Quote:
Originally Posted by freebeard
It's hard to keep up with everything happening in the World and you, OP. I was headed to the last thread to talk about water tunnels and ask about aluminum extrusions for vertical axis windmill airfoils.
So here it is. You speculate that the unlikely separation is due to the angle on the hood. Could it be that to optimize the air/water substitution, the overall fineness ratio might need to be 2 or 3X in the forward direction?
For prior art it's easier to point to the original source than a Pemalink within Ecododder.
Reducing Windnoise / Raingutter Fillers – Gerrelt's Garage
The airfoil has some built-in advantage as a cross-section. The scale might be no greater than the acoustic silencers.
I'm getting some new neighbors and I hope to rope them into helping put a windmill on an unused utility pole between us. I have a 25ft 1"hex bar for a vertical shaft and I would like a Savonius/Darrieus hybrid rotor at the top sized for a 1hp Fisher-Paykel washing machine motor (in hand) at the bottom for easy maintenance.
I'd though of 3-4" timber bamboo split into thirds and shaved into an airfoil green, then strapped into a spiral form to be carbonized. Thoughts?
edit: On the supposition that a vertical pole has a vibrational node at 2/3rd it's height, that's where I'd put a captive wheelbarrow wheel and tire as a vibration damper. Maybe you could suggest a tuned mass damper on the shaft below the bearing? The shaft is to store energy in torsion to overcome stiction. |
Yes, Gerrelt's A pillar modification is the one I cover in my book. Nice guy.
Re the Savonius/Darrieus hybrid wind turbine, I love VAWTs but in the real world, their efficiency always seems lower than a conventional HAWT. If I were building a wind turbine, I'd be using a truck fan as the driver. Not sure how the F&P motor will work at those speeds though. (I used to collect F&P motors - used to be lots in local tips - but I never used them so I finally threw them away!)
Re vibration dampers (and the wheelbarrow wheel sounds ingenious), it's a bit like aerodynamics. I prefer to experiment rather than theorise. (And if doing so, don't forget the ability of smart phone (equipped with a suitable app) to directly record, log and analyse vibration data. The use of a phone is a radical gamechanger in this area.)
(And re the GOE222 VAWT aluminum extrusion. I am enormously impressed with this. It really seems to do what it is supposed to. I 've had a good look around the web and it's the only one I can find like it, ie has a 'proper and official' aerofoil shape with specs available.)