Fuel Flow Computer

Hi All:

When I purchased my aircraft (I am the third owner) it was already fitted with a "NavMan" fuel flow computer (gives in litres  "Fuel Flow" - in real time,  "Gas" - fuel remaining, " Trip" - fuel used, "Tot" - accumulated fuel consumed and "Alarm" - can be set for whatever remaining tank quantity the pilot desires).

The instruction booklet is very basic as is the trouble shooting guide.

There is an installation advice section. which I have followed to the letter eg mounting the sender/impeller in/on a vertical fuel pipe.

Initially the unit worked very well and was highly accurate, within a fraction of a litre - but now the Flow readings are "all over the shop" but strangely enough the Gas/Trip & Tot are fairly accurate within about 2-3  litres.

Attempts to make small adjustments for accuracy (according to the instruction book) can and does lead to wild changes, so I am loath to try again for the umpteen time.

Even when it was spot on its not an instrument a safe pilot would rely on but it was kind of neet to see power changes reflected in fuel flow.

I believe the supplier (NZ ) has closed up shop (???)

Who of you has one of these or has experience with them???

Any advise that may help restore its former accuracy ??

Any constructive advice at all, would be most welcome.

Could you be getting electrical interference with the impeller pulse circuit.? Charging a device or any new equipment installed? 

The wiring is most likely shielded to prevent this happening.   

The instrument will consist of two parts. the sender, which you have mounted and the display.

There are several different senders on the market and I do not know which is used by Navman, but they all work on the same principle of counting pulses. There is probably a toothed wheel turned by the flowing fuel and the sender counts the teeth as they pass a sensor.

The fact that the total fuel use is OK, but I assume you are saying that the litres per minute is incorrect, says that the sender is working OK. Maybe the problem is due to vapour in the line. That would stop the pulses and then later increase them. The fuel flow would stop and you would be running on fuel in the carbie bowl, then suddenly it would flow at a high rate..

I am in the process of fitting one to my plane and haven't calibrated it yet, due to having to repair a leaking fuel tank.

The New Zealand one (that I have right here) is Northstar Explorer F210.

The fuel flow sender is a transducer. In the book, it says that they are not suited to EFI engines with a fuel return line to the tank.

At the time I bought mine (2010) there was some talk that there was an aviation "special" version for avgas, and the other regular one for boats, cars, whatever. I queried that with the manufacturer. They laughed. "Fuel is fuel is fuel matie! It doesn't know what's going up the pipe!"

Had one in my old Skyfox.  Paddle wheels seem to always wear in time and fail.  I don't  put my fuel burn trust in them. Monitor fuel sight tubes. If you can borrow another sender or if you can purchase a new sender. May turn out to be a waste of money but you will know if that was the fault. Cheers

The New Zealand one (that I have right here) is Northstar Explorer F210.

 

The fuel flow sender is a transducer. In the book, it says that they are not suited to EFI engines with a fuel return line to the tank.

 

At the time I bought mine (2010) there was some talk that there was an aviation "special" version for avgas, and the other regular one for boats, cars, whatever. I queried that with the manufacturer. They laughed. "Fuel is fuel is fuel matie! It doesn't know what's going up the pipe!"

 

Looks remarkably similar, especially the little impeller/sender housing, read out and the installation instructions (A re badge job ??). 

Company name now appears to be Northstarr which may have become Navco.

........................................... If you can borrow another sender or if you can purchase a new sender. May turn out to be a waste of money but you will know if that was the fault. Cheers

 

Hi Blue A,

Any idea where I might get another sender ???

Could you be getting electrical interference with the impeller pulse circuit.? Charging a device or any new equipment installed? 

 

The wiring is most likely shielded to prevent this happening.   

 

The wiring is shielded - but will double check wiring rout to avoid contact/ proximity with other devices. Thanks

Skippy , I have separate booklets for both Northstar F210 instrument head and Flow transducer. There was also a software upgrade (V3:1) about “How to enter fuel flow menu “ . Let me know if any of this may help...... Bob 

Skippy , I have separate booklets for both Northstar F210 instrument head and Flow transducer. There was also a software upgrade (V3:1) about “How to enter fuel flow menu “ . Let me know if any of this may help...... Bob 

 

Hi Biggles,

Yes very interested. It seem to me the NavMan metamorphosed into the Northstar F210 - even the operators manual looks the same, as does the readout GAS/TRIP/TOT. There were esthetic changes to the architecture of the "face" but the read out & number of buttons remain the same.

      Skippy, Send me a PM with your email address . Not sure how to send PM with pics !...... Bob