What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

How to calibrate the AFS 3500 FF-readings?

A

ao.frog

Well Known Member
Hi.

Today we tried to calibrate the FF-readings on the AFS-3500, but there must be an easier way than the metod we tried?

On the calibration page for FF, the K-factor was preset to 180, which gave a FF-reading of approx 110 gls/hr. (Fuelhose was disconnected just before the Silver Hawk fuel injector and put into a Jerry can)

When measuring the pumped fuel in the Jerry can, the actual FF was about 55 gls/hr.

We then adjusted the K-factor downard in increments and a K-factor at 80-85 seems correct to me.

Is there any other way to determine the exact K-factor, thus getting the indicated FF to be 100% correct?
 
ao.frog said:
Hi.

Today we tried to calibrate the FF-readings on the AFS-3500, but there must be an easier way than the metod we tried?

On the calibration page for FF, the K-factor was preset to 180, which gave a FF-reading of approx 110 gls/hr. (Fuelhose was disconnected just before the Silver Hawk fuel injector and put into a Jerry can)

When measuring the pumped fuel in the Jerry can, the actual FF was about 55 gls/hr.

We then adjusted the K-factor downard in increments and a K-factor at 80-85 seems correct to me.

Is there any other way to determine the exact K-factor, thus getting the indicated FF to be 100% correct?
Click to expand...

Alf - I would do what it says at top of p25 in the manual. That worked for me last time I did this, and it looks as though it is going to work well on my new -4. I am only puzzled that it is not closer out of the box. Mine is. I will look at my K-factor for you if that is a help?
 
ao.frog said:
Hi.

Today we tried to calibrate the FF-readings on the AFS-3500, but there must be an easier way than the metod we tried?

On the calibration page for FF, the K-factor was preset to 180, which gave a FF-reading of approx 110 gls/hr. (Fuelhose was disconnected just before the Silver Hawk fuel injector and put into a Jerry can)

When measuring the pumped fuel in the Jerry can, the actual FF was about 55 gls/hr.

We then adjusted the K-factor downard in increments and a K-factor at 80-85 seems correct to me.

Is there any other way to determine the exact K-factor, thus getting the indicated FF to be 100% correct?
Click to expand...

I just checked the calibration setting for your unit and it was shipped with a setting of 680. This number should be very close to what is actually required. The sensor is not going to read correctly pumping into a bucket at 55 gals/hour. You should do the following:

1. Set the number back to 680
2. Fill the tanks
3. Fly the plane for over half tanks.
4. Fuel the plane and compare the gallons used on the screen to the pump.
5. Use the following equation to adjust the K factor:


New Counts per .01 gals = (Old Counts per .01 gals) x (Disp GAL USED/PUMP GALS)

Rob Hickman
Advanced Flight Systems
 
Aha...

Hi.

Thanks for the advices guys!

I know a little more now:
I've set the quantity on the EFIS to show LITERS (we're using metric in Norway) and for liter-indication, the K-factor showed 180.

When I wrote the VAF-post however, I calulated the liters into US gls since I was writing on an american forum.
What I didn't think of or notice however, was that the K-factor changed from 680 to 180 when I switched the EFIS from US-gls to liters.

That's why Rob's and mine K-factor was so far apart...

Anyway: the K-factor is now set back to 180 (for liters) and I'll testfly it as Rob suggests.
Thanks for chiming in Rob and Steve!
 
You must log in or register to reply here.
Back
Top