We are developing a finite element library FEMClaw, which is based on the FEniCS project. The library solves variable density incompressible flow, compressible Euler equation, compressible MHD equations. The solver works in 2D and 3D and high parallel efficiency is obtained. The main focus of this project is to solve large-scale problems both for incompressible and compressible flows. Our particular applications in mind are: 1. Simulation of Gulfstream G550 nose landing gear, which requires about 30 million mesh points in 3D. We use our newly developed variable density solver; 2. Kink instability in Tokamak fusion reactor using compressible MHD solver. The usual mesh consists of 20-30 million points in 3D.