glider workbench

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looo
Posts: 2817
Joined: Mon Nov 11, 2013 5:29 pm

Re: glider workbench

Postby looo » Sun Jul 01, 2018 5:50 pm

a little motivation...
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triplus
Posts: 8670
Joined: Mon Dec 12, 2011 4:45 pm

Re: glider workbench

Postby triplus » Sun Jul 01, 2018 8:04 pm

Didn't know reverse engineering workbench has progressed so much.

P.S. Still can't do trees though!
looo
Posts: 2817
Joined: Mon Nov 11, 2013 5:29 pm

Re: glider workbench

Postby looo » Tue Jul 03, 2018 7:49 am

triplus wrote:Didn't know reverse engineering workbench has progressed so much.
No, reverse engineering workbench is still only a advertising placeholder...
Last edited by looo on Thu Jul 05, 2018 2:34 pm, edited 1 time in total.
Mx74
Posts: 23
Joined: Fri Dec 08, 2017 12:39 pm

Re: glider workbench

Postby Mx74 » Thu Jul 05, 2018 12:42 pm

Hello,

Just by curiosity, how did you do to decrease the number of cell to 7? Even by removing all lines I can't go lower than 10 cells
looo
Posts: 2817
Joined: Mon Nov 11, 2013 5:29 pm

Re: glider workbench

Postby looo » Thu Jul 05, 2018 2:29 pm

I pushed a commit which allows to create a glider with 3 cells. Some parachutes count double-cells as one cells. But in openglider there is no feature for double cells (like [1], 7 double cells = 14 cells) So if you want to model such a wing you have to set the full number of cells. A cell in openglider is defined by having two ribs(3d-airfoils) and one ballooning-function (additional material added to the lower and upper sheets)

[1]https://proxy.duckduckgo.com/iu/?u=http ... -2.jpg&f=1
Mx74
Posts: 23
Joined: Fri Dec 08, 2017 12:39 pm

Re: glider workbench

Postby Mx74 » Fri Jul 06, 2018 9:29 am

Ok, so you can't really design such a parachute with OpenGlider, as the "free" cell in the middle won't go up, and the shape of the panels will be wrong.
Might not be so easy to simulate...
looo
Posts: 2817
Joined: Mon Nov 11, 2013 5:29 pm

Re: glider workbench

Postby looo » Fri Jul 06, 2018 1:05 pm

Mx74" wrote:Ok, so you can't really design such a parachute with OpenGlider, as the "free" cell in the middle won't go up, and the shape of the panels will be wrong.
Might not be so easy to simulate...
for sure you can. We simple do not have all the tools available, but openglider itself is quite generic. I added some properties to adjust the offset of some ribs and also the aoa. I guess you have to adjust both parameters. The implementation is really simple. If needed we can also change this to be another feature where you can set the offset and delata_aoa of every cell. I guess ths could be done with some tables...
double_wouble.png
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But I don't think parachutes are modeled with the offset.
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parachute.FCStd
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Mx74
Posts: 23
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Re: glider workbench

Postby Mx74 » Fri Jul 06, 2018 3:11 pm

That looks great actually like that.
Adjusting visually the offset is already a great step ahead.

I was actually asking myself if they were modelled with or without the offset. I don't think so as they all look so basic, but when looking more carefully I think there would be much more wrinkle on the leading edge, coming form the loaded cell to the unloaded cell, if not.
looo
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Re: glider workbench

Postby looo » Fri Jul 06, 2018 4:13 pm

yes you are right maybe they really take the offset into account. The unwrapped patterns are quite a bit different:
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flat_patterns.png
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looo
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Re: glider workbench

Postby looo » Wed Oct 24, 2018 8:48 pm

progress: still some bugs, but the goal is not far away :D
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