John Simmons's (BAR-09) THUNK! Finless, Gas Dynamic Stabilized

A finless rocket that flies stable?  That is the mission of this rocket.

This rocket is a scratch build / scratch design that uses Gas Dynamic Stability (GDS) and Spin Stability.

An Ikaros Marine Flair uses GDS to stabilize the rocket launched flare.  It has openings below the motor nozzle and the motor exhaust sucks air into these openings.  That stabilizes the rocket as long as the motor is burning.

The problem with that concept for a model rocket is the motor only thrusts for a short period, after that it coasts.  You loose the GDS during the coast phase.

Spin Tabs, aka canted fins, are used on this rocket.  This gets the rocket spinning about its longitudinal axis, which stabilizes the rocket during the coast phase.

This rocket also features a custom wood lathe turned nose cone, made from pine.

Powered by a 24mm motor, recovery is via a 12" nylon chute.

A 2" PVC pipe is used as a launch silo.

Link to Build Thread: Lakeroadster's Finless Rocket Utilizing Gas-Dynamic-Stabilization | The Rocketry Forum


THUNK!: Photo Shoot
THUNK! Drawing: Outline and Section
THUNK! Drawing: Presentation View
THUNK!: Main Body Tube
THUNK!: Motor Mount
THUNK!: Motor Hook
THUNK!: TTW Spin Tab Slots
THUNK!: Spin Tabs Installed
THUNK!: Truing Up the Fin Tabs on the Lathe
THUNK!: Sanding the Fin Tabs on the Lathe
THUNK!: Swing Test Shows the Rocket Is Unstable




comment Post a Comment