted models only as expected i.e., M20A/B/C/D/G.

I hope that makes sense, and it took me a long time to decipher since I was only reading incorrectly as the union of the models and engine - mistake on my part.

We realize the use of our current aircraft models can be confusing but its going to take some time to make some significant changes down the road; meanwhile bear with us that the cohort is the unique tuple of our savvy aircraft model and engine combination.   

N943RW · M20 (A/B/C/D/E/G) · IO-360 · EDM-930

Includes 33 flights between Sep 05, 2016 and Sep 05, 2017, compared with 693 flights by a cohort of 31 M20 (A/B/C/D/E/G) aircraft.

So some of you may be wondering about differences in engine suffixes, like Dual mag versus separate mags and Anthony brings up 20 degree vs 25 timing differences. It gets much worse because we have clients that have installed electronic ignition, other STC engine mods for Merlyn pneumatic wastegates and/or Intercoolers on 231 K models, and STC HP increases on essentially same IO-550-G. It goes on and on. We do track most of this stuff for our clients that we report on, but we haven't yet incorporated these details into our Savvy aircraft model information so it neither available to our reporting software nor is the information even collected with our free account users. But just not yet though.  Give us time....

Edited September 6, 2017 by kortopates

[kortopates]

On 9/4/2017 at 7:16 PM, gsxrpilot said:

I'm a subscriber and am looking forward to the K's being added.

Chris just added support for our K's today. You should have gotten an email from Savvy.

another model covered. I believe we're now down to M & TN

[gsxrpilot]

1 minute ago, kortopates said:

Chris just added support for our K's today. You should have gotten an email from Savvy.

another model covered. I believe we're now down to M & TN

Yep, just got the email!  I'll be running reports soon.

Thanks!!

[thinwing]

Ok so waiting on the m addition