We study the vertical extent of propeller structures in Saturn's rings. Our
focus lies on the gap region of the propeller and on non-inclined propeller
moonlets. In order to describe the vertical structure of propellers we extend
the model of Spahn and Sremcevic (2000) to include the vertical direction. We
find that the gravitational interaction of ring particles with the non-inclined
moonlet does not induce considerable vertical excursions of ring particles, but
causes a considerable thermal motion in the ring plane. We expect ring particle
collisions to partly convert the lateral induced thermal motion into vertical
excursions of ring particles. For the gap region of the propeller, we calculate
gap averaged propeller heights on the order of 0.7 Hill radii, which is of the
order of the moonlet radius. In our model the propeller height decreases
exponentially until viscous heating and collisional cooling balance. We
estimate Hill radii of 370m and 615m for the propellers Earhart and Bleriot.
Our model predicts about 120km for the azimuthal extent of the Earhart
propeller at Saturn's 2009 equinox, being consistent with values determined
from Cassini images