PPRuNe Forums - View Single Post - Flapping, Lead Lag, Hooke's Effect
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Old 10th December 2017 | 10:24
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From: EGDC
Experienced recirculation in Northern Ireland landing in a wriggly tin fort in S Armagh - as the rotor got down towards the top of the walls we basically fell out of the sky with the lever coming up rapidly - than goodness for the Wessex undercarriage!

LGV9 - as for the rest, you are rather over thinking things unless you plan to be a test pilot or helicopter designer.

However when you add your 30 kt wind, don't forget that flapback (blowback) and inflow roll (transverse flow) occur before the onset of translational lift and both have to be countered with cyclic input so that you can continue to accelerate to translational lift.

To help visualise the hookes joint effect, make a shallow paper cone and draw 4 equally spaced blades/lines from the centre to the circumference. Look straight down at it - to see all the blades exactly equally spaced - and then , without moving your viewpoint, tilt the cone and see how the blades appear.
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