Low Fuel Sensor

[jiott]

I just purchased the Kitfox low fuel sensor option for my SS7. It came with a separate small round aluminum tank to mount the sensor in. This tank/housing is then mounted above the header tank, in the vent line. I know many of you just mount the fuel sensor in the upper side port on the header tank without using the additional housing that Kitfox provides.

I would like to hear some pros and cons of each method. Obviously the higher mounted separate housing would give you earlier warning of low fuel, but its extra complexity and more potential leak points. Any other opinions would be appreciated.

Jim

[DesertFox4]

I have the aluminum header tank behind the co-pilots seat with the sensor mounted in the tank. Either system works well.

[cap01]

I also have a aluminum tank , but its mounted aft of the cargo bag . It's a custom 2 gal tank with the level sensor from spruce installed in it . Works well. Also I know of a speedster with the can sensor installed in the vent hose that also has been working well . Guess you could call it a crap shoot .

[akarmy]

I have the same little tank inline. Seems to work fine. I did have a bit of a challenge getting the sensor sealed the first time and had a bit of a fuel leak to deal with.

http://www.teamkitfox.com/Forums/picture.php?albumid=143&pictureid=1795

[hansedj]

I would never want to be that low on fuel

[dholly]

Would like to revisit this topic.

I have a 4-1200 w/ center high mount poly header tank, which would seem to preclude using the 'aux tank for sender' style low fuel warning.

Header tank has (3) 'in' ports, (1) ea. for L/R wing supply and the vent line and single lower 'out' port, with no sump quick drain or extra port/fitting for the ACS 6905-400 low fuel sensor.

Best option short of switching to a new aluminum 'behind the seat' header tank?

When using a [new, ethanol resistant] HWllc vent line sensor, is it best to install as low as possible in the vent line to minimize false alerts (resulting in a near horizontal orientation), or does the sensor body need to be in a completely vertical orientation to operate properly?

Thnx.

[Jerrytex]

Dhollly,

I have the same set up as you with the center, higher mount header tank. The Aux tank with the sensor in it, is mount horizontal on top of the poly tank. If I get by the airport, I'll take a pic if that will help.

[henrysamson]

I would never want to be that low on fuel

I had plenty of fuel when my low fuel light came on during a cross country. Got my attention and I was on the ground at the closest airport in about 10 minutes. There are fuel supply issues besides running out of gas. I had a bad seal on a cap and the suction was able to prevent fuel flow once the level in the tanks had dropped to a lower level. Bought new gaskets as suggested on this forum and that fixed the problem.

Henry

[Jerrytex]

If I understand correctly, you can add a low fuel sensor directly to the aluminum header from Kitfox? However, I see on this thread that the low fuel sensor goes in a small cylinder tank above the header tank? The aluminum tank I have from Kitfox, has a 1/4" pipe connection on the side. The low fuel sensor that I have, is 1/2". Did something change on the header tanks? Or is there an adapter to convert to 1/2"?

[JayHenry]

The Low Fuel sensor is a separate tank that installs just over the header tank and sold as a kit form Kitfox.

[henrysamson]

If I understand correctly, you can add a low fuel sensor directly to the aluminum header from Kitfox? However, I see on this thread that the low fuel sensor goes in a small cylinder tank above the header tank? The aluminum tank I have from Kitfox, has a 1/4" pipe connection on the side. The low fuel sensor that I have, is 1/2". Did something change on the header tanks? Or is there an adapter to convert to 1/2"?

I have the older plastic header tank in my model IV. The low fuel sensor does fit in a port in the top of the tank. I have one installed. I have had trouble with some leaking around the various fittings of this tank. A few years ago, I removed the tank, removed all of the fittings, cleaned the threads and reinstalled everything with a two part polyurethane sealant. One version of this is trade named "Proseal". No leaks since.

At the time I was told that the aluminum header tank solved the problem with sealing around fittings but that I would lose the ability to have the low fuel light so I went the proseal route.

[Jerrytex]

I am going to try and adapt from 1/4" to 1/2" out of the side of the header tank, so that my 1/2" low fuel send will thread it. I'll see if I can make it work.

[Maverick]

I have the aluminum tank and my low fuel sensor was 1/2" so it did not fit. Murle drilled out the 1/4" hole out to a larger hole and then arced a 1/4" plate over the old hole. I then drilled through the plate and tapped it to take the 1/2" fitting of the low fuel sensor. We had to deal with a few pin holes in the weld but we finally got it done. It works well but, I do not recommend this route. If you can find a quarter inch sensor that will work through the 1/4" hole, I would go that route. It would seem that the factory would make the hole size for the sensor optional for the purchaser, either 1/4" or 1/2". JMHO.

Maverick

[Jerrytex]

On my header tank, the welded on collar is slightly larger than 1". My plan is to drill the 1/4" hole to 1/2" and tap it. That will leave plenty of "meat" on the collar. Seems like the easiest most reasonable thing to do, to retrofit it.

Edit: The low fuel sensor, the optical one that came with the kit, is actually 3/8" NPT not 1/2" as originally thought, so I'll being drilling and tapping to 3/8".

25698

[PapuaPilot]

Food for thought. Why do you feel you a need for a low fuel sensor?

I bought my Kitfox second hand and it came with an optical sensor (ooooh, shinny!) and it fit in the original plastic header tank. When I got the replacement aluminum header tank I went though these same thoughts. At first I convinced myself that I had to use this thneed (Dr. Seuss) in my new header tank, but the new header tank didn't have the fitting (whimper). I finally concluded that I would be a fool if I ever used up the 26 gallons in the wings or ever let myself get below 3 gallons/30 minutes. With my bigger engine my KF can go 4 hours and still have VFR reserves (my bladder won't go 4 hours any more).

Opinion here. Do you know of any other small airplanes like this with a low fuel sensor? The Kitfox has sight tubes on the wings that are very accurate if you calibrate them properly. I also installed a fuel flow sensor with the G3X that is spot on. I really didn't feel the need to add a light to tell me I'm a member of the ID10T club.

The only plane I have flown with low fuel sensors is the Cessna Caravan. This is a lot bigger plane than a Kitfox, and Part 23 certified. The FAA probably required them too. They light up the annunciator panel when a main tank has about 30 minutes remaining per side. But wait . . . I already knew that from the tank gauges, fuel flow totalizer and preflight planning. Honestly they are pretty annoying because they ding at you every time the fuel gets sloshed on & off the sensor. The Caravan also has a fuel sensor in the header tank. I like that one, it means your engine is going to quit in less than 3 minutes. But again, why would you ever unknowingly get in that situation.

No judgement here, just food for thought.

[jiott]

I agree with you Phil, I have the low fuel sensor and there is only one thing it has ever done that I think was useful: On a flight years ago I was heading into an airport to refuel, so my fuel quantity was quite low but not below the proper safety reserves. I had been flying high so I was in a long protracted descent at a fairly steep nose down attitude to lose altitude quickly. Sine the fuel was low my nose down attitude unported the wing fuel tank outlets and I was only running on fuel in the header tank, which quickly reduced the level and the low fuel warning light came on. I immediately leveled out my flight attitude and the fuel system started working properly again; a few minutes later I resumed my descent and landed with no problems. Without the low fuel sensor I probably would have starved and killed my engine before I realized what was going on and leveled the airplane. Most likely I could have leveled and done a restart with no problems, but who knows if it had happened near the ground. This was the one and only time I did appreciate the low fuel sensor. Just some food for thought from an actual experience.

[Jerrytex]

You definately make good points Phil and I agree.

Sad part is 56 percent of plane crashes are fuel starvation and 35%, fuel mismanagement. (https://flightsafety.org/fuel-management/)

We just had a triple fatality 3 weeks ago at my airport due to what is going to turn out to be fuel mismanagment.

My model 4 had one and I always liked the warm and fuzzies of having one. Probably just a mental thing since I like to think I plan for fuel management, but whatever helps quell the voices is always a good thing. Ha. I figured since I have the sensor, drill bit, and tap already, I might as well put it in. It won't cost any money, weight and not much time.

Thanks.

[PapuaPilot]

That is a sad reality.

FYI I use my fuel totalizer to verify the sight tubes. Where I work we teach our pilots to look at the back of the wing during our initial climb for streaming fuel from loose/missing fuel caps.

[Maverick]

In my first Kitfox 5TD, I never recognized the problem of fuel flowing forward in the tanks in a steeper descent. Dumb, I know! It was inadequate testing for sure on my part.

DesertFox4 and I flew to Apple Valley together once when I wish I'd had the low fuel sensor. I calculated that I had enough fuel to make it there from Phoenix and I actually did, although only by a very slight amount. That's when I was entering the traffic pattern having come down to altitude when at midfield the engine died. I looked up and saw fuel but it didn't register with me that it wasn't enough to feed the fuel port at the back of the tank. I declared my situation and did a dead-stick landing. As soon as I stopped, I tried the engine and it fired up and I taxied to the fuel station and filled up. I realize that my lack of diligence in getting to know my plane's quirks and cutting it too close on my reserve are pilot errors (as DesertFox4 doesn't let me forget, bless his heart) but, had I had the fuel sensor tell me I was running on fumes, I likely would have figured out the problem of the nose down attitude letting fuel move forward too much and could have raised the nose, slowed the descent and kept me from needing a clean pair of underwear. Certainly, after having this experience, my fuel management will be more conservative; partly because, like PapuaPilot, my bladder is not as young as it was 16 years ago but, certainly because experience is a good teacher, assuming you survive. . . :cool:

[109JB]

All I will say is this. For the past 21 years my job has been to investigate aircraft accidents. My project airplane is getting a new header tank fitted with a low fuel sensor.

[mooreaa]

Thank you for sharing these experiences. Wasn't something that was on my radar until reading your comments here. Interesting point about the steep descent attitude preventing fuel flow to the headers.

I assume the issue is mostly the same regardless of carbureted or fuel injected engines. I like the idea of having the low fuel sensor mounted directly to the header tanks. Does the fuel return path affect this at all? Curious what the installation options are and what to watch out for.

Thanks!

[jiott]

Why is everyone shying away from the factory optional low fuel sensor with its separate little reservoir? It works perfectly and is super easy to install with no modifications to the header tank. Just curious.

[Eric Page]

In the immortal words of Colin Chapman, "Simplify, then add lightness."

[Slyfox]

years ago I was coming back from Seattle and was flying in the area of Ellensburg, wa. well the engine quit. now before I go any further I have valves that turn off each tank, well I only fly on one tank, why, why not. not only that response, but my rv has a left and right and you can't have both on a low wing plane. but anyway, I ran out on the left tank. the engine quit. I switched to the other tank, it starts back up. everything ok. But... when I got home I put in the low fuel sensor and put a light on the dash. fast forward, through the years that has proved to be very nice for me, many times the light would come on, to find that one tank or the other would quit flowing for one reason or another. right now I had it come on just a couple days ago, I thought wait a minute the tank I'm on is full. I looked at the vent line, mine is clear, and I could see that the line was empty of fuel, than I saw fuel come back up and than the light went off, than the light came back on and yup no fuel again. I took the screen out of that tank and sure nuff it was plugged. so take what you want on this low fuel light, I love it.

[Dave S]

Thank you for sharing these experiences. Wasn't something that was on my radar until reading your comments here. Interesting point about the steep descent attitude preventing fuel flow to the headers.

I assume the issue is mostly the same regardless of carbureted or fuel injected engines. I like the idea of having the low fuel sensor mounted directly to the header tanks. Does the fuel return path affect this at all? Curious what the installation options are and what to watch out for.

Thanks!

Regarding descent attitude and what a person can count on for fuel feed is something a person can and should figure out during build and fuel system proofing. Since the fuel feed from the wing tanks is located near the rear of the wing tanks, the design indicates that nose down attitudes will, at certain descent angles, unport the fuel feed from the rear of the tank. The attached photo shows the Kitfox in a nose down attitude of 10 degrees (courtesy of removing some bricks in the driveway and digging a hole), estimated to be twice the nose down that would be experienced during normal operations. What this test revealed is that a 10 degree nose down attitude will start to unport the fuel tank with 6 gallons in a tank (or 12 gallons between the two tanks) which is just a tad less than half tanks. It is better at 5 degrees nose down with approximately 3 gallons per tank or 6 considering both tanks.

Many aircraft have fuel system limitations that are accounted for and as long as a pilot knows what those are (hopefully published in the POH), operations can be performed in agreement with the limitations.

The header tank on a Kitfox is a really good deal for a number of reasons including this one.

The low fuel sensor is certainly a good idea and saves a person from having to do math in their head to keep from exceeding the capacity of the header tank on a long steep descent.

[mooreaa]

Why is everyone shying away from the factory optional low fuel sensor with its separate little reservoir? It works perfectly and is super easy to install with no modifications to the header tank. Just curious.

Hi ya Jim, not so much shying away from the factory as much as trying to see the creativity and wisdom of others on this forum. I have no doubt that the factory solution works, but I do also like the idea of the sensor being integrated into the header tank.


Dave, wow thats really very interesting. No fuel flow at half tank with just -10 degrees doesn't seem like much. If my maths right, thats 65mph at a -1000fpm is around -10 deg. Maybe thats an aggressive descent but still. Just out of curiosity, what about mounting the low fuel sensor in the wing tank or, maybe having two ports on the tank (I understand its not necessary, but would it mitigate this)? I suppose you can lose 1000fpm with wings level so... that aside, the point would be that this is equivalent with respect to coming down at that angle.

[Dave S]

The only time during phase 1 (and afterwords) the nose down ever got near 10 degrees was VNE testing.

I doubt that anyone will be getting beyond 5 degrees nose down for any normal operation - a power off best glide is considerably less than that - at least on our bird.

If a person considers the Kitfox fuel placard - the no takeoff band is right about 3 gallons if I recall correctly.

I feel that the design of the Kitfox fuel system on the S7 is solid.

[rv9ralph]

Just out of curiosity, what about mounting the low fuel sensor in the wing tank or, maybe having two ports on the tank.

If there are 2 ports in the wing tank, the port with the least resistance will be the one that flows... in other words, if there is a unported pickup, the the fuel draw sill suck air. That is why you can't burn off both tanks on a low wing aircraft. Low fuel sensor in the wing will be inaccurate due to the sloshing and shifting of the fuel when changing pitch or yaw.

An option for fuel sensor is from Belight. The have several fuel sensors that will indicate low fuel status that can be used in the header tank.

Ralph

[109JB]

You can have two ports on a high wing fuel tank but each port has to be independent until well below the tank. Easiest would be to run each outlet all the way to the header.

[rv9ralph]

ou can have two ports on a high wing fuel tank but each port has to be independent until well below the tank.

After thinking about your comment, I stand corrected. However, to do as you recommend, it would take another fuel line from tank to header which could interfere with the wing folding. Also, it would have to tee in before the header tank due not any available ports on the header. Not an elegant solution.

Ralph

[Jerrytex]

So anyone wanting to add or retrofit their header tank for a low fuel sensor.

Drilled and tapped to 3/8". Worked with no issues.

25723

[Victory_Overland]

So anyone wanting to add or retrofit their header tank for a low fuel sensor.

Drilled and tapped to 3/8". Worked with no issues.

25723

Nice work; do you happen to have pics of the sensor when it's NOT installed?

[jiott]

So where are you going to put the fuel return line? That port that you enlarged for the low fuel sensor is usually used for the return line fitting. Again I wonder why not use the factory low fuel sensor kit and then everything goes together easy-peasy.

[Jerrytex]

The return line will Tee into the vent line.

This set up is just like the original factory poly tank and I used the same port it used for the low fuel sensor. So however people were running their return line originally, is how it would have to be run with this set up.

The low fuel sensor tank from KF is $182. That's a lot of money (I know, subjective when dealing with airplanes) for an aluminum can. in addition, it's more weight (negligible), 2 more connections to leak, and more fuel line to replace (i guess one could hard plump it in with aluminum, but as it comes, it's hose)


I just thought I would share this since this is a great forum for ideas whether or not you use them is up to you.



Pic of sensor.

25727

[DesertFox4]

Jerry, just an FYI. The low fuel sensor you have pictured looks like the original sensor SkyStar sold way back when. As I recall that when auto fuel was predominantly used with that type, many of those sensors failed due to the plastic tips cold flowing (melting) into the bottom of the header tanks.
Also I believe it is an optical type sensor so I’m wondering if it will even work in a totally dark aluminum tank. There are several members here who are more familiar with that early set up that could shed light on the function of that type sensor. Hopefully you will hear from some of them or test it’s function before going to any more efforts to incorporate it into you fuel system. I hope my memory is faulty and it will work perfectly but just in case, I had to mention it. Good luck.

[Victory_Overland]

Jerry, just an FYI. The low fuel sensor you have pictured looks like the original sensor SkyStar sold way back when. As I recall that when auto fuel was predominantly used with that type, many of those sensors failed due to the plastic tips cold flowing (melting) into the bottom of the header tanks.
Also I believe it is an optical type sensor so I’m wondering if it will even work in a totally dark aluminum tank. There are several members here who are more familiar with that early set up that could shed light on the function of that type sensor. Hopefully you will hear from some of them or test it’s function before going to any more efforts to incorporate it into you fuel system. I hope my memory is faulty and it will work perfectly but just in case, I had to mention it. Good luck.

Personally I would prefer a sender and low fuel light for each wing capacity; I understand some feel this is complexity and more this and more that means more leaks but the reality is if proper installation procedures, maintenance, and components prevents these perceived issues.

[Eric Page]

They work in the dark. The conical tip is a prism and there's an LED and a sensor inside. When immersed in liquid, the light escapes from the prism due to the refractive index of liquid against the prism surface, but when dry, it's reflected back (or maybe it's the other way around...).

I don't know what the old sensors were made of, but the ones I've seen lately are made of a plastic called Polysulfone, which is pretty chemically inert. As I recall, it got an A rating with gasoline (no reaction) and a B with 100LL (minimal reaction). The table I saw didn't define "minimal reaction." I believe it got an A with ethanol as well.

[Eric Page]

It looks like the Carlo Gavazzi VP03E sensor pictured above comes "in a Polyamide 12 housing resistant to various solvents." See datasheet here (https://www.gavazzionline.com/pdf/vp03epq.pdf). According to this article (https://en.wikipedia.org/wiki/Nylon_12), Polyamide 12 is used in the automotive industry to make gasoline resistant tubes.

[Jerrytex]

Thanks Desertfox4....turns out your memory is just fine. I sent an email to the the sensor manufacturer and they DO NOT recommend it for fuels.

I"ll look toward getting the float type instead.

Appreciate the heads up!

[Jerrytex]

No luck on finding a 3/8" float type sensor and I don't want to use an optic sensor that will melt away. I think I could drill and tap to 1/2" npt but it wouldn't leave much of a collar and I think the collar is too deep for the float sensor to work properly anyway. I think I am abandoning the idea of adding the sensor in the header tank.





Could someone post some pics of the remote low fuel sender tanks and set up showing the actual sensor location. I think it's what I had on my KF 4 but I just want to be sure.

Does it just use the vent line? In other words, does it run from the header tank into remote tank, from remote tank to right fuel tank?

Thanks.

[Eric Page]

I'm investigating an idea for low cost, non-contact low fuel level sensing.

After pondering this thread for a couple of days, I started searching for fuel level sensors. Most of the results were float switches, but I also found some optical sensors (http://www.digikey.com/short/zwn24t) like the one Jerry showed (http://teamkitfox.com/Forums/threads/3532-Low-Fuel-Sensor?p=94687&viewfull=1#post94687). Many of them aren't cheap and all of them require contact with fuel, which means a hole in the tank and the possibility of plastic deterioration.

Then I got to thinking... some time ago I built a project using an ultrasonic distance sensor. I recalled that while searching for that sensor I also found liquid sensors, but I couldn't remember any details. It took some online sleuthing, but I finally came up with the sensor manufacturer's website (http://www.dypsensor.com/pro.aspx?cid=72) (Chinese).

There are basically four versions of this company's sensor:


DS1603L - RS-232 (https://en.wikipedia.org/wiki/RS-232) output
DS1603DA - RS-485 (https://en.wikipedia.org/wiki/RS-485) output
DS1603AQ - analog voltage output
DS1603NF - "switch" output (pulls to 12V or to ground)

The first three are of little use to us, primarily because interfacing them to an EFIS or panel indicator would be a bit of a hassle. However, the last version is more interesting. It has a simple high-low output, which will talk to a digital or alarm input on an EFIS, or it could drive an LED indicator directly (like one of these flashing LEDs (https://www.digikey.com/short/zwnwzc), perhaps).

I ordered one of the DS1603NF sensors, and I have a new aluminum header tank on order from Kitfox. When those items arrive I'll run some tests and report back here. Stay tuned...

-----

P.S. For anyone who's interested in how these sensors work, this Texas Instruments application note (https://www.ti.com/lit/pdf/snaa220) gives a useful overview.

[PapuaPilot]

Anything that switches or has a variable (analog) output can be connected to the Garmin G3X and probably a Dynon. I have 3 or 4 user programed inputs to my G3X touch of things that were not already included inputs of the GEA. These come up as a CAS warning.

As an example, I added a starter warning with a small wire connected to the starter solenoid output incase the solenoid were to stick. I had it happen once on an amphibious C-206 and it destroyed the started because it was still engaged. After starting my Kitfox I always check the CAS warnings to make sure the "STARTER" warning is off. I also hooked up the warning wire from my EarthX battery.

[109JB]

Why not use a thermistor based sensor like cars have had for at least 50 years?

[4Hummer]

I'm using this sensor:

https://www.aircraftspruce.ca/catalog/appages/fuelwarn.php?clickkey=17718

with an AN 867-4 Bung welded into the header tank: I have the round header tank that is mounted behind the baggage sack:

[Eric Page]

Anything that switches or has a variable (analog) output can be connected to the Garmin G3X and probably a Dynon.
That's pretty much what I figured, given my quick perusal of the Dynon installation manual, but I didn't want to make a blanket statement that it would work with every EFIS. I'm glad to hear that Garmin supports direct analog inputs, and I'd be very surprised if MGL weren't similar.


Why not use a thermistor based sensor like cars have had for at least 50 years?
A thermistor based sensor would still require a hole in the tank and contact with fuel. Also, it would likely require significant signal conditioning to reliably convert a tiny resistance change into a binary logic flip without nuisance indications caused by changes in ambient temperature or refueling.


I'm using this sensor:

https://www.aircraftspruce.ca/catalog/appages/fuelwarn.php?clickkey=17718

with an AN 867-4 Bung welded into the header tank.
No doubt that system works well, and I wouldn’t suggest that anyone who already has a working sensor take it out or replace it.

I’m trying to come up with a solution for aircraft that don’t already have a low fuel alert. Hopefully one that weighs a few ounces and doesn't require any modification to the fuel system.

Maybe the sensor I found won't work, but for the price it seems like it's worth a try. Easy and cheap might entice owners who otherwise wouldn't have installed a low fuel sensor, and that can only improve the safety of the fleet!

[109JB]

A thermistor based sensor only needs a bulb and 12V to work.

https://youtu.be/UEmbRJKlSeI?t=328

[rv9ralph]

Belite radiant instruments have a series of light instruments, including several fuel sensor products that could fit your needs... if you don't want to use the Kitfox Aircraft factory recommendations.

Belite can be found at: https://radiantinstruments.com/bingo-4-liquid-detector/

Ralph

[Eric Page]

That detector uses exactly the sensor I listed above. They blacked out the part number in the demo video, but it looks identical and the QR code on the label confirms that it's the DS1603L.

The product description mentions a "USB port" but it doesn't explain how that's supposed to be used. RS-232 is not USB, so they would have to add a bridge IC and a USB connector, but why bother? If it were plugged into a USB port on an EFIS, it would be ignored unless the EFIS had been programmed to recognize the sensor and do something with the data. So, what is the sensor supposed to connect to, other than the LED indicator module they sell for it, and why do they sell the sensor by itself? Very strange.

At $129.95, their markup on the sensor is eye-watering. They sell individually for as little as $10 delivered, and probably less in quantity.

At least this is evidence that the sensor has already been tested and works for this purpose.

Good find, Ralph. Thanks.

[Eric Page]

The ultrasonic liquid sensor arrived yesterday. I didn't have time this weekend to test it, but I'll power it up soon and post the results.

25936

It came with three small plastic vials. The first is unlabeled and contains a clear, odorless gel substance, which I'm guessing is an acoustic coupling gel used for testing, similar to the stuff that medical technicians smear on patients while doing an ultrasound. The second is labeled "R" and contains what smells and feels like the resin half of a two-part adhesive, so I presume the third vial (unlabeled) must be the hardener.

[n85ae]

I have the poly header, and sensor in it. I had to cover the header with hvac metal tape to block out
extraneous light from making it false alert. It does flicker a bit when you get around 1/2-1/4 fuel and
tends to flicker more and more as you get lower on fuel. So I sort of like it, but you kind of have to get
used to that it's not a hard off/on in function, at least until you have a fuel stoppage ...

I don't have any fuel leaks, but I can still smell fuel in the plane when it's been sitting, and as far as I
can tell the odor of avgas (I run 100LL) is all that gets through the tank ...

Jeff

[Eric Page]

I've run some tests on the new sensor, attached to a Kitfox aluminum header tank. Results are posted in a new thread, here (https://teamkitfox.com/Forums/threads/11143-New-Low-Fuel-Alarm-Sensor).

[4Hummer]

Whats wrong with the low fuel sensor from spruce? Its what I use on my model IV header

And is 1/2" NPT.

26119

[Eric Page]

Whats wrong with the low fuel sensor from spruce?

A 1/2" NPT sensor won't fit any of the bungs on the current Kitfox header tank, which means you have to modify the tank or use an additional small tank for the sensor (and add a few more fittings and pieces of hose). If you don't mind all of that, or if you already have the Spruce sensor installed, then there's nothing wrong with it. My preference is for a sensor that doesn't need to touch the fuel and doesn't require extra plumbing.