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I'm studying blade element analysis and I tried applying it to curved rectangular blades instead of straight ones. It doesn't really show any significant changes in the inflow ratio computation. Why not use curved blades? Is there any reason apart from the obvious problem of increased flapping?

user31222
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  • What would the benefit of curved blades be that they'd be used @user31222? – GdD May 23 '18 at 11:11
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    I think this page answers the question in detail https://aviation.stackexchange.com/questions/8914/why-dont-helicopter-blades-look-like-other-propellers?rq=1 – CrossRoads May 23 '18 at 13:26
  • The majority of the length of a blade desn't run in high velocity, hence there's little benefit to swing forward/backward except at the tip. – user3528438 May 23 '18 at 15:04
  • @GdD for starters wouldn't the surface area be more and hence more lift for same power ? – user31222 May 23 '18 at 15:17
  • @user31222 Why do you think you'd get more lift for the same power? Wouldn't you just need more power to drive the bigger blades? And a lot of the extra area wouldn't be perpendicular to the blades' movement anyway. – David Richerby May 23 '18 at 18:15
  • To a first approximation, the force on a blade is purely tension along its length, no? It seems to me that making the blades curved would introduce a bending moment from the centrifugal force, so you'd have to add more mass to resist that moment. That mass would create more force, so you'd have to make the root stronger, which means still more mass... – jamesqf May 23 '18 at 18:40

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