Sketching inside a cylinder

[dutchfisher2005]

Hello,

I'm designing a two stroke cylinder. I'm trying to sketch the exhaust port and duct. I'm finding it difficult to sketch the outline of the port onto the cylinder wall and then extrude cut the duct. I have tried a 3D sketch on a plane at both the angle of the duct (20 degress from Horiz) and front plane. However then i try the extrude cut the edges of the port turn up at the surface of the cylinder wall. I want the top of the port flat as in the sketch.

Not sure if i'm going about this the right way.

Using SW 2008 Sp5

Thanks

 

[CorBlimeyLimey]

One method to find the cross-sectional area would be to create a surface at the Exhaust Port Contour EX face, and use the Measure tool.

 

[dutchfisher2005]

I'll give that a try in the next few days

 

[dutchfisher2005]

I've hit a snag. Although the wrap worked for leaving the top of the port flat, I now cannot do a lofted cut to make the duct using the wrapped outline. Is there a way of copying the outline onto a new sketch at the plane angle I'm using for the duct so I can make the cut but still leave the port on the cylinder wall with a flat top?

 

[CorBlimeyLimey]

Not sure what you mean by "copying the outline", but you should be able to use either Intersection Curve or Convert Entities to create new sketch profiles for lofting.

 

[dutchfisher2005]

CorBlimey, thanks again that worked.

I need advise on 'best practice' to form the duct. The duct at the cylinder end is split in two as per my prev. attachment, however this forms into a single duct as the duct progresses. As the section changes need to be precise I propose to sketch every few mm on the 'exhaust duct angle' plane. My question is this; should I sketch and form the duct as a single duct with a lofted cut and then add the vertical split at the cylinder end with a new sketch and extrude or start with the dual ducts and try to merge the loft.

Regards