Fuel tank sending units

[AKMac]

Hello, I'm new to kitfox's. I've been eyeballing them for a few weeks now and have what is perhaps a dumb question (though I did perform a search on the site).

I was reading the build manual and noticed that the only provision for fuel gauges is typically a sight glass at the wing root and an optional alarm that goes into the header tank. This is all great and is a system that has been proven for a long time.

However, I believe that a large portion of GA accidents are fuel starvation related. I feel that having float style sending units in the tanks would be a very nice safety feature since modern glass avionics (G3X) now incorporate fuel range rings, fuel calculators, and audible warnings.

I was just curious if anyone has put sending units in the tanks, or is this a large endeavor because of the fiberglass tanks?

[tjentzsch]

Does composite act differently then fiberglass? The tanks on KF are composite and I wonder if that makes working on them more difficult.

[jmodguy]

Fiberglass is a type of composite. I looked at sending units but these tanks are not very tall and I could not find a suitable sending unit.

[Rodney]

After you fly your airplane for a while, you will learn how many gallons per hour your airplane burns in cruise and how much to allow for the first 10-15 minutes of climb to altitude.

There are also flow meters that will tell you how many gallons per hour your engine is burning. I have mine calibrated to read 1/2 gallon per hour MORE than I actually burn. Just my conservative nature.

Between the fuel meter and knowing my fuel burn at cruise, I personally do not see the need to have gages in the tank. It's just another system to be maintained.

Finally - with 28.5 gallons onboard (26 main and 2.5 in header tank) the airplane will fly a lot longer than I can.

Regards
Rodney

[Bartman1959]

I'm with you 100% on that. Personally, I'm only good for about 2 hours per hop.

[Dave S]

Sight gauges on the kitfox has are about as Norwegian proof a device as you can get (I can that say that 'cuz my name ends in ...son).


I have never seen a float/electronic gauge on an airplane (or a car) which is anywhere near as reliable and accurate as a direct reading sight gauge.


Certainly a person can find a way to do this if that is what they want; but, not likely you will find many who have done this on a kitfox because the basic kitfox fuel gauge works perfectly for all the reasons Rodney indicated.

[tjentzsch]

After you fly your airplane for a while, you will learn how many gallons per hour your airplane burns in cruise and how much to allow for the first 10-15 minutes of climb to altitude.

There are also flow meters that will tell you how many gallons per hour your engine is burning. I have mine calibrated to read 1/2 gallon per hour MORE than I actually burn. Just my conservative nature.

Between the fuel meter and knowing my fuel burn at cruise, I personally do not see the need to have gages in the tank. It's just another system to be maintained.

Finally - with 28.5 gallons onboard (26 main and 2.5 in header tank) the airplane will fly a lot longer than I can.

Regards
Rodney

Very good info, thank you.

[GuppyWN]

There are also flow meters that will tell you how many gallons per hour your engine is burning. I have mine calibrated to read 1/2 gallon per hour MORE than I actually burn. Just my conservative nature.

If you have it programmed 1/2 gal more and you know it’s burning 1/2 more why wouldn’t you program the exact burn?

[PapuaPilot]

You mentioned the G3X, which is what I have. I am using the "Red Cube" fuel flow sensor and it is spot on accurate. All you need to do is program the amount of fuel into the G3X and it takes care of it from there. When I fill my tanks I tell it I have 26 gallons. I don't count my header tank as useable which actually gives me another 12-15 minutes reserve.

Like was mentioned, the sight tubes are as foolproof as you get. I calibrated mine by filling my tanks in 2 gallon increments and made lines next to the sight tubes. My plane is a tailwheel so I did it in two positions; level and on the tail wheel. When I do my preflight I compare the sight tubes to the G3X reading and they are always within a 1/2 gallon.

The G3X it totally capable of displaying fuel levels, but there is no reason to add that complexity to a Kitfox.

[Rodney]

GuppyWN. Thats a good question to which I honestly don’t have a good answer
other than to say I’m just conservative. On a three hour flight that gallon n one half is 15 to 20 minutes flight time.

As a friend of mine says. “That’s good enough for the girls we go with.”

After all, it is a mechanical piece of equipment and as such susceptible to some error. However, I have found a fuel flow reading consistently more accurate than having fuel gages. My Kitfox is the first airplane I have owned that has a fuel flow gage and I really like it

That is probably not a very good answer but if I’m going to err I want it to be on the side of having more fuel available. We read all the time about guys running out of fuel. I’m really trying to NOT be one of those guys. My Dad who spent WW2 as an instructor pilot in everything from P-51s to Stearmans to AT6’s would come down from Heaven n slap me upside the head if I ever did that.

Regards
Rodney