Belite fuel level.

[WaiexN143NM]

Hi Phil,
Good update and report , thanks.

WaiexN143NM

[Sonex1517]

Excellent update! I will give that a try (fuel vent inside cowling)

Thank you very much


Robbie Culver
Sonex 1517
Chicagoland
N1517S

[Mike53]

While I appreciate the input for problem solving the Belite fuel probe ,I remain concerned about the approach taken.
Sonex clearly states in the drawings ,for the Onex at least, that the vent tube shall be cut at an angle and protrude into the slipstream to receive ram air pressure.
I'm not smart enough to figure it out completely,but would the lack of ram air not effect the pressure of the fuel getting to the carb once the tank is say down 2/3rd's.
There is no fuel pump to take up the slack as we are strictly gravity feed.
The Belite fuel probe just might not work properly on a system that requires ram air .
It would be great if Sonex added there opinion about the need, or not, of adequate ram air for the safe supply of fuel to the engine in all flight parameters.
Mike

[Corby202]

I can not say one way or the other for the need for ram air although I have proven it is possible to get negative pressure in the tank which would not help a gravity feed only fuel system . All I do know is the Belite transducer, set up as per Belites instructions will not give you an accurate reading with anything but static air pressure in the tank.

[mike.smith]

While I appreciate the input for problem solving the Belite fuel probe ,I remain concerned about the approach taken.
Sonex clearly states in the drawings ,for the Onex at least, that the vent tube shall be cut at an angle and protrude into the slipstream to receive ram air pressure.
Mike

I have my fuel vent at the bottom of the cowl but not in the slip stream, and plumbed from there up to the vent in the tank. So I have no ram air for my fuel tank vent. I have 150 hours on my Sonex in all temperatures and conditions, and have never had a fuel flow issue. I plumbed it the way I did because when I originally plumbed it the Sonex way and did aerobatics, if I even got a split second of negative G's I got fuel on the windscreen, and then it seeped between the windscreen and the glare shield and came into the cockpit. With the vent at the bottom of the cowl, no more fuel issues.

Just my 2 cents and lessons learned.

[Sonex1517]

So I trimmed my fuel vent slightly and now it is inside the cowling. Two flight this weekend and no change in results.

It is, oddly, reading accurate when I taxi. I have a taildragger and calibrated the fuel sensor for level flight.

It is still showing full fuel at all times in flight.

Robbie Culver
Sonex 1517
Chicagoland
N1517S

[Mike53]

So I trimmed my fuel vent slightly and now it is inside the cowling. Two flight this weekend and no change in results.

It is, oddly, reading accurate when I taxi. I have a taildragger and calibrated the fuel sensor for level flight.

It is still showing full fuel at all times in flight.

Robbie Culver
Sonex 1517
Chicagoland
N1517S

Thanks Robbie.Please keep us posted .I will hold off buying a Princeton probe till You are either successful or cry uncle.
Mike

[DCASonex]

Robbie,

You last test may show that you have positive pressure inside your cowl. Nice and neat and simple as that Belite sensor looks, it may be that it is just not a viable answer for use in Sonex. Tough that you have to be the one finding the problems, but useful info for others.

David A.

[vwglenn]

My fuel gauge is the tank itself. I emptied it and filled it two gallons at a time. I set it level and on it's tail and marked each side of the tank with a sharpie (one side is for three point on the ground and the other is for flight). I installed a wifi reverse camera under the panel and facing the tank. Fuel level can be viewed in real time on my phone or ipad. I got the idea when I saw a video of a biplane with an efis that had a screen set up with a forward facing camera for taxi operations. Most of the backup cameras have a IR capability so it can see the tank with very little available light. I think I'm going to back light the tank with an LED to make the fuel more visible. The only problem with the camera is it projects the image in "reverse" as if you're looking in a mirror so the numbers written on the tank are backwards. Think it would work just as well with a GoPro or any other wifi camera. I chose the reverse camera because it was around $40 and I could use my Ipad/iphone as the display.

[Bryan Cotton]

Neat idea Glenn. We had also discussed at one point a hole in the panel for a phone or ipad camera to peek through when it is mounted.