Sensor for Fuel Tank Level

[coljones]

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Edited July 27, 2023 by coljones
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[facthunter]

Maybe I'm the only one who got to read it?   Nev

[skippydiesel]

On 25/07/2023 at 12:41 AM, lyle janke said:

hi 

 i have used a low level warning sensor from these guys . they have good customer focus & can not do enough to help 

see the range of gauges / sensors it take s fuel management to a new level/ thinking 

i have a dual fuel guage /sender set ( previous model ) which i was going to fit to my jabiru but won`t currently with the dynon but maybe if i feel an up-grade /replacement is needed 

https://www.radiantinstruments.com/#top

this may help in your quest for knowledge

Thanks Lyle - Could not find any reference to a fuel tank level sensor in Radient Instruments 

[skippydiesel]

KUS would seem to have a tubed variant, of their Australian offerings. Its called the MSD/HSD  aimed at off road applications - trying to find out more about it

[lyle janke]

16 hours ago, skippydiesel said:

Thanks Lyle - Could not find any reference to a fuel tank level sensor in Radient Instruments 

https://www.radiantinstruments.com/product/radiant-fuel-probe-system

here is the link  

[skippydiesel]

4 hours ago, lyle janke said:

https://www.radiantinstruments.com/product/radiant-fuel-probe-system

here is the link  

Ah! That's the same as the Belite system (I have and am trying to replace) that no one seems to have any luck getting to work consistently. As far as I am concerned its a con - Thanks but but thanks.☺️

[Area-51]

On 25/07/2023 at 9:13 PM, Markdun said:

Yeh yeh…you can never have too much back up. How many of us fly with a parachute?
 I haven’t removed the 3.5 l header tank low fuel warning light (might save a 100 grams) in the J200, but I wouldn’t have made the effort to install it.  Really a 20 minutes warning because you didnt plan the fuel reserve properly?  The risk is that with that system you don’t plan your fuel because your know you have the 20 minute warning .. its  like ignoring the risk of dingo attack on Fraser Is because you know the bad ones have been killed. As it goes if I’m flying at 2500agl I’ve got 3 minutes at 700fpm sink rate to do an outlandiing…. So to the chagrin of my snobbish GA mates whose Lycosaurs never fail, I fly with an outlanding paddock already picked out & I might actually diverge from the straight line course to ensure it is within gliding distance. Perhaps it’s that NZ gliding hours experience with instructors pulling the tow release at 150’agl, or deploying the spoilers to drop one below the ridge between you and the airfield and calmly saying, ‘it’s your aircraft’.

That's all totally correct; poor planning can lead to a poor outcome.

And poor design can also lead to a poor outcome, hence the use of a header tank and low level warning.

 

Why? Because the LSA manufacturer in this case refuses to acknowledge and rectify a known issue that results in an EFATO 15-20min after takeoff with full tanks.
 

Why? Because Rotax require a choked return line to mitigate vapour lock and the AC manufacturer in all their wisdom has sent the return line back to only one wing tank, and switching to the opposite wing tank will provide the pilot an EFATO within 15-20 minutes, or less depending on fuel volume being less than max. Why? Because the return line pumps all the opposite tank's contents out through the fuel vent of an already full fuel tank.. So what? Well if you've been flying on the opposite tank for 10-15minutes, switch tanks and fly some more before landing, then take off on both tanks and switch to the opposite tank thinking you have plenty fuel (because you have correctly run your inflight fuel logs haven't you), well you are at maybe 500', or less, departing and get an EFATO?
 

Hope the training kicks in but better to identify and fix the problem long before it gets to that; three forced landings due to unexplainable fuel starvation were trying to tell the pilot something was not right with the AC.

 

The idiot light is not there to deal with poor planning. The idiot light is there to notify the pilot that there is a situational issue with the planned fuel reserve and that an unforeseen leak down of the fuel system has occurred.

 

This is why a low level warning indicator and a header tank with 20min useable reserve is a good idea.

[lyle janke]

2 hours ago, skippydiesel said:

Ah! That's the same as the Belite system (I have and am trying to replace) that no one seems to have any luck getting to work consistently. As far as I am concerned its a con - Thanks but but thanks.☺️

hi skippy 

 belite was the aircraft side of the business before a major fire  radiant was the in struments. the instruments were all he was left with after fire . ive used the low level system although i never had it activate ,i have a twin tank gauge set-up ( which i haven`t used i will bench run it sometime to see how well it works )  i`m surprised that james wasn`t able to give you satisfaction with your issues , he was always very much a hands-on person 

[WayneL]

I have used the "Princeton"  capacitance type sender with good accuracy on Westach type gauges after doing the calibration setup. They say that different fuel types will alter the reading but I never used a different fuel type so I can't comment on what the gauge reading difference would be.

[skippydiesel]

20 hours ago, lyle janke said:

hi skippy 

 belite was the aircraft side of the business before a major fire  radiant was the in struments. the instruments were all he was left with after fire . ive used the low level system although i never had it activate ,i have a twin tank gauge set-up ( which i haven`t used i will bench run it sometime to see how well it works )  i`m surprised that james wasn`t able to give you satisfaction with your issues , he was always very much a hands-on person 

My problem with the Belite (& I suspect for many others) is that it works well on the ground (very accurate) but has no tolerance for changes in tank internal pressure, which may (does in my case) differ to ambient ie the sensor measures fuel pressure/weight above it relative to ambient (external to tank) - tank breather will create a posative (usual)/negative tank internal pressure, rarely a static/ambient internal pressure - this causes the sensor to give an erroneous reading.

The only way around this is to have the sensor linked to tank internal pressure.

I found a promising sensor https://www.safiery.com/tank-level. Unfortunatly I found that the sensor tube connection, to internals,  was not ignition proofed.

The system may work, one day, in an aircraft, but will require further development.

[Jabiru7252]

On 19/07/2023 at 9:22 PM, skippydiesel said:

A good number of "viewers" but no comment - nobody fitted a fuel tank level sensor?

I made a water level sensor using an ultrasonic sender/receiver unit purchased from Jaycar electronics. See the (poorly produced) video attached. I used the computer to display the level but that could have easily been a cheap 1 milliamp panel meter. With some thought one might be able to incorporate this into a fuel level meter. Naturally one would need to be able to dick around with electronics etc. I can produce code for the Arduino if required. It would depend on the plane but I originally developed my prototype for the Jabiru SK55 that has the fuel tank behind the seat. Fiber-glassing the sensor to the top of the tank was the plan. I hope this provides food for thought...

[facthunter]

Where the fuel is visible through the material just add measured fuel and mark it  progressively OR a sight tube teed into the feed line. Nev

[skippydiesel]

Thank you one & all for your assistance .

 

Have decided to go with the tried & true, a VDO Dip Pipe Sender. These have been around for very many years. Used in  a wide range of vehicles/boats & probably aircraft. Not sensitive to fuel type or small amounts of water. Have a fair degree of anti sloshing courtesy of the mechanism  (a float moving up/down two wires) being enclosed in semi sealed (two small holes) tube.  As the photo attached shows - they come in a range of lengths to suit diffrent tank depth.

 

Unfortunatly I will have to cut a hole in the top of my tank. The tank will be removed from the aircraft,  to facilitate ant fuel vapour ignition measures, followed by much rinsing out to remove water (anti ignition) and swarf from the cutting/drilling activity.

[Marty_d]

Top hole makes more sense than what I have (and haven't installed) - I've got a couple of VDO bent-leg float senders where you have to cut a hole in the side of the tank.  After hearing some stories about leaking tanks I decided not to use them.  If you end up sourcing the dip senders and they do the job, please let me know - I might look at them myself.

[facthunter]

Why  touch the tank at all? A stand tube from the outlet pipe will give the same indication. Simplest is best.  Nev

[Marty_d]

That's another alternative Nev but I'd question whether it's simpler, as you're adding another component which requires plumbing in just to move the top-mounted sender from the tank.  

I wouldn't mind cutting a 59mm hole in the top of the tank, but I very much don't want to cut any holes in the side or bottom.

[Jabiru7252]

3 hours ago, facthunter said:

Why  touch the tank at all? A stand tube from the outlet pipe will give the same indication. Simplest is best.  Nev

Perhaps you're missing something here. The bloke I knew who wanted a better fuel level indicator wanted something on the dash because it was a pain in the neck trying to twist around see the tube on the tank.

[facthunter]

You can have a dash mounted indicator if that is your need. IF it's NOT reliable though it's not much use. Same with any indicator Head temp Oil pressure etc  . Some have a TEST function that might put a bit more confidence in it..  Nev

[Marty_d]

You're limited with some aircraft for sight tubes.  On mine for instance the wing roots reduce in size close to the cabin, so there's no way to have a full height sight tube.  

[facthunter]

Presumably your fuel  will be taken from the lowest point. There will have to be compromises with many situations. It's just not possible to make at a reasonable cost , a very accurate and reliable gauge in many light aircraft. Even if you managed it you can't legally use gauge readings alone to determine your fuel load. Flow meters and ON loads from recognised Tankers back up RPT stuff. Proper dip sticks can be used or full minus a known qty or run dry of useable fuel and a Known QTY added..  Your fuel usage rate over an extended verifiable period or the Aircraft POH figure must be used for Planning. Nev

[skippydiesel]

Just mulling over the best way to do the new sensor install;-

 

Never cut a hole in a fuel tank before - done a few water tanks in metal & plastic.

 

After removing the tank from the aircraft, I plane to rinse it out with water/detergent (x3), with final fill to be just water (will be dried out before reinstallation).

Mark prefered sensor location - deepest part of tank taking care to be clear of any in/outlets.

Cut hole - the instructions call for a 59 mm hole. It seems that I can purchase a 59 mm hole saw. My limited experience of hole saws, rotating in thin metal, is that they tend to wander a bit, with a resulting untidy/out of circle hole. I am considering using a smaller diameter hole saw , then carefully enlarging, to correct diameter, with a file - what thinks the Forum?

Does the Forum have any advice as to best tool (s)/technique  for the job?

[facthunter]

Do it with a good curved pair of  snips or a nibbling tool, Scribe the circle accurately before you do anything. How are you going to support the area you cut out to keep it somewhere near FLAT?. I would not be doing it. . You're creating a problem>   Nev

[skippydiesel]

UPDATE:

 

I ordered, from The Gauge Shop/Namiiss Gauge & Control, a VDO part number 224011000020G – Dip Pipe Level Sender, length 200 mm. The invoice verifies my order as part number 224011000020G.

 

They sent me, without consultation,  a Veratron Dip Pipe Level Sensor, length 200 mm, part number A2C1750040001.

 

Veratron now produces VDO’s Marine products.

 

The VDO and Veratron products have similar external appearance: 

Features	VDO	Veratron
Top	Unpainted Aluminium Alloy	Black Plastic
Cut out	54 mm	59 mm
Compensating chamber	Yes	Yes
Electrical Connection	Spade Connectors	Short lead with plug
System	Float/Resistance	Float/Magnetic Read Switches x 8
Ohms Ω	Full 5 - Empty 90	Full 04 - Empty 90
Length Options	20-40 mm increments	10 mm increments
Cost	$133.00	$107.00

 

The Gauge Shop did not pass on the cheaper cost.

 

I contacted the supplier only to be informed that the sensors were basically the same product and that the VDO was out of production ie they wilfully substituted without consultation.

 

I returned the sensor requesting a full refund including my return postage costs.

 

They have agreed to refund the purchase cost but not my return postage.

 

Note: Because the Veratorn product comes in smaller incremental length, than the VDO, it may suit my application better and be more cost effective.

 

Moral of the story; beware of purchasing from The Gauge Shope/Namiiss Gauge & Control

Edited August 11, 2023 by skippydiesel

[Jabiru7252]

Sometimes, with the cost of postage you just cannot win. A mate ordered an item online, it arrived okay. Failed after a week, to send it back for repair/replacement costs as much as a new item.

[skippydiesel]

What p---d me off the most was the substitution, without consultation.

 

When I spoke to them about this, there was no apology just a weak attempt to convince me it was the same product, by a diffrent manufacturer.

 

I had committed to the (VDO) resistance sensor, hoping for greater potentially accuracy of a continuous signal. The (Veratron) magnetic read switch has, in the 200mm prob, 8 switches/stages which I assume results in a stepped signal.

 

It could be that the pilot would notice no practical difference in reading between the two systems but I wasn't about the accept their duplicity and failure to pass on the cheaper price.

 

My fuel tank is 230mm at its deepest point - the nearest VDO sensor of this type is 200 mm long HOWEVER the nearest Veritron is 220mm and increases the number of read switches from 8-9. The Veritrons increased length & read switch stages, makes it  worthwhile considering (in the absence of the VDO).