topic Re: Create Fairing Between Two Bodies in Fusion Design, Validate & Document Forum

Create Fairing Between Two Bodies

MaxHugen — Sat, 01 May 2021 20:39:48 GMT

For my SailGP F50 model, I've now created the forward cross beam between the two hulls. In reality, a very thin aero fairing is added to smooth out the are between beam and hull:

I haven't searched for a way to do this as I don't know where to start, so I'd be grateful for some pointers to info to get me going. This is where I'm at:

Cheers, Max

Re: Create Fairing Between Two Bodies

davebYYPCU — Sun, 02 May 2021 05:48:42 GMT

Down the back, is a plain fillet. (Arrow far left)

You seem to be putting the cart in front of the horse. You have nice "filleted" bodies, but the construction phase is not over, it is normal to fillet the edges real late in the project.

These will get in the way....

Any close detail of the inside hull shape of the fairing, here?

There is a flat platform to come for the foil area, and I would need that done before trying to fair in the platform to the hull, should become part of the whole thing?

Might help..

Re: Create Fairing Between Two Bodies

MaxHugen — Sun, 02 May 2021 07:53:36 GMT

Hi Dave. I did the fillet because the one-piece fairing needs to wrap around it I think. No sharp angles.

I don't have much in the way of clear shots of the detail. I do know that looking down from top, there is a curve between the hull and the beam, as well as the aero curve looking at it side-on.

Thought I had a good idea, but it seems that it's not possible to either extrude or sweep in the direction of the plane, only perpendicular to it? Was going to use some curves from the profiles, and extrude/sweep them 2-mm. These would have become profiles for lofting, together with rails.

This is all I have to work with, nothing any better:

Cheers, Max

Re: Create Fairing Between Two Bodies

davebYYPCU — Sun, 02 May 2021 09:39:40 GMT

Breaking down those photos to find the merging lines / seams,

I still think the foil holding surface should be next,

the red lines are where I would would be having rails or paths.

Re: Create Fairing Between Two Bodies

MaxHugen — Mon, 03 May 2021 02:23:10 GMT

Sounds like we're trying the same approach?

My plan was as follows:

Create a thin (2mm) body on the top of the curved cross beam. For this I made copies of the sketches with the 2 profiles used for lofting in that area, and cut away the parts of the curves I didn't need. Then I tried to create a vertical 2mm face from the 2 resultant curves which I'd use for a Loft.
Use the same technique forward of the beam on the hull to create a new face there, and then loft from the "beam body" to this new face, using some shaped rails.
So the same on the aft side of the beam to the hull again.
Side piece from beam to hull.
Add in the missing fairing sections

I'm reasonably confident that I could manage this, if I could create the 2-3mm face profiles I need for the lofting. This is a stumbling block so far.

Starting with Body (1)

Used the profile at the inboard side of the beam, duplicated it on the same plane, and removed the part of the curves I didn't need.
Using this curve on the new sketch, I tried using Extrude, then Sweep, to create a surface in the same direction as the plane, in the Z direction. No go, these tools would only do it in the Y direction.
Then I had another idea, create a profile in the Y direction using sweep, and then use Thicken to give me a body with a face in the plane I needed.

The sweep actually worked, but then F360 couldn't display it, after I zoomed back out (I had zoomed in a long way to do this) to see the new surface. Not sure if it's F360, or the limited graphics ability of my 12+ year old laptop. Unable to see the new surface at all, I couldn't try the thicken method.

Re: Create Fairing Between Two Bodies

MaxHugen — Mon, 03 May 2021 03:08:42 GMT

FIXED MY ERROR!

Thinking that the 0.002 measurement was problematic, I tried the Sweep again at 0.01. No problem, AND in the right direction - on the XZ plane! I think I incorrectly swapped the Profile and Path.

I now have the my first "profile" to use for a loft. I also used Thinken, so it would be easier to see when zoomed out, as I won't be using this body ultimately. Not sure I'll need this 3D body, or just the 2D swept body. I'll find out in due course. 🙂

Re: Create Fairing Between Two Bodies

MaxHugen — Mon, 03 May 2021 06:02:01 GMT

Quick update, using the 2D bodies as profiles for a Loft is AOK.

Have lofted 1a and 1b in my diagram above - the easy ones.

Now for a challenge, lofting from Fairing Panel 1a to the hull. Will need a number of Rails for this one.

Re: Create Fairing Between Two Bodies

MaxHugen — Sun, 09 May 2021 19:14:27 GMT

This was a learning exercise, and with many aborted attempts along the way, I did get to something I can live with. The next fairing part should correct some technique omissions, and probably simplify the overall design.

Many thanks to @davebYYPCU and others who have steered me on this course!