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Thank you for your help! I just noticed I did not put the updated image up. Shortly I will do that.
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If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub. -
This is the corrected and complete plan.
Peace,
TomIf you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.Comment
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OK, with the radius points identified on the graph, you can determine the true cord at each radius point. Take a compass (divider) to a radius point (concentric circle) and measure the apparent (projected) cord of the blade at that point. Lay that measurement onto the X-line under the radius point and make a box, connecting the right and left sides of the box to the pitch-line.
This defines the actual (developed) cord of the blade at that radius point. You use this to define the profile of the blade which is marked atop the blade blank you're going to carve out.
DavidWho is John Galt?Comment
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You willing to sell me a chunk of Renshape? I cannot see myself buying a large sheet of it. I do have some pale colored reshape (I bought from Mike), not sure if it is good for this. Thoughts?If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.Comment
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Pale, as in vanilla-white? That's likely the porous 20lb. stuff. You want the dense 40lb. RenShape (the stuff in my hand).
$1,000.00 for a hunk of the dense RenShape should do it. I'll fix you up. E-mail me your current address. RenShape is to model-builders what U235 is to bomb-makers.
DavidLast edited by He Who Shall Not Be Named; 02-18-2017, 01:50 PM.Who is John Galt?Comment
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Thank you! I received the box with RenShape scraps. I can do this. I am studying your photos.If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.Comment
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Seems like Renshape is as rare as rocking horse ****. Can't get it down here.Comment
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Our workshop has always called it ‘plastic wood’, and in Australia at least, many suppliers seem to know it by this name. Here it is a pink colour, comes as “boards” up to several tens of mm thick, is very heavy in the lager sizes, and frightfully expensive. But for SO many things it is absolutely invaluable!
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Maybe this helps
Grtz,
Bart
Practical wisdom is only to be learned in the school of experience.
"Samuel Smiles"Comment
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I need a crayon drawing and some definitions. I have re-read this and I sort of get it. Does the center axis of a blade remain the same and it is just a twist along the axis? I am not sure I completely understand the markings of the block you are about to carve.
Cord is angle, I am assuming.
If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.Comment
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The center of the disc has the blade angle along the main axis of the propeller shaft -- zero angle. Or, an angle perpendicular to the plane of the disc.
Cord is the length of the foil at any specified radius point along the span of the blade. Span is perpendicular to the mean blade span.
DavidWho is John Galt?Comment
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I did this just to watch the veins in your temple bulge out:
Yes, it is a 3D printed prop.
Moving on to our topic at hand.
I am going to need the "short bus" instructions or the simple step by step. I have a chunk of foam. I draw the shape of the blade on it. The thickness is estimated by the maximum the hub will hold or is there a better way?
If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.Comment
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Refer to my first post -- it shows how to lay-out the propeller blade blank.
(just bumped you one spot below Bart on my official 'hate' list).
DavidWho is John Galt?Comment
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Does that mean you hate him more or less?Comment
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