Stopping the line f...
 
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Stopping the line from "jumping"...  

 

Lunatic
(@lunatic)
Active Member
Joined: 3 months ago
Posts: 5
13/06/2020 11:12  

Hi, in one of your aircraft videos, you had a situation where the line kept jumping in 5 degree increments.

I haven't tried it in that specific case, but it works on other lines - just hold down the CTRL key as you move it.

I used to draw 2D things using the grid function in Word - a bit tedious I know - but it worked fine for what I wanted.  To overcome the same sort of issue I used to have to hold down the ALT key - that's why I tried Shift, ALT and CTRL in Fusion 360, and the CTRL worked.

Maybe it will work for you with the angled line.

Regards, Steve

PS: Can someone please tell me how to change my profile image - that purple thing is just weird !!!


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Ben K.
(@benk)
Member Admin
Joined: 2 years ago
Posts: 316
13/06/2020 19:17  

@lunatic,

Thank you for your feedback. You are right, in order to move freely you need to press on the CTRL while dragging the mouse. There is another option and it's to uncheck the Snap to Grid.

Do you still need help with your profile image?


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Lunatic
(@lunatic)
Active Member
Joined: 3 months ago
Posts: 5
14/06/2020 04:22  

I'm just learning Fusion, but a lifetime ago I was a structural draftsman (pre-CAD if you can imagine it).

I used your method of 'fit point spline' to create my airfoils, but for some reason they "rounded" the trailing edges, so I just made a spline for top and bottom surface - that worked ok.  Then I could not get the 'sweep' to work (the TE upper-surface had jagged surfaces spiking out of it!!) so I copied and scaled the root profile to make the mid profile (same airfoil).  After that I simply lofted between the root and mid, and the mid and tip.  Great result.   Using the spline, as you point out, creates a beautifully smooth surface - awesome.

I am now trying to work out how to "twist" the airfoils to create the progressive washout required for this model.

My thought is to rotate the airfoils by the required degrees, then using the "allow lines to be drawn in 3D" option, either edit or replace the planform sketch to pick up the trailing edge points that have moved.  This may or may not require re-lofting.

For future reference, if you understand why the trailing edges rounded off instead of staying relatively straight to the TE point, please let me know.  I've attached a couple of screen shots to illustrate.

Any comments on my plans to rotate the airfoils will also be welcome.

Thanks, Steve.

 

 


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Ben K.
(@benk)
Member Admin
Joined: 2 years ago
Posts: 316
14/06/2020 05:48  

@lunatic,

In order to avoid a rounded corner, the top and the bottom lines must be two separate lines that are connected coincidently to each other.

I hope it makes sense. If not, then please attach the file and I will show you.


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eastdave2
(@eastdave2)
Active Member
Joined: 2 months ago
Posts: 6
08/08/2020 10:26  

If you think about it, most aerofoils do not join at a point a trailing edge, unless you're designing a starfighter.

Model aerobatic model aircraft have a thick flat trailing edge for example as this gives more aerodynamic power to the control surfaces. The Piper Cherokee has at least 3mm- 4mm flat edge as this is where the skins join.


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