Actual fuel quantity

[Bob - S50]

FWIW.  When we calibrated our fuel gauge, we drained the tank through the gascolator.  Once it stopped, we got the rest out through the sump.  We only managed to get about a quart out through the sump.  However, this was with the plane sitting on the ground, not in level flight attitude.  To be legal, the book says each tank on the J has 1.25 gallons of unusable fuel so we put that much back in the wing and called it empty.  However, I'm pretty confident, that in a real world of hurt, some of that 1.25 would be burnable.  I have not had the opportunity to check.

Once we install the Cies floats, I may do that on purpose.  My plan would be to calibrate as required (calling 1.25 gallons as empty), then go fly and run one tank dry.  Time how long the engine runs after the gauge says zero.  With a known fuel flow I would then also know how much of that unusable was really usable in level smooth flight.

Looks like I have a lot to do once those Cies floats are in.

[Bolter]

On 10/29/2016 at 11:33 AM, Bill Mnich said:

[edit]

Now, leveling the aircraft when filling the tanks is another issue. In fact there is a procedure in the Mooney Maintenance Manual for Fuel Tank Transmitter Adjustment which states that "AIRCRAFT MUST BE LEVEL TO CALIBRATE FUEL GAUGES". In my airplane the factory analog gauges are gone and fuel quantity is now on the JPI, but the refill procedure from empty tanks would be the same to get a 5-point calibration for the EDM-900 (for empty, 1/4, 1/2, 3/4, full). I wasn't there to observe this process but no doubt the airplane was rolled onto the ramp to get fuel from the truck, and that ramp is not nearly as level as the hangar floor. From the MM, the final step in the procedure to establish the FULL reading on the gauge is to "Finish filling tank until fuel just starts to spill over outer wing surface". Well, when I got to the airplane after the fuel calibration, my tanks were extremely full, but not that full! 

So, my first target is to do a slow, methodical top-off of each tank to where the fuel starts to spill over the wing. I know from experience in this and previous Mooney's that you can squeeze a lot of fuel into those wings if you're patient. Assuming that in fact 68 gallons was loaded from the truck into assumed empty tanks, because my fuel flow meter is pretty accurate, I know how much I burned. Sure, there's the possibility of an error stack from the fuel truck meter that loaded that 68 gallons, variations in fuel temp and therefore fuel density, aircraft attitude on the ramp at the self-serve pump, etc. But it's a start. 

[edit]

I am confused with repeated references to level floors.

I always interpreted "AIRCRAFT MUST BE LEVEL" to mean in pitch as well as roll to match FLIGHT level.  This would require jacking the plane, and the near-levelness of the floor is a non-issue (as long as it is safe jacking platform).  Resting on gear, we are nose up.  In flight, we have beautiful, graceful machines with tails level with the nose.  

Is this wrong?  

-dan

[Hank]

Dan--

"Level" is defined in the Maintenance Manual for your plane. For mine, it's the bottom of the radio access hole in the rear fuselage. Should be for your J, too. I think.

[kortopates]

On the mid-body's and later it's in reference to a couple screws on the outside skin right above the avionics bay door. Leveling is usually accomplished by adjusting tire pressure.


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[Bolter]

4 hours ago, kortopates said:

On the mid-body's and later it's in reference to a couple screws on the outside skin right above the avionics bay door. Leveling is usually accomplished by adjusting tire pressure.


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Paul and Hank, thanks for the added info.  I think it means I am due for another Mooney PPP course! :-)

-dan

[Guitarmaster]

On the mid-body's and later it's in reference to a couple screws on the outside skin right above the avionics bay door. Leveling is usually accomplished by adjusting tire pressure.


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I never thought about using tire pressure to level the plane... I learn so much from this site!


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[carusoam]

There is a picture where Mooney was showing their latest plane at a show(?).  The plane is leveled as if in flight. The blocks under the mains were visible to the Knowing...

Best regards,

-a-