// The Estes A8-3 and C6-7 motors have diameter of 17.7 mm,
// length 69.5 mm. The Estes Alpha launch pad has rod diameter 3.4 mm.
-motor_diam = 17.7 + 0.5; // add some tolerance
+motor_diam = 17.7 + 1.2; // add some tolerance
motor_len = 69.5 + 0.5;
-motor_wall = 2;
segment_overlap = 15;
+loose_fit_diam_diff = 1.1; // cylinder with outer diameter d1
+ // will fit loosely into the hole with inner diameter
+ // d1 + loose_fit_diam_diff
+tight_fit_diam_diff = 0.4; // cylinder with outer diameter d1
+ // will fit tightly into the hole with inner diameter
+ // d1 + tight_fit_diam_diff
+
thin_wall = 1.0; // depends on the print width
-thick_wall = 2.5*thin_wall;
+thick_wall = 2*thin_wall + loose_fit_diam_diff/2;
+ // motor_diam + 2*thick_wall is the outer diameter of the rocket
+motor_wall = thick_wall; // above the motor
+
+clip_height = 3.5;
+clip_width = 1.2;
+clip_clearance = 1.0;
+clip_inner_space = motor_diam/2 - 1.5;
-clip_spring_angle = 45;
-clip_spring_depth = 20;
+rod_diam = 3.4 + 1;
+rubber_beam_height = 3;
+rubber_beam_width = 1.5;
-rod_diam = 4;
+fin_thickness = 1.5;
eps = 0.01;
-infty = 1000;
+infty = 250;
+
+// rod holder
+
+module rod_holder() {
+ // rod hole holder
+ hull() {
+ translate([motor_diam/2 + thick_wall + thin_wall + rod_diam/2, 0, 0])
+ cylinder(r = rod_diam/2 + thin_wall, h = thick_wall);
+ translate([motor_diam/2 + thick_wall - thin_wall - rod_diam/2, 0, 0])
+
+ cylinder(r = rod_diam/2 + thin_wall, h = 3*thick_wall);
+ }
+}
+
+module rod_hole() {
+ // rod hole
+ translate([motor_diam/2 + thick_wall + thin_wall + eps + rod_diam/2, 0, 0])
+ cylinder(r = rod_diam/2, h = infty);
+}
//----------------- MOTOR MODULE -----------------------------
h2 = 20, // far end height
h_off = motor_len, // height offset of the far height
w = 30, // distance of the far height
- fin_w = thin_wall)
+ fin_w = fin_thickness)
translate([0, -fin_w/2, -h1])
hull() {
cube([eps, fin_w, h1]); // near end
// alternative fin layout
module fin2() {
assign(h1 = motor_len/2, // near end height
- w2 = 18, // bottom/far end width
- h_off = 50, // height offset of the far height
+ w2 = 23, // bottom/far end width
+ h_off = 60, // height offset of the far height
w = 30, // distance of the far height
- fin_w = thin_wall)
+ fin_w = fin_thickness)
translate([0, -fin_w/2, -h1])
hull() {
cube([eps, fin_w, h1]); // near end
};
};
-rod_hole_height = 15;
+rod_hole_height = 20;
rod_hole_side = 1.5*(rod_diam + thin_wall);
module motor_module_solid()
{
- // the lowest part is for joining the segments
- cylinder(r = motor_diam/2 + thin_wall, h = segment_overlap + eps);
+ // cone from loose_fit to tight fit, 1/3 of segment overlap
+ cylinder(r1 = motor_diam/2 + thin_wall,
+ r2 = motor_diam/2 + thick_wall - thin_wall - tight_fit_diam_diff/2,
+ h = segment_overlap/3 + eps);
+
+ // tight fit cylinder, 2/3 of segment overlap
+ translate([0, 0, segment_overlap/3])
+ cylinder(r = motor_diam/2 + thick_wall - thin_wall - tight_fit_diam_diff/2,
+ h = 2*segment_overlap/3 + eps);
// conical joint between the two cylinders
translate([0, 0, segment_overlap - thick_wall + thin_wall])
- cylinder(r1 = motor_diam/2 + thin_wall,
+ cylinder(r1 = motor_diam/2 + thick_wall - thin_wall - tight_fit_diam_diff/2,
r2 = motor_diam/2 + thick_wall,
h = thick_wall - thin_wall + eps);
- // protrusions to hold the main tube in place
- for (a = [60, 180, 300]) {
- rotate([0, 0, a]) {
- translate([motor_diam/2 - thin_wall, 0, 0])
- cylinder(r1 = thick_wall-thin_wall/2, r2 = thick_wall, h = segment_overlap/3 + eps);
- translate([motor_diam/2 - thin_wall, 0, segment_overlap/3])
- cylinder(r = thick_wall, h = 2*segment_overlap/3 + eps);
- };
- };
-
// the thick cylinder above it
translate([0, 0, segment_overlap])
cylinder(r = motor_diam/2 + thick_wall,
h = motor_len + motor_wall - segment_overlap);
- // clip spring
- translate([0, 0, motor_len + motor_wall])
- intersection() {
- translate([motor_diam/2+6, infty/2, 4])
- rotate([90, 0, 0])
- cylinder(r = 8, h = infty);
- cylinder(r = motor_diam/2 + thick_wall, h = infty);
- rotate([0, 0, -clip_spring_angle/2+eps])
- cube(infty);
- rotate([0, 0, clip_spring_angle/2-eps])
- scale([1, -1, 1])
- cube([infty, infty, 8]);
- };
-
// fins
for (a = [60, 180, 300]) {
rotate([0, 0, a])
fin2();
};
- // rod hole holder
- hull() {
- translate([motor_diam/2 + thick_wall - rod_diam/2 - thin_wall,
- 0, segment_overlap])
- scale([1, 1.4, 1])
- cylinder(r = rod_diam/2 + thin_wall, h = eps);
- translate([motor_diam/2 + thick_wall + rod_diam/2, 0, segment_overlap + rod_hole_side])
- scale([1, 1.1, 1])
- cylinder(r = rod_diam/2 + thin_wall, h = rod_hole_height);
- translate([motor_diam/2 + thick_wall - rod_diam/2 - thin_wall,
- 0, segment_overlap + 2*rod_hole_side + rod_hole_height])
- scale([1, 1.4, 1])
- cylinder(r = rod_diam/2 + thin_wall, h = eps);
+ // motor clip
+ for (angle = [120, -120]) rotate([0, 0, angle]) intersection() {
+ translate([clip_inner_space, -infty/2,
+ motor_len + motor_wall + clip_clearance])
+ cube([clip_width, infty, clip_height]);
+ rotate([0, 0, -60])
+ translate([-infty/2, 0, 0]) cube(infty);
+ rotate([0, 0, -120])
+ translate([-infty/2, 0, 0]) cube(infty);
};
+ translate([0, 0, motor_len + motor_wall])
+ scale([1, 1, -1])
+ rod_holder();
};
module motor_module() {
translate([0, 0, motor_len - segment_overlap - 2*thick_wall])
cylinder(r1 = motor_diam/2 + thin_wall, r2 = motor_diam/2, h = thick_wall + eps);
};
- for (a = [60, 180, 300]) rotate([0, 0, a])
+ for (a = [0, 120, 240]) rotate([0, 0, a])
translate([motor_diam/2 + 2.5, 0, -eps])
cylinder(r = 3, h = infty);
};
- // clip spring
- for (r = [-clip_spring_angle/2, clip_spring_angle/2]) {
- rotate([0, 0, r])
- translate([-thin_wall/2, 0, motor_len + motor_wall - clip_spring_depth])
- cube([infty, thin_wall, infty]);
- };
- translate([0, 0, motor_len - eps])
- intersection() {
- cylinder(r = motor_diam/2 + thin_wall,
- h = thick_wall + 2*eps);
- rotate([0, 0, -clip_spring_angle/2+eps])
- cube(infty);
- rotate([0, 0, clip_spring_angle/2-eps])
- scale([1, -1, 1])
- cube([infty, infty, 8]);
- };
-
-
- // rod hole
- translate([motor_diam/2 + thick_wall + eps + rod_diam/2, 0, 0])
- cylinder(r = rod_diam/2, h = infty);
+ rod_hole();
};
};
// -------------------- CENTRAL TUBE ---------------------
-central_tube_h = 80;
+central_tube_h = 97;
+
+central_clip_r = 12;
+central_clip_w = 4;
+central_clip_wall = 1.5;
+central_clip_clearance = 2.5;
module central_tube_solid() {
cylinder(r = motor_diam/2 + thick_wall, h = central_tube_h);
+ rod_holder();
};
module central_tube() {
translate([0, 0, -eps])
cylinder(r = motor_diam/2 + thick_wall - thin_wall,
h = infty);
+ rod_hole();
};
};
//------------------------- FRONT CONE -----------------------
cone_h = 45;
cone_resolution = 40;
+cone_solid_h = 10;
function bez_i4(t, ctls) =
(pow(1-t, 3) * ctls[0])
translate([0, 0, segment_overlap])
bezier_cone([
[ 0, motor_diam/2 + thick_wall ], // start
- [ cone_h/2, motor_diam/2 + thick_wall ], // cp 1
+ [ cone_h/4, motor_diam/2 + thick_wall ], // cp 1
[ cone_h - motor_diam/2 - thick_wall, motor_diam/2 + thick_wall ], // cp 2
[ cone_h, 0 ],
], 40);
module front_cone() {
difference() {
front_cone_body();
- translate([0, 0, segment_overlap])
- bezier_cone([
- [ 0.7*thin_wall, motor_diam/2 + thick_wall - thin_wall ], // start
- [ cone_h/2-0.7*thin_wall, motor_diam/2 + thick_wall - thin_wall], // cp 1
- [ cone_h - motor_diam/2 - thick_wall + thin_wall - 1.4*thin_wall, motor_diam/2 + thick_wall - thin_wall ], // cp 2
- [ cone_h - 1.4*thin_wall, 0 ],
- ], 40);
+ intersection() {
+ translate([0, 0, segment_overlap])
+ bezier_cone([
+ [ 0.7*thin_wall, motor_diam/2 + thick_wall - thin_wall ], // start
+ [ cone_h/4-0.7*thin_wall, motor_diam/2 + thick_wall - thin_wall], // cp 1
+ [ cone_h - motor_diam/2 - thick_wall + thin_wall - 1.4*thin_wall, motor_diam/2 + thick_wall - thin_wall ], // cp 2
+ [ cone_h - 1.4*thin_wall, 0 ],
+ ], 40);
+ cylinder(r = motor_diam/2 + thick_wall + eps,
+ h = cone_h + segment_overlap - cone_solid_h);
+ };
translate([0, 0, segment_overlap-thick_wall+1.7*thin_wall])
cylinder(r1 = motor_diam/2,
translate([0, 0, -eps])
cylinder(r = motor_diam/2, h = segment_overlap + 2*eps);
-
- // debug
- // translate([0, 0, -eps]) cube(infty);
};
};
-module thread_holder() {
- rotate([0, 90, 0]) {
- translate([0, 0, -1.5]) difference() {
- cylinder(r = 10, h = 3);
- translate([0, 0, -eps])
- cylinder(r = 8, h = 3 + 2*eps);
- };
- };
-}
+debug = 0;
-// thread_holder();
+if (debug == 1) {
+// debug
+difference($fn = 16) {
+ front_cone();
+ central_tube();
+ motor_module();
+ translate([0, 0, -infty/2]) cube(infty);
+};
+
+} else {
+
+// production
$fn = 128;
translate([motor_diam + thick_wall, 0, 0])
translate([motor_diam + thick_wall, 0, 0])
front_cone();
+}
https://www.fi.muni.cz/~kas/git / things.git / blobdiff