Rigs of Rods (also known as RoR), is a truck, car, airplane and boat simulator. You can drive, fly or sail in total freedom in an open environment. What makes RoR different to most simulators is its unique soft-body physics: vehicles chassis and wheels are simulated in real-time as flexible objects, giving the simulation an extremely accurate behavior, while allowing the vehicles to be simply specified by their structural composition, as a network of interconnected nodes (forming the chassis and the wheels). Crashing into walls or terrain can permanently deform a vehicle in a realistic manner. In addition to its unique soft-body physics, RoR also features an advanced flight model based on blade element theory, allowing the accurate simulation of any airplane, base on their physical dimensions and wing airfoils. It also features an accurate buoyancy model based on elemental pressure gradients, enabling boats with complex hulls to move realistically in the swell.

http://www.rigsofrods.com/