ORIGINAL: tf2psycho
i bet you could invent VPP for gas planes the military uses it on the apache helicopter
its called a swash plate assembly
[link=http://science.howstuffworks.com/helicopter5.htm]swash plate link[/link]
Most 1:1 scale prop planes use variable pitch. They don't do 4D with them though. Also, Almost all helicopters have variable pitch blades, including 3D rc helicopters.