This catapult uses a slingshot rubber band to accelerate a cart on which a glider is set. The cart is assembled from 3D prints. Wood stock is used to build the rail system and mount the slingshot band.
STL files in the catapult.zip (below) are assembled to make the cart and bracket to attach the slingshot rubber band. This cart is designed for a glider or aircraft of about 9 inch width.
To the right is an early version of the catapult with CAD images of the cart.
Below is a later version including a trigger release mechanism and a powered airplane on the cart.
WARNING - The providing of images does not assure or imply a safe mode of operation. Operating a catapult and/or RC airplane can lead to injury and should only be performed with a thorough safety review of both possible causes of injury and precautions to prevent injury. A propeller of an aircraft can become dislodged from the vehicle with the result of a flying blade that can cause injury. An improper design of a catapult or catapult-aircraft match can lead to the propeller hitting a section of the catapult resulting in projectiles like a flying dislodged blade. For this reason, exact specifications of the catapult are not provided, and the warning is given that catapult design and the matching of a catapult with an aircraft should be reviewed and fabricated relative to various hazards and with safety being the highest priority.