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Old 5th Nov 2007, 11:27
  #972 (permalink)  
HOSS 1
 
Join Date: Oct 2002
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DC Gen = Mo Powa

Regarding the increase in Arriel Power with a fully loaded DC Generator.

The Arriels limit power based either on N1 (compressor) speed or output torque. If you are not limited by torque, the engine will achieve a certain N1 speed and hold it there.

The catch is, the DC generator is driven by the N1 spool of the engine. So, here's how it goes: you are at 104.3%N1 power then increase the power requirement of the DC generator. The N1 spool slightly decreases speed due to the increased load. The DECU senses this speed decrease and increases fuel flow to bring N1 back up to 104.3% (or whatever the active limit is). BUT, due to the (in)efficiency of the N1 turbine, there is also more energy delievered to the power turbine as well.

Admittedly, it's not much more power, but it IS measurable, as proven by the Sikorsky powerplant flight test guru.

Now, to shift gears, I'd like to hear from anyone that has experience with "OEI training mode" on the 2S2. Is it an improvement over the 2S1?

Hoss
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