Fuel starvation in a constant turn?

[ArVeeNiner]

Something occurred to me the other day and I haven't figured out the answer.

In a turn, with the low wing tank selected, does the fuel slosh down hill and away from the fuel pick up? If so and if the turn is persistant is there a chance of fuel starvation? I'm thinking that this just isn't an issue but why? Could it be that since the turn is coordinated, the fuel just doesn't move much outboard? How about in a slip?

[n5lp]

Originally Posted by ArVeeNiner

Something occurred to me the other day and I haven't figured out the answer.

In a turn, with the low wing tank selected, does the fuel slosh down hill and away from the fuel pick up? If so and if the turn is persistant is there a chance of fuel starvation? I'm thinking that this just isn't an issue but why? Could it be that since the turn is coordinated, the fuel just doesn't move much outboard? How about in a slip?

In a sustained slip this could be an issue. In a coordinated turn it isn't. As far as your airplane knows it is in straight and level flight with a slightly heavier load.

Well I've already edited this message 4 times in 2 minutes. Let's say for all practical purposes a coordinated turn should not affect the amount of usable fuel. Actually there are some differences in level flight and a coordinated turn.

[aerhed]

Correcto, as long as A/C is coordinated the vector of G's is straight down. The tanks think they are on a level surface and if G's is above 1 you actually have increased head pressure. I've never had an RV tank unport, but you can do it pretty easy in a cherokee (if you try).

[asav8tor]

Your assumption is correct. In a coordinated turn the fuel will ride in the tanks in the same position as straight & level flight. In a slip, it depends how much you slip it how far the fuel will displace.

[WenEng]

I believe if you are in a coordinated turn, normal G force keeps your fuel where is was in your wing tanks. Not necessarily so if you are skidding.

[ArVeeNiner]

Thanks! That's what I thought. With most of my time in high wings I just never thought about that before.

[Geico266]

Originally Posted by ArVeeNiner

Thanks! That's what I thought. With most of my time in high wings I just never thought about that before.

Don't worry, if you run out of fuel you'll know.

[RV6_flyer]

As everyone has said, in a coordinated turn, the bottom of the tank does not change from what it is sitting on the ground.

I may be the only one to have tested this. I wanted to only have enough fuel in the tanks to fill the containers I had before doing the Service Bulletin on safety the fuel pickups. I had enough containers to store 9-gallons of fuel. I desired to only have about 5-gallons on one side when I landed. I circled the airport at 3,000 AGL in a left turn while burning fuel out of the left tank. Since I have fuel flow in addition to fuel pressure, I ran till I saw a drop in fuel flow and a decrease in fuel pressure. As soon as that happened, I switched to the other tank then landed.

Back in the hangar, I drained the left tank and got less than 8-oz of fuel out. The other tank that I thought I had 5-gallons in actually turned out to be 8.5 gallons.

Yes what everyone one is saying about coordinated flight is true. I tested it.

[Greg Arehart]

And it doesn't matter if high-wing or low-wing. I tested this in my C172 a couple years ago while doing some photography with relatively low fuel (actually I was flying, wife was doing photography). I put the airplane in a slip and held it for a couple minutes and pretty soon.... cough.... cough.... the engine stopped for a minute. It was obvious what the problem was, although I quickly switched tanks as well.

greg

[gasman]

I ran a tank empty to calibrate my dip stick. At 2200 rpm, I ran the tank out of gas, and when the engine quit, I switched tanks and did not turn on the electric pump....... The motor fired in three seconds! No altitude lost, just a slight deccrease in speed for a few seconds.