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Author Topic: Sharp 1000  (Read 1661 times)

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Re: Sharp 1000
« Reply #180 on: November 12, 2025, 05:09:02 pm »
The first pivot block is off the printer (actually the second, but the other one was a prototype and I had to tweak some dimensions).  I like it so far.  I hope it will balance using the large set screw.  Here is a comparison between the old and the new.  The small notch in the leading and trailing edges is just a help for balancing; to know what is level.  The wing is mounted at a 5 degree angle, so the rest of the pivot block will be level when balanced.







« Last Edit: November 12, 2025, 05:24:34 pm by Caleb »
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Re: Sharp 1000
« Reply #181 on: November 12, 2025, 07:20:57 pm »
even if you need more weight you can cut the head off a bolt and bullet nose it on a grinder; it will be more aerodynamic even with a slot cut for driving it in and out.
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Re: Sharp 1000
« Reply #182 on: November 12, 2025, 08:17:01 pm »
So the pink plastic part is also part of the counterweight ?
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Re: Sharp 1000
« Reply #183 on: November 12, 2025, 08:49:23 pm »
Quote from: CG on November 12, 2025, 08:17:01 pm
So the pink plastic part is also part of the counterweight ?
According to the CAD, the center of mass for the plastic part is not far away from the pivot.  So I don't think it adds much to the counterweight.
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Re: Sharp 1000
« Reply #184 on: November 12, 2025, 08:57:51 pm »
Quote from: ROB25038072 on November 12, 2025, 09:15:06 am
Quote from: Caleb on November 12, 2025, 08:15:22 am
A prototype of the new pivot block is being printed.  I didn't change the stops; they aren't horrible.  They sound bad in the video because the camera's automatic gain control tends to amplify the impact.  I'm going to try and balance the wing using a 1/2-13 x 1" long set screw instead of the washers.  The wings ended up weighing 55 grams with paint.  I moved the pivot point 3.5 mm because the wings were a little heavy compared to their area.  Setting the wing away from the pivot will give the aerodynamic forces a little more leverage.  We shall see if the calculations are worth a darn.

I’m of the opinion these tiny changes (such as 3.5mm) do make a difference but whether or not we can see, measure or demonstrate that difference without being ‘clinical’ is different story.
I agree.  But I like to think it helps.  :-)
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Re: Sharp 1000
« Reply #185 on: November 13, 2025, 11:10:06 am »
It's definitely better looking and looks more compact and together despite being larger. Fingers crossed for screw - Im sure your not taking a guess it might be heavy enough :D
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Re: Sharp 1000
« Reply #186 on: November 13, 2025, 12:16:26 pm »
Those setscrews are hollow with the hex recess. If it needs more weight you could try Maybe a bolt with the head cut off and a slot cut in the end?
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Re: Sharp 1000
« Reply #187 on: November 13, 2025, 12:57:17 pm »
curious why you printed it toe out on the new one? being smaller and more streamlined I know there's space limitations but it looks like there was room to not?
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Re: Sharp 1000
« Reply #188 on: November 13, 2025, 04:00:17 pm »
Quote from: CG on November 13, 2025, 12:16:26 pm
Those setscrews are hollow with the hex recess. If it needs more weight you could try Maybe a bolt with the head cut off and a slot cut in the end?
Grok told me that the set screws would weigh 24 grams, but I measured only 17 grams on these.  I've got some stainless steel ones on the way that should be a few grams heavier.  I think it will balance if they are moved forward a bit.
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Re: Sharp 1000
« Reply #189 on: November 14, 2025, 09:28:26 am »
Quote from: itsandbits1 on November 13, 2025, 12:57:17 pm
curious why you printed it toe out on the new one? being smaller and more streamlined I know there's space limitations but it looks like there was room to not?
I doubt there will be much difference either way, but here are a few reasons to set the wing angle in the pivot block:
It makes it easier to balance because I can just measure to the same height on each side of the pivot block and the wing will be at the desired angle.
The leading edge of the pivot block will be more square with the oncoming wind.
The center of mass will stay in the designed position.  Making the nose a bit heavy to get the toe in moves the center of mass away from the leading edge.
Just tweaking things.
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Re: Sharp 1000
« Reply #190 on: November 14, 2025, 10:43:12 am »
Does the added mass of the pink part adversely affect the performance? It seems like it would limit the pitching frequency. I think less is best.
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Re: Sharp 1000
« Reply #191 on: November 14, 2025, 03:30:45 pm »
I'm sure there is some effect, but I can't make it out of nothing. :-)
Here is one of the new wings on the VAWT.  We had about a week of good wind, but now that I have something to put out there, it is dead calm.  I would like to go with a 4 bladed VAWT, so I put the new one with the three paper ones.  The 1" long set screw could balance the wing, but only if it was just about to fall out.  So I replaced it with a 1-1/4" long set screw.

https://youtube.com/shorts/vHmm6GUNXkM?feature=share
« Last Edit: November 14, 2025, 03:37:46 pm by Caleb »
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Re: Sharp 1000
« Reply #192 on: November 14, 2025, 08:46:28 pm »
We are supposed to get some wind tomorrow.  If we do, I'll take some video.
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Re: Sharp 1000
« Reply #193 on: November 15, 2025, 01:16:47 am »
be nice to see it spinning up with the hardware; maybe a light wind with gusts so you can see the action.
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Re: Sharp 1000
« Reply #194 on: November 15, 2025, 07:27:57 am »
Come on wind.
Actually, I'm surprised you get that much wind with all those tree's. If your trees were deciduous then at least you could get more wind in the winter after the leaves fall. Most of my trees have leaves so at least I get more flow after the leaves fall.
« Last Edit: November 15, 2025, 08:17:52 am by CG »
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