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MattM
New Member
USA
92 Posts |
 Posted - 05/02/2008 : 03:30:17
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Yep, you're right. And he also said he used the aluminums because the bad hub already destroyed a set of fiberglass blades and a tail. We haven't got any details from the Gill person how his bent set worked out. I have a strong feeling it will be similar to wllewellin's experience.
Those blades look awfully brittle; its probably are a cheap mix of silica and aluminum.
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Go Huskers! |
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fungus
Moderator
299 Posts |
Posted - 05/02/2008 : 16:37:04
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| I'd still trust wooden blades any day ; very low levels of fatigue, strong, cheap, easy to shape/carve, they dont bend but arent brittle etc etc ... |
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ghurd
Junior Member
USA
313 Posts |
Posted - 06/02/2008 : 00:07:32
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Fungus,
Some poeple just need to have a Catastrophic Failure before they belive anything.
Notice how he changed from the cause was bending, to cheap AL, and even blamed race for the mix of silica and aluminum?
He never mentioned how much more he knew than the ME people at Comet or Boeing.
Seems like the ME or SE guys, even then, would understand AL.
And implies how he can determine the properties of AL alloy from a low quality JPG.
I simply new want people to understand aluminum blades are a real danger and not at all reliable.
Maybe he can show us detailed results of his working AL blades which were in servivice for a few years making some kind of power?
Gosh. Maybe he can make a tiny bit of power with the free spinning blades?
Until then, my photos of FAILED blades will satisify my interest.
I simply want to point out AL blades can be a serious danger.
A side note would be my family and myself fly in a 50+ year old de Havilland DHC-2 Beaver on a regular basis.
Thank the Lord it is not made of AL. (that's a joke. It is made of AL)
http://www.otherpower.com/images/scimages/2050/1stlook.jpg
I'm done now, and will not reply to this again.
I am truely sorry to Hefhoover his question went in this direction.
G-
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MattM
New Member
USA
92 Posts |
Posted - 06/02/2008 : 01:35:24
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Get out while you got a hide left.
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Hefhoover
New Member
United Kingdom
69 Posts |
 Posted - 06/02/2008 : 08:17:46
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"I am truely sorry to Hefhoover his question went in this direction."
On the contrary it's been a valid and interesting discussion. 
If anything, it's probably reinforced the fact that good quality Al blades are available, but so are inferior quality, but even if you had top quality Al the engineering work done to mount them must be of the highest integrity, whereas you will get away with being a lot more "sloppy" with wood (and this is meant as no reflection on anyone)
All the best to you all, Hef. 
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MattM
New Member
USA
92 Posts |
Posted - 06/02/2008 : 14:38:01
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Hefhoover's original post has me thinking how to turn an old 12v dc drill made for running off automotive batteries into a mini-generator. It has a 3/8" chuck on it that would probably come off easy enough. It just requires an incredible amount of startup torque to spin so it might not be all that useful in this case.
An update on sheet metal as a blade material:
So far my 26 ga. steel blades on the 5' diameter ten bladed have survived gusts of over 30mph. The 15' big guy did not fare so well, with one blade striking the pole and it is hopelessly bent. We didn't really think 26 gauge material was going to survive on either rig because its only 3/4 pound of material per square foot. I purposely overweighted the tail on the ten blade to keep it in the wind w/o furling yet its still happily churning today. The 16 ga. two blade design (actually built in a single piece) has survived much worse storms and we don't even have a furling system on it. Also surviving w/o any problems are a pair of 10' three blade systems using massive internal chord tapered to smaller tips, one of each aluminum and steel. I suspect the latter pair is heavy enough to survive twice the wind the way they are built reinforced; I stood on the steel one's hub and the blades handled my weight.
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Go Huskers! |
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gotwind
Forum Admin
United Kingdom
949 Posts |
Posted - 06/02/2008 : 21:10:39
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I think this discussion has been exhausted now - thankfully.
I have to admit that forum member Ghurd has always gone out of his way to help.
12 (or so) months ago he spent the time to draw up an LED diagram suited to the dynohub projects I was working on.
Help like this takes time and patience for no financial gain but is very much appreciated by me and all I suspect.
http://www.gotwind.org/images/Glenn_Hurd.jpg
The Futures Green - Getwind of it. |
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What an excellent idea!
