Helix Sweep
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Helix Sweep
I am trying to model a shaped blade, as shown in screenshot attached, which is on a helix sweep. Any suggestions would be appreciated.
OS: Windows 10 (10.0)
Word size of FreeCAD: 64-bit
Version: 0.20.25429 (Git)
Build type: Release
Branch: master
Hash: acce57a25d82b0408fa07b9452ed31c8a06c7a1b
Python version: 3.8.10
Qt version: 5.12.9
Coin version: 4.0.0
OCC version: 7.5.2
Locale: English/New Zealand (en_NZ)
OS: Windows 10 (10.0)
Word size of FreeCAD: 64-bit
Version: 0.20.25429 (Git)
Build type: Release
Branch: master
Hash: acce57a25d82b0408fa07b9452ed31c8a06c7a1b
Python version: 3.8.10
Qt version: 5.12.9
Coin version: 4.0.0
OCC version: 7.5.2
Locale: English/New Zealand (en_NZ)
- Attachments
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- Forum Screenshot.jpg (32.92 KiB) Viewed 2492 times
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- Forum Helix 15-9-21.FCStd
- (10.3 KiB) Downloaded 58 times
Re: Helix Sweep
I guess that it is only caused by the perspective distortion of the photo that the helix looks thicker in the middle.
For such a helic you need only one of the helices, e.g. the outer.
- create a sketch in XY plane with a section of the helix
- attach it to the helix with mode Frenet NB
- create a sweep with the section and the helix
- mirror the sweep
- make a union of the sweeps and the center.
For such a helic you need only one of the helices, e.g. the outer.
- create a sketch in XY plane with a section of the helix
- attach it to the helix with mode Frenet NB
- create a sweep with the section and the helix
- mirror the sweep
- make a union of the sweeps and the center.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
Re: Helix Sweep
Its not a distortion, the blade is thicker in the middle.
The only reason the inside helix is there is because I was trying solve the problem by creating an inside and outside "airfoil" shape and make an extrude on two rails (from outside to inside airfoil).
The only reason the inside helix is there is because I was trying solve the problem by creating an inside and outside "airfoil" shape and make an extrude on two rails (from outside to inside airfoil).
Re: Helix Sweep
A two rail sweep exists in addon Curves workbench.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
Re: Helix Sweep
That's the one I tried but could not get to work. I could create the two rails but could not create the right inner and outer profile sketches.
Re: Helix Sweep
You may have to create two sweeps, both based on slightly different 3D parametric curves (addon macro).
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
- papyblaise
- Veteran
- Posts: 8026
- Joined: Thu Jun 13, 2019 4:28 pm
- Location: France
Re: Helix Sweep
you research the dimensions of the heliptical parts, you place them on planes tangent to the hub, in the middle and tangent to the outside diameter
you make a loft, then a common with a cylinder with the outside diameter
it is a rustic propeller for river transport boat or canal with a low efficiency due to strong cavitation because of this little tapered shape
you make a loft, then a common with a cylinder with the outside diameter
it is a rustic propeller for river transport boat or canal with a low efficiency due to strong cavitation because of this little tapered shape
- Attachments
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- helice.FCStd
- (138.97 KiB) Downloaded 71 times
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- helice.PNG (12.91 KiB) Viewed 2192 times
Re: Helix Sweep
Thanks papyblaise you have given me a clue on how to proceed. I will work on it today. Cheers Sandy
Thanks Chrisb I will investigate 3D parametric curves (addon macro).
Thanks Chrisb I will investigate 3D parametric curves (addon macro).
Re: Helix Sweep
... based on helix helper (and a lot of placement) a 2-blade prop by eye and "flexible" profiles
- Attachments
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- Profiles_7.FCStd
- FC.18.4
- (612.33 KiB) Downloaded 57 times
Re: Helix Sweep
Thanks Hammax but a question - Under your "Loft" is "Mixed_Curve_1" and under that "Sketch001" and "Master_Prof_001". How did you create "Mixed_Curve_1" with "Sketch001" and "Master_Prof_001"?
When I downloaded your file there was nothing under "Mixed_Curve_1" as shown in screenshot!
When I downloaded your file there was nothing under "Mixed_Curve_1" as shown in screenshot!
- Attachments
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- Snap 2021-09-20 at 07.56.25.png (9.68 KiB) Viewed 1862 times