Simple way to read 85 litre fuel tank

[shajen]

Interested in what ideas are being used to read the fuel level in an 85 litre tank behind the seats. I find its easy enough to read down to about 45 l, then it gets too difficult to see easily.

i dont want to be adding electrics or dials on the dash, just a simple manual way of reading it. Also dont want to be removing tank to add sensors etc.

[coljones]

Yes, a pain in the bum. I have taken to using my phone to take a picture at startup, every half hour and at shutdown. Makes a good fuel log as well. Not sure about the last 5 litres but the last 10 is my reserve in a J120.

[skippydiesel]

19 hours ago, shajen said:

Interested in what ideas are being used to read the fuel level in an 85 litre tank behind the seats. I find its easy enough to read down to about 45 l, then it gets too difficult to see easily.

i dont want to be adding electrics or dials on the dash, just a simple manual way of reading it. Also dont want to be removing tank to add sensors etc.

To the best of my knowledge there are only two ways to have a panned read out:

 

(Both systems may be achieved without tank removal from aircraft however the site tube system may require "loosening" the tank to gain access for hole cutting)

 

Level tube/Site tube - this would require making a hole in or near the bottom of the tank. Putting in a tube connection/fitting. Fixing tube and taking it forward to the panned where you just might be able to see the level (a small fuel resistant ball floating in the tube might assist).

Up side - cheap, simple , reliable system. Similar system used on many aircraft (mostly high wing)

Down side of this sister is the potential for leaks, on going fuel smell in cockpit and ignitable fumes. 

 

Electric gauge - A suitable sized hole would need to be cut in top or upper side of tank. There are many sensor/sender options that can be fitted. 12 volt supply from aircraft system. Must have sender compatible gauge on panel.

Up side - neat compact fume free

Down side- cost, unreliable (always found mine to be spot on), potential for spark ignition

 

 

The only other content indicator would be some form of float.

 

A hole would need to be cut in the top of the tank to accommodate a long rigid clear view tube, sealed at the top. A float with "high visibility "stick"  attached. Stick goes into clear tube. Float into tank.  Obviously there would be dimensional considerations so that stick remines in clear tube when tank near empty and again will slide all the way up tube, when tank full.

Up side- cheap, reliable (if suitable fuel resistant materials found),accurate, fume & leak free.

Down side - any hole in tank may leak, site tube vulnerable to damage, behind pilot (not in field of view)

Edited August 12, 2021 by skippydiesel

[turboplanner]

A mirror mounted at an angle?

 

[onetrack]

The Radiant LCD fuel gauges, coupled with the Radiant Perfect Fuel Probe (an Ultrasonic probe), seem to me, to be the best choice of a fuel gauge for UL aircraft.

 

https://radiantinstruments.com/radiant-fuel-gauges/

 

https://radiantinstruments.com/perfect-fuel-probe/

 

At the end of the day, though, a timepiece, and knowledge of exact, real-time fuel flow measurement, is your best hedge against an engine sucking air!

[Old Koreelah]

54 minutes ago, skippydiesel said:

…The only other content indicator would be some form of float.

I wasted lots of time installing sight tubes on my wing tanks, in the hope they’d be visible in flight (they’re right next to my butte). I imported from USA some special red fuel floats to put in the sight tubes. One is readable, the other sank in the fuel. They’re still impossible to see while flying (a contortionist might be able to).

[skippydiesel]

35 minutes ago, onetrack said:

The Radiant LCD fuel gauges, coupled with the Radiant Perfect Fuel Probe (an Ultrasonic probe), seem to me, to be the best choice of a fuel gauge for UL aircraft.

 

https://radiantinstruments.com/radiant-fuel-gauges/

 

https://radiantinstruments.com/perfect-fuel-probe/

 

At the end of the day, though, a timepiece, and knowledge of exact, real-time fuel flow measurement, is your best hedge against an engine sucking air!

 

1 minute ago, Old Koreelah said:

I wasted lots of time installing sight tubes on my wing tanks, in the hope they’d be visible in flight (they’re right next to my butte). I imported from USA some special red fuel floats to put in the sight tubes. One is readable, the other sank in the fuel. They’re still impossible to see while flying (a contortionist might be able to).

Yeah! Despite the reluctance to cut a hole in the top of the tank, for sender installation, I think the best compromise is the good old automotive style fuel gauge. lots of sender type options out there, just be sure that whatever you chose is compatible with the gauge itself.

 

Your primary fuel quantity management system, must always be as per Onetrack's advice.

[Old Koreelah]

I rely on good planning and dipping tanks before flight.
The second-hand Fuel Mizer I bought from Maj Millard yonks ago has also proven to be quite reliable.

 

Unfortunately these skills can go rusty. How many of us have been able to do a long trip in recent times?

[shajen]

Thanks everyone! Agree the best thing is to know what you start with, how much you use per hour (I have a fuel Misor fitted to filter), and how long you’ve been flying. I also like some of the other suggestions and will toss them around.  I know shining a torch from behind through the tanks works great, just a bit difficult getting into position , especially when busy😀

Might look at fitting a flexible led desk lamp behind with an on/off switch near the armrest. I could Velcro it to the tank so it shows through and just turn on off as required.

Thanks , Jenny

[Keenaviator]

I have a 65 litre tank in the same position.  A strip of led's stuck to the back of the tank would illuminate the contents making it easy to see the level from the front.  I haven't done it yet but a torch behind the tank works really well. Laurie

[coljones]

Backhanded photoshoot on mobile phone.

[skippydiesel]

All this "rubber necking" to see tank contents behind you, must be an interesting skill when flying in turbulence

[coljones]

19 minutes ago, skippydiesel said:

All this "rubber necking" to see tank contents behind you, must be an interesting skill when flying in turbulence

There are those, mePad and mePhone owners, who will claim that those devices are all you need - fuel gauge, navigation system and autopilot all in one (and inflight flight attendant services)

[tillmanr]

Is there a cheap camera with Bluetooth to link to your EFB?

[coljones]

28 minutes ago, tillmanr said:

Is there a cheap camera with Bluetooth to link to your EFB?

There are some cameras, like GoPros and Panasonic Lumix, which can be set up as wireless hotspots to allow apps on phones and tablets to take and display photos or stream video from these cameras.

[skippydiesel]

Sorry folks - I dont understand why the resistance to an automotive style fuel level gauge. They are relativly cheap & easy to install. At worst give an erroneous reading and you have to fall back on time aloft/power setting/known consumption. At best give you a good indication of fuel remaining which you should still compare to time aloft/power setting/known consumption.

 

When I was in GA, the fuel gauges weren't worth looking at, complete waste of panel space. In the 12 years or so,  I have been in RAA, I have found my fuel gauge to be a great X refence tool, in my fuel management system, which includes a flow meter and time aloft/power setting/known consumption.

 

On one memorable occasion, when I took a mate on a  day trip down & back to the south coast of NSW. I loaded full fuel for the round trip - my flight plan showed I would get back home with 60 minutes plus flying left in the tank. The weather changed on the flight back with unexpectedly strong head winds. The combination of all the aforementioned systems, had me divert to Goulburn, load extra fuel. I arrived home with 20 L fuel remaining - at my normal cruise about 80 minutes flying time - a nice safe margin, that would not have been there, had not diverted..

[coljones]

1 hour ago, skippydiesel said:

Sorry folks - I dont understand why the resistance to an automotive style fuel level gauge. ........

Not always possible, sometimes the planes are owned by others so you do what you have to do, looking over your shoulder at the tank and flying by calculated rates of consumption and the clock. (And bladder)

Edited August 12, 2021 by coljones

[lyle janke]

hi all 

 i have a J120 jab so share the frustration of my fellow pilots but my research has led my to use the following set- up : 

1-MGL FF-4  fuel flow meter  which has fuel flow  virtual tank & GPS  for real time fuel calculations  currently ( i also check the no`s  manually ) i will fit an Ultrasonic probe to my existing MGL FF-4  fuel flow meter ( to give fuel level rather than virtual tank ) then all the calculations will happen real time on gauge 

The Radiant LCD fuel gauges, coupled with the Radiant Perfect Fuel Probe (an Ultrasonic probe)  they also make a LLwarning sensor (an Ultrasonic probe) of which i had the earlier ver. fitted but need to up-grade as was damaged in recent vandal attack older ver repl. obsolete.

  the Radiant Perfect Ultrasonic Fuel Probe will adapt to most avail fuel gauges as well so can be fitted to existing set-up`s 

 i hope my knowledge /research  is of some help to those considering option s & how to decide going forward 

 lyle