Rotortramp Posted November 28, 2012 Report Share Posted November 28, 2012 This is your jet engine refresher course, Still amazes me that someone was able to think of this stuff. Enjoy. 2 Quote Link to comment Share on other sites More sharing options...
gary-mike Posted November 29, 2012 Report Share Posted November 29, 2012 Suck Squeeze Bang Blow. No heli-turbine video? Quote Link to comment Share on other sites More sharing options...
superstallion6113 Posted November 29, 2012 Report Share Posted November 29, 2012 Suck Squeeze Bang Blow. No heli-turbine video? The helicopter turboshaft engine works much the same as the turbofan, minus the fan. A shaft passes through the center of the engine to the front(or exits out the rear) and is driven by the free power turbine. But on a turboshaft, a torque tube or torque shaft would connect to the output shaft of the engine, instead of a turbofan, then drives a gearbox. Quote Link to comment Share on other sites More sharing options...
Nearly Retired Posted November 29, 2012 Report Share Posted November 29, 2012 Interestingly, in some engines (e.g. the PT6) the turbine and gas producer wheels spin in opposite directions. There are some turboshaft engines in which the airflow through them is anything but straight front-to-back. And then of course there is the infamous RR 250 series where air from the compressor is piped right around the outside to the back of the engine where it reverses course and flows forward through the turbine to exhaust somewhere around the middle - which looks odd until you figure it out. This allows the compressor/turbine sections to be very compact, with only the gearbox between them. Keep those shafts short! Jet engines are neat! 1 Quote Link to comment Share on other sites More sharing options...
gary-mike Posted November 29, 2012 Report Share Posted November 29, 2012 Interestingly, in some engines (e.g. the PT6) the turbine and gas producer wheels spin in opposite directions. There are some turboshaft engines in which the airflow through them is anything but straight front-to-back. And then of course there is the infamous RR 250 series where air from the compressor is piped right around the outside to the back of the engine where it reverses course and flows forward through the turbine to exhaust somewhere around the middle - which looks odd until you figure it out. This allows the compressor/turbine sections to be very compact, with only the gearbox between them. Keep those shafts short! Jet engines are neat! It took me a minute to wrap my head around that the first time I saw on (Allison/RR 250). I am very familiar with axial flow dual spool engines, It seemed odd to shove air in from both ends. It works though, less parts, and more compact. That small size was quite a shock to me too, amazing that such a tiny turbine can power the aircraft. It is about the same size engine used to start the engine(s) on a fighter. Quote Link to comment Share on other sites More sharing options...
Rotortramp Posted November 29, 2012 Author Report Share Posted November 29, 2012 Suck Squeeze Bang Blow. No heli-turbine video?The helicopter turboshaft engine works much the same as the turbofan, minus the fan. A shaft passes through the center of the engine to the front(or exits out the rear) and is driven by the free power turbine. But on a turboshaft, a torque tube or torque shaft would connect to the output shaft of the engine, instead of a turbofan, then drives a gearbox. Exactly. A quick glimpse of this is at 8:20 on the second video. I was mainly looking for helicopter turbine videos, but the concepts are all pretty much the same. Just a matter of hooking a gearbox on the end versus a fan/prop. Quote Link to comment Share on other sites More sharing options...
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