Fuel tank balance

Peter Duniho writes:

IMHO, the main reasons that aircraft engines require so much fiddling is
two-fold: one is that aircraft engines operate at constant settings for most
of the time they are on; another is that improvements cost big bucks in the
form of certification costs, bucks that most pilots won't pay when the
current (albeit ancient) technology suffices.

I suppose that makes sense. I know that I'd rather have older
technology that is certified than newfangled technology that isn't, at
least for aviation (and for many other things, but I guess I'm getting
tired of seeing complex, poorly designed systems fail so often).

--
Transpose mxsmanic and gmail to reach me by e-mail.

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.

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)

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.

--
Transpose mxsmanic and gmail to reach me by e-mail.

Mxsmanic wrote in
:

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.


Only if the fuel-air sensor was designed to handle that altitude.
Estimating from the performance I experienced, the limit seemed to be
somewhere between 11,000 and 12,000 feet.

--
Marty Shapiro
Silicon Rallye Inc.

(remove SPAMNOT to email me)

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?

You can
have total electrical failure and the engine will keep on running.

They may not be connected to the battery or alternator, but those magnetos are
an "electrical system" all of their own, and the engine will not keep running
if they have an electrical failure.

How do you stop the engine after you land?

Disconnecting the magnetos (or actually just grounding their output) stops the
engine pretty well. No need for a mixture control. (Of course if you want to
restart that engine without blowing away the exhaust......)

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..."