SonexBuilders.net

Ok , I hate my fuel tube running up the side of the panel ! I have been making longer trips , when the fuel gets to the last 6 gal .... Leaves an uneasy feeling when it gets to the bottom of the tube :) I want a fuel flow meter add on to my eis. But what about a gauge??? I am also wondering if anyone has tried routing the tube up the middle of the panel?? Any ideas?? Thanks

Wow. Down to the last 6 gal is when I really like to know how much further I can get. An easy fix could be to calibrate / mark the levels on the tank with a sharpie, it's translucent and the fuel level is visible. I know I can bend down and look at the remaining fuel inflight without a passenger.

I have the sonex supplied princeton sender with the MGL single F1. For a gauge and it is more accurate than any other fuel gauge of any vehicle/plane I have ever owned. Whether Avgas or Mogas it always agrees with my calibrated dipstick. Should be able to make the sender work with any other EFIS.

I would also like to add fuel flow

Steve 892

I have the tube calibrated with graduation marks while on the ground...... But I'm sure u know that is different in the air. Got quite a scare with that! :) I don't know if its the shape of the tank or what but also marking the tube comes out funky too ? A one point when it starts getting to the fill mark , the level in the tube will go down? Oh , just realized that I failed to mention I have a tail dragger :) that's why marking is such a pain.

I used a Sharpie to mark the gallon amounts physically on the tank at the same time I was calibrating my capacitiance probe. In a pinch, I can, with no passenger on board, look under the panel and see the exact fuel level. It's come in handy a few times when I reached the magic "sub-three gallon" point... :shock:

With the appropriate passenger, I can't see why visually checking the tank would be a problem?

I rigged my tank with both the capacitance probe and the sight tube. But after calibrating my tank, I've found the sight tube to be useless and will probably remove it. It doesn't show fuel below 6 gallons and that's when I really need to know what the level is. I will probably replace the upper sight tube fitting with some sort of quick connect that will allow me to connect a auxiliary fuel bladder and pump to extend solo cross countries and plug the lower one.

I don't route my sight tube as shown on the plans. I don't run it through the bottom hole in the panel, instead I run under the bottom of the panel and then up to the top hole. This allows me to see the entire length of the sight tube. I have markings at each 4 gal point. The main issue is getting the markings to agree with the fuel in the tank during flight as opposed to sitting on the ground.

BTW, I didn't have any luck getting my capacitance probe and EIS to work consistently accurately. After the 3rd or 4th calibration attempt I gave up.

My last few flights I have seen an issue with my Princeton probe and xTreme EIS. I'm getting erratic readings, like its reading 14 Gals for a while, then dropping down to 9 Gals, then back up. I don't trust it now.
So what has changed?
I'm now over 70 hours total time, this never was a problem pre-annual.
I'm now a taildragger (can't be that).
I am experimenting running AvGas (water/ethanol?).
I recalibrated the instrument during the annual.

Searching the archives I've found some references to water in the fuel tank right at the probe threads. I'll check that tomorrow and probably recalibrate again.

Any thoughts?

I too find the Princeton probe not accurate enough to trust. Now it so far off as to be unless. I have recalibrated the probe but it doesn't hold. It use to show a difference based on the type of fuel as well. I have the Floscan fuel flow meter it and it has always been within a half a gallon of what I was able to put back in regardless of the type of fuel. Although I did just have to back flush the probe as it recently was reading a little weird. Maybe this all just part of the Sonex experience. ;-)

fastj22 wrote:My last few flights I have seen an issue with my Princeton probe and xTreme EIS. I'm getting erratic readings, like its reading 14 Gals for a while, then dropping down to 9 Gals, then back up. I don't trust it now.

Could be a wiring issue? I had the probe ground wire screw loosen off a bit. The bad connection gave similar symptoms.

Steve
Sonex 892

Check the ground wire fom the probe end to ship ground. mine came off and the eifis read fuel intermittently. I had the throttle cable resting against the probe and that was giving a path to ground part of the time, hence intermittent. My probe was calibrated with auto fuel, when I fill up with av gas it reads lower than true level.