WHY DON'T WE HAVE AUTO GAS AT GAS STATIONS HERE LIKE THEY DO IN AUSTRALIA???

[Pete Masterson]

In aircraft, the two issues are the weight of the fuel container and the amount of fuel (for range) that can be carried. The higher the pressure, the more natural gas can be carried. However, the higher the pressure, the the heavier the container must be. This is much less of an issue for ground based vehicles. For example, with most passenger cars, they are rarely filled to full weight capacity, so the loss of carrying capacity caused by heavy fuel containers isn't a serious issue.

In commercial passenger jet aircraft, the fuel capacity is pretty amazing. A Boeing 767, for example, carries nearly 24,000 US gallons or about 91,000 liters of kerosine-like fuel. As it is, Jet-A, the most used fuel has a relatively high flash point and with current additives is not as likely (as some other potential fuel choices) to catch fire in an accident. 

Natural gas, at whatever pressure, in those quantities, represents a very significantly higher explosion risk under the wrong circumstances. Indeed, when a "bomb train" exploded in Roseville, CA back in the 70s, the resulting fire set off a number of LP Gas freight cars that were in the rail yard at the time. The explosions of these LP gas freight cars was substantially more energetic than any of the bomb-car explosions.

I note that the capacity of a typical rail car of LP gas is near the same fuel quantity carried by an airliner. Since these cars weigh over 200,000 lbs. to safely contain that quantity of gas, it might represent a fairly significant 'hit' to the weight of an airliner. For example, the maximum take off weight of a 767 is just under 400,000 lbs. Currently the weight of a full tank of Jet A in a 767 is about 164,000 lbs. So, the more substantial fuel container required for pressurized natural gas will simply cut the load capacity of the aircraft and cause it to be much less economic to operate.

At the heart of your query is actually "what can be done to reduce fuel cost?" Natural gas is an alternative to gasoline, but it is still a petroleum-well produced product. In the U.S., natural gas supplies are actually quite tight, and even a small increase in demand is likely to drive prices much higher and probably they will then surpass the cost of gasoline. 

Without getting into the politics, the only way to change the direction of the current prices is to either increase production or reduce demand -- or both. I'll observe that speculators have driven crude oil prices higher over the past few months to levels that aren't justified in the long term. Eventually, this speculative bubble will burst (they always do), but, of course, no one knows when it will occur. The psychological effect of simply starting the process to allow U.S. producers to increase production (by, for example, drilling off our coasts) might be sufficient to burst the speculative bubble (these are always caused by psychology rather than underlying market values). Also, taking steps to increase the strength of the U.S. dollar (the currency that crude oil is price in world wide) will also tend to deflate crude prices. The recent "pause" in Fed interest rate reductions is a tiny first step in that direction. (This is an indication that the Fed will start to raise interest rates in the future, which will further strengthen the US dollar relative to other currencies. Soft economies in Europe will also cause EU interest rates to be lowered, also giving strength to the US dollar.

The issues and problems you raise are highly complex -- and there's a lot of disagreement about what to do based on political agendas rather than cool, hard, economic analysis. But we'll all survive the current crisis and "things" will eventually work out as we adjust to the conditions.

Pete Masterson

'95 Blue Bird Wanderlodge WBDA 42

El Sobrante CA

"aeonix1@mac.com"

On Jun 21, 2008, at 10:52 AM, Henry Jay Hannigan wrote:

Pete:

Appreciate your comments.  I am not an engineer so I do not know 

about capacities/volumes etc.  However, my 85 liter stainless steel 

LPG tank in my Toyota looks about the same size as my 100 litre 

Petrol tank underneath my car in Australia. I get over 600 kilometers 

out of a tank of LPG.

Regards,

Hank

90SP36

--- In "WanderlodgeForum@yahoogroups.com", Pete Masterson  

wrote:

Such engines can be designed. Many power stations run "gas 

turbines"  

for generating electricity. These are essentially the same as jet  

engines used on aircraft. The only engineering challenge is to 

carry  

enough natural gas on board an aircraft to have a decent range ---  

and, still have room for passengers. The downside is that natural  

gas, unless highly compressed, is very bulky for the amount of 

energy  

carried in the volume required for storage.

Pete Masterson

510-222-6743 (Voice & Fax)

510-407-0422 (cell)

aeonix1@...

On Jun 21, 2008, at 10:35 AM, Henry Jay Hannigan wrote:

anybody wonder if airplane JET ENGINES  can run on "AUTOGAS?"

Regards,

Hank

90SP36

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