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**lamarglobe** · 10-30-2018, 12:52 PM

Looks good, I guess that works. I was concerned about the 5/15 hose to 1/4 inch tube being a potential for leaks but Apparently it is not a factor. Thanks

**whee** · 10-30-2018, 01:00 PM

Originally posted by lamarglobe View Post

Looks good, I guess that works. I was concerned about the 5/15 hose to 1/4 inch tube being a potential for leaks but Apparently it is not a factor. Thanks

You are right to be concerned, it is a factor. Mine dripped a little fuel but after tightening them again they haven't dripped at all. They've been holding fuel for over a month. Just to make myself feel better I may add a second hose clamp like is done in pressurized water systems. A better solution would be to use a AN816-5D nipple and 5/16 aluminum tube.

**Battson** · 10-30-2018, 03:59 PM

Another way of doing it - much more simply:

Parts:
Two AN822 elbows.
One length of clear, rigid Schedule 40 PVC pipe for sight gauges (Spruce P/N 03-54100).
Sight gauge float ball.

Thread the PVC tube with NPT threads each end. Insert float ball. Screw the elbows into the PVC with Loctite thread sealant.
Job done.

These things are bullet proof and don't leak, the PV is perfectly sized for float balls. They are also really easy to install / remove. This is what Bob recommends.

Sorry about the grainy photo:
Screenshot_2018-10-31-10-04-43.png

**svyolo** · 11-05-2018, 10:59 AM

I didn't know PVC came in clear. I might have a look at that.

**Bcone1381** · 01-01-2019, 10:01 AM

Beartracks came today. I read Jared's article and will fabricate mine like that as well.

But a small note was in there that Curtis Penner mentioned when describing his Beautiful Patrol. The Canadian authorities mandated that a shutoff valve be installed between the tank and the sight gage to prevent fuel leaks into the cabin in case of failure of the sight gage.

**AZBearhawk272** · 01-01-2019, 01:34 PM

I really like the electrical system circuit breakers
co located with potential leaking fuel.
Have experience with the Stevens sight glass system working well in the desert heat, chilled to 0 at altitude in winter, fuel dribbling everywhere, holding pressure on the joint to minimize the leak. Long 30 min till landing.....

Bearhawk # 272

**svyolo** · 01-01-2019, 10:16 PM

Brooks;
"Canadian Authorities" meaning by regulation, or by the opinion of one regulator? You can extrapolate that logic out to having a shutoff valve for everything, including a shutoff valve upstream of the shutoff valve in case it leaks. I thought really hard about putting small Earls' Racing shutoff valves for the fuel feed lines, but is just seems more complicated. More fittings means more chances to leak. Seems counterproductive too me.

I like Battson's PVC pipe, and I think that is what I will use. I bought the Superthane line and AN fittings, but the fittings were way to small to seal inside the spec-ed superthane line.

**Chris In Milwaukee** · 01-02-2019, 08:52 AM

Originally posted by svyolo View Post

You can extrapolate that logic out to having a shutoff valve for everything, including a shutoff valve upstream of the shutoff valve in case it leaks. I thought really hard about putting small Earls' Racing shutoff valves for the fuel feed lines, but is just seems more complicated. More fittings means more chances to leak.

Or forget. We had a local builder put a pair of shutoff valves, one on each A-pillar, for his fuel tanks in his CH-801, in addition to the central one. Somehow he managed to miss turning them *both* on and ended up in a cornfield. Two less things

**svyolo** · 01-02-2019, 09:29 AM

Back to the Johnathons PVC sight gauge, which I like. ACS lists the tubing as "Excellent resistance to gasoline" . But googling PVC chemical resistance gets different results. Some are the same, some are "fair", which is defined as not for continuous use. Not sure now.

**Bcone1381** · 01-02-2019, 09:44 AM

Originally posted by svyolo View Post

Brooks;
"Canadian Authorities" meaning by regulation, or by the opinion of one regulator? You can extrapolate that logic out to having a shutoff valve for everything, including a shutoff valve upstream of the shutoff valve in case it leaks. I thought really hard about putting small Earls' Racing shutoff valves for the fuel feed lines, but is just seems more complicated. More fittings means more chances to leak. Seems counterproductive too me.

I like Battson's PVC pipe, and I think that is what I will use. I bought the Superthane line and AN fittings, but the fittings were way to small to seal inside the spec-ed superthane line.

The voice inflection in the Beartracks article found on p.8. appears as though its mandatory for all, and not an opinion of a regulator.

Truth exists, and my impressions are not truth. They are not opinions....rather they my feelings/interpretations of tidbits of info that I analyze and then question conventional practices.

Truth....Fittings that leak are counter productive, fittings themselves are not counterproductive. We must build fittings that don't leak and leak check all fittings.

Impression.... Most sight gages penetrate a rigid interior fuselage panel so tube is viewable to the pilot. An accident could result where the wing root is bent somewhat from the fuselage and damages a sight gage at the fuselage. A safer installation is designed so the sight gage remains with the wing and separates from the fuselage without damage. (That one might be a Truth)

Truth is .....Yes, more valves increase complexity. Complexity kills. Arguable, the best designed fuels system, according to Bengilis, has a single ON - OFF valve. Extra shut-off valves increase risks, and possible of fuel starvation in most applications. They add cost, weight, and increases risk of a valve being placed in the wrong position.

Impression....The sight gage shut-off valve is not connected to the fuel system. A miss set valve would provide an erroneous fuel quantity indication. But they still add eight, complexity, cost, and risk.

Truth is.....a safer way to measure fuel quantity exists than using a sight gage, but it won't be simpler, lighter, less costly, or more reliable.

Truth is....A shut off valve is about $18 each from Spruce, but a solution to install it so it can be remotely shut-off must be solved.

Truth..... is if I installed shut-off valves for the sight gage and got into an accident 10 years from now, I might forget to use them....at least thats my impression.

I don't know yet if I will install a shut-off valve, but if a wing separates from the fuselage, elegant simplicity demands that the sight gage goes with it.

**rodsmith** · 01-02-2019, 09:54 AM

Some sort of restrictor can be installed in the wing fittings going to the sight gauges. Some have used drilled out rivets. Not a perfect solution but would limit the volume of a leak at the sight glass or in an accident involving a wing separation. That is what I plan to do.

**JimParker256** · 01-02-2019, 04:13 PM

I like simplicity. I like reliability. Sight gauges are great, but as I discussed above, I've had bad experiences with difficulty reading them, and don't like the fact that you have one set of "marks" for normal flight and a second set for "tail-on-ground" readings.

Because of all this, I'm considering using a pair of these fuel probes from Belite (picture below). This system measures the quantity of fuel in tank by ascertaining the weight of the fuel column, with a scale accuracy of 0.5%, according to James Wiebe, Belite's CEO. I asked James Wiebe about using these probes on a T-fitting inline in the system, and he said that should work beautifully. I'm thinking that I will install one on each tank, attached to a T-fitting inline with the aft fuel line where it attaches to the tank. Then I can either use the Belite Radiant dual-tank gauge (which unfortunately reads in "percent" rather than gallons) or connect the probe output to an EFIS system that accepts 0-5v probe inputs (most do) and read directly in gallons. One nice thing about the Belite gauge is that it shows "time to empty" (34 minutes in the sample pictured) along with a 15-minute history of the fuel level in each tank.

Assuming all this works as advertised, it would be a very clean and simple installation with incredible accuracy. Cross-checking the indicated fuel level with a fuel-flow meter indicating what SHOULD be remaining on board would give me a good sense of comfort about fuel status.

And for those of you using a header tank, take a look at the Bingo3 liquid detector. It will light up a Green LED as long as fuel is present in the tank, and turn the LED Red if the level drops below the sensor level. He calls it the "bingo" fuel detector because if that light turns red, you're at "Bingo" fuel and need to get on the ground ASAP, because your header is not being refilled... At $100 for the "plug and play" version, it's pretty cheap insurance for header-based systems. (Could work for regular tanks as well, but requires a hole in the tank that I would be hesitant to drill in a big tank - just because it would be hard to know at what level to put it... You don't want it going off when tanks are half full. On a small 4-6 gallon header tank, on the other hand, I would put that sucker near the top of the tank...)

Thoughts and comments?

**whee** · 01-02-2019, 04:30 PM

Looks like a great option to me Jim. Rather than T into a supply line why not just screw it into the lower sight gauge fitting on the tank?

**JimParker256** · 01-02-2019, 06:08 PM

Ever have one of those "Doh!" moments? Whee just gave me one... Thanks! Using the lower sight gauge fitting for the fuel probe would be even better...

**whee** · 01-02-2019, 06:27 PM

I've had more of those moments than I'd like to admit.

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