New composite blades

waynep

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Apr 2, 2019
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I'm designing some new composite rotors blades and hub for myself. Pretty much 50 year old underutilized technologies. Carbon rod, fiberglass, standard adhesives. My target is 1250 MTOW, safety factor of two. I'm also looking at a highly fatigue resistant hub. Is anyone interested in this? I want to share plans/kits that would be of general interest. If others have an interest, I'll cooperate and design beyond just what I want. I would also appreciate people that would pitch in/provide moral support.
 

waynep

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So the core of these blades is carbon rod. Nominally rated at 300 k PSI in tension. 280k in compression. Transfer of blade forces is easily accomplished via fiberglass fabric and epoxy to point load bolts. See Marske studies, applications and tests. Multiple fabric layers with epoxy accomplish necessary bearing loads. Pretty much a no brainer if strict materials and procedures are used. On hub bars and pillow blocks: how f'ing stupid most designs are. It seems they are designed to fracture and fail. Ask me why.
 

Kevin_Richey

Yamaha gyro...Oregon, USA
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I'd like to hear what you have to say about "designed to fracture and fail"...
 

waynep

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Example of poor design: a square metal block pressed against a bending metal bar. The block edges create point loads on the bar. These points will eventually cause fractures.
 

Kevin_Richey

Yamaha gyro...Oregon, USA
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So, something along the design of how Magni designed their way of attaching their rotorblades, then, with two large vertical plates of metal, in lieu of a traditional Bensen-style hub bar?
 

waynep

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I like really the Magni design. I don't know how they adjust for tracking. I am looking to go mostly composites to eliminate fatigue issues. But metal in the right places will still be necessary.
 

waynep

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All I'm saying here as an engineer, let's move forward. Safer, stronger, better, cheaper. Europe and others have moved ahead. America is complacent. Get off your ass. Let's fly.
 

waynep

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BTW, extruded aluminum blades are available for cheap from China. I'm guessing this is where Vortek gets theirs.
 

waynep

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Christ! Finally, Jason posts some excellent opinion and observation. What is needed? Tell me about the high speed issue. Tell me more. I'm designing new blades for myself. Your experience and knowledge can only make it better. I'm an engineer and do engineering things. However, real world trumps engineer. Please, please give your observations and experience.
 

waynep

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Thanks Jason. You're the kind of guy that makes forums like this great. A little honesty goes a long way.
 

AirCommandPilot

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Am I the only one here that thinks JasonS and waynep sound like the same person, talking to himself and stroking his own ego?
 
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