I’m setting up a Fiorotti timer on a new plane. I used this same timer on my previous SV11. This is a new SV11. Both were ARFs. I have leveled the plane both upside down and upright using a level and the same surface of the airframe. I verified the wing to be level both ways as well. The reference “C” on the Jeti programmer says 418. I set the sensor so that it read 418 and mounted it on the wing. Just to double check, I flipped the plane over and releveled it. Now the sensor is reading 408. I thought that the C reference was the zero point. From the looks of it, I need to reposition the sensor so that it reads 413 both upside down and right side up. I don’t remember questioning this when I mounted it on the last SV11 but the 413 number had a familiarity to it when I figured that is what would be needed for level both directions.
I actually set it to the 418 initially without double checking and flew several flights. I noticed that inverted and upright lap times were noticeably different. That’s why I am now investigating the sensor position.
Hs anyone else ran into this where the neutral point of the sensor doesn’t match the C reference number?

Thanks, Matt

Ken,
After you tweak yours, what do you get for numbers from the timer Y and X when the plane is leveled on the bench upright and inverted?  What does the plane look like on the bench upright and inverted if you level the sensor to Y = C, upright and inverted?  As you noted, the C value is a value sent from the sensor on a carefully leveled table, then stored.  That is the reference value and the reason that Y should equal C.