Fuel starvation

[Ed Cesnalis]

40 minutes ago, Ben2k9 said:

So as long as you can SEE fuel in at least one tube, no prob right?  I was flying yesterday and somehow left side got down very low but right side had a lot, like a full tube.  I got worried and entered into a slip, maybe that was not necessary?

 

 

I routinely fill my right wing only.  I don't give a second thought to an empty tank.  As long as you can see fuel so can you engine, that's right.

[Buckaroo]

If you indicate say zero fuel in the left tube and say 6 gallons indicated in the right tube and you make a skidding left turn you will throw fuel out to the far right end of the long flat right tank and probably see a empty right tube followed by an immediate loss of engine power. Six or even 8 gallons of usable fuel does not mean you’ll have say and hour of flying left. An uncoordinated turn can steal fuel with engine failure followed by a forced landing followed by a re-appearance of the fuel in the tube while sitting at the of field setting. Believe me I know!

[Ed Cesnalis]

14 minutes ago, Buckaroo said:

If you indicate say zero fuel in the left tube and say 6 gallons indicated in the right tube and you make a skidding left turn you will throw fuel out to the far right end of the long flat right tank and probably see a empty right tube followed by an immediate loss of engine power. Six or even 8 gallons of usable fuel does not mean you’ll have say and hour of flying left. An uncoordinated turn can steal fuel with engine failure followed by a forced landing followed by a re-appearance of the fuel in the tube while sitting at the of field setting. Believe me I know!

don't do that.

when one tank is empty and the other is low you can easily maintain a slip that favors the fuel inboard.  You can turn either way and even fly the pattern like this.  The visible fuel becomes the anchor, don't let it disappear.  control it with your rudder and control your direction by your balance of rudder and flaperon.

[WmInce]

4 hours ago, Ed Cesnalis said:

. . . . . when one tank is empty and the other is low you can easily maintain a slip that favors the fuel inboard.  You can turn either way and even fly the pattern like this.  The visible fuel becomes the anchor, don't let it disappear.  control it with your rudder and control your direction by your balance of rudder and flaperon.

[Warmi]

4 hours ago, Ed Cesnalis said:

don't do that.

when one tank is empty and the other is low you can easily maintain a slip that favors the fuel inboard.  You can turn either way and even fly the pattern like this.  The visible fuel becomes the anchor, don't let it disappear.  control it with your rudder and control your direction by your balance of rudder and flaperon.

I think I would rather fly with extra fuel rather than bother with all that unnecessary and pointless workload ...

[Buckaroo]

15 minutes ago, Warmi said:

I think I would rather fly with extra fuel rather than bother with all that unnecessary and pointless workload ...

My CTSW is a brilliant Light Sport aircraft that I really cannot find a better example. There fast, carry a lot, beautifully built, quality, pretty and roomy. 

Just don’t fly on less than 10 or 12 gallons of gas until you learn the idiocy’s of operating with low fuel load of say less than 12 gallons! 

I honestly cannot find a better machine for fun, sport, crisp handling etc. They are like a fun sports car only in the sky! Also very safe!

[Warmi]

Well, I don't fly FD planes but that's cause I am hopelessly in love with low-wings and wide open cockpits etc ... and thus own and fly a Sting ... 

Anyway, I did get about 30 hours in Remos GX/G300 models  ( my initial training ) and as far as high wings go -  when I ended up checking out CTLS afterwards , the plane seemed so much better than the Remos I used to fly in...

- seemed much bigger inside and with much better desiged cockpit ( imho)
- much better visibility , probably the best for any high wing LSA (the new A32  http://www.foxbat.com.au/a32 could probably rival CTLS in that regard )
- quite fast and with great range
- very easy to get into  ( I only realized that after 100 or so hours worth of climbing into my Sting - going back for a flight in CTLS recently , it was soo damn easier , just open the damn door and you are in )

The only thing I didn't like about CTLS  ( beside the fact that it was a high wing ) was spring loaded controls. Frankly, I had only 2 hours in CTLS so I am sure I would find some other stuff to dislike but that's the only thing I remember now.

 

[FlyingMonkey]

5 hours ago, Ed Cesnalis said:

don't do that.

when one tank is empty and the other is low you can easily maintain a slip that favors the fuel inboard.  You can turn either way and even fly the pattern like this.  The visible fuel becomes the anchor, don't let it disappear.  control it with your rudder and control your direction by your balance of rudder and flaperon.

I’ll go a step further, and say don’t let either tank go dry.  That way slip, skid, whatever, you will never get in a situation where you don’t have at least one tank feeding the engine.  Balancing fuel is easy enough in these airplanes that there’s not a good excuse to fly around with an empty tank, when a moment of inattention in that condition could result in a stoppage.

Just IMO, your mileage may vary.

[Mike Koerner]

I agree with Monkey and Buckroo. I balance the fuel as it gets low. I've always been on the ground before the fuel disappears from either tube. I wouldn't consider any other approach prudent.

Mike Koerner

[Ed Cesnalis]

7 hours ago, FlyingMonkey said:

I’ll go a step further, and say don’t let either tank go dry.  That way slip, skid, whatever, you will never get in a situation where you don’t have at least one tank feeding the engine.  Balancing fuel is easy enough in these airplanes that there’s not a good excuse to fly around with an empty tank, when a moment of inattention in that condition could result in a stoppage.

Just IMO, your mileage may vary.

 

22 minutes ago, Mike Koerner said:

I agree with Monkey and Buckroo. I balance the fuel as it gets low. I've always been on the ground before the fuel disappears from either tube. I wouldn't consider any other approach prudent.

Mike Koerner

 

7 hours ago, Buckaroo said:

My CTSW is a brilliant Light Sport aircraft that I really cannot find a better example. There fast, carry a lot, beautifully built, quality, pretty and roomy. 

Just don’t fly on less than 10 or 12 gallons of gas until you learn the idiocy’s of operating with low fuel load of say less than 12 gallons! 

I honestly cannot find a better machine for fun, sport, crisp handling etc. They are like a fun sports car only in the sky! Also very safe!

The good advice quoted here should not cause you to reject the technique I laid out for critically low fuel.  If you get below legal reserves in your CT you will want to transition for the final few gallons.

You will likely never pull your chute but you do want to know how to go about it.  You may never get critically low on fuel but then again you might realize a fuel leak or just screw up one time.

[Mike Koerner]

Thanks for that clarification, Ed.

I agree. In the unfortunate event that you only have fuel on one side, you need to keep it showing. That's an emergency procedure that's good to know.

Mike Koerner

[JLang]

7 hours ago, Mike Koerner said:

In the unfortunate event that you only have fuel on one side, you need to keep it showing. That's an emergency procedure that's good to know.

In the scenario being discussed, fuel has been used predominately out of one tank, presumably from intentional or unintentional trim adjustment, until it is dry.  Then, the plane is re-trimmed/flown in a slip to move the remaining fuel outboard to inboard, to keep it showing.  However, that action also starts to transfer fuel back to the dry tank.  So in this emergency procedure, if the fuel stops showing or gets critically low, which will happen faster than normal due to the fuel going both to the engine and the other tank, you should then swap sides again to get access to the newly-transferred fuel.  Right?

[Ed Cesnalis]

25 minutes ago, JLang said:

In the scenario being discussed, fuel has been used predominately out of one tank, presumably from intentional or unintentional trim adjustment, until it is dry.  Then, the plane is re-trimmed/flown in a slip to move the remaining fuel outboard to inboard, to keep it showing.  However, that action also starts to transfer fuel back to the dry tank.  So in this emergency procedure, if the fuel stops showing or gets critically low, which will happen faster than normal due to the fuel going both to the engine and the other tank, you should then swap sides again to get access to the newly-transferred fuel.  Right?

You have a remarkable degree of fine adjustment.  Once critical you do want to keep that last couple of gallons inboard but don't slip more than necessary.  

I have used this technique more than once and the fuel gets consumed it doesn't get transferred to the other side.

[JLang]

5 hours ago, Ed Cesnalis said:

You have a remarkable degree of fine adjustment.  Once critical you do want to keep that last couple of gallons inboard but don't slip more than necessary.  

I have used this technique more than once and the fuel gets consumed it doesn't get transferred to the other side.

But wouldn't the fuel "follow the ball" to the other tank?  Or perhaps in the scenario with little fuel to start with, the head pressure is small enough to make the transfer too slow to notice?

[Ed Cesnalis]

5 minutes ago, JLang said:

But wouldn't the fuel "follow the ball" to the other tank?  Or perhaps in the scenario with little fuel to start with, the head pressure is small enough to make the transfer too slow to notice?

it wall follow the ball and flow to the engine.  again this is a matter of degree.  think strait and level slip so we can compare bank angle.  The tanks are low and flat so with no slip the last couple gallons wants to distribute evenly and not be collected at the port, at the root where it can do good. 

A very small bank collects that remaining fuel at the root where a steeper bank provides a faster transfer rate to the other tank.  Best course is to use your rudder trim to keep fuel inboard without excessive yaw force.  Judge by the resulting level, Dry is bad, wet but low level is best.

[Roger Lee]

1/2 ball out usually keeps tanks equal and 1 full ball out transfers fuel to the other tank and feeds the engine.

[WmInce]

2 hours ago, Roger Lee said:

1/2 ball out usually keeps tanks equal . . . 

So does the occasional glance at the wingtips, ensuring that they are approximately the same distance above the port and starboard horizons.

[Ben2k9]

By the way, side note: empty 5gal Tuff Jugs fit perfectly in the baggage compartment of th CTLS. I used them on a recent XC voyage and at some airports I could just use the courtesy car to take the jugs to a gas station. 

[Roger Lee]

Just take a look at the sight tubes in LEVEL COORDINATED flight every half hour.

[sandpiper]

Too bad they didn't come with a header tank. Seems that would solve the issue. Since Andy is experimental maybe he could retrofit one and sell the kit to the rest of us who would have added incentive to go experimental.If it worked, I'd do it.

[FlyingMonkey]

On 7/21/2018 at 8:26 PM, sandpiper said:

Too bad they didn't come with a header tank. Seems that would solve the issue. Since Andy is experimental maybe he could retrofit one and sell the kit to the rest of us who would have added incentive to go experimental.If it worked, I'd do it.

I have considered adding a left/right/both valve to the fuel system, or making other changes.  In the end I realized the system as designed works fine and I didn't want to add complexity where it's not needed.