Thanks Monty. Alibre was the tool I was thinking of. Never seen Rhino but I will take a look. Building an airplane is sort of an excuse to learn the tool. I suspect that I could design/build what I want without it. But it might help me visualize the end result before I go to far down the wrong path. Clearly I'm not going to invest huge $ in a cad package to build a one off.

Mike

Mike,

If you are going to design an airplane I would go with Rhino http://www.rhino3d.com/. Not free. Not parametric. But you will have an easier time transitioning to it with your experience. It is capable of doing the surfaces necessary for an aircraft. Autocad experience translates nicely into Rhino. The solid modeling is pretty crappy in Rhino, but I never use it.

If you must have a parametric solid modeler you can try Alibre for free: http://www.alibre.com/

It is a very good and cost effective package for doing parametric solid modeling. It also has a sheet metal module. The free version is not the most capable thing in the world. I think you can upgrade to the hobby version for very little money. I have the full blown professional package. I like it. It will do 95% of what Solid Works will do for much less money.

If you need to be able to do real parametric surfacing for something like an aircraft, forget all the mid range packages and ProE, nothing short of Catia or Unigraphics is going to work satisfactorily. For either of these you will be spending $20K+ and about $4K/year on maintenance.

Makes Rhino look REALLY GOOD.

Parametrics can be more trouble than they are worth with complex models.

If I really must have a complex surface with parametric detail, I create surfaces in Rhino and import them to Alibre. I add all the parametric detail there.  

Try everything else first, but you won't regret spending the money on Rhino. I've been using it since Rhino 1.0.

Monty