Aviation fuel - price of crude...

kontiki wrote:
Friedrich Ostertag wrote:

It IS neccessary. Just to name an example, evaporation proporties
need to be adjusted to climatic conditions. Try and fill your car in
AZ, preferably at a high altitude location, then drive it to one of
the northern states without refueling (probably won't work with the
mileage you get on current US cars..:-)) and try to start it in the
morning at below freezing temperatures. You will be surprised.

By that logic then, we'd need to have a different blend of AVGAS for
each density altitude that we fly at,

Only if you require to cold-start it at altitude...

And if you expect a clean, instantaneous runup like you get from any
current production car. From what I have seen the starting behavior of
aircraft engines couldn't be further from it even at "normal" ambient
temperatures.

Another point, of which I'm not perfectly sure, but could it be, that
the detailed and stringent requirements on many properties of Avgas,
which ensure that it will work properly under very different
conditions, are part of what makes it so expensive?

Motor vehicle engines are not weight limited and are generally far
more advanced in design than the average piston aircraft engine. This
technology gives them the capability to adjust their fuel air
mixtures and ignition timing based upon real time conditions so they
can always operate at maximum efficiency at any altitude or
temperature (after being warmed up of course).

partly true, but to warm it you have to start it first. And no car user
would accept having to warm up his vehicle for 10-15 Minutes before
driving away. Cars today are expected to perform flawlessly even when
cold (or, for that matter, very hot). This does require different fuel
properties depending on climatic conditions. Although I will admit,
that you have a point in the following:

Different fuel blends
are not necessary unless you carry emission standards to exaggerated
extremes, which is exactly what is going on in this
country today.

At least, the emission standards, and therefore the dependant fuel
properties, should be handled at federal level.


regards,
Friedrich

--
for personal email please remove "entfernen" from my adress

kontiki wrote:
Friedrich Ostertag wrote:

It IS neccessary. Just to name an example, evaporation proporties
need to be adjusted to climatic conditions. Try and fill your car in
AZ, preferably at a high altitude location, then drive it to one of
the northern states without refueling (probably won't work with the
mileage you get on current US cars..:-)) and try to start it in the
morning at below freezing temperatures. You will be surprised.

By that logic then, we'd need to have a different blend of AVGAS for
each density altitude that we fly at,

Only if you require to cold-start it at altitude...

And if you expect a clean, instantaneous runup like you get from any
current production car. From what I have seen the starting behavior of
aircraft engines couldn't be further from it even at "normal" ambient
temperatures.

Another point, of which I'm not perfectly sure, but could it be, that
the detailed and stringent requirements on many properties of Avgas,
which ensure that it will work properly under very different
conditions, are part of what makes it so expensive?

Motor vehicle engines are not weight limited and are generally far
more advanced in design than the average piston aircraft engine. This
technology gives them the capability to adjust their fuel air
mixtures and ignition timing based upon real time conditions so they
can always operate at maximum efficiency at any altitude or
temperature (after being warmed up of course).

partly true, but to warm it you have to start it first. And no car user
would accept having to warm up his vehicle for 10-15 Minutes before
driving away. Cars today are expected to perform flawlessly even when
cold (or, for that matter, very hot). This does require different fuel
properties depending on climatic conditions. Although I will admit,
that you have a point in the following:

Different fuel blends
are not necessary unless you carry emission standards to exaggerated
extremes, which is exactly what is going on in this
country today.

At least, the emission standards, and therefore the dependant fuel
properties, should be handled at federal level.


regards,
Friedrich

--
for personal email please remove "entfernen" from my adress

They were, and that's how the goddamned farmers in Iowa got California mandated
to go to this frikkin' gasahol.

Jim


"Friedrich Ostertag"
shared these priceless pearls of wisdom:


-
-At least, the emission standards, and therefore the dependant fuel
-properties, should be handled at federal level.


Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com