rc-landing-gear.scad

   1 eps = 0.01;
   2 infty = 300;
   3
   4 /*
   5 sirka trupu u nabezne hrany 80mm
   6 max sirka trupu 90 mm
   7 sirka trupu 50mm pred nabeznou hranou 84mm
   8 rozchod klidne 150mm
   9 vyska osy se spodni hranou trupu az cca 30mm pod trupem
  10 kolma cast asi vpredu
  11 */
  12
  13 base_h = 95;
  14 base_w = 83;
  15 base_top = 5; // above the xz plane
  16 base_wall = 0.6;
  17 base_l = 45;
  18
  19
  20 axle_cube = 7;
  21 axle_hole = 3.5;
  22
  23 strut_wall = 1.2;
  24 base_top_l = axle_cube;
  25
  26 bottom_strut_l = base_l-5;
  27
  28 wheel_h = 60;
  29 wheel_base = 110;
  30
  31 module base() {
  32         difference() {
  33                 $fn = 128;
  34                 scale([base_w/base_h, 1, 1])
  35                         cylinder(r = base_h/2, h = base_l);
  36                 // cut the top half
  37                 translate([-infty/2, base_top, -infty/2]) cube(infty);
  38
  39                 // cut the rear angle
  40                 translate([0, base_top, base_top_l])
  41                 rotate([-atan((base_l - base_top_l)/(base_h/2 + base_top)), 0, 0])
  42                 translate([-infty/2, -infty/2, 0]) cube(infty);
  43         }
  44 }
  45
  46 module wheel_cube()
  47 {
  48         translate([wheel_base/2-axle_cube,
  49                 -wheel_h-axle_cube/2, 0])
  50                 cube(axle_cube);
  51 }
  52
  53 module top_strut() {
  54         hull() {
  55                 // top
  56                 translate([base_w/2 - strut_wall/2, 0, 0])
  57                         cylinder(r = strut_wall/2, h = base_top_l, $fn = 16);
  58                 // bottom
  59                 translate([wheel_base/2-strut_wall/2,
  60                         -wheel_h+axle_cube/2, 0])
  61                         cylinder(r = strut_wall/2, h = axle_cube, $fn = 16);
  62         }
  63 }
  64
  65 module bottom_strut() {
  66         hull() {
  67                 // center
  68                 rotate([0, 0, 30])
  69                 translate([0, -base_w/2 + base_wall/2, 0])
  70                         cylinder(r = strut_wall/2, h = bottom_strut_l, $fn = 16);
  71                 // side
  72                 // translate([wheel_base/2-axle_cube+strut_wall/2,
  73                 //      -wheel_h+axle_cube/2-strut_wall/2 , 0])
  74                 translate([wheel_base/2-strut_wall/2,
  75                         -wheel_h-axle_cube/2+strut_wall/2 , 0])
  76                         cylinder(r = strut_wall/2, h = axle_cube, $fn = 16);
  77         }
  78 }
  79
  80 module horiz_strut() {
  81         translate([-wheel_base/2, -wheel_h-axle_cube/2, 0])
  82                 cube([wheel_base, strut_wall, axle_cube]);
  83 }
  84
  85 module body() {
  86         base();
  87
  88         for (x = [-1, 1]) scale([x, 1, 1]) {
  89                 wheel_cube();
  90                 top_strut();
  91                 bottom_strut();
  92         }
  93
  94         horiz_strut();
  95 }
  96
  97 difference() {
  98         body();
  99
 100         // hole in the base, no matter what gets in
 101         translate([0, 0, -eps])
 102                 scale([(base_w - base_wall)/(base_h - base_wall), 1, 1])
 103                 cylinder(r = base_h/2 - base_wall, h = base_l + 2*eps, $fn=128);
 104
 105         // hole for the wheel axle
 106         translate([-infty/2, -wheel_h, axle_cube/2])
 107                 rotate([0, 90, 0])
 108                 rotate([0, 0, 90])
 109                 cylinder(r = axle_hole/2, h = infty);
 110 }
 111