A very strange fuel flow...

[Andrea1]

Hi,
I have my psx upsated at Alpha 30 version.
This evening i've discovered a very strange thing...
I was performing a takeoff using the "typical" Departure 001 Sydney-Los Angeles situ" so normal weather situation: pressure 1020 mbae, temp 18°C at 20 ft MSL (similar to ISA standard). I have choosen a GE CF6-80C2B5F turbofan version so I can just imagine that (according to a CF6-80 brochure, not being specified the various engine thrust ratings into Aerowinx manual , thrust rating should be about 60.800 lbs) having a selected takeoff de-rate limit -5% I had a static t.o. thrust of about 95%°60800=57.760 pounds considering a static at sea level ISA specific fuel consumption of about 0,33 lbs per lbs of thrust I should have a consumption (fuel flow) of 0,33*57760 lbs= 19.060 lbs*0,4536=8645 kg (8,6 tons) per engine but my flowmeters gave me a FF of only 4,7 tons per engine! But that is totally wrong! Also considering an incredible specific fuel flow of 0,25 lbs per lbs of thr my engine thrust would have been only 4.7/0,25= 18,8 tons (41,4 K pounds) so only about 68% of the rated power....
What is it wrong in my considerations?
Should I check for any FF failure (wrong fuel flow) added at that situ?
Or maybe my fuel was hydrogen (calorific "power" 28000 kcal/kg instead of the about 10400 kcal/kg of the jet-A1)
Best Regards
Andrea Buono - I

[Hardy Heinlin]

Hi,

looks like a bug in the takeoff power model.

Will check ...


Thanks,

|-|ardy

[Andrea1]

Hi Hardy,
Thank you very much for your very fast answer!

Ciao

Andrea