shaddin digaflo-l

[rick bell]

Originally posted by Bob Cook
Has anyone accurately tested the digiflo against usage ?
if so what were the results ?

Has anyone accurately calibrated a Digiflo against a known flow rate?

Does anyone have it connected to their GPS?

Bob

have not tested accurately, just by knowen distances and setting and it seem close,
finall got mine hooked up to the gps(some of the older models of gps were not compatable, gx55 is)
rick

[Gord]

Bob - also use Shadins in my T337H, keep the tanks full, and am within 1 gallon per side when filling myself. Never have had any problems. Gord

[Bob Cook]

I have a Shadin as well, however, I found I needed to calibrate as after 6 or more partial fills, I found I was out be about 15 gallons per side (out of 74 gallons / per side.

I eventually made adjustments to more accurately reflect the actual flow. If you just fill the tank each time then I found the error to be within a gallon or two and within the accuracy of trying to fill the tank..

Guess we are dealing with accumulative errors and I was trying to compare notes. Not always able to just fill the tanks, consequently I end up with more fuel than anticipated.


Bob

[Kevin McDole]

Bob, I use Shadin DigiData systems in several aircraft and each exhibits their own small, but predictable error. In every case it errs on the "safe" side (says more fuel was consumed than actually was). The worst case unit indicates about 6% too high of a few burn. So when I fill it up, it takes a little less fuel than the Shadin predicts.

This should be a simple thing to calibrate - although I've never taken the trouble to do it. The fuel flow transducer has a "K-Factor" printed on its tag - and this number gets entered into the Shadin through a setup menu. The K-Factor is the number of pulses per gallon that the fuel transductor will output. As I recall, one of my units had a 28,500 K-Factor. To make the 6% correction I should be able to tell the Shadin that the K-Factor is 6% higher than the tags says. In other words, if I enter 30,210 into the Shadin it should cancel out the error.

I have no idea whether this is legal. You'd have to check with your avionics shop or Shadin to see what the rules are.

[Bob Cook]

Kevin

Re calibration

I was planning on doing this calibration. I find I am off about 6-7% over 500 gallons (same on each engine). There is a 1.5-2% difference between front and back engine.

When I go to add 120 gallons I can't get all the fuel in. This gets frustrating when you are running close to gross weight .... 180 lbs (or more) than requred. This is the error I need to correct. I am usually fighting a gross weight take-off.

Depends which error you can live with; too much weight or not enough fuel..........

I have the shadin interfaced to the kln90B which gives to fuel totals for EACH engine and alternate reserves if put in your flight planned route. Works very well.

The sensor values (K factor) are the same for each sensor which leads me to believe the sensor is not calibrated to a finite value.

Bob