Lonewolf
Thanks for your reply. Everytime I try to log on to this site I get like 5/6 refusals so if I don't get back and reply you prolly will guess that I am onto an embarrasing scent. Too close to the truth for the well being of RR plc.
"Flash point 210° C (~ 410° F). I appreciate that an ambient pressure less than atmospheric would likely induce a flash to vapor at lower temps." Thanks for that info. The bearing chamber that RR uses is unique and patented. It uses pressure differentials to work as designed. So YES reduced pressure/partial vacuum lowe flash point. We know the T972 ran at 180C cruise so a spontaneous ignition inside the chamber is within probablilty. So the oil temp only has to rise about 9% to attain that unstable state at one atmosphere pressure.
"But lubricating oil in a jet engine is a fluid / liquid, under pressure." Not in this case it ain't. Especially if a pipe was fractured as the ATSB has identified.
"I guess my question to you is: at what point when operating at cruise altitude do you believe that the lubricating oil is operating at ambient (20K feet, 30K feet 35K feet) pressures? The oil system remains under positive pressure, and contained ... or it leaks and sprays oil and you run out post haste and the issue of "flash" is far less than it is oil starvation."
This happened at about 5K feet I think under about 85% load on TO. There is evidence that a lot of these T970s had oil leaks. The basic principal of by pass jet propulsion demands controlled pressures and are independent of outside air pressure. This is not the case with ambient temperatures at TO thrusts.
Kelvin Gas Pressure Law. Any liquid unless at absolute zero temp has an atmosphere just above the liquid state. This depends on both temp and pressure and is governed by a gas contsant value which I forget..ahem..I was 17 when I did this stuff.
Using the Kelvin laws I believe that the 9% temp leeway preventing a spontaneous combustion is not only possible but likely. Throw in a fractured oil pipe and a few places where the oil has accumulated and bingo you have an explosion.
I have to say if that 210C flash point is correct I want to know just WTF this company are seeking to achieve with this engine design.