// lowerknuckle.scad

// (c) Simon Brooke 2025; CC-BY-SA

include <BOSL2/std.scad>
include <NACAAirfoils/files/Naca4.scad>
include <library/skew.scad>
include <wheel.scad>

$fn=64;


module lower_bar_end_knuckle_old(chord=100, pivot_radius=12, rise=8,lat_skew=30) {
    l_body=chord * 1.5;
    w_body=pivot_radius * 2.5;
    h_axis=pivot_radius * 2.75;
    
    difference() {
        union () {
            translate([l_body/2, w_body/2, h_axis])
                rotate([0, 90, 0])
                    cyl(h=l_body, r=w_body/2, rounding=5);
            
            // 'except=TOP' in phrase introduces the spurious hulls
            translate([l_body/2, w_body/2, h_axis*.75])
                cuboid([l_body, w_body, h_axis * .75], rounding=5);
            // bulge for wheel axle; the fork insertion end of
            // a lefty axle is 25mm diameter
            translate([chord * 0.25, w_body/2, 0])
               rotate([90, 0, 0])
                    cyl(h=w_body, r=25, rounding=5);
            // fairing for this
            translate([chord * 0.25, w_body/2, -3])
                rotate([80, 0, 90])
                    prismoid([w_body, 45], [w_body, 10], rounding=5, h=l_body * .75);

        }
        translate([ chord*0.25, -1, pivot_radius * 3])
            cube([chord, pivot_radius * 4, pivot_radius * 4]);
        // scoop for leg-bottom knuckle to rotate within
        translate([ chord*0.25, w_body/2, h_axis])
            rotate([0, 90, 0])
                cylinder(h=chord, r=pivot_radius * 1.3);
        // through hole for pivot axle
        translate([-1, w_body/2, h_axis])
            rotate([0, 90, 0])
                cylinder(h=l_body+2, r=pivot_radius/3); 
        // through hole for wheel axle  
        translate([ chord * 0.25, w_body +1, 0])
            rotate([90, 0, 0])
                cylinder(h=w_body-5, r=12.5); 
    } 
    
    // airfoil stub to be epoxied into the lower bar of 
    // the linkage
    translate([chord*1.25, 1, 30])
        rotate([90 + rise, 360 - lat_skew, 0])
            airfoil(h=chord, L=2 - chord);
    
//    // brake disk
//    translate([(0 - (chord*1.25)), (l_hlb * cos(rise)), 1])
//        rotate([90, 0, 0])
//            color("silver")
//                cylinder( h=1.5, r=75);
//    // wheel (obviously)            
//    translate([(0 - (chord*1.25)), (l_hlb * cos(rise)), -10])
//        wheel();

}

module lower_bar_end_knuckle(chord=100, pivot_radius=12, rise=8,lat_skew=30, colour="blue") {
    l_body=chord * 2;
    w_body=pivot_radius * 2.5;
    h_body=70;
    h_axis=pivot_radius * 2.75;
    v_axis = 0;
    
    difference() {
        union () {
            // (more streamlined) body
            translate([158, 0, -22])
                rotate([0,0,180])
                    scale([1, 2, 1])
                        color( colour)
                            airfoil(h=h_body, L=l_body);
            // boss for wheel axle
            translate([ chord * 0.25, w_body * 0.4, 0])
                rotate([90, 0, 0])
                    color( colour)
                    cyl(h=w_body * 1.25, r=20, rounding=5); 
            // airfoil stub to be epoxied into the lower bar of 
            // the linkage
            translate([chord*1.25, 0 - pivot_radius, 30])
                rotate([90 + rise, 360 - lat_skew, 0])
                    color( colour)
                        airfoil(h=chord, L=2 - chord);
        }
        // scoop for leg-bottom knuckle to rotate within
        translate([ chord*0.25, v_axis, h_axis])
            rotate([0, 90, 0])
                cylinder(h=chord, r=pivot_radius * 1.3);
        // space for the airfoil leg to emerge. TODO: This shape is
        // NOT right, and a square section is not what's called for!
        translate([chord*0.75, v_axis, h_axis])
            rotate([lat_skew, 0, 0])
            prismoid([chord, pivot_radius*2.6], [chord, chord], h=chord);
        // through hole for pivot axle
        translate([-1, v_axis, h_axis])
            rotate([0, 90, 0])
                cylinder(h=250, r=pivot_radius/3); 
        // through hole for wheel axle  
        translate([ chord * 0.25, w_body *1.5, 0])
            rotate([90, 0, 0])
                cylinder(h=w_body * 1.4, r=12.5); 
        // slice off the front bottom
        translate([chord * 1.25, 0, 0 - w_body])
            rotate([270-lat_skew, 0, 90])
                color( colour)
                    cuboid([2* w_body, 2*w_body, l_body *.75]);
        // slice off the upper back
        translate([0, 0, w_body * 2.5])
            rotate([270-lat_skew, 0, 90])
                color( colour)
                    cuboid([2* w_body, 2*w_body, l_body *.75]);
        // radius the top
        translate([158 - l_body/2,0,h_body-(w_body/2) - 22])
            color( colour)
            scale([1, 1.6, 1])
                difference() {
                    translate([0, 0, w_body/4 + 1])
                    cuboid([l_body, w_body, w_body/2]);
                    rotate([0, 90, 0])
                    cylinder( h=l_body + 2, r=w_body/2, center=true);
                }
    // radius the lower surface
         color( "blue")
         difference() {
            translate([60, 0, 10])
                cuboid([l_body + 4, w_body*1.6, 80]);
            translate([127 - l_body/2, w_body * 0.8 +1, 179])
                rotate([90, 0, 0])
                    cylinder( h=w_body *1.6 + 2, r=l_body);
         }
    } 
}

//translate([-125, 0, 0])
//    lower_bar_end_knuckle();
//translate([-125, 0, 125])
//    color("blue")
//    lower_bar_end_knuckle();
//translate([-100, 74, 0])
//    wheel();