Best option for replicating custom mirage wing?

[TheGloriousTachikoma]

I'm customizing a Kinetic Kfir kit as part of a what if model. I have a few versions of this planned and need to replicate a wing that takes inspiration from the Tejas and F16. I am going to keep the alterations limited to the upper wing panel only. I need some advice on the best method for replication of this altered wing panel. 

 

First idea is straightforward, silicone mold and resin casts. But I have no experience and I know the 

 

Second idea is sending the wing panels out to be 3D scanned and then make alterations in CAD and 3D print replacements in a resin printer. This would even enable me to just make the leading edge extension and glue it onto the wing. 

 

I could just make a template for the rough shape of the leading edge extension and cut pieces out but that still introduces the possibility of differences. 

 

Just curious what people think is the best option for this dive into madness. 

[Nate]

I'm sure others with more experience will chime in, but I can tell you from my work/CAD instruction experience that, if you go the 3D printing route, build the wing in your CAD environment from scratch based off measurements you take from the kit. You do not want to scan the part and modify the CAD point cloud if you're new to CAD (and probably still don't if you're experienced with CAD either 😉 ) 

 

Point clouds are "noisy" and you will have a little lumps and bumps that you will never be able to smooth out without basically remaking everything from scratch.  Also, point clouds are not easily editable and customizable like a true CAD solid or surface would be - you're basically stuck with a zillion discrete XYZ points in space and software that tries to interpolate a best-fit surface.  They are good guidlines, but some time with a scale and calipers will get you equally good reference points to start your design.

 

The nice thing about CAD and printing is that you can do many, many iterations very quickly, you can get symmetrical parts (I'm currently chasing my tail trying to fabricate 6 little symmetric shapes by hand and am currently on failure number 4), and you can probably buy your own 3D printer for the price of a bunch of failed molds and resin casts.  Granted, learning 3D printing isn't trivial either, but a few hours messing with Fusion 360 (free) would give you a good idea of which battle you want to fight: CAD and printing, or molds and resin.

 

Hope that helps,

Nate

[TheGloriousTachikoma]

On 4/12/2022 at 12:34 PM, Nate said:

Hope that helps,

Nate

 

It does actually. Thank you very much for your input. I'm apprehensive about having to draw the complex curves in CAD as the Mirage wing doesn't have any straight edges except for the rear flaperon joints. But this is the final push I need I suppose. It let's me do all the other stuff I want like designing custom anti radiation missiles and a larger version of the Matra JL-100.

[Nate]

If you can find the airfoil type(s) used in the wing from some Mirage/Kfir plans or some other information source, you can just plug in the airfoil type and have an airfoil generator like this create the cross-section curves for you to start your loft from: http://airfoiltools.com/

 

Bit of messing around with importing/exporting into your design so it works how you want, but might save some of the guesstimating at the early phase of your design....

[TheGloriousTachikoma]

I went ahead and downloaded Fusion. I watched a tutorial on YT and I'm lowkey blown away by how powerful the software is. My last exposure to CAD was AutoCad 2005 back in High School where rotated extrusion was the fanciest tool the course had us use. I was afraid of what it would be like trying to draw the leading edge of the wing profile but now, I'm not nearly as apprehensive.
 

However now I want to try making CFT's for the Mirage-III/Kfir...I wonder if Mr. Chung would be willing to sell me the files for certain parts of the kits for subtracting to get proper parts mating.

Edited April 20, 2022 by TheGloriousTachikoma