Hello guys,
I asked personally to a friend, who is CPL in a PC-6, and was ATR42 PiC before.
He told me, you obtain it ( on the PC-6, not generally spoken ) by pulling the Power Lever all the way back, against idle stops. This way the prop enters into beta mode.
The Np ( Prop RPM in % of max RPM, 100% is 2200 RPM ) is around 60%, if you activate the beta in flight, while the Prop Control is usually not full fine, but in a cruise config. You can reach around 80% by increasing this lever, to get out of vibration range. The higher the Np is, the more effiscient is the brake effect ( zero thrust become stronger, because the higher it spins, the closer it comes to a real full disc, like a round table )
Until that, I understand, but beta is NOTHING TO COMPARE WITH reverse range, wich is totally forbidden to use in flight, because so much torque and vibration would destroy all the engine mount, airframe etc, adn the slipstream around the fuselage ( so back controls surfaces like elevators and rudder ) would not be blowed at all.
Now, I would love to know how they can use beta for taxiing, or is it just for braking ? Airbrake on taxi speed are useless isn't it ? And is beta mode really a fixed and definitive pitch ? If so, I would like to know the exact beta angle.
I'll eventually ask directly to Pilatus Switzerland, but if any PC-6 pilot or mechanic see that, please help.
Sorry for my bad english I'm 17 YO, and french
Last edited by Hueyman; 29th Dec 2012 at 15:20.