Running dry?

"Dylan Smith" wrote in message
...
On 2005-08-21, Roy Smith wrote:
Carb ice isn't going to form in a few seconds.

It's even less likely to form if there's no fuel!


Oh?

Carb ice forms because the reduction of pressure in the intake, causes the
air to cool below freezing, and if moist enough, the moisture condenses and
freezes onto the butterfly.

If there is no fuel but the motor continues to be turned by the prop, does
not carb suction (reduction in pressure ) still exist to some extent?

In article ,
"Icebound" wrote:

"Dylan Smith" wrote in message
...
On 2005-08-21, Roy Smith wrote:
Carb ice isn't going to form in a few seconds.

It's even less likely to form if there's no fuel!


Oh?

Carb ice forms because the reduction of pressure in the intake, causes the
air to cool below freezing, and if moist enough, the moisture condenses and
freezes onto the butterfly.

If there is no fuel but the motor continues to be turned by the prop, does
not carb suction (reduction in pressure ) still exist to some extent?

The biggest heat sink in the carburetor by far is gasoline being vaporized.
The adiabatic cooling you're describing is an infinitesimal effect compared
to the heat of vaporization being sucked up by the gasoline.

In article , RST Engineering wrote:
Not if you look at your gauges to the full tank, see that it has gone down
to quarter tanks an hour before you expected it to, and start looking around
for a long straight stretch of concrete with gas pumps at one end.

That's asking a lot.

Jim, I fly an RV-6A. Given the closeness of remaning fuel to fuel
added over many many refuelings I know my plane better than you think
I do. You don't have to buy. I know what is true.

Ron Lee


"RST Engineering" wrote:

Oh, goodie two-shoes.

Mr. Lee, what brand of aircraft do you fly? Pipers where you can just open
the fuel cap and looksee? Or Cessnas where you have to drag the ladder back
after Gomer has put it away and look?

And what are you looking for? In a lot of aircraft with reasonable
dihedral, a quarter of an inch up or down the filler neck is 8 gallons or
so. Can you calibrate your eyeball that well? In wind? With the airplane
on a slope?

Sorry, no buy.

Jim



"Ron Lee" wrote in message
...


For mr that is a non-concern. I visually inspect each tank if I do
not fill it and any "shortfall" is well below my acceptable refueling
level anyway.

I like having a totalizer functionality.

Ron Lee

john smith wrote:


I can tell you that on some airplanes, if you look in the filler neck
and see it within an inch of the top, you can still get 10 or more
gallons into it.

And in others, if it's within an inch of the top, fuel is already running out
the vent tubes.

George Patterson
Give a person a fish and you feed him for a day; teach a person to
use the Internet and he won't bother you for weeks.

Ok, then give us just one example to back up your belief. Just one. And
next
time, do it before you start calling people dumb - because I am sure you
can't
find an example. Which, well, would make YOU look pretty dumb, wouldn't
it?

You know, Thomas, I don't know if it's a language thing, or what, but
calling an idea "dumb" is not the same as calling the person quoting the
article about the idea "dumb".

Try not to be so thin-skinned about this kind of thing -- this *is* usenet,
after all, and you, of all people, should be aware of the fact that getting
a point across to some people is all but impossible without resorting to
blunt language.

I always start off any thread as nice as pie. However, when posters
continuously (and, of course, purposefully) misconstrue what I'm saying (as
you are doing now), it gets aggravating. Only then will I resort to firmer
language that pretty much *can't* be misconstrued.

Yet, despite all this, I STILL have not called you "dumb"...

;-)

(Because, BTW, I certainly don't believe you are. I wouldn't waste my time
responding if I thought you were.)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Icebound wrote:

Oh?

Yep.

Carb ice forms because the reduction of pressure in the intake, causes the
air to cool below freezing, and if moist enough, the moisture condenses and
freezes onto the butterfly.

The evaporation of fuel in the carb throat also accounts for about 20 degrees of
the temperature drop. The carb will warm up when you cut of the gas.

George Patterson
Give a person a fish and you feed him for a day; teach a person to
use the Internet and he won't bother you for weeks.

I fly an airplane with a 1633 pound useful load and I find quite an
advantage to being light on fuel.

Holy cow. What GA plane has that kind of a useful load? A Caravan?

And, of course, if I were thinking about landing at a short field on a hot
day, I'd plan ahead and go light on fuel. As a matter of routine, though,
our average flight is into a paved strip of more than 3500 feet, somewhere
in the Midwest -- so more sprightly take off performance isn't as important
as knowing that I've got enough fuel on board.

Remember, our last plane was a 150 hp Warrior. Even at full gross, our 235
outperforms the Warrior, so my climb expectations are easily met!

:-)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

1. I have learned from this discussion that everyone has an opinion,
and their opinion is quite strongly held. Does anyone have any data,
on either side, to back up their opinion? How often do planes have
trouble caused by not knowing precisely how much gas they have,
perhaps influenced by inaccurate gages? How often do planes have
trouble caused by running a tank dry (NOT running the _last_ tank
dry)?

I don't know if there's a way to adequately answer your question, as no
records (to my knowledge) are kept of this kind of thing.

The one record we all know, however, is the appallingly high number of
"accidents" that happen each year because of planes running out of gas.
This is a statistic that should be easily improved, yet, year after year,
the numbers stay stubbornly high.

Why? Carelessness and stupidity. There simply IS no other reason for
running out of gas. (Short of a fuel leak, of course.)

My wife and I are both pilots. We have both had it pounded into our heads
(by instructors, FAA seminars, and magazine articles) that it is the
ultimate display of ignorance to ever run out of fuel. Thus, our *very*
conservative fuel management system has evolved over the last decade, and it
has served us well.

In the end, we may ultimately succumb to some sort of an aviation mishap --
but I can almost guarantee that it will *not* be due to fuel exhaustion.

2. There seems to be a lot of discussion mentioning that the only way
to be sure of your tank's capacity is to run it dry. In my reading
about flying, I notice that folks talk about measuring fuel by looking
in the tanks and perhaps using a dipstick. Couldn't you calibrate
your gages by filling the tanks, going for a flight, then sticking a
ruler into the tank to see how much is left? Is running the tank dry
any more accurate or useful?

The bottom line is that with a dipstick (or, in our plane, with the gauges)
you will be accurate to within a gallon -- maybe two. The truth is, if this
amount of gas is the difference between a safe arrival, and an off-field
landing, you have made a VERY dumb mistake in your fuel management.

In short, if you need it more accurate than *that*, you are pushing your
range too close to the razor's edge.

Is my characterization accurate?

Quite.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Now, here's one for you. You reset your totalizer but the Line Goober
used an "auto off" nozzle that left you ten gallons short on a side. You
run one dry, but now your totalizer thinks you have twenty gallons more
than you have. Who now is the safe one? The one that timed a tank to see
how long it ran dry (and hence remaining time in the other one, since
Goober probably used the same technique on one tank as the other) or the
one that relies on the totalizer with about two hours less than
calculated?

Who the heck flies a plane without visually examining their fuel supply
before each flight?

Oh, wait -- I forgot about those silly *high wings* and that whole "find a
ladder" thing.

Sorry, man.

:-)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"