Painting the propellers of an Apache Helicopter

Although it takes time to learn, you get a superior (in MY opinion!) finish using an airbrush. And by the way, they usually refer to them as rotors.......

I airbrush about 98% of a model.

Personally, I would airbrush it.

DO NOT paint Tamiya acrylics straight from the bottle. Decant a small amount and add about 30% by volume of Tamiya X-20A acrylic thinner. Stir well.

Before loading your brush with paint, moisten (moist, not wet) by dipping in clean thinner and removing the excess by touching the tip to a paper towel. Repeat this step every other time you load your brush. 

Brush in short smooth strokes, preferably in one direction. DO NOT attempt to brush over areas which appear dry or have begun to dry, or you will pull it up in big ugly lumps. Allow to cure (preferably overnight) before re-coating.

An airbrush  usually gives a better finish than brush, hence why so many people prefer it. As for tamiy and thinner, ALWAYS even when only brushing, you'll get a better coverage. When airbrushing go for a consistancy of milk. I usually use plain 100% alcohol (methylated spirits), others only use the tamiya thinner, some use plain water (personally I have never tried so I cant comment on its results).

HTH

Andrew