Switching fuel tanks

Is there any danger in letting a tank run dry and the engine quit before switching fuel tanks?

The fuel gages are not accurate enough when they are below a quarter tank. I routinely run a tank dry (usually right side) to the point when the engine sputters or quits. This is my way of knowing that it is time to switch tanks.

Does anyone know of a specific danger in doing this? Meaning can there be any problems like air getting trapped in the fuel lines or so?

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Is it still the case if you do not have header tanks? I still think the fuel flow meter would be a nice addition to keep track of fuel burn for max range.

With or without headers, no difference: when it's empty the engine quits and you switch tanks. If both tanks are empty, put it in a field, do your mea culpas and start walking the state of mind. As for flow meters, my $.02 is KISS

All same/same with or without headers. Be advised, however, that at least on a stock Cub, you DO NOT want to run the left tank dry. The left tank has a forward pickup tube, which is absent from the right.

That's why the admonition to takeoff and land on left tank only.

So, your procedure is fine: Run the RIGHT tank dry, then go to the left.

Of course, you definitely want to verify you can get fuel from the left tank BEFORE you run the right dry. Following the takeoff and climb on left tank only admonition will take care of that.

The fuel flow computers now available are absolutely GREAT tools. Like any other tool, they have some limitations, but that is almost the first thing I'd put in an airplane these days, even a Cub.

I've got one in every airplane I fly, and I use them all the time, mostly as a "warm, fuzzy" about my range and route.

MTV

Mike, I agree 100% on the fuel flow gadget. My math is not as good as it used to be. This is also a bigger deal when you have 31 gallons underneath you that you can't see (i.e. you have to climb out on the strut to see the sight guage on the side of the tank) that can be pumped up when you need it.

BTW, although it pumps slooooowly it is just faster than the plane burns it. Don't ask me how I know this.

I LIKE the left right system (although I have a both system now) because it makes you pay more attention to fuel, and if you are absent minded it gives you one reprieve. In the both system (without a belly pod), there is no reminder..

sj

KenyaCub said:

Is there any danger in letting a tank run dry and the engine quit before switching fuel tanks?

The fuel gages are not accurate enough when they are below a quarter tank. I routinely run a tank dry (usually right side) to the point when the engine sputters or quits. This is my way of knowing that it is time to switch tanks.

Does anyone know of a specific danger in doing this? Meaning can there be any problems like air getting trapped in the fuel lines or so?

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A JPI 450 would be an instrument I think you would like. Keeps track of all the fuel and its affordable. What year is your cub.

Every time you run a tank dry your sucking everything that might be in the tank. Vigilance on the gasolator would be in order. The specific danger would be not enough altitude if there was any kind of an issue with a restart.

I don't believe that you should be getting any more crud through the system just because you ran a tank dry. If anything is drifting around in there, and it's heavier than gas, it should go to the low point (which can move around, depending on attitude, so beware) and if it's neutral bouyant in gas, you'll get it sooner or later anyway.

I really don't see any risk to running all the useable gas out of a healthy airplane's tank. As long as there's still another tank full of fuel, and you've verified that it works, that is.

Vigilance to one's gascolator is always a good idea.

MTV

I have never had a problem running a tank dry and then switching.....seems to me, I ran a left tank dry once inadvertently without a problem.