Running dry?

Recently, Greg Copeland posted:

On Thu, 18 Aug 2005 17:21:16 +0000, Neil Gould wrote:
Besides being pointless? How about being uneccesarily risky?


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

It's a non-event *if* the tank runs dry at a convenient time and place,
*if* the engine restarts (I've had one heck of a time restarting a warm
fuel-injected engine at times), etc. Even if these risks are low, they're
still uneccesary, so I'll stand by my opinion. ;-)

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".

What's the point in all of this? If he can't figure out fuel consumption
rates from the amount of fuel that he replaces after the flight, what good
is running the tanks dry? One is supposed to have a 45-minute reserve VFR;
that's quite a bit more fuel than running dry. The whole idea is *not* to
run dry. To me, it sounds like a fools game to do otherwise.

Neil

On Thu, 18 Aug 2005 19:02:46 +0000, Neil Gould wrote:

Recently, Greg Copeland posted:

On Thu, 18 Aug 2005 17:21:16 +0000, Neil Gould wrote:
Besides being pointless? How about being uneccesarily risky?


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

It's a non-event *if* the tank runs dry at a convenient time and place,
*if* the engine restarts (I've had one heck of a time restarting a warm
fuel-injected engine at times), etc. Even if these risks are low, they're
still uneccesary, so I'll stand by my opinion. ;-)


At a convenient time? That's the difference between running out of fuel
and running the tank dry. After all, if you chosen to run the tank dry,
it better be because its both a convenient time and place. If you allowed
your self to run out of fuel at an "inconvenient time and place", then you
ran out fuel, which is not what is advocated here. Remember, this is
part of a fuel management strategy and not blindly flying until the tank
reads empty and the engine sputters.

Deakin's article clearly spells out that there are some planes which
this should not be done on. Fuel injected engines is probably one such
category to not try this on because of vapor-lock issues. In most
carborated engines, in most planes, I must admit it sure sounds like a
non-event to me. Again, as even Deakin points out, there are exceptions
to every rule; whereby he even provides one.

Also, I do thank you for sharing your opinion.

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".

What's the point in all of this? If he can't figure out fuel consumption
rates from the amount of fuel that he replaces after the flight, what good
is running the tanks dry? One is supposed to have a 45-minute reserve VFR;
that's quite a bit more fuel than running dry. The whole idea is *not* to
run dry. To me, it sounds like a fools game to do otherwise.

Fair enough.


Neil

Greg

I remember reading that article several months ago, so I just breezed
through it this time. A couple points that I've thought about, along with
the author. I've never ran a tank dry, and don't intend to. Why not?
Well, even disregarding the potential safety issues, we have fuel injected
engines and our electric fuel pumps have great big red stickers on them that
say DO NOT RUN DRY. $632 each for rebuilt models, I think I won't gamble
that kind of cash.

I haven't done it yet, but I would like to examine, with a mirror as Denny
has, our rubber fuel bladders. I would also like to know their exact
current capacity. I would like to assure myself that they are still
"buttoned" down and have not even partially collapsed. To date, I've fueled
each of our 36 gallon tanks, with 30 gallons each, 6 gallons remaining in
each, about 2 of which was unusable according to the book. So I'm fairly
confident that they hold at least 30 gallons each.

But rather than running a tank dry, what's wrong with simply running it low,
then draining the remainder through the sump? This is "supposed" to be the
lowest point on the tank or in the system, right? It would seem that any
"crud" that hasn't been sucked through the fuel filter, would then just
dribble out into your gas can.

Afterwards, the bladders can be inspected and filled to the brim for an
accurate capacity. All done on the ground.

Jim

"Jim Burns" writes:

Well, even disregarding the potential safety issues, we have fuel injected
engines and our electric fuel pumps have great big red stickers on them that
say DO NOT RUN DRY.

I concur. Don't run them dry. Leave 'em off.

--kyler

Greg Copeland wrote:

How many run their tank(s) dry as part of their fuel
management strategy? If you don't run dry, why not? Aside from the heat
beat skipping which is sure to follow the first couple of times, what's
the down side to this strategy?

I do not. The examiner for my PPC recommended a variation of this -- he said to
switch tanks every half an hour. He said "When the tank you're on runs dry,
you'll know exactly how much is left in the other tank." Well, I wasn't going to
argue with him, but what if it runs dry two minutes after you switched? You'd
better be on final approach.

As for the down side to this strategy, that's what killed Will Rogers and Willie
Post. Willie used to fly on one tank until it ran dry and then switch to the
next. The tank he was on ran dry a few hundred feet up on takeoff.

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.

On Thu, 18 Aug 2005 19:25:45 +0000, George Patterson wrote:

Greg Copeland wrote:

How many run their tank(s) dry as part of their fuel management
strategy? If you don't run dry, why not? Aside from the heat beat
skipping which is sure to follow the first couple of times, what's the
down side to this strategy?

I do not. The examiner for my PPC recommended a variation of this -- he
said to switch tanks every half an hour. He said "When the tank you're
on runs dry, you'll know exactly how much is left in the other tank."
Well, I wasn't going to argue with him, but what if it runs dry two
minutes after you switched? You'd better be on final approach.

Doesn't sound like that's a winning strategy for night VFR either. Seems
like a 45-minute to an hour switch would be better.


As for the down side to this strategy, that's what killed Will Rogers
and Willie Post. Willie used to fly on one tank until it ran dry and
then switch to the next. The tank he was on ran dry a few hundred feet
up on takeoff.


On take off? Doesn't that mean the PIC failed to properly fuel the plane
rather than invalidate the strategy? How was that not pilot error, pure
and simple?


George Patterson

Greg

Greg Copeland wrote:

On take off? Doesn't that mean the PIC failed to properly fuel the plane
rather than invalidate the strategy? How was that not pilot error, pure
and simple?

This was a floatplane operation in Alaska. He landed at an Eskimo hunting camp
to determine where he was. No fuel available. Yes, it was pilot error. His
aircraft had 7 tanks of somewhat indeterminate size. Only one had a gauge. Post
would run one dry after another until he was flying on the one with the gauge.
He was still on number 6 when the engine quit. His floatplane takeoff technique
also left something to be desired, so the plane almost immediately stalled and
went in. Post was crushed by the engine. Rogers was not strapped in.

Me, I prefer to never let the gauges get below 1/8 tank on either of my mains
(and I had no auxiliary tanks in my aircraft). For one thing, that ensures that
I have fuel in that sort of situation even if I forget to switch to the fullest
tank for takeoff.

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.

Don't do it. Upsets the wife.

Greg Copeland writes:

How many run their tank(s) dry as part of their fuel
management strategy?

I sometimes do. I did it much more years ago than I do now (mostly because
I'm lazy). I especially like that it lets me calibrate my calculations. I
usually run on both sets of tanks (switching at least once) before I run
one dry. It scares me to think that I might switch to a set of tanks with
contaminated fuel. (I sometimes only top off one set of tanks.)

--kyler

"Greg Copeland" wrote in message news
In September 2004 issue of AOPA Flight Training, Mark Cook has an article,
"No Fueln' Around". Under the "Selector boy" side article, he mentions
that he runs some of his tanks dry in his Bellanca Viking. In at least
one of John Deakin's articles
(http://www.avweb.com/news/columns/182044-1.html), he not only recommends
running tanks dry but puts forth a powerful argument that it's a
responsible fuel management strategy. Furthermore, Deakin also offers
that he has never found an NTSB accident report related to a failed engine
start when running a tank dry and switching to the next. Both guys
recommend setting a timer a couple of minutes before the tank should run
dry; which acts of both early warning and as validation of your
anticipated fuel consumption.

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

Lastly, I did cross post this message as I feel it's of value to both
student and general pilot population alike.

Cheers,

Greg



The Ercoupe had it right. Both wing tanks are pumped into the header tank behind the engine in front of the pilot.
Excess fuel is routed back to one of the wing tanks (right side?). Gravity feeds the engine. When all of the fuel is
gone in the wing tanks the header tank bobber starts to go down; leaves something like 5 gallons available and you know
you used up the mains and you have about an hour left...