// 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_axis=pivot_radius * 2.75;
    
    difference() {
        union () {
            // (more streamlined) body
            translate([160, w_body/2, -22])
                rotate([0,0,180])
                    scale([1, 2, 1])
                        color( colour)
                            airfoil(h=70, L=l_body);
            // boss for wheel axle
            translate([ chord * 0.25, w_body * 0.9, 0])
                rotate([90, 0, 0])
                    color( colour)
                    cyl(h=w_body * 1.25, r=20, rounding=5); 

        }
        // 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);
        // space for the airfoil leg to emerge
        translate([ chord*0.25, w_body*.75, pivot_radius * 2.25])
            rotate([lat_skew + 45, 0, 0])
                cube([chord, pivot_radius * 4, pivot_radius * 4]);
        // through hole for pivot axle
        translate([-1, w_body/2, 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, w_body/2, 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, w_body/2, w_body * 2.5])
            rotate([270-lat_skew, 0, 90])
                color( colour)
                    cuboid([2* w_body, 2*w_body, l_body *.75]);
    } 

    // 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])
            color( colour)
                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();

}

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