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Joe Berki

Fuel system

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What is the preferred fuel gauge / probe being used? Are Vance's site gauges enough? How did you mount the fuel probe in the strake? Any thoughts on electric fuel pumps for auto engines external versu submersible? Thanks for any help

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In this same vein, and hopefully not changing the subject of the thread too much, I'd like to ask whether anybody who has used capacitive probes has had problems when switching between mogas and avgas?

 

I was reading some old Canard Pusher articles on ez.org and saw a story about having problems with the probes reading too low when avgas was used because it has different electrical qualities. It was a rather old story so things may have improved since then, but the author recommended float type probles.


Rui Lopes

Cozy MkIV S/N: 1121

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We used the Westach capacitence probes. I got mine from AS as a package with dual reading single gauge. Cost under $300. Mine are 5" bendable and go through the side under the top longeron, then bent up to top of tank and back down. They can be calibrated so even if their was a difference in readings with different fuels, you can calibrate them to what you are using. Some folks go straight down from the top of the strake near the fuselodge body and build a blister to cover it up. We think we like our mounting location better. As far as vances visual gauges go, we have them but have decided not to install them.


Dave Clifford

"The Metal Man" Musketeer

Vise grip hands and Micrometer eyes!!

 

Cozy MKIV Plans #656

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Any idea what happens when you mix fuels? ie. half tank of 50% avgas/50% mogas?

 

It seems to me that in this situation on one setting you would show empty and on the other you would show full. Have you tested this?

 

I'm loath to use float probes, but capacitance probes seem to have their own

problems for the person planning on using mogas from their home field, but avgas when at other fields. Granted, in most cases you would have "mostly" either avgas or mogas but it still may cause a problem. I can see the situation where the pilot want to get his tanks empty so that when he refills he doesn't have this problem and then some delay causes him to run out of fuel. Its a one in a 1000 thing, but from my reading of accident reports, it's stuff like this that often bites you.

 

I guess the best solution is to use a fuel flow system and keep track of the fuel this way when you suspect the guages to be showing bad data.


Rui Lopes

Cozy MkIV S/N: 1121

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I used the Princeton probes with the remotely-mounted sensor heads. This allowed me to place each probe into the strake (inboard aft corner) and to mount the sensor heads somewhere else (firewall). The probes are totally under the cosmetic strake fairings without using extra humps/bumps. Check my Chapter 21 page for pictures and words.

 

I second Dave's thoughts on calibration. Most probes can be calibrated for the installation location and fuel used.

 

I have had the fuel site glasses since Chapter 5. These are great to have as you can see your fuel level without using electricity and other instrumentation (like when refueling). I made the conscious decision to add the probes when I flew with Marc Zeitlin to Sun-N-Fun. Our luggage was piled high enough to totally block the view of the site glasses. So I added the probes too.

 

If you decide to go with probes, be aware that some fuel gages require using a certain brand of capacitance probes. So check first.

 

====================

Wayne Hicks

Cozy IV Plans #678

http://www.maddyhome.com/canardpages/pages/waynehicks/index.html


Wayne Hicks

Cozy IV Plans #678

http://www.ez.org/pages/waynehicks

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To answer Rui's question, all probes will read empty when there's no fuel in the probe! :-) Generally, the probes are cut to the depth of the tank so that they rest 1/8th to 1/4-th inch off the bottom of the tank.

 

...Wayne


Wayne Hicks

Cozy IV Plans #678

http://www.ez.org/pages/waynehicks

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Most probes can be calibrated for the installation location and fuel used.

What if the fuel used changes? Dave said that his are dual calibration which I understand to mean that they can be calibrated for 100% avgas and 100% mogas. My question is what do you do when you have a mixture of 50% avgas/50% mogas? If you had 1/2 a tank of such a mixture on one of the calibrations it would under read, on the other it would over read. Of course 50/50 mixture is just one mixture ratio, the possiblities are endless. If the probes are able to auto-adjust for the current fuel ratio then thats great, problem solved. If not....

 

I realize that these are great if you plan on only ever using one type of fuel, but I plan on using a rotary and mogas most of the time and avgas when its not avialable. Even with a dual calibrated system I would have to empty the tank totally to get 100% avgas so that the probes read correctly using the avgas calibration tables.

 

As I said these are my assumptions, I have never actually tested any of this and was wondering if anybody else had and what they found.


Rui Lopes

Cozy MkIV S/N: 1121

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I have capacitance probes. The calibration screw on mine is VERY sensitive and the readings need more adjustment. I noticed the right gauge was reading zero today. :o I'm glad I had the sight gauges to confirm the fuel status. :cool:


I can be reached on the "other" forum http://canardaviationforum.dmt.net

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Maybe I'll re-think that bit about not putting the sight gauges in!! We are at that point now. :rolleyes: They are here at the shop already, so its no big deal to go ahead and do it.


Dave Clifford

"The Metal Man" Musketeer

Vise grip hands and Micrometer eyes!!

 

Cozy MKIV Plans #656

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I'd recommend that. Its always better to have a way to confirm critical information. Actually SEEING the fuel gives a nice comfort level, especially as you get used to the (probably non-linear) electronic readings.


I can be reached on the "other" forum http://canardaviationforum.dmt.net

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To Rui:

 

The vance site glasses are certainly the simple solution. They never need calibration :-) no matter how you mix mogas and avgas. Over time, mogas will discolor the site glasses. They will still function and you will still be able to see the fuel level, but they will eventually take on a yellowish haze. They stay relatively clear with avgas.

 

....Wayne


Wayne Hicks

Cozy IV Plans #678

http://www.ez.org/pages/waynehicks

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I just got my set of Atkinson sight gauges. I had always planned on putting them in there. I totally agree with with being able to see the fuel.

 

I'm just questioning my initial decision to use capacitive probes. seems like the old float types are the best for my situtation.

 

I'm also planning on using the Blue Mountain EFIS (already starting saving up for this sucker....) and I like the way that it measures fuel by you telling it how much you have on takeoff and then it keeps track of how much you have used during the flight to get the amount remaining.

 

So it looks like I'll have 3 ways of telling how much fuel I have in my plane, EFIS, probes, sight gauges. If I ever run out it will be a truly boneheaded mistake!!


Rui Lopes

Cozy MkIV S/N: 1121

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AH the EFIS/One I gotta get me one of those (one day).

 

I think the EFIS/One uses capacitance probes. I think they recommend a particular brand which works well with their unit.


I can be reached on the "other" forum http://canardaviationforum.dmt.net

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John,

 

When you get the chance, can you try putting in some avgas and see how the probes respond?


Rui Lopes

Cozy MkIV S/N: 1121

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blue mountain, 0 to 5 volt westach 1 foot long bendable

 

just put 2 in a month or so ago

 

enjoy the build

 

dust


maker wood dust and shavings - foam and fiberglass dust and one day a cozy will pop out, enjoying the build

 

i can be reached at

 

http://www.canardcommunity.com/

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I decided to order Vance's guages and called Princeton to get more info on their probes. I think I can get away with one probe. Both of my tanks are connected via a sump tank that is lower. I thought they would not level so I connected to water bottles with a tube and filled one and they both seek the same level. Princeton was supposed to email some ing but have not yet. Thanks for everybody's input.

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