Summary

I wanted to make a completely 3D printed helicopter that flies, without having to fiddle with wire for the rotary joints or plastic/tissue for the wings' surface.

Inspired by seeing science Olympiad helicopters on YouTube.

You do have to use a rubber band, and (optionally) some lubricant for the rotary joint.

https://youtu.be/imDvlCpEniI

Print Settings

Printer:

Micromake delta printer

                                            <p class="detail-setting rafts"><strong>Rafts: </strong>                     <div><p>No</p></div></p>                                                                                <p class="detail-setting supports"><strong>Supports: </strong>                     <div><p>No</p></div></p>                                                                                <p class="detail-setting resolution"><strong>Resolution: </strong>                     <div><p>0.1mm layer height</p></div></p>                                                                                <p class="detail-setting infill"><strong>Infill: </strong>                     <div><p>20%</p></div></p>                                                        <br>                        <p class="detail-setting notes"><strong>Notes: </strong>                    </p><div><p>Your printer must be able to print without rafts in order to get the wings, which are 0.2mm thick.</p><p>Using Cura 15.04:</p><blockquote><p>Nozzle diameter: 0.4mm<br>Shell thickness: 0.39mm<br>1.75mm PLA @ 200C</p></blockquote><p>Quantity:</p><blockquote><p>1 x body<br>1 x hook<br>1 x wing connector<br>1 x rotary joint<br>4 x wing</p></blockquote></div>

Post-Printing

Trim wing struts

            <div><p>The four wing insert into the triangular holes on the body and wing connector. You may need to shave down the triangular struts to fit them in.</p></div>                <p class="detail-title"><strong>Insert wings</strong></p>            <div><p>To visualise which way to insert the triangular (equilateral) struts, think about when the helicopter rotates - the wings must be pushing air downwards.</p><p>I prefer that the rotary joint is 'down', and the body is 'up'. This way, I can wind up the rubber band, pinch the helicopter by the rotary joint, and then release it into the air easily.</p></div>                <p class="detail-title"><strong>Assemble helicopter</strong></p>            <div><p>Slide the hook into the wing connector and then the rotary joint. </p><p>You may need to trim the rotary joint and/or add a drop of oil to the joint so that it rotates smoothly.</p></div>                <p class="detail-title"><strong>Wind it up</strong></p>            <div><p>I use sports tan rubber, which is super stretchy rubber made for model aircraft. Given a good twist (100+ turns) , it can keep the helicopter in flight for a minute(s).</p><p>Use one hand to hold the helicopter by its body. Use a finger from the other hand to turn the wings and thereby wind up the rubber band. </p></div>                <p class="detail-title"><strong>Lift off</strong></p>            <div><p>Make sure that whichever way you are releasing the helicopter, the rotation of all four wings pushes air <strong>down</strong>. If not, the helicopter will crash when you release it. You will then need to either<br>(a) wind the rubber band in the opposite direction<br>(b) rotate the helicopter 180 degrees before releasing<br>(c) re-insert the wings in a new orientation (I find that having them in an inverted-V orientation makes the helicopter most stable.</p></div>

How I Designed This

using Onshape

all-printed flying toy heli