Pneumatic or mechanical stunt device that rapidly pulls a performer in a specific direction to simulate impacts such as gunshots, explosions, punches, or supernatural forces – controlled remotely and calibrated for safe, repeatable, dramatic physical reactions on camera.
What is a Ratchet?
A Ratchet is a mechanical or pneumatic stunt device that rapidly pulls performers in a specific direction. It simulates the impact of gunshots, explosions, or supernatural forces, creating dramatic reactions on camera.
Basic Principle
| Aspect | Description |
|---|---|
| Function | Rapid Pull |
| Propulsion | Pneumatic/Mechanical |
| Control | Remote-controlled |
| Usage | Impact Simulation |
Types
| Type | Description |
|---|---|
| Air Ratchet | Pneumatically powered |
| Bungee | Elastic |
| Mechanical | Spring/Weight |
| Winch | Motor-driven |
Air Ratchet
| Aspect | Description |
|---|---|
| Propulsion | Compressed air cylinder |
| Control | Precisely adjustable |
| Speed | Very fast |
| Popular for | Gunshot effects |
Bungee System
| Aspect | Description |
|---|---|
| Propulsion | Elastic band |
| Characteristic | Smoother pull |
| Simplicity | Less technical |
| Usage | Lighter effects |
Applications
| Effect | Description |
|---|---|
| Gunshot | Being hit by a bullet |
| Explosion | Being thrown back |
| Punch | Impact of a punch |
| Supernatural | Being thrown by unseen forces |
Gunshot Effect
| Element | Description |
|---|---|
| Combination | With squibs |
| Timing | Synchronized |
| Direction | Away from the "impact" |
| Intensity | Caliber-dependent |
Harness System
| Component | Function |
|---|---|
| Vest | Main attachment point |
| Cables | Connection to the ratchet |
| Quick Release | Safety feature |
| Padding | Protection |
Cable Concealment
| Method | Application |
|---|---|
| Costume | Within clothing |
| Set Piece | Behind props or scenery |
| Paint-Out | Removed in post-production |
| Angle | Camera perspective |
Safety
| Measure | Description |
|---|---|
| Rehearsal | Without speed |
| Incremental | Gradually increasing intensity |
| Padding | On the body |
| Landing | Prepared mats |
Crew
| Position | Role |
|---|---|
| Stunt Coordinator | Planning |
| Rigger | Setup and operation |
| Operator | Triggering the device |
| Safety Officer | Supervision |
Setup Process
| Step | Description |
|---|---|
| 1. Design | Plan the effect |
| 2. Rig | Set up the equipment |
| 3. Test | Test with weights |
| 4. Rehearse | With the performer |
| 5. Perform | Action |
Calibration
| Parameter | Setting |
|---|---|
| Force | Pulling force |
| Speed | Velocity of the pull |
| Distance | Travel distance |
| Direction | Vector of the pull |
Performer Preparation
| Aspect | Training |
|---|---|
| Reaction | Physical response to the pull |
| Landing | Safe falling techniques |
| Timing | Reacting to cues |
| Communication | With the operator |
Combination with Other Effects
| Effect | Combination |
|---|---|
| Squibs | Simulating bullet hits |
| Air Mortar | Creating debris |
| Pyro | Enhancing explosions |
| Wire Work | Simulating flight or levitation |
Timing Cues
| Cue Type | Description |
|---|---|
| Visual | On a visual signal |
| Audio | Triggered by a sound (e.g., gunshot) |
| Remote | Activated by a button press |
| Sync | Timed with other effects (e.g., squibs) |
Camera Considerations
| Aspect | Planning |
|---|---|
| Frame Rate | High frame rates for detail |
| Angle | Concealing cables and rigging |
| Coverage | Using multiple cameras |
| Safety Zone | Positioning crew safely |
Post-Production
| Task | Description |
|---|---|
| Wire Removal | Digitally removing cables |
| Speed Ramp | Adding slow-motion effects |
| Sound Design | Creating impactful sound effects |
| Enhancement | Adding visual effects |
Risks
| Risk | Mitigation |
|---|---|
| Whiplash | Neck padding |
| Impact Injuries | Landing mats and proper technique |
| Equipment Failure | Redundant systems and thorough testing |
| Miscommunication | Clear protocols and communication channels |
Best Practices
| Practice | Reason |
|---|---|
| Progressive Testing | Ensuring safety and effectiveness |
| Clear Communication | Coordinating the crew and performer |
| Backup Equipment | Having redundant systems in case of failure |
| Medical Standby | Preparedness for emergencies |
Today
Ratchets remain an essential tool for action filmmakers. The technology has evolved with digital control and more precise pneumatic systems. Combined with VFX enhancement, modern ratchet effects create convincing physical reactions that blend practical authenticity with digital perfection.