Running dry?

Roy Smith wrote:
I've only flown a couple of models with tip tanks (Cherokee Six and
aftermarket tips on a Bonanza). In both of those, takeoffs and landings
are done on the main tanks. I'm guessing that's standard for all tips.
Wouldn't it make more sense to drain the tips, *then* drain the mains?


On the Cherokee Six, I'd generally start on one main, climb to altitude and
after about half an hour, switch to the opposite tip tank. Then to the other
tip tank (after I don't remember how long... I think it was 45 minutes).
Anyway, it was my intention to burn the tips off first; the theory being that
the arm was longer and would have more effect on the weight of the wing,
therefore it was a good thing to get those tanks out of the equation first.
Subsequently the fuel burn would have a minimal effect on the lateral balance of
the aircraft... you could run for an hour on each side before switching again
without really feeling it.

The mains held 25 gallons each and the tips were 17 each, IIRC.



--
Mortimer Schnerd, RN

VE

Michael 182 wrote:
3. Never try to stretch your range. Bite the bullet, land and buy gas.

Absolutely.


If you're worried about fuel, you don't have enough. Learn it. Live it.



--
Mortimer Schnerd, RN

VE

Recently, Roy Smith posted:

"Neil Gould" wrote:

I would feel more comfortable with 4 in each tank than with a dry
tank.

Let's examine that. We're comparing the relative risk of two events.

Event 1 is that the fuel selector valve fails when you go to switch
to the tank containing the remaining 8 gallons.

Event 2 is that your estimate of how much fuel is left in the tank is
wrong by 4 gallons (16%).

Which is more likely?

Talk about straw men! If the *only* risk in running a tank dry in flight
was the fuel selector valve failing -- probably the *least* likely thing
to happen -- there wouldn't be much point in this discussion, would there?
Yet, a variant on the "least likely thing to happen" happened to me in
flight. OTOH, my fuel consumption estimates have NEVER been off by 4
gallons (which is closer to between 20-25% in the planes that I fly, btw).
So, what can be concluded from this data? IMO, nada.

I recently read an article by a pilot that ferries aircraft between Hawaii
and Australia. Part of his prep was to test actual fuel flow in flight,
because the jump would necessitate reliance on the reserves. He didn't
mention doing it by running a tank dry in flight.

In the flying that I do, there is no direction that I can go where there
isn't fuel well within the range of the plane's fuel capacity without
considering reserves. So, I plan accordingly. You can fly however you
wish. I just see no point in unnecessarily pushing limits.

Regards,

Neil

On 2005-08-19, Michael wrote:
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?

I think this is why it is important to have fuel gauges that are at
least useful, and give a reasonable indication of how much fuel is left
- so you can tell if there's less fuel in the tank than you expected
there to be. It can alert you to a problem. The first time I took a
Cessna 182 (the 1960 model, which didn't have overly capacious fuel
tanks to start with) for a long cross country, I landed short of my
destination because the fuel gauges showed that I had less fuel than my
time/fuel burn calculation said I had. The fuel gauge was right - I did
have less fuel than I expected. Reasonably working fuel gauges can alert
you to fuel leaks, missing fuel caps and other sources of having less
fuel than you expected to have.

--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"

"Jay Honeck" wrote:
If the flight is longer than an hour, we will then run the tips in 15 minute
increments. (Or 10, or 20 -- whatever it takes to keep them even when we
arrive at our destination.) In our plane, having 17 gallons WAY out at the
end of the wing means that you had better keep things balanced, or you're
gonna be flying tipped at an angle pretty quickly!

If I understand what you're saying, you always take off with the tips
filled, even for a short flight. If that's the case, aren't you hauling
200 lbs of fuel around all the time that you don't really need? If your
mains give you (I'm guessing here) 4 hours endurance, and you're planning a
1 hour flight, I would think having 3 hour reserve would be more than
enough for even the most conservative pilot.

It sounds like (correct me if I'm wrong), that if you're making a 1:20
flight, you'll run 0:30 on one main, 0:30 on the other, 0:10 on one tip,
0:10 on the other tip, then switch back to one of the mains for landing?

On 2005-08-21, Roy Smith wrote:
My club has been installing JPI's on most of our planes. It is true that
they're over-priced, and have totally inscrutable user interfaces, but this
is true of almost all avionics. What in particular makes you not like JPI?

JPI have done many dubious things as a company. The most recent example,
after finding out that pilots are hooking up computers to one of their
gauges and the pilot community has made useful programs to analyse the
data, they encrypted the data to stop people doing that. That, to me, is
basically sociopathic behaviour. They basically found out people were
making the instrument they bought more useful - so decided to cripple
the instrument.
http://www.avweb.com/newswire/11_18b.../189696-1.html

They have also bullied a smaller firm (Matronics):
http://66.102.9.104/search?q=cache:M...ient=firefox-a

The encryption issue is enough to make me not want to use a company's
product.
--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"

On 2005-08-22, Jay Honeck wrote:
1. Refuel after every flight. You will be ready to go for your next flight,
and can rest assured that you have gas on board. (Renters will have to
switch this to refueling BEFORE every flight.)

Again, this is not a hard and fast rule. It is NOT stupidity to NOT do
this, and often it's necessary. Indeed, airlines routinely fly without
full tanks.

I'm making an assumption here - by refuelling, you mean top the tanks. I
apologise if this isn't what you really mean, but let's assume that you
(or the generic 'you') do mean that. It probably works well for you with
your aircraft and your typical mission. But consider this.

I did my multi training in a Piper Apache (Geronimo conversion) which
carried rather a lot of fuel. Seven hours of fuel in fact. 7 hours of
fuel weighs quite a bit, even at the fuel burn of a Piper Apache. The
plane has 5 seats. I need to be able to trade off fuel for payload in
case a bunch of us are going somewhere. 7 hours of fuel and 5 filled
seats = way over gross, which in a Piper Apache means you are not going
anywhere other than down should one of the donkeys decides to take the
day off. To fly with half fuel to go to an airport an hour away is
NOT bad decision making - it is called trading off range for payload,
and as I said, it's common practise with the airlines.

Really, the same goes for taking 4 people in a Cessna 172 or a Warrior -
you're going to have to trade off fuel for payload. I don't consider it
"stupid" to carry only 2.5 hours of fuel to take three friends on a 30
minute sightseeing trip around the local area.

About 2 weeks ago, I was flying with my friend Paul in his Cessna 180.
We were departing from an 860 foot long back country airstrip with a
field elevation of 4200 feet. If the airfield sold fuel (it doesn't), it
would have been foolish in the extreme to top the tanks before departing
this airfield. (Of course, some people may argue it's foolish in the
extreme to use that airstrip at all, but IMHO the rewards exceeded the
risks).

My old Cessna 140. I've flown it up in the mountains. Flying with half
fuel was a given. With 85 horsepower you need all the help you can get
at high elevations.

Towing the gliders at Andreas. Taking a full tank of fuel in the Auster
simply prolongs the climb and means you have to run the engine at full
power (where it gets hot because the installation doesn't exactly have
the best cooling in the world). Much better to avoid flying with more
than half tanks.

If your normal mission and your aircraft allows it, by all means top off
after every flight. However, it is not stupid or wrong NOT to top off
after every flight - especially if you don't know what your next flight
will be and you fly a plane where you can usefully trade range for
something else (rate of climb or non-fuel payload). The main thing is to
use your brain when deciding how much fuel to carry.

4. Measure your gas with your watch, never your fuel gauges.

No. Measure your gas with your watch AND KEEP THE FUEL GAUGES IN YOUR
CROSS CHECK. If the fuel gauges indicate less fuel than you expect to
have at the given stage of the flight, land and check it out. Do NOT
ignore your fuel gauges. If you own the plane, it behooves you to make
sure your fuel gauges are at least useful enough so that you can detect
the situation where you have less fuel than you calculated. If you rent,
get to know the planes you fly and know how useful the fuel gauges are
for cross-checking.

Working fuel gauges provide a useful cross check. In most things in
aviation - you should avoid relying on a single source of data and at
least have a cross check. For your watch and fuel calculations, cross
check with the gauges. For your GPS, cross check by using VOR and
pilotage. There's lots of emphasis on cross checks when flying IFR. It's
not just IFR that benefits from cross checking - pretty much anything is
less likely to land you with an unpleasant surprise if you can perform a
cross check.

--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"

On 2005-08-22, Ron Rosenfeld wrote:
As a matter of fact, I believe that the fuel quantity indicators are only
required to be accurate at zero fuel in level flight (for a/c certified
under Part 23).

Close, but no cigar. That one is a bit of an OWT. The fuel quantity
indicator must be calibrated to read zero when there is no usable fuel
left, but:

23.1337:

b) Fuel quantity indication. There must be a means to indicate to the
flightcrew members the quantity of usable fuel in each tank during
flight. An indicator calibrated in appropriate units and clearly marked
to indicate those units must be used. In addition:

(1) Each fuel quantity indicator must be calibrated to read
zero during level flight when the quantity of fuel remaining
in the tank is equal to the unusable fuel supply determined under
§23.959(a);

--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"

RN,

If you're worried about fuel, you don't have enough.


Well, I, for one, like to worry before I don't have enough.

--
Thomas Borchert (EDDH)

In article ,
Dylan Smith wrote:

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!

Duh, I should have realized that. Touché!