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jjuutinen · Joined: 13 Jul 2003 Posts: 180

Question: assuming constant TIT at which bypass ratio the bypassed air starts producing more thrust than the combustion gases?

jschauer · Joined: 19 May 2004 Posts: 93 Location: Justin, Texas

I contacted one of our powerplant engineers about that question. It may be a few weeks before I get an answer. I'm using a GE CF6-80C engine as an example.

jschauer · Joined: 19 May 2004 Posts: 93 Location: Justin, Texas

OK here's the answer. I contacted our Lead powerplant engineer and this is what he said in regards to a GE CF6-80C.
"The CF6 engine is a high bypass fan engine. 80% of the thrust is produced by the 1st stage fan, while 20% comes from the core through the low pressure turbine. The question of at what point the fan produces more thrust than the core is a very difficult, if not impossible, question to answer. There are too many variables such as atmospheric conditions and engine efficency that would have an affect. At idle, the fan is already producing more thrust than the gases produced through the core."