fdr
15th Nov 2022, 00:49
Aviation is a "mature" technological activity. What we do everyday is dependent on very simple, well established R&D, application and approvals. Not much changes, and we become moribund. We teach half truths and approximations, as they are good enough. We make assumptions and teach that at truths, as that is what we were told way back when. It's a mature industry.
Occasionally oddities arise.
Here is a photo of a takeoff run with two engines producing the same thrust, and behaving rather differently. The one on the right hand side is just the usual blender. The one on the left is proving some physics that seems to have been lost in translation. This is at low speed, when this effect is the least interesting outcome. Cruise, it is more than double that.
Question for entertainment;
does this break thermodynamic law? If not, why not?
Why does a CFM56, PW4060, GE90 etc have a Thrust Specific Fuel Consumption, TSFC that is really really good parked at the end of the runway, and yet burns twice as much fuel for a pound of thrust in the cruise, a point of more than curiosity, as a pure jet, J-85/CJ-60 doesn't... And when that is guessed, have another look at the photo below....
Anyone with an idea of what this does, feel free to PM me... :}
This is indeed strange behaviour from a "major kitchen appliance..."
For those needing to visit Specsavers, the left engine is N1: 91.8 EGT 839 (it has a measured offset of 25C at this point, it is actually 814C)
N2 of 96.2%, fuel flow of 1390pph. The Right engine is as born, N1: 97.0%, EGT 884C, N2: 98.4% fuel flow of 1675pph.
No bleed... no defects... the engines matched before this little test, other than the 25C offset. The video gives proof that the thrust is equal on these two engines.
So, to all rocket scientists, fleet managers, accountant types, in the vernacular,
"' ullo 'ullo 'ullo, wot's going on 'ere then..."
(hint: Schroedinger's cat is alive and well, I think living with Special Kherson Cat).
How much gas does the A380 burn in cruise?
https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/606x1280/whatsapp_image_2022_11_14_at_15_58_23_e6391e797fb75d99892955 4141ded038f75fbb12.jpeg
Occasionally oddities arise.
Here is a photo of a takeoff run with two engines producing the same thrust, and behaving rather differently. The one on the right hand side is just the usual blender. The one on the left is proving some physics that seems to have been lost in translation. This is at low speed, when this effect is the least interesting outcome. Cruise, it is more than double that.
Question for entertainment;
does this break thermodynamic law? If not, why not?
Why does a CFM56, PW4060, GE90 etc have a Thrust Specific Fuel Consumption, TSFC that is really really good parked at the end of the runway, and yet burns twice as much fuel for a pound of thrust in the cruise, a point of more than curiosity, as a pure jet, J-85/CJ-60 doesn't... And when that is guessed, have another look at the photo below....
Anyone with an idea of what this does, feel free to PM me... :}
This is indeed strange behaviour from a "major kitchen appliance..."
For those needing to visit Specsavers, the left engine is N1: 91.8 EGT 839 (it has a measured offset of 25C at this point, it is actually 814C)
N2 of 96.2%, fuel flow of 1390pph. The Right engine is as born, N1: 97.0%, EGT 884C, N2: 98.4% fuel flow of 1675pph.
No bleed... no defects... the engines matched before this little test, other than the 25C offset. The video gives proof that the thrust is equal on these two engines.
So, to all rocket scientists, fleet managers, accountant types, in the vernacular,
"' ullo 'ullo 'ullo, wot's going on 'ere then..."
(hint: Schroedinger's cat is alive and well, I think living with Special Kherson Cat).
How much gas does the A380 burn in cruise?
https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/606x1280/whatsapp_image_2022_11_14_at_15_58_23_e6391e797fb75d99892955 4141ded038f75fbb12.jpeg