@aerobat77:
Your (typical) engine starts doesn't look like in the book. You are supposed to leave your prop in feathe. And, opening fuel at 12% is not very good, exept if you've got a flat battery. I recommand stabilized NG before fuel. The highest you reach, the best it is for your turbine
Regarding the question about NG drops to 45% in feather, it looks like twin otter rigging.
The A27 is rigged in the manner to create a NF leak on feather ( smal lever on RH side of the CSU) then your engine is running below idle, on min flow 44/45% NG.
When you unfeather your prop, your beta valve moves forward and blocks the air leak and your engine reaches the idle (+/-52%)
@Adis:
I'm very surprised that your procedure says to unfeather the prop before start inflight.
As you say, 20% NG is enough to run your accessories gearbox and then run the oil pumps. If your prop lever is out of feather, you gonna admit oil in your prop dome and force your prop to go out of feather. Then the windmilling does the rest. Huge drag!!
I did a lot of flight test on beech family, and I never saw that. You have to relight your engine on feather to minimize your drag, then, at idle, you unfeather it and be prepared to compensate with rudder.
I have some questions on the PT6A and would be very happy, if anyone knows some answers!
1. If you switch from LO Idle to HI Idle - is the distance of the Powerlever you would use for setting 52->70 % NG without function?As said before, when you push your fuel lever to HI, your just accelerate your engine to a preset value (+/- 72% NG) you incrase a little bit your deadband on your power lever
2. If the Beta system controls the Propeller Pitch, does the Prop Lever get useless?Don't be confused between beta system (Reverse system) and Beta mode, a non governing mode of the prop. Exept during reverse operation, the prop speed is uncotrolled until it reaches the selected speed on the CSU.
3. Is there any data or information about the Prop Pitch angle during the corresponding to the Power Lever positions during Beta Mode?As far as I remember, your prop pitch is on primary blade angle during the beta mode
4. If the Prop Lever gets useless during Beta Operation, what does the Prop pitch do at the moment the system switches from Beta to Alpha with different positions of the Prop Lever? Or does the adjustable angle of prop pitch become very "narrow" with lower NG settings so there only one "position" left just before switching from Alpha to Beta?You have the answer on the question Beta mode means non governing mode, means your prop will accelerate as long as you push power lever. When you reach the max prop speed, then you enter to the Alpha mode, your CSU keeps your prop speed constant (CSU: Constant Speed Unit) If you ad more power, the CSU will maintain the prop speed by coarsing the pitch of your blades, then your torque will rise.
5. What is the Propeller Pitch angle during Reverse operation? Does the angle increase due pulling the Power Lever further backwards or only the NG rise?I think your angle should be around -9°! When you pull your power lever backwards, first you decrease the pitch of your blades by pulling the beta valve backwards. You are then in beta range, means 0 torque. If you pull further back, you start operating the FCU lever and then accelerate NG
6. Does reverse start with more power while operating in HI Idle? you will have reverse even in HI idle? but I've never try that
7. At which point during engine startup does the oil start to allow changes in Prop Pitch? When your oil pumps will built up pressure on your prop dome, means I think around 35/40% NG
8. With what kind of power settings is it possible to feather the propeller? I noticed, while being in idle, feathering reduces NG to about 45%. Is that due drag or some kind of mechanical controlling?Stay at Idle to feather your prop!! Do NOT try with power. You gonna kill your reductiongear box with the extreme overtoque!!
As I told above, depending the airplane you operate, the rigging can allows to go below LO idle, down to min flow. I know the DHC6 is rigged like that, but I don't know about your aircraft.
9. Is the whole system of propeller and engine influenced due airspeed?Hemm, not sure o understand your question... sorry