CAD Forum

Hi there,
My name is Jake and I’m 17, I love aviation, engineering and CAD. I have been trying to design an airliner in CAD for a long time but I just can’t seem to get accurate geometry for the nose. Let me explain the situation.

I know this is a Solidworks forum and I am using Fusion 360, but I thought my questions, and any advice I got would be applicable.

I want to design a commercial aircraft that I could eventually make into an RC model. I want it to have very accurate geometry and be very detailed.

I don't have a big problem with most parts of the aircraft, but I just can’t seem to get the nose geometry, specifically the cockpit windows right. As you can see from the two pictures below, I’m using an ERJ-135 and 757-200 for practice. I can get everything on the nose looking pretty good but I just can’t get the cockpit window area.

I keep trying and deleting it.

I guess my questions Are:
- Are there any specific or more broad concepts that I should be doing or learning about?
- Am I approaching this the right way with splines and surfacing?
- Do you have any advice on how to create accurate geometry for commercial aircraft cockpit windows, and nose section?

Any help or advice would be greatly appreciated.

Jake

Fun challenge! I think using splines and surfacing is the right approach. I don't have time right now to give you an example, but here are a few recommendations.

Start with a picture of the shape you want to develop, and sketch in the "seams" where different surface patches would stitch together, with tangency or C2 continuity, to form the final nose cone. Ideally each of these patches are "simpler" surfaces that you know how to create. Sometimes it helps to build these patches larger then you actually need, and then trim them back to where the seams will be located. Add the larger patches that control the shape in first, and then fill in the gaps.

Here's a presentation that Andrew Lowe gave at Solidworks World a few years back called "Have a Seat" where he describes this approach to model the Eames LCW Chair.


I expect you can find the slide desk online. Here is a newer presentation he gave that covers some of these ideas.
https://dimontegroup.com/wp-content/upl ... facing.pdf

Lot's of those parts are "Surface" parts lofted along a series of sketches.
So most of the solid workflow will not work.

Jake123 wrote: ↑Wed Jul 26, 2023 3:41 pm
I know this is a Solidworks forum and I am using Fusion 360, but I thought my questions, and any advice I got would be applicable.

Jake

Hello Jake, imho, this is not a SW site as much as it has.. it's more. so with nurbs in either Fusion or any other tools, you need to focus on the boundaries. or break up your patches or divisions to blend.

ryan-feeley wrote: ↑Thu Jul 27, 2023 12:00 pm Fun challenge! I think using splines and surfacing is the right approach. I don't have time right now to give you an example, but here are a few recommendations.

Start with a picture of the shape you want to develop, and sketch in the "seams" where different surface patches would stitch together, with tangency or C2 continuity, to form the final nose cone. Ideally each of these patches are "simpler" surfaces that you know how to create. Sometimes it helps to build these patches larger then you actually need, and then trim them back to where the seams will be located. Add the larger patches that control the shape in first, and then fill in the gaps.

Here's a presentation that Andrew Lowe gave at Solidworks World a few years back called "Have a Seat" where he describes this approach to model the Eames LCW Chair.

Andrew Lowe -- Have a Seat.png



I expect you can find the slide desk online. Here is a newer presentation he gave that covers some of these ideas.
https://dimontegroup.com/wp-content/upl ... facing.pdf

Thank you for your reply,

That's good advice and I will definitely check out the video.

I'll try to do what you said, but it is still challenging as someone with much less experience, to know how to approach this and begin building that geometry without seeing someone demonstrate it.

Thanks for the help!

Hi Jake, good stuff getting into this at 17! Steep learning curve as you have discovered.

I modelled a 747-100 (based on the first 747) in Rhino a few years back and one of the most challenging things was the cockpit side glass.
Lots of models you see if aircraft, the modeller has just trimmed the glass out of a larger surface with single or compound curvature, when in reality several aircraft have planar side and/or front cockpit windows. With the 747 getting the position/angle of the side windows dictated the curvature of the surrounding surfaces, so it was fairly critical to get the planar glass surface in the right place before building the surrounding surfaces. It'll be a similar situation in SW. I've attached a STEP model of the 747 fuselage, you may be able to get some ideas of surface layout from this. Another area you may have difficulty with is the nosecone. You may have to overbuild the surfaces, then trim back to give you a hole for a 4 sided surface. Here's an old video I uploaded on building similar geometry.

Also highly recommend watching '36 Verts' on youtube. https://www.youtube.com/c/thirtysixverts
They are Rhino videos, but the surface layout is applicable to SW as well. The person behind the vids is in the aerospace field, so it is relevant information. Good luck!

Thank you for the replay, sorry for the delay in responding. I will check out the channel and I appreciate your help!

Jake

The 757 is harder than the ERJ because I have to somehow blend the flat windows into the nose

since you are using Fusion 360 you should be using Sub-D aka T-Spines, know need to do all the splines.

search out vids on it, sweat sweat sweat.

but it never hurts to learn surfacing.

check out this from Mark, #25 thru 27 he makes a mouse first with surfaces then Sub-D https://www.youtube.com/@spannerproduct ... 633/videos