You can replace the propeller mesh to your own, with Milkshape3D.
Download page: http://www.marisa9.com/imvu/misc/milkshape.html
* You need Milkshape 3D, Milkshape 3D SDK and Milkshape 3D plugin of Cal3D 0.9 installed.
Direct Download link: http://www.marisa9.com/imvu/misc/ms/milkanime.zip