does the 'mesh' mean this was done with some sort of scanning then reproduction ?

I designed them in Discreet Plasma and made the G-code with Vectric Cut3D

Discreet's Plasma software is/was a 3D application. Vectic's Cut3D will take these models (A.K.A. "meshes") that were created in Plasma, and create G-code to manufacture them.
You could indeed "scan" some blades and make replicas that way. You could also use a digitizing probe and again make replicas. If you model them yourself, the design options are limitless.

Would you form the root of the blade whilst it was still in a block of wood form then clamp the root in your 4th axis

A 4th axis is not required, and was not used, as you can see from his video.

The video wasn't working for me yesterday but works good today. I can see now it's all done from a flat piece of wood. The finished articles are pretty splendid. The blades don't appear to have a twist in them as a lot do and thus that's why I was thinking a 4th axis would be needed but I suppose even with a twist is can still be done with the same method (3 axis) only would probably require a bit more sanding on the leading edges. Is it called plasma due to it primarily being used for plasma cutters? Interesting to see how you'd make one of these with a plasma cutter.  Good stuff.

Is it called plasma due to it primarily being used for plasma cutters? Interesting to see how you'd make one of these with a plasma cutter.  Good stuff.

No, Discreet named their products after things that are hot, Flame, Inferno, Plasma..... I did some poking around, and Plasma was released quite a few years ago, before Discreet was bought by Autodesk, and apparently no longer exists. It was primarily a 3D modeler for web graphics, I think.

What would I look for now then ? Is it still part of the Autodesk stable ? I've already got Inventor and that's pretty good for 3d stuff.  So if I'm reading your post right you make a drawing in autodesk and it'll be saved as a IAM or IPT or something like that and CUT3D can import this and convert it to GCode. That's pretty impressive stuff. I've seen a pic in a model mag where some fellow had CNC'd a turbine blade for a jet engine I don't know how many axis he used but the mind boggle as the complexity of it.

Is it still part of the Autodesk stable

No, I don't think so.

you make a drawing in autodesk and it'll be saved as a IAM or IPT or something like that and CUT3D can import this and convert it to GCode

Yep, that's pretty much it, in a nutshell. Have a look at the features here...http://www.vectric.com/WebSite/Vectric/cut3d/c3d_features.htm
Turbines would likely be done with a 5 axis, due to their complex curvature.

What would I look for now then ? I've already got Inventor and that's pretty good for 3d stuff.

If you can't do what you want with Inventor, there are plenty of 3D modelers out there, from really cheap to really expensive. Perhaps Rhino might work better for what you want to do?

Thanks to you both. I'm a little premature as I haven't actually got my machine up and running yet (due to some fellow going on hols with the half built base locked in his tool locker grrrr). Still it gives me time to look at the different software packages without feeling rushed as I know once it's up and whirring I'll be wanting to cut stuff and in my experience once you've used a package once or twice and it did the trick it's difficult to force yourself to learn another one which may turn out a lot better. I haven't got a use for a turbine wheel but would sure love to machine one just to have it sit on my side board looking nice.

Wow some impressive stuff on those websites. I think the V carve software will prove a little too expensive for me as I'm only a home fiddler rather than a serious CNC professional but still good to see what can be done if ever I turn pro.

Here's a video we shot today of the plane flying with the home made propeller. View it in high quality mode for the best experience, I forgot to zoom the camera in before I handed it to my friend: http://www.youtube.com/watch?v=YQ95gR9yQM4

The plane has a wingspan of 185 cm and weighs 6 kg.

That's a nice plane. Nice view of the country, too!