Build a drone: landing gear

Each leg is made once, along the x axis, in parts/landing-gear.ts, and around repeats it as many times as sizes.legs says.

1. A leg is a carbon tube bent twice on its way down: a polyline whose corners are filleted, with a circle swept along it, and a flange and a boss that pass through the leg opening. around repeats it once per leg.

   • Make parts/landing-gear.ts:

   export async function leg() {
       const path = await bitbybit.occt.shapes.wire.createPolylineWire({ points: [[52, 0, 0], [58, -18, 0], [78, -34, 0], [78, -48, 0]] });
       const bent = await bitbybit.occt.fillets.fillet3DWire({ shape: path, radiusList: [12, 6], indexes: [0, 1], direction: [0, 0, 1] });
       const tube = await bitbybit.occt.operations.pipeWireCylindrical({ shape: bent, radius: 4, makeSolid: true, trihedronEnum: Bit.Inputs.OCCT.geomFillTrihedronEnum.isConstantNormal, forceApproxC1: false });
       const flange = await bitbybit.occt.shapes.solid.createBox({ width: 20, length: 12, height: 3, center: [52, -1.5, 0] });
       const boss = await bitbybit.occt.shapes.solid.createCylinder({ radius: 5.5, height: 6.4, center: [52, -3, 0], direction: [0, 1, 0] });
       return bitbybit.occt.booleans.union({ shapes: [tube, flange, boss], keepEdges: false });
   }

   • Import at the top of main.ts:

   import { leg } from "./parts/landing-gear";

   • Add at the end of main.ts:

   await draw(looks.carbon, await around(await leg(), sizes.legs));

   • Run it with Run The Code.
   

2. At the end of each leg a damper: an aluminium body revolved from a profile of twelve points, and a steel spring, a pipe swept along a helix.

   • Add at the end of parts/landing-gear.ts:

   export async function damper() {
       const profile: Bit.Inputs.Base.Point3[] = [
           [0, 0, 0], [6.5, 0, 0], [6.5, -4, 0], [5.5, -4.5, 0], [5.5, -14, 0], [6.2, -14, 0],
           [6.2, -16.5, 0], [4, -16.5, 0], [4, -18, 0], [2.2, -18, 0], [2.2, -30, 0], [0, -30, 0],
       ];
       const outline = await bitbybit.occt.shapes.wire.createPolygonWire({ points: profile });
       const face = await bitbybit.occt.shapes.face.createFaceFromWire({ shape: outline, planar: true });
       const body = await bitbybit.occt.operations.revolve({ shape: face, angle: 360, direction: [0, 1, 0], copy: false });
       return bitbybit.occt.transforms.translate({ shape: body, translation: [78, -46, 0] });
   }
   
   export async function spring() {
       const helix = await bitbybit.occt.shapes.wire.createHelixWire({ radius: 4.2, pitch: 2.8, height: 12.5, center: [78, -75.8, 0], direction: [0, 1, 0], clockwise: false, tolerance: 0.0001 });
       return bitbybit.occt.operations.pipeWireCylindrical({ shape: helix, radius: 0.9, makeSolid: true, trihedronEnum: Bit.Inputs.OCCT.geomFillTrihedronEnum.isCorrectedFrenet, forceApproxC1: false });
   }

   • In main.ts, change import { leg } from "./parts/landing-gear"; to import { damper, leg, spring } from "./parts/landing-gear";.
   • Add at the end of main.ts:

   await draw(looks.aluminium, await around(await damper(), sizes.legs));
   await draw(looks.steel, await around(await spring(), sizes.legs));

   • Run it with Run The Code.
   

3. A rubber foot is lofted through five circles, and two M3 bolts fix each leg's flange to the plate.

   • Import at the top of parts/landing-gear.ts:

   import { m3Bolt } from "./bolt";

   • Add at the end of parts/landing-gear.ts:

   export async function foot() {
       const rings: Bit.Inputs.OCCT.TopoDSShapePointer[] = [];
       for (const [y, radius] of [[0, 3.2], [-2, 7], [-5, 9.5], [-8, 9], [-10, 7]]) {
           rings.push(await bitbybit.occt.shapes.wire.createCircleWire({ radius, center: [78, -76 + y, 0], direction: [0, 1, 0] }));
       }
       return bitbybit.occt.operations.loft({ shapes: rings, makeSolid: true });
   }
   
   export async function legBolts() {
       const bolt = await m3Bolt(8);
       const inner = await bitbybit.occt.transforms.translate({ shape: bolt, translation: [44.5, -3, 0] });
       const outer = await bitbybit.occt.transforms.translate({ shape: bolt, translation: [59.5, -3, 0] });
       return bitbybit.occt.shapes.compound.makeCompound({ shapes: [inner, outer] });
   }

   • In main.ts, change import { damper, leg, spring } from "./parts/landing-gear"; to import { damper, foot, leg, legBolts, spring } from "./parts/landing-gear";.
   • Add at the end of main.ts:

   await draw(looks.rubber, await around(await foot(), sizes.legs));
   await draw(looks.steel, await around(await legBolts(), sizes.legs));

   • Run it with Run The Code.
   

Next: payload and sizes.