Reduced power take-off's in King Air and other turbo-props.
There's a BIG difference between:
1: setting 2050ftlbs and allowing ram rise to take it up to 2230ftlbs during the take off; and
2: doing a reduced power take off (having a max pwr of say 2000ftlbs during the takeoff phase.
(talking about a B200 here).
CS
1: setting 2050ftlbs and allowing ram rise to take it up to 2230ftlbs during the take off; and
2: doing a reduced power take off (having a max pwr of say 2000ftlbs during the takeoff phase.
(talking about a B200 here).
CS
Join Date: Jan 2005
Location: Alice Springs
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There is another thing that we must all consider if using reduced thrust for take-offs in a King air and that is the affect it MAY have on the operation of the autofeather. Even though you check the armed annunciators after initial power application, if you are using a reduced thrust setting, if there is even a slight movement rearward of the power levers it may prevent the auto feather from operating normally in the event of an engine failure.
On the SKA 200,B200 the autofeather is armed(if the switch is in arned position) as the power levers are advance beyond 90% N1.This 90% setting is calibrated on power lever position, not on an absolute value of 90%(ieon the gauge)(eg autofeather may arm at 88% or 92% based on an average position where the power levers would attain 90%-hope people can understand my dribble).
Now, in the event a reduce torque take-off is used there may not be a huge margin between the position of the power levers at the reduced torque setting and the 90% value for the operation of the autofeather. The chance that a power lever may creep back after initial setting of power does happen, regardless of how tight the friction nut is.
Once again I hope some engineers can comment to put it all into perspective.
JarJar
On the SKA 200,B200 the autofeather is armed(if the switch is in arned position) as the power levers are advance beyond 90% N1.This 90% setting is calibrated on power lever position, not on an absolute value of 90%(ieon the gauge)(eg autofeather may arm at 88% or 92% based on an average position where the power levers would attain 90%-hope people can understand my dribble).
Now, in the event a reduce torque take-off is used there may not be a huge margin between the position of the power levers at the reduced torque setting and the 90% value for the operation of the autofeather. The chance that a power lever may creep back after initial setting of power does happen, regardless of how tight the friction nut is.
Once again I hope some engineers can comment to put it all into perspective.
JarJar
