Blending Compound Surfaces

Hello, friends

I am very new to Rhino and I was suggested to come to you guys and ask for advice on how to resolve a tricky situation on the nose section of a turboprop aircraft I am modeling as a practice subject. At this point I’ve created these 3 surfaces that should blend and form a soft depression right below the engine exhaust:

Needless to say I have tried in so many ways but sadly, I can’t get a convincing solution. Then comes the intake lip and the way it blends with the top cone surface. I recognize this is far above my current knowledge level and so here I am requesting advice and assistance with this exercise. Below is my 3dm file and a couple of extra images for reference.

Many thanks in advance!

Nose&intake.3dm (525.0 KB)

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I’d suggest getting into SubD modeling… Here’s a one minute shot:

I don’t have the motivation to get this done with NURBS, it’s difficult to fine tune. Still, an easy way is with two revolved surfaces combined and merged all faces, then fillet the edge. Sort of gets you there too:

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Hello - if you want to stay with surfaces, I’d consider at a layout something like this:

The devil is in the details of course but if I am reading the gist of the images, I’d try that. The surface is matched to the two inputs with MatchSrf > CurveOnSurface=On. History will allow making adjustments too. Once you get some inner surfaces on the intake, you’ll need to wrap that transition surface around and inside - here it just ends at the edge that is there.

Nose&intake_BasicSurface.3dm (411.1 KB)


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@pascal method is how I’d do it. It’s really tricky to do with variable widths.


Thank you guys for all your suggestions. I will give them a try and report back with news!

The completed model for CFD.


Wow, great looking PC-12, Stratosfear. Could you share how you came to create the intake/nose and wing/fuselage blends or point me to a video tutorial you may know of? As i mentioned, i’m at the rookie stage and still struggling with this sort of things… :roll_eyes: Any advise is most welcomed!

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A-29 variant? Looks good. When you gonna do the wing root blend?

Thanks, Stratosfear. This is a Swiss-made Pilatus PC-7. Similar to Brazilian A-29 but much older. In fact it’s already being phased out in favor of newer models like PC-9/Texan II or their latest PC-21.

There isn’t much of a wing blend on this one as you will see in the pictures below. Anyway, the model is still not finished to that detail will also be added at a later stage. Lots of work yet to be done!

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