Fuel tank balance

Dave S wrote:

Mxsmanic wrote:
You'd think that the engine would be
able to measure the static air pressure and adjust the mixture for
itself. Cars have complex engine computers, so why not aircraft
engines?

There are aircraft engines that do (piston).. Look up FADEC.

But if the non FADEC engine can give similar performance with a skilled
operator, then what do you want to spend your pennies on.. a new fangled
electronically controlled engine? or keep using the old one with a few
extra knobs and dials.

Given that reasoning, cars should have the option of maintaining mixture
settings ourselves (if the EPA would allow it).

"Fred" wrote in message ...
Dave S wrote:
But if the non FADEC engine can give similar performance with a skilled
operator, then what do you want to spend your pennies on.. a new fangled
electronically controlled engine? or keep using the old one with a few
extra knobs and dials.

Given that reasoning, cars should have the option of maintaining mixture
settings ourselves (if the EPA would allow it).

First, in the application of automobiles, a manually-controlled mixture
*can't* give similar performance, as it can in an airplane. But even if it
could, there are lots of things about cars that are mandated by the
government, and which add cost to cars. So what? It doesn't in any way
invalidate the comment to which you're replying.

Fred wrote:
Marty Shapiro wrote:

Mxsmanic wrote in
:

new_CFI writes:

the more complex adjusting of the fuel comes from the mixture control.
I don't understand the mixture control, either. Fortunately I can
have MSFS worry about that.

I'm surprised at all the fiddling that pilots are expected to do with
their propulsion units, as compared to other types of vehicles. Bad
enough that one must know how to fly, but apparently one must be a
qualified engine mechanic as well.

Have you ever driven a non-turbocharged car from a low lying city up into
the mountains, like above 5,000' MSL? If you did, you would understand why
the pilot has to manipulate the mixture.

Also, the design of the aircraft engine is such that once it is started,
the engine driven magnetos provide the spark to keep it running.

Yes, doens't that remind you of a basic lawn mower engine?

Not really. Granted, I'm not a lawn mower engine expert, but I believe
they are two stroke engines, yes? Completely different than a four
stroke piston aircraft engine. Going farther, a turbine aircraft engine
generally doesn't stop once it starts running, and I'd hardly compare
*that* to a lawn mower engine.

"Fred" wrote in message ...
Marty Shapiro wrote:

Mxsmanic wrote in
:

new_CFI writes:

the more complex adjusting of the fuel comes from the mixture control.

I don't understand the mixture control, either. Fortunately I can
have MSFS worry about that.

I'm surprised at all the fiddling that pilots are expected to do with
their propulsion units, as compared to other types of vehicles. Bad
enough that one must know how to fly, but apparently one must be a
qualified engine mechanic as well.


Have you ever driven a non-turbocharged car from a low lying city up into
the mountains, like above 5,000' MSL? If you did, you would understand
why
the pilot has to manipulate the mixture.

Also, the design of the aircraft engine is such that once it is started,
the engine driven magnetos provide the spark to keep it running.

Yes, doens't that remind you of a basic lawn mower engine?

Actually it, reminds me more of the engine in my 1967 VW Bug (horizontally
opposed aircooled engine)... :-) It just doesn't use magnetos for the
ignition system. I have always kind of thought of the engine in the 172 I
fly as "just a bigger bug motor, and uses magnetos, and the mixture is
controllable while it is running..."

Wade Hasbrouck writes:

Service Ceiling I believe is defined as "where Vx equals Vy", which where
they meet will result in a minimal to non-existent climb rate. Vx increases
as altitude increases, Vy decreases as altitude increases. Also as you
climb less dense air produces less lift (get to a point where there is not
longer "surplus" lift to produce a climb), and less engine power to move the
aircraft through the air. To climb a 172 to that altitude takes a long
time... :-) which is because as you climb the wings produce less and less
lift and the climb rate decreases, along with the engine not being able to
produce as much power.

Yup, that's what I noticed. At least it's a gradual thing, so it
doesn't come as a nasty surprise. It became obvious that the aircraft
didn't want to go higher, and as the slopes loomed in the window I
decided to turn around and explore other areas. The scenery for KSEA
and its surroundings is unusually detailed and performant, for some
reason.

Yesterday, I flew up to KBVS from KRNT at 4500',
which I didn't reach until I was almost over KPAE, but then I had to hang
out at 2500' for a bit waiting for the Center Controller to get me a squawk
code and clear me through the Class B. :-) Coming home, I was telling my
passenger..."The question for the trip home is 5500' or 3500'?" And she
asked "Why?" I explained the VFR Altitude Rule, and then said "It takes a
'long time' to get to 5500' and then by the time you get there you pretty
much have to start descending, as it is easier to avoid the Class B."
Picked 3500' for the trip home, as that is sufficient to clear the Class D
at KPAE (Class D at KPAE goes to 3100') Route was basically
KRNT-KPAE-KBVS, KBVS-KPAE-KRNT

In a sim I have the option of ignoring such things. Also, the ATC
simulation is pretty limited, so if you go outside what the sim
provides for, you have to pretend that ATC is talking to you, and I
don't have much imagination for that.

I'm trying to learn all the rules about airspace and ATC, but it's
complicated. And I don't have any charts, which makes it hard to
figure out where I am in terms of airspace in some cases. (You _can_
ask to transit Class B airspace in MSFS's ATC, but the clearance is
always granted unconditionally, so it's not very realistic.) The GPS
and other instruments do faithfully indicate changes in airspace, but
I'm not very good at watching for them.

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Fred wrote in :



Marty Shapiro wrote:

Mxsmanic wrote in
:

new_CFI writes:

the more complex adjusting of the fuel comes from the mixture
control.

I don't understand the mixture control, either. Fortunately I can
have MSFS worry about that.

I'm surprised at all the fiddling that pilots are expected to do
with their propulsion units, as compared to other types of
vehicles. Bad enough that one must know how to fly, but apparently
one must be a qualified engine mechanic as well.


Have you ever driven a non-turbocharged car from a low lying city up
into the mountains, like above 5,000' MSL? If you did, you would
understand why the pilot has to manipulate the mixture.

Yes, except I've gone far higher than 5,000' MSL. Take a morning
drive from any (sea level) beach in Maui, for example to the summit of
Mt Haleakala (10,000+ ft). And the 'pilot' of the car doesn't have to
do a damn thing for the mixture, the injector pulse width (aka the
mixture) is adjusted by the computer automatically for max performance
of power/emissions. Pretty basic stuff for any car today, too bad so
many aircraft are still using 1930s era design engines.



Try going a little higher, like to Pike's Peak, 14,110. You will find
a noticeable drop off in power. For extra fun, do it on a hot summer day
in a rental car with the a/c on and watch the "check engine" light come on
at about 12,000'.

--
Marty Shapiro
Silicon Rallye Inc.

(remove SPAMNOT to email me)

Mxsmanic wrote:
Is there any reason to drain fuel tanks in any way other than
symmetrically in normal flight? I notice that most aircraft have
complex controls for fuel flow from the tanks, and I wonder if there
are things one is suppposed to do during normal flight, or if this is
just to provide for possible equipment failures or a need to shift the
center of gravity of the aircraft in an emergency.

Not all tanks can be used in all flight regimes. My tip tanks
can not be used for takeoff or landing (well I don't think they
will make a difference on landing, but you want to be able to
do a go-around don't you). Also, the injected fuel system
returns fuel back to the main tank alone in my system, so
you don't start using the aux tanks until you have sufficient
headroom in the mains.

new_CFI wrote:


as far as left/right/both/off, normaly you set it on both and forget it.

Even Cessna recommends using Left or Right at high altitude cruise to
alleviate vapor locking problems. Of course, which tank level is
going down on a 172 is only marginally related to the selector
position.

Judah writes:

Does MSFS let you set whether you have oxygen in the plane?

The Baron 58 has a place for pilot oxygen, but apparently it's not
installed. In real life I would probably keep oxygen at hand on every
flight, irrespective of my planned cruising altitude.

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Marty Shapiro writes:

Try going a little higher, like to Pike's Peak, 14,110. You will find
a noticeable drop off in power.

But the engine will still be automatically optimized for peak power,
whereas an aircraft engine will not. I think that's the point.

Also, human beings tend to start losing power at 14,000 feet, too.

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