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fallowdeer

Low fuel warning light

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Australian dealer sends out stickers that you place between fuel level meter and says level, and another sticker mentioning how many liters each line is.

 

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You should calibrate any gauge and dipstick used on your aircraft. That would entail filling and decanting a known measured fixed quantity till only unusable fuel remains. There is no other way to be sure and legal. Nev

 

 

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GREAT... just what I wanted ...although it says 38 lts max while the capacity is 36 ???thanks Rick

Yep, try it and see, it's 185mm to the bottom of the filler neck.

 

Australian dealer sends out stickers that you place between fuel level meter and says level, and another sticker mentioning how many liters each line is.

Really, those sight gauges are only good to show if you've got some fuel or not.

 

 

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When the tanks are mounted with the filler necks together, one dipstick doesn't measure the same in each tank, the outer tank has unfillable volume because of the dihedral of the wing. Another reason to install them like the factory built ones with the fillers outboard of the tank.

 

 

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I found that if the a fuel cap isnt sealing then a air bubble can form at the top of the reserve tank causing the low fuel light to come on. The reason for this phenomenon is the low pressure air in the boundary layer on the upper wing surface, ICP attempts to fix this by passing the cap breather tube through the wing to the high pressure botton side. I changed my breathers to forward facing hockey stick tubes facing forward on each cap and purchased some better cap seals from Reg.

 

 

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Really, those sight gauges are only good to show if you've got some fuel or not.

Mine are calibrated on a level surface so I can see exactly how much fuel I have when parked on a level piece of ground. Its accurate enough for me to decide before I take off again if I have enough fuel for the trip or when I get there to decide if I need to get more. I agree they are a bit useless inflight unless you have a restricter in the bottom of the sight tubes to stop the sloshing. I will get around to fitting the restrictors. But being able to see your fuel is a big plus.

 

 

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unless you have a restricter in the bottom of the sight tubes to stop the sloshing

Mark, you seems to say there are more than one sight tube...Isn't it only one on the left side ???? as the POH says... sure I'ld like to have one each side

 

 

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Hi Jacques

 

When I built my VG XL I made up new fittings on my lathe to fit into the tanks and installed 4 sight tubes so I could see all the fuel in the 4 tanks that I fitted. In the original from memory it only has 2 tanks and they are plumbed together this is why you only need the 1 sight tube. I made mine with the 4 tanks and each tank is individually switched into the reserve tank and each tank has a sight guage so I can see all the fuel I have at a glance

 

 

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very clever installation, I like it. Only one sight gauge does not make sense to me .... even wonder if it's legal here for Advanced ultralight.....I guess I will have to deal with it for the trip.. one more stress pull_hair.gif.3994f465d56951521f66ae0593c25df0.gif

 

 

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Hi Re comment "With the AAK range the fuel can been seen (or not)running through glass fuel filters" Do you every get a small leak between the glass and the end piece (outlet end) that requires a slight tightening of the end pieces to stop the leak? I vae had this a coulpe of times. I also now carry a spare glass filter item. Just wondering if its a common leak situation with this type of filter. I like the fact you can see the fuel flow and any debris caught in the filter.

Regards

 

Mike

I have my filters supported either side by p clamps and have not had a problem. This type of glass filter was standard on Airborne Trikes also. I do believe there has been some problems if not tightened properly. I still believe if you maintain them and fit them properly there is the advantage of seeing (or not seeing) the fuel flowing.

 

 

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I have my filters supported either side by p clamps and have not had a problem. This type of glass filter was standard on Airborne Trikes also. I do believe there has been some problems if not tightened properly. I still believe if you maintain them and fit them properly there is the advantage of seeing (or not seeing) the fuel flowing.

I'm in a hurry at the minute Scotty but just thought I would add this.

 

It might be worth asking Ole about it as he changed my filters from the glass ones back to a more 'agricultural' sized steel filter after having one 'let go' and drain all the fuel from one tank into the fuse:-)

 

He had thought before that that it only happens if they were over tightened but he had done that one himself.

 

I still have one glass one near the pax ankle but he machined a new piece up to go through the guts of the glass and it hasn't caused any trouble.

 

Anyway I gotta run will try and recollect a few finer details and come back with some better info.

 

 

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I'm in a hurry at the minute Scotty but just thought I would add this.

It might be worth asking Ole about it as he changed my filters from the glass ones back to a more 'agricultural' sized steel filter after having one 'let go' and drain all the fuel from one tank into the fuse:-)

 

He had thought before that that it only happens if they were over tightened but he had done that one himself.

 

I still have one glass one near the pax ankle but he machined a new piece up to go through the guts of the glass and it hasn't caused any trouble.

 

Anyway I gotta run will try and recollect a few finer details and come back with some better info.

Hi SDQDI I have had the same happen to me. Like Ole I took time to tighten well without over tightening. I believe the the reason for the leaks I experienced included poor quality of the metal stem (aluminium) that parts under stress and that the threads tapped into the end caps are not square therefore the ends at set at a slight angle. You can check this by threading the centre post into each end with out the glass and it will show as not being at right angles (a slight lean to one side.)

 

Cheers

 

Mike

 

 

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Yes I believe they just aren't the highest quality Mike, but it doesn't take much effort to machine a little bit of decent stainless to replace the dodgy centre bit and then they are quite good.

 

I definitely like the principle of being able to see fuel flowing!

 

 

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Yes I believe they just aren't the highest quality Mike, but it doesn't take much effort to machine a little bit of decent stainless to replace the dodgy centre bit and then they are quite good.

I definitely like the principle of being able to see fuel flowing!

Agree. I made one up and the end piece I was putting it into had the thread tapped a bit crooked so I tried to bend the s/s centre to align it to the other end. Didn't work out so have scrapped that one. I have two good filters fitted so I'll make two more centers on the lathe soon. Need to get some more threaded rod. The poorly made ones certainly lack a good quality control.

 

Not a big issue any more as I know what to look for. I also carry a good spare so when on a trip I can fit it if needed and I check the glass security as part of my daily D.I. and also turn on the fuel taps at start of day so I can detect any leak.

 

Cheers

 

Mike

 

 

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I also carry a good spare so when on a trip I can fit it if needed and I check the glass security as part of my daily D.I. and also turn on the fuel taps at start of day so I can detect any leak.

Carrying a spare is all very lovely, but if you have a glass filter failure in flight it is going play havoc with your fuel planning. Agricultural maybe a better overall solution and trust that you get to burn all the fuel you carry instead of losing it enroute, even if you can't see it going to work.

 

.

 

 

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Carrying a spare is all very lovely, but if you have a glass filter failure in flight it is going play havoc with your fuel planning. Agricultural maybe a better overall solution and trust that you get to burn all the fuel you carry instead of losing it enroute, even if you can't see it going to work.

.

In flight failure of a glass filter wouldn't be a big deal, well in the hornet at least, as all it would require would be to turn off the fuel coming out of the relevant wing. Of course simultaneous failure of both would require a precautionary search and landing within the 15 minutes that the header tank gives.

 

Having said that I do now prefer the half coke can sized ones that I have and don't mind throwing them away at a 100 hourly interval.

 

I do still have the improved glass one after the header tank, but the only thing that could cause it to fail would be glass breakage and if I get hit that hard I will be wanting to land pretty quickly anyway.

 

 

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Fully aware of the problems with the filters Sam and they have been covered already in this thread ie. The tendency of people to overtighten the filters ( you don't need 2 x 15" shifters to tighten them) and there was a batch that had very poor threads on the connecting rod between the two end caps and as you have stated the remaining glass filter in your plane has a different connecting rod. A third problem that has shown up seems to be when the fuel is turned off and the filter drains and the gaskets dry out. The gaskets seem to shrink and then leak when the fuel is turned on again after some time. Which in turn then may lead back to the over tightening issue. Maybe the gaskets could be changed to a better material? Given the problems mentioned Ole has advised some to change to the different filters as fitted to your two primary filters. I still retained the glass filters when we serviced my plane at the factory a couple of weeks ago. I see the advantages of being able to see fuel flow and filter contamination through the glass a big plus. If you do get a bad batch of fuel that contaminates the filter you can see it and clean the filter before it totally blocks or servely restricts the fuel flow, well in theory anyway. Just don't overtighten after cleaning them.

 

As I stated before these filters were fitted as standard to certified Airborne Trikes but I don't know if they still use them now but can still be bought from http://www.aircraftspruce.com/pages/ep/fuelfilters/univinlineff.php

 

Cheers Scotty

 

 

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Many Carburettor and fuel pump/accelerator pump washers dry out when the fuel is left off. Leather, cork and cardboard do it. Neoprene shrinks and goes hard. Rubber grows and distorts. Nev

 

 

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Many Carburettor and fuel pump/accelerator pump washers dry out when the fuel is left off. Leather, cork and cardboard do it. Neoprene shrinks and goes hard. Rubber grows and distorts. Nev

As you know Nev there is also the quality of the fuel as in Mogas and ethanol that comes into play too. That is why I suggested it may pay to look at a different material for the gaskets. I still believe, given the quality of the fuel that may be used at different locations in the outback that a glass filter that can show contaminates in the system is a good investment as long as it is maintained properly. In the Hornets these filters are a primary filter, just under the wing tanks before the header tank and the gascolator. Can't see the gauze in the gascolator and can only drain it to check for contaminates on a daily preflight. Even though the alloy tanks were sloshed I was supprised how much swath showed up in the glass filters after the build. Nice to be able to see that before it gets further down the line.

 

Cheers Scotty.

 

 

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Mine are calibrated on a level surface so I can see exactly how much fuel I have when parked on a level piece of ground. Its accurate enough for me to decide before I take off again if I have enough fuel for the trip or when I get there to decide if I need to get more. I agree they are a bit useless inflight unless you have a restricter in the bottom of the sight tubes to stop the sloshing. I will get around to fitting the restrictors. But being able to see your fuel is a big plus.

This is where you have it over the Boeings and Airbuses.

 

 

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Thin section wings present a problem for gauges. Remember fuel quantity is not permitted to be determined by the gauge indications alone, by law, but with the type of fuel tanks in the Skyranger for example, Transparent plastic that has been filled incrementally and marked, you are sure of what you see, as far as quantity goes Nev

 

 

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Have no idea what the set up in your aircraft but the system I have in my jabiru consists of a contact float switch and a simple open/close circuit connected to the Dynon on one of the general contact switches.

The switch is located about two thirds or so up the vertical height of the header tank. When the fuel level is above the switch the floating half lifts up and is closed and the contact circuit reads tank "Full" on the Dynon. (OK its not quite full but close enough) when the fuel level drops below the switch the floating end drops away and the Dynon reads "Tank Low".

 

Pretty simple.

 

I must admit I believe almost diametrically opposite to Facthunter. The sight tubes in the jab are particularly unreliable. The jabiru ones are quite wide bore and they slosh around all over the place. This is especially a problem in turbulence and if you aren't flying properly coordinated.

 

I filled in the holes with epoxy when I built it and drilled out tiny ( 1/64th) holes for the fuel to dribble slowly in and out of the tubes. So it changes much more slowly.

 

Next the fuel level is often hard or impossible to see when the tanks are more than about 80% full so I made some coloured float balls.

 

Lastly I have never had the float switch give a false reading either false low or false full.

 

But that's just my experience.

Hi jaba-who,

 

I have a sav and I was thinking of putting some floating balls in my fuel level sight tubes for easier fuel level sighting but could not find any to use. Do you know where I can get some from please?

 

Phil

 

 

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Hi Phil. Sorry but I had to make mine because I couldn't find any for sale.

 

Hand made ( after much trial and error.

 

Basically epoxy with Q cells and flouro orange paint mixed in.

 

But a bit complex because I found I needed to seal it with straight resin else the fuel gradually seeped in and they sank. But with the outside seal layer they were not buoyant enough.

 

So I made hollow versions.

 

Final ones have been successful for a couple of years now.

 

 

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