Fuel Level Sensor

Unless you had a neucleonic type, I doubt it would be very accurate. The planes bounce around too much while flying. One thing I have seen is a clear window on one side of the tank compartment. With highly colored fuel you could see the level on a slow fly-by.

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GET A AIRMADILLO THE TANK IS IN FULL VIEW FOR A FLY BY

That's fuuny. I had one for about 2 years and that is EXACTLY what I did. Do a low pass and take a look.

BTW, we can hear you no need to SHOUT. ;-)

Jim

This is a very large scale twin engined scale aircraft where "bouncin

around" is not too much of an issue and aerobatics are rare. Sid windows won't work nor will colored fuel. I need a general way, othe than time, to detect the fuel level when in level flight - woul attach a strobe on the aircraft that would flash when in level fligh during a tank check run. Any ideas

-- SoarScale

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Telemetry is now reporting receiver battery voltage, some way of reporting fuel level via telemetry would be good. Pressure transducers? Because the fuel is sloshing around during flight, an innovative way of measuring this is called for!

On Sat, 3 Jul 2010 23:33:55 -0500, Syntax wrote in :

Even the full-scale general aviation planes haven't got great fuel-level sensing.

I doubt we're going to get it down at our level any time soon.

You should be able to measure what's in the tank on a few test flights, extrapolate to an ounces-per-minute number, figure your max endurance, and run a timer.

That seems a whole lot simpler to me than getting sensors inside of a tiny little tank!

Marty

in:

Back in the days of bladder tanks, we used a spring loaded flap that pressed on the tank. When it moved far enough, it caused a microswitch to operate.

Marty's way puts less load on the airframe which means better performance for a given engine.

(so says the guy who puts .32's on .19 sized airframes)

YMMV

in:

I think a lot of the reason that general aviation planes don't have it is the shape dictated by wing tanks -- sensing the up/down level of fuel in a wide, low tank ain't easy.

Our tanks are more square -- but our acceleration vector tends to vary a lot more unless the flight is very boring.

That only works with a predictable throttle profile (like our club president, whose throttle positions are "full on", "land" and "shut off").

If you could think up a small accurate flow meter you could integrate flow -- but the meter wouldn't be trivial.

On Sun, 04 Jul 2010 14:19:26 -0700, Tim Wescott wrote in :

Well, if you calculate the "full on" endurance, every time you throttle down, you add to your margin of error.

Landing with too much fuel is not usually as troublesome as landing deadstick (I know that's not true of full-size airliners, but at our fuel loads, I think it is a reasonably accurate statement).

I thought about a flow-meter, too. I think the mechanism and wiring would be vastly simpler and more reliable than gauges in the tank. If you remember to fill your tank every time and reset the fuel flow meter, it should be fairly accurate. If you know you have

10 oz of accessible fuel in the tank, when the flow meter says that you've provided 10 oz to the engine, it's time to land.

Our tank designs are so simple that most installations should provide the full amount of fuel that the tank is rated for.

But that still seems like too much work for too little gain.

Marty

in:

It might make sense if you were doing some serious airplane tuning and wanted to know if you needed to put in a bigger tank or could put in a smaller one -- but then, you can do that just by going out and flying, then measuring how much fuel you had left.

This entire discussion is one of the types of things that keep me active in my flying community, but more importantly reading here. Where else can you get into a discussion about how many angels can dance on the head of a pin and not have hurt feelings running rampant?

On Sun, 04 Jul 2010 23:42:12 -0700, Tim Wescott wrote in :

I think that's how Maynard Hill did things.

Over and over and over ...

Amazing man!

Marty