Aluminium or copper will give you a short flash and a bang on mains. Stainless wire or inconel driven by low voltage should work, but only with the speed control of a CNC stage. And leaving adventure aside, doing all that for a single item is far from justified. S.M.

if i want to go for less dia wire i.e. Copper 0.1mm then what kind of supply i have to use.

For safety's sake, keep it 12V and below....

http://en.wikipedia.org/wiki/Hot-wire_foam_cutter

Nickel chrome wire is the preferred wire. These work very well after you get the cutting speed figured out.

Hot Wire cutters will tackle anything from RC plane wings giant blocks of foam for mattresses.

A scroll saw would cut your profile OK, I use one at work for cutting polystyrene.

Link

Thanks all above after making wing i will post its pics.

That length of resistance wire will require about 15 Volts to work. However when this wire gets inside the foam, it will get hotter and you have to move the foam faster. Practice first before cutting the profile you are working on.

Also bear in mind the drag factor when cutting the profile. When the wire is pulled through the polystyrene, the wire forms an arc and this can lead to mis shape of the profile.

Take the blade and holder from an x-acto knife and put it in a cheap pencil type soldering iron. this can be used as a cheap "hot knife".

I was thinking an old-fashioned soldering gun to get the voltage down, a variac or dimmer switch to vary the input voltage and some stainless wire, or even just plain steel floral wire would probably do too. I prefer the variac because dimmer switches add all kinds of funny harmonics that make strange noises in your transformer. With a soldering gun you could probably also jig up some curved shapes using small pieces of sheet metal.

Good luck with your quest.

Look here:-

http://www.instructables.com/id/Hot-wire-foam-cutter/

He spent $30, it could be done cheaper too if you already have a workshop etc..

You do not need a CNC machine if you are only building one aircraft.....