The riddle of the day --
What shows 18.2 GPH at take off, 18.1 GPH at top of climb (5500ft), 12.5 GPH in cruise (2500RPM, 24" MAP)?
My RV-7
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Back story: I've been trying, with varied degrees of success, to get my G3X Touch to display correct fuel flow #'s for the past 200+ hours.
I have a Red Cube (FT-60) with straight steel fittings (AN816-6) and fuel lines without any appreciable bends within 6" of the cube. The cube is mounted with Adel clamps and AN4 bolts to the #2 & #4 intake runners (identical to RV-14 suggestion, page 43-09), and a heat shield mounted on the #4 exhaust stack.
Connections from cube to GEA 24 is a 3 position TE Mate-N-Lok connector, which in turn is strain relieved and secured to adjacent structures (read: not wiggling or vibrating in the breeze...)
I started with a K-factor of 68000, then adjusted to 72000, then 84000, then 77400, then 75009, then 73201, then 83024, and so on and so on. Adjusting the parameters became a lot easier with the more recent software revisions of the G3X touch (v8.6 and later), but each/every flight I adjust the gallons burned/filled as reported by the G3X to what the pump says I took on board, a gallon or two over, or under, ad-infinitum...
For what its worth, I had this exact same setup (engine, propeller, cube, cube location, ignitions, airframe, etc...) except I was using Rob Hickman's AF-3400EM -- the fuel flow readings were D.N.O., each time, every time...
So, I'm begging for the wisdom of the hive-mind; Is this just the way it is? Is there something else I should look at?
B
What shows 18.2 GPH at take off, 18.1 GPH at top of climb (5500ft), 12.5 GPH in cruise (2500RPM, 24" MAP)?
My RV-7
---
Back story: I've been trying, with varied degrees of success, to get my G3X Touch to display correct fuel flow #'s for the past 200+ hours.
I have a Red Cube (FT-60) with straight steel fittings (AN816-6) and fuel lines without any appreciable bends within 6" of the cube. The cube is mounted with Adel clamps and AN4 bolts to the #2 & #4 intake runners (identical to RV-14 suggestion, page 43-09), and a heat shield mounted on the #4 exhaust stack.
Connections from cube to GEA 24 is a 3 position TE Mate-N-Lok connector, which in turn is strain relieved and secured to adjacent structures (read: not wiggling or vibrating in the breeze...)
I started with a K-factor of 68000, then adjusted to 72000, then 84000, then 77400, then 75009, then 73201, then 83024, and so on and so on. Adjusting the parameters became a lot easier with the more recent software revisions of the G3X touch (v8.6 and later), but each/every flight I adjust the gallons burned/filled as reported by the G3X to what the pump says I took on board, a gallon or two over, or under, ad-infinitum...
For what its worth, I had this exact same setup (engine, propeller, cube, cube location, ignitions, airframe, etc...) except I was using Rob Hickman's AF-3400EM -- the fuel flow readings were D.N.O., each time, every time...
So, I'm begging for the wisdom of the hive-mind; Is this just the way it is? Is there something else I should look at?
B