Victech From United States of America, joined Jun 2000, 546 posts, RR: 2 Posted (13 years 6 months 17 hours ago) and read 1742 times:
Hello, I have two question about 777 engines. One, can anyone tell me the average CFM of the engine at cruise? And two, someone told me that at takeoff in semi-humid conditions, the engine will form a cloud from the outer metal rim to the 1st compressor fan. Is that true?
Dash8 From New Zealand, joined Aug 2005, 1 posts, RR: 0 Reply 1, posted (13 years 5 months 3 weeks 2 days 15 hours ago) and read 1529 times:
1. Don't know what CFM means.
2. It's true. Caused by accelerating airstream. Faster stream means reduced local pressure. Which means colder temperature, which means a lower dewpoint (temperature at which water in gas state condenses to fluid). Because of this excess water vapour in the air will become visible as a greyish cloud.
p.s. If at No1 you mean fuel consumption?
It's about 15,000 pound per hour.
Victech From United States of America, joined Jun 2000, 546 posts, RR: 2 Reply 3, posted (13 years 5 months 3 weeks 2 days 7 hours ago) and read 1509 times:
Dash8, thanks for the clarification on the cloud question, I guess I'm not remembering my physical science classes as well as I should. As to CFM, yes, I was asking for how many Cubic Feet per Minute the engine "sucks in" while at cruise.
Victech From United States of America, joined Jun 2000, 546 posts, RR: 2 Reply 5, posted (13 years 5 months 3 weeks 1 day 17 hours ago) and read 1488 times:
Thanks for that info, now if I remember correctly, one cubic meter of air is 1.3kg. Therefore, that's about 983 cublic meters per minute; so about 34,714 CFM or 259,758 GPM of air. Please correct my math if it is off.