Buzz From United States of America, joined Nov 1999, 697 posts, RR: 24 Reply 1, posted (10 years 11 months 3 weeks 3 days 8 hours ago) and read 780 times:
Hi Lmml 14-32 (wonder what runway that is?) Buzz here. You're right, on the "super guppy" only the fan airflow is blocked. Seems that the turbine airflow is more trouble than it's worth.
On the Classic 747 and DC-10 we deactivated the turbine (core, hot section) reversers 20 years ago. They would often get a bunch of cooked turbine oil in them an jam anyway. And there was enough reverse thurst available from the fan to do the job.
Buzz Fuselsausage: Line Mechanic by night, DC-3 Crew chief by choice
Bio15 From Colombia, joined Mar 2001, 1089 posts, RR: 7 Reply 4, posted (10 years 11 months 3 weeks 2 days 5 hours ago) and read 673 times:
There's not another explanation. Turbofan engines, opposite to turbojets, have a high bypass ratio (8:1 or so) which means almost 8 times as much air passing through combustion is bypass air. Turbofans generate most of their thrust with the 'cold air' rather than with the 'hot air', so it is adequate to use the bypass air for reverse thrust. On 'bucket' type reversers the whole thrust is diverted.
On the 737-200 (although I believe these are torbojets)
NKP S2 From United States of America, joined Dec 1999, 1714 posts, RR: 6 Reply 7, posted (10 years 11 months 3 weeks 1 day 5 hours ago) and read 612 times:
I'm not completely sure of your "all stages" reference. But yes, the engine core's internal gaspath is unchanged during use of T/R's. As has been said, it is only fan air that is blocked and directed fwd through cascade vanes.