Posted on 10/02/2009 7:11:27 AM PDT by larry hagedon
The Germans had no alternative. And they made fuel out of coal not biomass.
Well we are at the point where the government gets one out of every twelve things it does right. So essentially we have a “Stopped clock government”.
Yeah they were older cars. ‘94 & cheap, and I was never quite sure whether there was a mileage drop-off that countered the lower cost of the oil. Some cars are better than others.
I suppose in case of a protracted war you’d want to have options.
“suadies”?
You mean the Bedouins that struck it rich and moved to Beverly Hills?
That could very well be true.Perhaps bio-diesel is "do-able" *and* a good idea for your typical truck or car.But as I said before...when you're talking military aircraft *why* fool around when you know something works (the current fuels used)? IMO,when it comes to our military...if ain't broke,don't fix it.
Why test the heck out of it? To make sure it's a viable and reliable alternative source.
IMO,when it comes to our military ... .if ain't broke,don't fix it.
IMPO, declining to improve current capabilities, with "ain't broke don't fix it" as the excuse, is a guaranteed road to stagnation, eventual inferiority, and defeat.
I don't like defeat.
That would be bad.
Remember last winter when school buses in a Minneapolis suburb stalled leaving kids stranded in the cold because their mandated bio diesel gelled in the cold. I’d hate to be flying in a plane experiencing that problem.
Great! so when our millitary planes are dropping out of the sky over Afghanistan it wont be because of shoulder fired surface to air missiles at it but because of our millitary shooting itself int he foot. Our own idiocy when it comes to trying to make the planet a “greener place” will come back to haunt us.
Nor do I.Perhaps you're an engineer...and if you are your opinion on the feasibility of this would be worth considering.I am *not* an engineer.And I do understand your argument about alternative sources of supply,etc.But I smell a rat here.An Environmental Defense Fund rat."Oh my goodness...the aircraft of our Department of Peace are using bio fuels.How very progressive".
Jet fuel can be...and is...stored.I'd wager that the DoD has the resources to store *very* large quantities of fuel if it wanted to.But if the darn manufacturer of my silly little car only allows 5% bio-diesel,why in God's name are we thinking of putting it into F-18s and F-22s?
Think of the horror when people in a certain part of the world realize our jets are spewing PIG Fuel into the very air they breathe.
OMG! MOG!
OK - I warmed up to the idea!
Exactly.All diesel fuels "gel" in cold weather,as I'm learning from various literature about my new car.I've read that jet fuel and diesel fuel are almost identical.If true,one would think that "gelling" would be of particular concern for aircraft in general and military aircraft in particular.
Especially because people don’t realize it can get far far below freezing for aircraft flying at nearly 500MPH at 10,000 ft or more.
I am all for Bio-fuels if they can be “Bio-identical” to conventional fuels in terms of operational and energy characteristics.
“Close but no cigar” won’t cut it in critical applications.
That being said I read recently there was a company working to make a biologically sourced form of Octane rather than ethanol, looked promising.
I'm an engineer, but not in fuels ... so my opinion isn't worth that much, and I only invoked it to defend the idea of continual improvement.
As for the fuels ... Jet-A is not JP-8 is not Highway Diesel. And a diesel engine is very different from a jet engine (duh!). I don't know why your car manufacturer will not warrant its engine for bio-fuel use. It could be for engineering reasons, legal reasons, or logistical reasons. I suspect the last ... they cannot control the bio-diesel supply chain, don't know what's in it, and don't have the resources to sort it all out.
DOD, however, can and does control its supply chain. If testing validates the use of one or more synthetic fuel formulas in jet engines, DOD can obtain that formula in large quantity. Finally, I believe that turbine engines are much more flexible in regard to the sort of fuels that they can digest than are piston engines.
“I’ve read that jet fuel and diesel fuel are almost identical.If true,one would think that “gelling” would be of particular concern for aircraft in general and military aircraft in particular.”
Jet fuel is essentially kerosene, not diesel.
It doesn't surprise me to hear that they're not *identicle*.But am I mistaken in believing that jet fuel,highway diesel and home heating oil are very similar?
And a diesel engine is very different from a jet engine (duh!).
Understood
I don't know why your car manufacturer will not warrant its engine for bio-fuel use. It could be for engineering reasons, legal reasons, or logistical reasons. I suspect the last ... they cannot control the bio-diesel supply chain, don't know what's in it, and don't have the resources to sort it all out.
It's a BMW.I think it's the Germans that have done much of the heavy lifting in recent times in refining the diesel for passenger car use.They have two fuel requirements...1)that fuel is no more than 5% bio-diesel and 2)that it meets some obscure (to me,at least) standard for quality,purity,etc.
Finally, I believe that turbine engines are much more flexible in regard to the sort of fuels that they can digest than are piston engines.
One would think that an engine capable of putting an aircraft into a pure vertical climb at Mach 2 would be substantially more picky about the fuel it uses than any car would be.But then,you're the engineer and I'm not.
Bacon? I smell bacon
Piston engines, as in your BMW, are much more sensitive to fuel viscosity, burn rate, burn temperature, ignition temperature etc than turbine engines. In a piston engine a small, metered sample of fuel must burn within a very narrow time frame, and at a very precisely determined time. In a turbine engine, the fuel burns continuously. Temperatures must remain within design range, and the fuel must still flow through injectors, but the fuel tolerances for the turbine are much less strict. Although that monster P&W turbofan in an F16 can drive the plane well in excess of Mach 1, it is in many ways a simpler engine than your BMW diesel.
As others have correctly noted on this thread, gelling is a problem with heavy fuels. The entire aviation industry (civil, commercial, and military) is well aware of this issue, and fuels are carefully formulated with anti-gel additives to keep them fluid at the -60 (or worse) temperatures experienced at high altitudes. The testing program for the synthetic jet fuels includes operation at high altitudes to validate the anti-gel compounds' effectiveness.
But Im rambling. I guess I find this stuff interesting, even if it is more than a little bit outside my field of expertise.
Dont try it with petroleum based #2 diesel fuel either.
That was a foul up in fuels somehow, but a very isolated incident. I always suspected that they had inadvertently used #2 petroleum based diesel, which jells just like that, but I never heard for sure.
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