Talk:Coning (aerodynamics)

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Aviation: Aircraft / Rotorcraft

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What is it?

@Cagliost: This article presents readers with a mystery. The first sentence says coning is a phenomenon affecting helicopter rotor discs but it doesn’t describe this phenomenon or say what it is. The second sentence attempts to explain why coning occurs but still doesn’t explain what it is.

The third sentence is poorly worded and suggests that coning is the result of centrifugal force! This contradicts the cause implied in the second sentence.

There is a paragraph devoted to pre-coning of the blades in the Bell UH-1H/204/205. The cited source is citation number 4. I have downloaded this cited source and read it. I found nothing about the rotor blades or the rotor system installed in this helicopter. If there is something written in this document about pre-coning of the blades please quote it here on the Talk page, or tell us where to find it. If it turns out you have cited the wrong document please delete the citation.

Even when a reader reaches the end of the page they are unlikely to have any idea of what coning is. Readers will also want to know why coning is sufficiently notable (or significant) to warrant its own Wikipedia page. Thanks. Dolphin (t) 10:52, 7 July 2022 (UTC)[reply]

It appears that some improvement has been made although it's still not entirely clear. Basically if the rotors move too fast they generate too much lift and bend upwards? Doesn't explain why the aircraft doesn't just rise in the air instead. This would make sense on a helicopter chained to the ground, but why should the rotor base remain fixed while the outer part lifts excessively is not clear. Even less clear is how the blades "fold up without a chance of recovery". What does that even mean? It's clearly not talking about being overly stressed until they fail, since it occurs at too low rotor RPM. Is it something to do with the flapping hinges (which dont exist on most modern designs)? They aren't held out by centripetal (not centrifugal) force so they enter a mode where they move to the topmost flapping position, fully coned, and can't be recovered? Is it because the AOA increases to try to maintain the same lift at a lower speed, until the loss of centripetal force allows them to hinge up? If this is a thing that can happen it ought to be discussed on the article covering rotor hubs. They talk about flapping hinges and how many helicopters don't use them now, and why they are used, but I couldn't find any explanation of how if the rotors are hinges to flap they don't just immediately move to the upper position when lift is applied and stay there. Centripetal force could explain this but it's this supposed to be obvious to the reader? And if that's the case, then from this article I must conclude that excessive rotor speed causes the disc to cone (by flexure and not hinging? Because centripetal force holds the hinges flat?) but insufficient rotor speed causes coning at the hinges by loss of centripetal force to hold them in a level plane. Does this apply to hingeless designs? Is this why they don't use them? Is coning still a problem but "folding up" isn't? Why is coning a problem in the first place? Does is effect control? Does it overstress the blades? Idumea47b (talk) 11:26, 13 May 2024 (UTC)[reply]