SRAD

Student Researched and Developed

SRAD Endeavour 1

Active Pitch and Roll Control

Small movable tabs on every fin steer the rocket in flight — researched, designed and built by students. Our first test vehicle, Moonfall, was the University of Florida’s first fin-tab controlled rocket.

Follow the timeline
  1. Cradle to Grave

    The path to controlled flight

  2. Stage 01 Control surface development
  3. Design

    Whiteboard to CAD

    The fin-tab mechanism starts as a sketch of the root profile and a side view, becomes a CAD cross-section with the actuator and linkage inside the fin, then a model we can run through its full deflection.

    Sketch to CAD
    The tab in motion
  4. Fin tabs

    A small tab on every fin

    Each fin carries a small movable tab on a hinge. The main fin stays rigid while the tab pivots. This close-up shows the aft hub where the tab mechanisms mount.

    Close-up of the aft hub with fin tabs mounted on all four fins
  5. Bench test

    On the bench, then on the airframe

    The tab is cycled by itself on the bench first, then again built into the aft end of the airframe.

    On the bench
    On the airframe
  6. Actuation

    Deflecting the tabs

    Tabs pivot to either side of their fin. That is all it takes to create a controlled rolling moment:

    1. Air flows from the nose toward the tail.
    2. Deflecting a tab creates an aerodynamic side force.
    3. Forces acting away from the centerline create torque about the rocket’s longitudinal axis.
    Fin tabs deflected to the left, seen from behind
    Tabs left
    Fin tabs deflected to the right, seen from behind
    Tabs right
  7. Electronics

    Wiring it up

    Every tab actuator is wired back to the flight electronics, so the control software can command each one.

    Avionics board with leads soldered on
    Hands connecting an actuator lead near the aft hub
  8. Stage 02 · Early Fall Subsonic test vehicle for IREC
  9. Launch day

    Briefing

    A pre-launch briefing.

    Team gathered for the pre-launch briefing
  10. Build and prep

    Fin tabs go on

    Moonfall’s tabs are installed and checked at the table before the trip to the pad.

    Team member fitting a fin tab to Moonfall on a work table
    Moonfall’s airframe with its eclipse mark
  11. Flight

    Under parachute

    Moonfall flew, deployed its parachute and came down in the field.

    Parachute descending through a cloudy sky
    Red and white parachute lying in the grass after landing
  12. Recovery

    Found and carried home

    The airframe and its fin-tab hub came back with the team.

    Moonfall’s airframe lying in the brush after recovery
  13. Result

    The data says: roll

    Flight data indicated successful implied roll on Moonfall — the first step toward full active control. Watch the Block I reel.

  14. Stage 03 Still ahead
  15. Coming up

    To be announced

  16. Coming up

    To be announced

  17. Coming up

    To be announced

  18. Coming up

    To be announced

  19. End of semester

    Fully developed

    Active pitch and roll control, complete.