Billy Mitchell Was Right

[The Hangar]

Hi
What you have just said is more or less what I’m doing right now for an me 109 build.
I tried for ages to use paper model plans but when scaled up ,just too many errors for me
I built the wing using nerdnics videos and illustrator.
The rest was done on fusion 360
I use 3 view drawings that have formers drawn withcentres so I can line them up. Big thanks to flitedesign 3D for all his help in the last few weeks getting this far on 360.
Just got to get mesh mixer working,then going to create a parallel surface which apparently can be done with the thicken tool that turns a surface body to a solid body.
Then pull out formers probably using unstitch tool
I also plan to hang formers and skin off a central keel which has the vertical stab included so I know it’s vertical .Its like nerd Nic did on his Corsair
https://www.nerdnic.com/content/2200mm-nncorsair-build
The wing also goes on ithe keelso I know I’ve hopefully got the angle of attack correct.
Anyone that wants/can help with meshmixer,and the last steps,I’d be greatful
as I’m worried I’ve overloaded flitedesign 3D !
View attachment 171098

So do you draw the formers and fusion, or do you draw them up in illustrator and export them? I was planning on using illustrator since I'm more comfortable working with it, but it is a lot of files to save and export...

 

[Apple Pie]

@Apple Pie @Flitedesign 3d @smiling albert
Just curious how you all go about starting a design. Do you get a 3 view (or balsa plans) and draw up the formers in your 2D program first, then export them into fusion 360, insert the SVG onto the appropriately spaced planes, then loft them, and then use the skins you get from there? When you finish that do you decrease the size of the formers to account for the thickness of the foam, then design the whole internal structure in your 2D program? Also, when you paste the formers into fusion, how do you make sure that they are all in line with each other and not one being up or down from another? I've mentally come up with a method but I want to know if there's a better way out there.
Thanks all for your help!

So when I designed my B-25 fuselage I imported the aircraft three view PDF’s to my 2-D CAD program and laid out the former locations and profile sketches there. In Fusion 360 I then created a series of offset planes at the former locations and created a sketch on each plane using an imported 2-D DXF. I wasn’t all that happy with the process as Fusion just chokes on DXF files.

I’m working on another design but this time I’m following this workflow for the fuselage
1) import the three view PDF’s onto the three planes at the origin. Scale each appropriately so they all match in size and location.
2) create offset construction planes at each location along the fuselage where a transition in skin shape occurs, or where structural support is needed
3) create a side view sketch of the fuselage profile on the vertical mid plane
4) create a top view sketch of the fuselage on the horizontal mid plane. Make sure to include intersections with the side view so the points are in exactly the same 3-D space
5) create a sketch on each of the offset construction planes from the nose back to the end of the empennage. Make sure to include the intersection points with the side and top view sketches. This ensures that the points of intersection between the sketches are all shared in 3-D space. I only sketch one half of the plane as you will mirror the skins and formers later.
6) beginning at the nose I create a surface loft between the first and second profiles. Include the top view sketch as one rail, and the side view sketch as a second rail. This produces a skin that conforms to each of the three view inputs. Repeat down the length of the fuselage.
7) in the browser view, rename the newly created surface feature and right click on it to “export as stl”.
8) open meshmixer and import the stl. Unwrap the stl using the default settings. Then export the unwrapped surface as an Inkscape SVG. Inkscape SVG setting I understand uses mm as the default. When I bring this SVG back into my 2-D CAD program (Vectric VCarvePro which I use to run my CNC and needle cutter) I have to scale the imported SVG to 28.5% of imported size to have it scaled properly. I have absolutely no idea why this is, but have read a variety of forum posts which indicate it’s a Fusion surface export issue. Regardless, it’s easy enough to do and it works so I’ve quit asking why. I then duplicate and mirror the flattened skin and stitch it into a full entity so it will wrap back up into the full fuselage shape.
8) for the formers I make sure there is a common point identified on each former sketch (for me that has been an internal box structure down the length of the fuselage) and then export a DXF of each former and import them into the 2-D CAD. Offset the former shape by 4.8mm inwards to account for the thickness of the foam.

This is about the limit of my knowledge on the design process using Fusion and meshmixer. I’ve run into all kinds of situations with busted meshes and lofts that didn’t work the first time, and had to work around them. Still in the learning phase which involves a healthy dose of trial and error. I’m looking forward to hearing how others are doing their designs and what workflow works for them.

Anyone doing their lofts as solids then exporting surfaces as stl? I’ve thought about it but haven’t tried it yet.

Also, what do you guys think of starting a dedicated thread for this topic?

 

[The Hangar]

So when I designed my B-25 fuselage I imported the aircraft three view PDF’s to my 2-D CAD program and laid out the former locations and profile sketches there. In Fusion 360 I then created a series of offset planes at the former locations and created a sketch on each plane using an imported 2-D DXF. I wasn’t all that happy with the process as Fusion just chokes on DXF files.

I’m working on another design but this time I’m following this workflow for the fuselage
1) import the three view PDF’s onto the three planes at the origin. Scale each appropriately so they all match in size and location.
2) create offset construction planes at each location along the fuselage where a transition in skin shape occurs, or where structural support is needed
3) create a side view sketch of the fuselage profile on the vertical mid plane
4) create a top view sketch of the fuselage on the horizontal mid plane. Make sure to include intersections with the side view so the points are in exactly the same 3-D space
5) create a sketch on each of the offset construction planes from the nose back to the end of the empennage. Make sure to include the intersection points with the side and top view sketches. This ensures that the points of intersection between the sketches are all shared in 3-D space. I only sketch one half of the plane as you will mirror the skins and formers later.
6) beginning at the nose I create a surface loft between the first and second profiles. Include the top view sketch as one rail, and the side view sketch as a second rail. This produces a skin that conforms to each of the three view inputs. Repeat down the length of the fuselage.
7) in the browser view, rename the newly created surface feature and right click on it to “export as stl”.
8) open meshmixer and import the stl. Unwrap the stl using the default settings. Then export the unwrapped surface as an Inkscape SVG. Inkscape SVG setting I understand uses mm as the default. When I bring this SVG back into my 2-D CAD program (Vectric VCarvePro which I use to run my CNC and needle cutter) I have to scale the imported SVG to 28.5% of imported size to have it scaled properly. I have absolutely no idea why this is, but have read a variety of forum posts which indicate it’s a Fusion surface export issue. Regardless, it’s easy enough to do and it works so I’ve quit asking why. I then duplicate and mirror the flattened skin and stitch it into a full entity so it will wrap back up into the full fuselage shape.
8) for the formers I make sure there is a common point identified on each former sketch (for me that has been an internal box structure down the length of the fuselage) and then export a DXF of each former and import them into the 2-D CAD. Offset the former shape by 4.8mm inwards to account for the thickness of the foam.

This is about the limit of my knowledge on the design process using Fusion and meshmixer. I’ve run into all kinds of situations with busted meshes and lofts that didn’t work the first time, and had to work around them. Still in the learning phase which involves a healthy dose of trial and error. I’m looking forward to hearing how others are doing their designs and what workflow works for them.

Anyone doing their lofts as solids then exporting surfaces as stl? I’ve thought about it but haven’t tried it yet.

Also, what do you guys think of starting a dedicated thread for this topic?

That's an intresting approach - I like it. It seems a lot easier than exporting each former individually. I'll have to try to figure out how to offset the former 4.8mm - not quite sure how to do that in Illustrator. When you say scale the imported SVG, do you mean that in the scale section you type in 28.5 so it's slightly under 1/3 the size of the original imported SVG? I do think we should start a separate thread on it and stop hijacking @BATTLEAXE 's thread.

 

[smiling albert]

I agree ,sorry battleaxe its my fault.
I was going to start a separate thread if I actually got this all to work ,’ll Try to invite anyone that might be interested to the one I’ve already started with 3d design.
It doesn’t start to get really (!)interesting until page 3 as I started with no knowledge of 360 until about a month ago.
I only spotted this thread yesterday and am glad I’ve found at least one similar minded person ,I was beginning to think I was going crazy!
Regarding importing svg files to 360, I had to import my wing from illustrator and apparently you need to use a scale factor of 1.333333,again not sure why and beyond caring!
If anyone can help me with my meshmixer problem I’d be eternally grateful.
Sorry again battleaxe,will invite you to it if you want to vandalise my thread.
Over and out

 

[Apple Pie]

Ok, so today I finally maidened the B-25. It flew pretty darn well but it’s a big, heavy plane and it flies pretty much exactly like that. No idea if the cg was optimal but I balanced it about a third of the way back from the leading edge. Twin 3536 on 3S 5000 battery with 11x5 props and it could pretty much go vertical. And in true B25 fashion I ditched the landing after 12 minutes which didn’t end up on video. All in all it was a grand flight.

 

[BATTLEAXE]

Ok, so today I finally maidened the B-25. It flew pretty darn well but it’s a big, heavy plane and it flies pretty much exactly like that. No idea if the cg was optimal but I balanced it about a third of the way back from the leading edge. Twin 3536 on 3S 5000 battery with 11x5 props and it could pretty much go vertical. And in true B25 fashion I ditched the landing after 12 minutes which didn’t end up on video. All in all it was a grand flight.

That flies great man! Good job. I really like the sound of the twin, what props are you using

 

[Apple Pie]

That flies great man! Good job. I really like the sound of the twin, what props are you using

11x5.5 APC Two blade props from hobby king. I would like to find some three blade props with a CW and CCW combo. Both of the props I was flying are CCW

 

[Mr.Grinch]

I ordered the master airscrew 3 blade props for the SeaDuck and P38, they should work perfect for the B25. Now, what about 4 blade props??