Lag hinging and hub bars

[asra]

If I remember right, helicopter rotor blades need to flap up and down, and also a bit forward and back.Gyro's handle the first by assuming the forward blade lift and the backward blade lacg will cancel out, and so be correctly handled by the teeter hige. Does anyone know how accurately these to are balanced?The second problem seems to be completely ignored in Gyros.Again, forward/back lag may cancel out, but if not then there will be vibration and metal fatigue.I image a suitable solution might be dual hub bars, one above the other, with a hinge bearing mounted verticaly between them at each end, to provide blade mobility forward and back. Centrifugal force would keepo them in line once spinning.When not spinning, the hinges would allow the rotor blades and bar assemblies to fold up for easier transport.Don

[Greg Mitchell]

G'Day Don,Off Larry Neal's Super Sky Cycle.Mitch.Image Insert: 37.96

[asra]

Thats the idea! Thanks Greg.Mitch. Why don't we go to this trouble with Gyros?Instead we just let it vibrate away and hope we catch the metal fatiquein an inspection before it breaks.Don

[asra]

MitchThe above pic is very interesting, and would make assembly very quick and easy.But it is still a rigid rotor system, as normally used.Mitch, once you have assembled the blades, do you tighten all 3 bolts or only the centre blade one.Regards Sam.

[NiqueNaque]

We had an R22 drop in on us today, no lead and lag hings on that one either - two bladed rotor system, yes, teeter block same as ours..Cheers,Nick.

[asra]

Your Lead and Lag hinges are only required if your rotor system has individual flapping hindges for each blade.As a blade rises due to an up draft, it speeds up (coriolis forces)and therefore requires lead/lag hindge to overcome this problem.An R22 has a semi rigid 2 blade rotor system, therefore not requireing the extra hindges.Regards Sam.

[Greg Mitchell]

G'Day Gents,Dont quote me, BUT..that golden coloured donut thingy is I believe, made from the "magic bush" material. (similar material that Raf use and is used on the mast of the Golden Butterfly). This allows for some lead/lag. Again dont qoute me. I'll try and get some more detail from Larry Neal with respect to the whole system. Larry will be flight testing this system soon on the Super Sky Cycle.CheersMitchwww.thebutterflyllc.com