Is a rigid 3-bladed rotor for UL possible? I think yes….ignoring the 254 thing….

RotoPlane

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If I understand correctly what you've said Dave, the area at 75% of the span is twisted by some kind of torque tube or bar that extends inboard to the blade root. When twisting this torque tube in one direction it will wrap/twist more at the root than at the 75% point….the longer this distance is, the more it will wrap. When used on a relatively short prop blade, the blade will be stable because it twists the blade in one direction, but a rotor blade will be twisting and wrapping both in positive and negative directions…twice per rev. I very well could be all wet, but I can imagine it would be difficult to precisely control this blade. I'm not saying this can't work….just that I can't imagine how to make it work.

One must be careful using carbon cloth….bend it beyond its min bend radius and its fibers will easily break….I am way too clumsy to use that stuff on aircraft ;).
 

Rotor Rooter

Dave Jackson
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Hi Ed,
If I understand correctly what you've said Dave, the area at 75% of the span is twisted by some kind of torque tube or bar that extends inboard to the blade root.
Yes, similar to this IVO blade during better times.




When twisting this torque tube in one direction it will wrap/twist more at the root than at the 75% point….the longer this distance is, the more it will wrap. When used on a relatively short prop blade, the blade will be stable because it twists the blade in one direction, but a rotor blade will be twisting and wrapping both in positive and negative directions…twice per rev.
The intention (for a helicopter) is to duplicate the activity of the Kaman blade in that the root end has a fixed pitch (perhaps +10-degrees). Implementing linier twist, the 'Active Twist' will result in the pitch at the tip of the blade varying between a low negative number and a high positive number. This can be done at 2P. In fact they are R&Ding piezoelectric means of twisting the blades.

One of the features of composite construction, particularly with carbon, is that you can create the flexibility where you want and create the rigidity where you want.

One must be careful using carbon cloth….bend it beyond its min bend radius and its fibers will easily break….I am way too clumsy to use that stuff on aircraft ;).
The radius required to brake the threads is smaller than would ever be used on a rotor.


It was only an idea for consideration, since composite construction is no longer the future. It is now the present. :)


Dave
 

RotoPlane

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Quotes from Rotor Rooter
Yes, similar to this IVO blade during better times.

Holy smoke….during better times….is right on!

The intention (for a helicopter) is to duplicate the activity of the Kaman blade in that the root end has a fixed pitch (perhaps +10-degrees). Implementing linier twist, the 'Active Twist' will result in the pitch at the tip of the blade varying between a low negative number and a high positive number. This can be done at 2P. In fact they are R&Ding piezoelectric means of twisting the blades.

One of the features of composite construction, particularly with carbon, is that you can create the flexibility where you want and create the rigidity where you want.

I'm not saying your idea cannot work Dave…..I'm saying….I do not know how to make that work properly. I'm trying the simpler stuff.....

The radius required to brake the threads is smaller than would ever be used on a rotor.

I wasn't referring to a radius on a part….I was referring to my klutziness and my absentminded ability to rest my hand on a fold in carbon cloth while it is on the cutting table ;).
 
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