Joe, everyone is entitled to their own opinion. I prefer to use the option to change my opinion when the facts make the need to change obvious.
We would not have been able to make it across the Atlantic once, let alone twice a week ( for me personally) for the last 30 years. The operating oil reservoir capacity for each CF6 engine on a DC 10 was approximately 14 gallons, with a minimum dispatch of 6 gallons. The maximum allowable consumption was around 1 qt per hour ( from memory, but I still have my books and can look it up). The oil is constantly recycled through a oil to fuel cooler to both warm the fuel and cool the oil.
It is more logical to think of a standard petroleum oil as a mixture of light and medium components from the cracking tower.
A good premium synthetic should be thought of more as a compound. The analogy is quite reasonable, that is why synthetics are more shear stable, less volatile, have a film strength of 4 to 7 times of an equivalent petroleum oil and not prone to varnish.
You can actually make very suitable synthetic oil from vegetable oils, and that day is coming fast. It is a matter of cost and availability.
Bob
