fuzzybabybunny Posted June 30, 2016 Share Posted June 30, 2016 So I've got a question on my exam that's going to be something like "what's PTE?" For me this is a pretty general question because there are a lot of forces at work and I'm trying to understand them all. Let me know if I've got this right: On my machine, a ROS 125, the prop spins clockwise if viewed from the back. 1. When accelerating the prop, because the prop is going CW, myself and the cage will want to spin CCW. This would lift my right riser and pull down on my left riser, which would make my wing want to do a left banked turn (the roll axis). 2. If the prop is angled upwards, the right half of the prop will produce more thrust than the left half due to P-Factor / Assymteric Blade Effect. This makes me and the cage want to yaw to the left. I've heard this effect is small though? 3. Precession would cause me to want to yaw to the right because the prop is spinning CW. I don't know how this interacts with #2 or if it would cancel out? 4. Prop Wash is not an effect on paramotors since the prop is behind us and there's no vertical tail for the prop wash to hit, as there is in airplanes. So.... lets of weird stuff going on. The worse effect of PTE is really a combination of all these effects plus the pendulum nature of paragliders. The PTEffects cause me to yaw to the left, twist the risers, and the thrust, being directed to the left and no longer aligned with the axis of the wing's travel, causes the wing to go into a right bank due to pendulum effect. So my body is physically pointed left but I feel like I'm in a right bank and my risers are twisted (and there is some twist energy + pendulum energy stored up as well so if I completely let go of the throttle the glider and my body would then swing in opposite directions as the stored up energy gets released). The best thing is to lay off throttle in a measured way and allow the glider to straighten itself out. Am I missing anything else concerning Propeller Torque Effects? Quote Link to comment Share on other sites More sharing options...
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