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Old 2nd May 2011, 09:12
  #36 (permalink)  
Arm out the window
 
Join Date: Jan 2001
Location: North Queensland, Australia
Posts: 2,980
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Inflow roll is most definitely a fact of life ... the aerody texts I learnt about it from (probably not dissimilar to what Crab would use) talked about a progressively increasing inflow into the disc from front to back in the early stages of forward flight, with associated lift reduction leading to flapping down on the advancing side.
This, along with flapback, is easily demonstrated (in the real thing) by initiating a transition from the hover and then holding the cyclic steady while watching what happens to the attitude - a pitch-up and a roll towards the advancing blade side.
Obviously any realistic simulator should replicate that.

Regarding the cyclic lag, it's easy to demo (in a teetering head like a Huey at least) by sitting in the hover and fairly rapidly moving the cyclic back and forth a couple of centimetres whilst watching the attitude and the tip of the disc. The disc will wobble back and forth quite a bit without significant fuselage movement, as by the time it would be thinking about moving you've already made the opposite input.

Which reminds me - hands up if you experienced something like this when you learnt to hover: working bloody hard to stay in one place, waving the cyclic around madly with arm muscles tensing up, instructor takes over, puts one finger on top of cyclic and says "See how much I'm moving the stick? Why don't you just do the same...?"
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