Aviation Fuel price record

AirlinePilot · Posted: Sun Nov 11, 2007 6:15 pm Post subject: Re: Aviation Fuel price record

Ill have to ask around Tanada, I have heard nothing about that around here. I dont see how the mechanics here could get at the JP anyway. There are no terminals or supply areas around our maintenance facility in Atlanta.

AirlinePilot · Posted: Fri Nov 23, 2007 2:14 am Post subject: Re: Aviation Fuel price record

Thanksgiving Day.

Avgas is up to 4.60/gal national average.

Jetfuel is at 2.70/gal nationally.

Both are up again this week.

AirlinePilot · Posted: Tue Dec 04, 2007 11:32 am Post subject: Re: Aviation Fuel price record

More great news......

Avgas is at 4.68/gal

Jet fuel is at 2.80/gal

We may see a reprieve with lowering crude costs but my guess is its going to be short lived this time as rising margins for refiners may not come down as much as the crude price. Once it does catch up we will be into the spring and the upward push will continue anew.

AirlinePilot · Posted: Fri Dec 21, 2007 3:02 am Post subject: Re: Aviation Fuel price record

Well at least a trend in a "better" direction.

4.62 for Avgas this week and 2.66 for Jetfuel. Its better, but still in ugly territory.

frankthetank · Posted: Fri Dec 21, 2007 2:09 pm Post subject: Re: Aviation Fuel price record

Tanada-

This was back in the early 90's, but my sisters boyfriend had a vw diesel and they would fill it up at the airport (he refueled planes). Not sure if this still goes on.
_________________
"Oil is going up because we use too much oil, and the capacity to replace reserves is dwindling"
-President Bush 11/07/07

AirlinePilot · Posted: Fri Dec 21, 2007 10:42 pm Post subject: Re: Aviation Fuel price record

Yup you can still use 100LL in the car. I do know some who do it.....but why??? Unless your stealing it, it's dumb. Wink

Rabbit · Heavy Crude Joined: Aug 30, 2005 Posts: 119

whereagles · Posted: Sat Dec 22, 2007 7:12 am Post subject: Re: Aviation Fuel price record

kerosene might cause knocking to a diesel engine. But I think if you add in some toluene, you might get away with it...

Tanada · Posted: Sat Dec 22, 2007 7:38 am Post subject: Re: Aviation Fuel price record

Rabbit · Heavy Crude Joined: Aug 30, 2005 Posts: 119

drew · Posted: Sat Dec 29, 2007 1:17 am Post subject: Re: Aviation Fuel price record

There are two types of detonation in a gasoline motor caused by different phenomena. Predetonation, or preignition, is typically caused by a hot spot such as carbon build up or a glowing exhaust valve. The name is self-explanatory. Knock (also detonation) is caused by incorrect ignition timing or lower than required octane levels in the fuel. The 'knock' is caused by an abrupt explosion of the remaining unburned fuel/air mixture in the outer reaches of the combustion chamber (the squish band) before the flame front (travelling outward from its origin at the sparkplug) has time to consume said mixture. This detonation typically throws the piston away from its normal thrust face into the opposite cylinder wall causing the metallic rattle that is heard.

Diesels are noisy mostly because of the injectors. The fuel is injected at up to 5000 psi, causing the rattle you hear. The fuel itself is designed to light spontaneously and the rate of burn is entirely controlled by the injection computer which controls both the length of the injection cycle but also the volume of fuel injected per millisecond. These two parameters are crucial to prevent overloading of the engine's intenal componentry and also to keep exhaust gases temp. relatively low. The timing is also important for fuel economy and emissions.

The robustness of a diesel is required by running very high compression ratios, from 20 or 22 to 1. This gets the design way more bang for the buck thermodynamically than a c/r of 10 or 11 to 1 as seen in gas motors. For a gas motor to run much higher ratios racing fuel or alcohol is needed.

I had two T birds, a '70 and a '75. The former had a 429 ci 360 hp engine, the latter a 460 ci 260 hp. The '70 had 10:1 c/r, the '75 had 8.5:1. (the 429 and 460 are essentially the same engine) That drop of 1.5 cost about 100 hp.

Edit:talking out of my ass again!!

see 3rd para above-pressure spike resulting from combustion of a quantity of fuel injected into cylinder is responsibe for the rattle. Modern diesels give a small pre squirt (sounds kinky?) before the main injection event, initiating combustion and lowering the pressure rise rate, which is why they are so much quiter than your 88 benz diesel

Drew

AirlinePilot · Posted: Mon Jan 14, 2008 3:14 am Post subject: Re: Aviation Fuel price record

We are back to early Dec prices from 07 already.

4.67 national avg for Avgas

2.79 national avg for jetfuel.

I am thinking the refiner margins are going up. They couldnt stay low forever.

whereagles · Posted: Tue Jan 15, 2008 6:38 am Post subject: Re: Aviation Fuel price record

back to the diesel/kerosene thing:

Kerosene has a lower resistance to compression than regular petrodiesel, right? If you put kerosene on a diesel engine, it seems to me that you run the risk of igniting it before compression is complete..

Now, is the above right or not, and is it called knocking or predetonation?

Tanada · Posted: Tue Jan 15, 2008 7:08 am Post subject: Re: Aviation Fuel price record