Running dry?

That's why God invented fuel computers. I know exactly how long I have
left on each tank...

You think you know. You might find that the computer has a surprise for
you. All the other computers in my life have surprises for me.

Jose
--
Quantum Mechanics is like this: God =does= play dice with the universe,
except there's no God, and there's no dice. And maybe there's no universe.
for Email, make the obvious change in the address.

I've had excellent results with my JPI fuel computer. Unless you are
leaking gas (something the fuel gauge may clue you into) it should work
great. I am able to take trips deep into Mexico that I would not have
felt comfortable doing without the fuel computer. I measure my fuel
before and after every flight. I've never had the computer be off by
more the 0.1 gals.
There is only a universe if you are looking at it. If you are not
looking at it, whether or not there is a universe is undefined.

-Robert

That's why God invented fuel computers. I know exactly how long I have
left on each tank and I don't need to scar the crap out of my wife and
pax to do it.

Interestingly enough, that was exactly the logic I was using the one
time I inadvertently ran a tank dry on my Twin Comanche. I was quite
surprised - there was supposed to be another 30 minutes of fuel left in
that tank.

Fuel computers are not infallible. However, I do agree that if you use
your fuel computer to draw ALL the fuel from the tank that is supposed
to be there, that's just as good as running one dry. It just doesn't
work if you leave, say, a 30m minute reserve there that you plan to get
later if you need it. It may not be there.

Michael

Robert,

I know exactly how long I have
left on each tank


No, you don't. You know how much is gone from the tanks, not how much
is left.

--
Thomas Borchert (EDDH)

Too many of you have been reading "The Cheap *******'s Pilot's Guide".
I have good working gauges and a fuel computer that has been
professionally calibrated and verified at each 100 hour inspection. I
don't need to make the wife want to leave me in order to know how much
fuel I have. Flying over the Sierras, dodging TS's is exciting enough,
I don't need to turn off the fan to add more excitment to my life.

Are your gauges accurate enough to reliably tell the difference between
30 minutes fuel at 60% power and empty in tyubulent air?
Will your fuel computer account for fuel that leaves via a cap that has
developed a leak?

Michael

"Robert M. Gary" writes:

Flying over the Sierras, dodging TS's is exciting enough,

Yeah, been there, didn't enjoy it.

I don't need to turn off the fan to add more excitment to my life.

We seem to have diverging groups. Some of us see running a tank (nearly)
dry as a non-event. Others see it as "turn[ing] off the fan". I've seen
a few references to the *possibility* that some planes will actually lose
power for more than an instant if the tank is run down. Are any of us
who run the tanks "dry" actually experiencing this? I suspect that the
reason most of us who do this don't get so excited about it is because it
is such a non-event. Is that plane-specific?

(I've had it take a long time to figure out which tank just went dry when
an engine started surging. It wakes me up but it's sure not so exciting
that I'd avoid the practice.)

--kyler

On 19 Aug 2005 10:48:45 -0700, "Robert M. Gary"
wrote:

Too many of you have been reading "The Cheap *******'s Pilot's Guide".
I have good working gauges and a fuel computer that has been
professionally calibrated and verified at each 100 hour inspection. I
don't need to make the wife want to leave me in order to know how much
fuel I have. Flying over the Sierras, dodging TS's is exciting enough,
I don't need to turn off the fan to add more excitment to my life.

What happens if a tank develops a leak? We had a Comanche go down a
few years ago due to running out of fuel. He took off with full fuel
and at that point should have had near half left.

The verdict? Mice had chewed holes in the bladders. When he fueled
up the pressure kept the bladders sealed against the metal so no leaks
were apparent, but once in the air the turbulence kept him bouncing
enough that the tanks lost a lot of fuel.

He knew how much he burned, but the gauges were bouncing too, or at
least until they were near empty. He was doing really well on that
paved mountain road until he found that mail box sent on a steel pipe
full of concrete.

No injuries except for the airplane and with a new wing it's been back
flying for some time.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Recently, Greg Copeland posted:

Is this common? How many run their tank(s) dry as part of their fuel
management strategy? If you don't run dry, why not?

Two main reasons; there are better ways to gauge your fuel consumption
rate, for example, logging how much fuel you put back in the tank after
the flight; and why play with the trim to keep the plane going in a
straight line, then start all over again with that fiddling when you
switch tanks?

Aside from the
heat beat skipping which is sure to follow the first couple of times,
what's the down side to this strategy?

Besides being pointless? How about being uneccesarily risky?

Neil

On Thu, 18 Aug 2005 17:21:16 +0000, Neil Gould wrote:

Recently, Greg Copeland posted:

Is this common? How many run their tank(s) dry as part of their fuel
management strategy? If you don't run dry, why not?

Two main reasons; there are better ways to gauge your fuel consumption
rate, for example, logging how much fuel you put back in the tank after
the flight; and why play with the trim to keep the plane going in a
straight line, then start all over again with that fiddling when you
switch tanks?

Aside from the
heat beat skipping which is sure to follow the first couple of times,
what's the down side to this strategy?

Besides being pointless? How about being uneccesarily risky?


"I know of no accidents that have occurred because an engine would not
restart when supplied with fuel in flight. I have personally done this
literally thousands of times myself, and never seen more than a couple of
seconds of interruption, even when I was completely unaware the engine was
about to quit. If we count all the people I know who routinely did it,
there are literally millions of such events." -John Deakin

"This is simply not true of recips. When a recip runs out of fuel, nothing
else has changed. The spark is still there on every power stroke, the
piston is still pumping air, driven by the prop, which is nearly
impossible to stop, inflight even when you want to. Two of the "three
necessities" (fuel, air, spark) remain, totally unaffected by the lack of
fuel." -John Deakin

So what risk factor can you assign to what is more or less, a non-event?

As for the "why", John Says, "I'd like to take a look at fuel management,
and since my method sometimes calls for running a tank dry, let's get that
out of the way first." In other words, its his strategy for fuel
management which lets him known and understand how much he really has in
reserve and how much can he get out of the "unuseable". Should he have an
event where he has to bite into his reserves, he never has to say, "I sure
hope I have enough. I wonder how much is there".

This is not to say that I've bought into it, but hey, someone has to play
Devil's Advocate!

Greg