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  #51  
Old 08-05-2018, 09:37 PM
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czechsix czechsix is offline
 
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Marvin, remember there can be minor variations in how well an airplane is leveled during AHRS calibration, plus G3X gives you the ability to enter a pitch offset in flight. I would not use pitch attitude to try to compare performance. IMHO the more important reference is the vertical speed which is zero in the first image and around 250 fpm descent for your airplane to achieve the same numbers...so if you let it stabilize in ALT hold you probably would see the expected reduced cruise speed (due to your larger wheels).
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  #52  
Old 08-05-2018, 11:57 PM
crabandy crabandy is offline
 
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Keep at it Marvin, Iím liking and learning with your post updates.

I thought I would have a defenitive timing map to post after a couple test flights since receiving my programmer, but itís taken me 50 hours (ignition only) of piddling to feel like Iím starting to get the hang of the testing-seeing-recording part of it all. Lots of variables that pop up during testing to skew true results.

Iíve long since given up on the time and money it costs for Test flights, I just try to work it in as I can on flights Iím gonna do cause Iím a fly-in anyway.
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  #53  
Old 08-06-2018, 05:46 AM
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M McGraw M McGraw is offline
 
Join Date: Dec 2012
Location: Greenback, TN
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Quote:
Originally Posted by czechsix View Post
Marvin, remember there can be minor variations in how well an airplane is leveled during AHRS calibration, plus G3X gives you the ability to enter a pitch offset in flight. I would not use pitch attitude to try to compare performance. IMHO the more important reference is the vertical speed which is zero in the first image and around 250 fpm descent for your airplane to achieve the same numbers...so if you let it stabilize in ALT hold you probably would see the expected reduced cruise speed (due to your larger wheels).
Hmmmm.... I had not considered a pitch offset. I’m not sure why I would do a pitch offset because pitch required will increase with altitude. I will ponder that one.

Those minor variations in G3X setup are again reinforcement that comparisions need to be made against a consistent baseline airplane and very difficult to get real data across multiple airframes when looking for very small changes.
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Last edited by M McGraw : 08-06-2018 at 05:48 AM.
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  #54  
Old 08-06-2018, 08:48 AM
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M McGraw M McGraw is offline
 
Join Date: Dec 2012
Location: Greenback, TN
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Quote:
Originally Posted by crabandy View Post
Keep at it Marvin, Iím liking and learning with your post updates.

I thought I would have a defenitive timing map to post after a couple test flights since receiving my programmer, but itís taken me 50 hours (ignition only) of piddling to feel like Iím starting to get the hang of the testing-seeing-recording part of it all. Lots of variables that pop up during testing to skew true results.

Iíve long since given up on the time and money it costs for Test flights, I just try to work it in as I can on flights Iím gonna do cause Iím a fly-in anyway.
Hello Andy,
I agree the testing can be time consuming and expensive. I went down a bit of a rabbit hole trying to compare to another aircraft on the rich of peak side, all the while knowing the actual advantage of the variable timing will be on the lean of peak side. When comparing across airframes I cannot control weight, form, trim or cooling drag. I cannot control calibration, repeatability, etc...

I repeat all my data a minimum of three times to see if any should be dicarded. The value of the data is a controlled change against a baseline not the total number. For me the time and expense is more of a learning experience since Iím not trying to feed three kids like you
I post the data because people on this board can point to errors I may have overlooked. That is the value I find on this messageboard.

Sandy and I did look for your airplane at OSH several times. We came up short even though I know you were there.
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Last edited by M McGraw : 08-06-2018 at 12:39 PM.
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  #55  
Old 08-06-2018, 06:21 PM
crabandy crabandy is offline
 
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Originally Posted by M McGraw View Post
Hello Andy,
I agree the testing can be time consuming and expensive. I went down a bit of a rabbit hole trying to compare to another aircraft on the rich of peak side, all the while knowing the actual advantage of the variable timing will be on the lean of peak side. When comparing across airframes I cannot control weight, form, trim or cooling drag. I cannot control calibration, repeatability, etc...

I repeat all my data a minimum of three times to see if any should be dicarded. The value of the data is a controlled change against a baseline not the total number. For me the time and expense is more of a learning experience since Iím not trying to feed three kids like you
I post the data because people on this board can point to errors I may have overlooked. That is the value I find on this messageboard.

Sandy and I did look for your airplane at OSH several times. We came up short even though I know you were there.
Short OSH for me due to work, had to leave Tuesday am. Glad to catch you for the short visit!

And itís 4 kiddos......and a horse
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  #56  
Old 08-06-2018, 06:50 PM
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rmartingt rmartingt is offline
 
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Quote:
Originally Posted by czechsix View Post
Marvin, remember there can be minor variations in how well an airplane is leveled during AHRS calibration, plus G3X gives you the ability to enter a pitch offset in flight. I would not use pitch attitude to try to compare performance. IMHO the more important reference is the vertical speed which is zero in the first image and around 250 fpm descent for your airplane to achieve the same numbers...so if you let it stabilize in ALT hold you probably would see the expected reduced cruise speed (due to your larger wheels).
Yes, you should use level flight as indicated by zero feet per minute and/or your velocity vector (the little green airplane symbol in the upper picture) on the horizon line. The yellow waterline marks represent the deck angle, and you'd expect that to be a little above the horizon in cruise unless you've programmed an offset so it's on the horizon at typical cruise conditions. And even then it will vary--at light weights and high speeds it may well be below the horizon in level flight.
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