The Real Apache Cyclic — Controls & Dimensions
The AH-64D cyclic grip packs roughly 10 discrete controls into a single right-hand pistol grip, following the HOCAS (Hands On Collective And Stick) philosophy — pilots never release the controls to access weapons or communications. Understanding this layout is essential before designing or modifying a grip.
Primary controls documented in TM 1-1520-238-10 include a 4-way Force Trim / Hold Mode hat switch at the thumb position on top, a 4-way Weapon Action Switch on the left upper face (forward gun, left rockets, right missiles, aft air-to-air), a Flight Mode Symbology Select 2-way toggle on the right side, and a dual-stage trigger with guard on the front face. Additional push buttons handle chaff/flare dispensing, FMC release, and DASE release.
| Dimension | Estimated Value | Source / Notes |
|---|---|---|
| Overall length | 180 – 200 mm | Community measurements, MIL-STD-1472 |
| Grip diameter | 35 – 40 mm | Accommodates Nomex flight gloves |
| Finger groove spacing | 20 – 25 mm center-to-center | Groove depth 2–3 mm |
| Trigger position | 50 – 65 mm above base | Natural index finger curl |
| Pistol rake angle | 15 – 18° forward | From shaft centerline |
For a simplified simulator version, a practical minimum includes: one 4-way hat (trim), one 4-way hat (weapons), two to three momentary push buttons, and a front trigger — matching the components you've already sourced.
Existing 3D Models You Can Start From
Several community members have already designed Apache-specific grips optimized for 3D printing with electronics integration. Starting from one of these saves weeks of modeling.
Strongest starting point: Cammando58's AH-64 Cyclic Grip on Printables — free, 671+ downloads, includes Blender source files and cutouts for RKJXT1 hat switches, Salecom T80-p push buttons, and a trigger module.
Modeled in Blender from DCS reference. Hollow split/unsplit versions, embossed labels, hat switch and button cutouts, trigger module. Blender source included for modification.
Free25 STL files + STEP for gimbal. PDF assembly instructions. FreeJoy controller board with 4021 shift registers. Tested in aluminum-infused PLA. Mounts to Thrustmaster bases.
PaidCPG left + right grips. Hat switch housings, trigger with 2mm steel rod pivots and 5.5mm springs, modular handle-link system.
FreeComplete 1:1 TEDAC system with build guide, assembly timelapses, Leo Bodnar board electronics. No coding required. Firmware on GitHub.
FreeFor the cyclic base/gimbal, j0q's DIY Cyclic (Thingiverse) provides a complete system with Arduino Pro Micro, Hall effect sensors, RC car dampeners, and a 25mm shaft accepting interchangeable grips. The SimChair MKIII by hc625ma is a fully open-source helicopter control set (cyclic, collective, pedals) with software force-trim emulation.
CAD Workflow — FreeCAD vs Blender
The most effective approach combines both tools in a hybrid workflow — but if you must choose one, FreeCAD is the more practical choice for a functional, dimensionally accurate grip with button cutouts and internal cavities.
Part Design workbench: Pad, Pocket, Additive Loft, Thickness. Precise rectangular cutouts for switches, cylindrical screw bosses, internal wire channels, hollow walls at exact thicknesses. Parametric — change grip diameter and the whole model updates. Part CheckGeometry validates printability.
Sculpt mode with Grab, Clay Strips, Crease, Smooth brushes. Shape palm contours and finger indentations intuitively. Voxel Remesh for uniform mesh density. Export as STL, import into FreeCAD via Part → Create Shape from Mesh → Convert to Solid.
The recommended FreeCAD grip workflow uses cross-section lofting: create 5–8 B-spline profile sketches on datum planes spaced along the grip's vertical axis, each capturing the cross-section at that height (wider at the palm swell, narrower at top and bottom), then use Additive Loft to interpolate between them. For finger grooves, use Subtractive Loft or Boolean Cut with positioned ellipsoids. Apply Fillet to all edges for comfort.
The Curves Workbench add-on (install via Addon Manager) provides Gordon Surface and Sweep 2 Rails tools for more complex organic shapes. DigiKey's "Introduction to FreeCAD" tutorial series (Parts 4, 7, and 8) covers heat-set inserts, sweeps/lofts, and curved surfaces — directly applicable to this project.
If starting from Cammando58's existing Blender file: modify the external shape in Blender's sculpt mode, then bring it into FreeCAD for mechanical changes — adjusting button cutout positions for your specific switches, adding custom mounting posts, or redesigning wire channels.
Designing for Buttons, Switches & Trigger
Integrating electronics into a 3D-printed grip requires precise cutout dimensions with appropriate tolerances. The key principle: FDM holes consistently print undersized — design all cutouts 0.2–0.5mm oversized per side.
| Component | Body Size | Cutout Size (FDM) | Mounting Notes |
|---|---|---|---|
| 6×6mm Tactile Button | 6.0 × 6.0 mm | 6.3 – 6.5 mm sq. | Retaining lip 0.5–1mm. Choose stem height for 1.5–2mm protrusion. |
| Mini Toggle (MTS-1xx) | 13 × 8 × 8 mm | ⌀ 6.2 – 6.5 mm | M6 threaded collar. Nut + washer retention. |
| 4-Way Hat (RKJXL) | 12.4 × 12.4 mm | Flat platform + slot | Hot glue or snap bracket. Alt: 10×10×9mm 5-way SMD hat. |
| Microswitch (trigger) | 13 × 6 × 7 mm | Pocket + actuator access | No lever variant. Trigger arm presses actuator at full pull. |
Trigger mechanism: Use a pin hinge, not a living hinge (PLA/PETG living hinges fail quickly). Design two pivot bosses on the grip interior with 3.2mm holes for an M3 bolt pivot pin. A 5mm OD torsion spring provides return force. For dual-stage matching the real Apache, use two microswitches at different depths — first contact at ~1mm, second at ~3mm.
Internal wiring channels: Design troughs 3mm wide × 2mm deep for individual wires (22–26 AWG) and 10–12mm wide × 5mm deep for the main bundle. If your button count exceeds 16, place 74HC165 shift register chips inside the grip to multiplex all buttons down to 3–4 wires. Use JST-XH connectors at the grip/base junction for easy disassembly.
Printing on the Ender 5 S1
The Ender 5 S1's 220 × 220 × 280 mm build volume comfortably fits a full-size cyclic grip (~180–200mm tall × ~45mm wide) even printed vertically. However, splitting the grip into left/right halves is strongly recommended: it eliminates internal supports, provides direct wiring access, and enables flat printing for excellent surface quality.
| Setting | Recommended Value | Rationale |
|---|---|---|
| Material | PETG | Better impact resistance than PLA. Slight flex prevents cracking. 230°C / 70°C bed. |
| Perimeters | 5 (≈ 2.0mm wall) | Structural integrity under gripping forces. |
| Infill | 30% Gyroid | 100% locally around pivot points and screw bosses. |
| Layer height | 0.2mm standard | 0.12mm for button pockets via variable layer height. |
| Orientation | Flat on split plane | Max dimensional accuracy on mating surface. |
Assembly: Use M3 heat-set brass threaded inserts (5mm OD × 4mm long) with 4.7mm pilot holes. Install with a soldering iron at print temp + 10–20°C. Add 3mm alignment pins along the split line for perfect registration. Secure with M3 socket head cap screws.
Post-processing: Sand progressively 120 → 400 grit. Apply Rust-Oleum Filler Primer to fill layer lines, wet-sand at 320 grit, then flat black or olive drab spray paint. Plasti-Dip (3–4 thin coats) or self-adhesive tennis racket grip tape adds realistic grip texture.
Build Sequence & Timeline
Learn Fundamentals & Gather References
Complete DigiKey's FreeCAD tutorial Parts 1–4 (sketching, padding, pocketing, heat-set inserts). Print a simple test box with button cutouts using your actual switches to calibrate tolerances. Gather reference images from the DCS AH-64D model viewer and Cammando58's Printables page.
Model or Modify the Grip
Download Cammando58's Blender file and modify for your switches, or build a new grip in FreeCAD using cross-section lofting. Apply Thickness to hollow the body to 2.5–3mm walls. Cut button pockets, add screw bosses for M3 heat-set inserts, carve wire channels. Split into halves with Boolean Cut.
Print, Test-Fit, Iterate
Print both halves in PETG at 0.2mm. Test-fit all switches — if tolerances are off, adjust in FreeCAD's parametric model and reprint just the affected section. Verify trigger pivots smoothly on its M3 bolt with spring return.
Wire, Flash & Finish
Solder switches to hookup wire with JST connectors, route through internal channels, connect to Arduino Pro Micro (or shift registers if exceeding 16 buttons). Flash Arduino Joystick Library firmware. Sand, prime, paint, add grip texture. Mount to cyclic base.
Bookmarks
The HOTAS/SIMPIT Wiki catalogs every known 3D-printable flight sim component, gimbal design, grip design, and electronics approach. The DCS World forums (AH-64D section) and r/hotas on Reddit are the most active communities for Apache-specific builds. The DCS Documentation on AH-64D controls provides detailed control descriptions and reference diagrams.
The critical technical decisions are: PETG over PLA for durability, split halves for internal access, heat-set inserts over glue for repeatable assembly, and shift registers inside the grip to minimize wire count through the shaft.