We’re announcing a brand new rocket – Dart! The main goal of Dart is to achieve Mach 1 with an 18-millimeter motor and carry the necessary electronics to verify the flight. The Dart program will require a combination of electronics, propulsion, and aerodynamic skill in order to succeed, and will fly out of the Friends of Amateur Rocketry site in Randsburg, CA, sometime in the later half of 2021.
Dart requires the parallel development of three separate systems:
- The rocket itself, Dart
- A flight computer small enough to fit inside Dart’s highly limited payload bay
- An experimental motor powerful enough to carry Dart and its payload to supersonic speed
Dart itself will be a very small rocket. Its design is not finalized, but it will be about a foot tall (~30 cm), with three fins, with a 2-inch root chord, quarter-inch tip, inch height, and 2.5-inch sweep. In order to achieve maximum performance, Dart will be minimum diameter – with a half-inch internal diameter (18mm) and a to-be-determined body thickness (likely 2mm or less). It will be printed out of PETG.
Dart will carry the first version of Refresh – a flight logger and computer that will provide tracking, control, and flight information throughout Dart’s various phases of flight. Refresh must be able to activate pyrotechnic charges on Dart to deploy its parachute (or streamer) and must be able to verify that the flight was supersonic. To do this properly, Refresh will carry a high-acceleration single-axis accelerometer, as well as a standard 6-axis IMU and a barometer. The barometer will not be used to verify Dart’s maximum velocity due to the effects of Mach dip.
Refresh also has to be able to communicate Dart’s location and current phase of flight, as tracking is practically impossible due to Dart’s size. It will transmit telemetry over radio, as well as its touchdown location, acquired by GPS (due to COCOM limits GPS will likely not work in flight).
Finally, the most critical part of the Dart program is its experimental motor – currently expected to be designated an F35W. This motor is derived from three Aerotech D13W motors, combined together into a single, 3-grain motor. Due to the experimental nature of this motor, Dart will be confined to launching only at FAR, which has all of the necessary certifications to allow legal and safe operation of experimental motors. The motor will be assembled in a standard half-inch phenolic casing and nozzle, the exact same used in commercial Aerotech disposable motors. Each grain of the motor is a 1.75 inch White Lightning C-slot.