Hobbs vs tach time

[goldthwaite flyer]

Second owner for a legacy Sonex with Jabiru 2200 engine. The original owner didn't track tach time but did all time related maintenance based on Hobbs. Is this normal in the experimental world? All of my experience was in certified where we went off tach time for things like oil change, overhaul, etc.

[Bryan Cotton]

Tach time will be less than Hobbs time. So if you maintain by tach time you are maintaining less. FBOs charge by Hobbs and maintain by tach. Minimizes costs, maximizes money coming in. Maintaining by Hobbs is fine.

[N111YX]

Consider all of the ways to "clock" time...

-engine "on" time
-tach at "cruise" values
-oil pressure above a certain value
-"off chock" time (is this "flight" time?
-GPS groundspeed derived targets
-landing gear proximity switches
-a manual switch for a Hobbs meter (what I have)
-manual noting of ON/OFF/ON/IN times
-reviewing one's flight in Flightaware

I'm sure I'm missing a few. :)

[builderflyer]

John, go to the Jabiru Austrailia website and read Jabiru Service Letter 010-1. This Service Letter explains how the Jabiru factory wants the engine time to be recorded. Bottom line.......they want you to use "Hobbs" time. When Jabiru came out with this information back in yr 2014, I took the time to correct my engine log books to reflect their directive. While you're on the Jabiru website, read the rest of their bulletins and letters as they can be very informative in the proper operation and maintenance of their engines. Hope this helps.

Art,,,,,,,,,,,,,,,,,,Sonex taildragger #95,,,,,,,,,,,,,,,Jabiru 3300 #261