Théo Lepage-Richer

Fab Academy / Digital Fabrication 2015

Homage to Aeronautic Engineering; or How to Justify Making a Paper Plane

This week’s lecture was definitely one of the most insightful ones to me. As the word ‘composite’ is, for the collective imaginary, pretty much nothing but a nebulous term sporadically used in all the “How it's made?” shows across the world, I found Neil’s explanations on the material properties unlocked by the combination of various resins/unifying agents and fibers especially interesting. Yet, even if one can use composites to build cars, planes, boats and bikes alike, I found it quite difficult to come with a workable project – they might use composites to build jumbo jets, but let’s just say that I am pretty far from there. It is in that context that I decided offer my own little (quirky) homage to composites’ legacy in the field of aerodynamics and made my own little ‘paper’ plane made out of composites.

I therefore went to the darkest, wildest parts of the web to find all these bizarre websites for paper plane aficionados, to finally stumble upon this model, the Spirit Dragon, by Paper Art Land. I then built a first prototype using very sophisticated A4 pieces of paper to make sure that it had satisfying flying capacities and that it could be built with a single-sided mold. After few rigorous tests (I might have hit some visitor in the face with it), I took the plane’s measurements and design a similar piece using the same proportions on Rhino. I then helped Ferdi to bring together a homemade hot wire cutter with some old guitar string and a voltage-generator, and cut a piece of foam fitting my piece’s size. I could finally translate my Rhino mesh into commands for the Precix 11100 using RhinoCAM, and milled the appropriate mold for it in the piece of foam.

The actual ‘composites’ part went quite well (mostly because Francesca took the time the explain me how to do it). For the fiber part, I took some old tablecloth and some industrial resin to bring the whole thing together. I (very approximately) cut two pieces of cloth in the shape of the plane – I was afraid that having more layers would render the plane too heavy – as well as a third one only for the front part of it, just to add some weight. I then mixed the resin, covered the pieces of cloth with it, put a first layer of plastic sheet around my mold, added the three layers on top, put another layer of plastic sheet, threw in a layer of breathing textile, wrapped the whole thing into a plastic bag and finally inserted the whole thing under the industrial vacuum bag.

Six hours later, the plane came out surprisingly well, and I simply had to cut the excesses of cloth around the mold with a mechanical saw. Saying that the final result flies would be a bit of a bold statement though. The third layer of cloth that I added to the front part to increase its flying properties actually made things worst, as the plane simply starts flipping over and over as soon as it is thrown. I might try to add some modelling clay in the back of the plane to make it more stable (i.e. to make it fly rather than simply crash), but, in the meantime, here is a great demonstration of my plane’s aerobatic capabilities:

Aerobatics - Inside Loop from Theo L. Richer on Vimeo.

And as if this wasn't humiliating enough, here is the second attempt from a three-stories tall standpoint (in slow-motion):

Falling is the First Step to Flying from Theo L. Richer on Vimeo.

See below for all the details/for each step.

Your Name

  • Week: 12
  • Subject: Composites
  • Tools: Rhino, RhinoCAM, Precix 11100, industrial vacuum
  • Objective: Design and make a 3D mold (~ft2), and produce a fiber composite part in it
  • Files: Click here

Project 01a
As I have already extensively covered my 3D design workflow and RhinoCAM throughout the last weeks, I will directly skip to the milling (but here is the image of my piece in Rhino, nonetheless).
Project 01a
As IAAC’s reserve of foam comes in various shapes (mostly irregular excesses from bigger projects), it was essential to trim the pieces into small blocks in order to mill them. Using a guitar string and a voltage-generator, Ferdi and me quickly brought together a hot wire cutter but stretching the string perpendicularly to a table. When one connects the wire to the power source, it quickly becomes hot as heat dissipates, and it becomes easy to cleanly cut the foam. We could have indeed used a smaller string, which would have increased the wire’s temperature and consequently made the cutting process easier, but the whole process went quite well nonetheless.
Project 01a
The milling went well, even though my mold was close to being short, and the mill therefore constantly threatened to run into the piece of wood that I was using to hold the foam in place. Luckily enough, it never did (for it would have probably shot pieces of broken wood and metal across the room), but I spent the whole time anxiously looking at the process while keeping the hands close to the STOP button.
Project 01a
The mold itself came out well and I simply had to take off the border by hand and clean the borders with a knife.
Project 01a
To select the proper fiber, I looked into IAAC’s reserve of spare clothes and textiles, and found one that was both dense and fairly light, as I needed something that could offer a decent consistency with only two layers. I cut pieces with approximately the same proportion as my piece and covered them with resin.
Project 01a
I then stacked up all the layer on my mold, following the same order as the one mentioned before – plastic sheet, cloth/resin layers, another plastic sheet, some breathing textile, and finally a plastic bag – and two little pieces of foam inside the interior part of my mold to make sure that the vacuum’s cover would correctly push the textile inside the gap.
Project 01a Project 01a
I then put the whole thing under the hood of the industrial vacuum for six hours. This machine definitely does a good job, but I quickly realized that foam might not be the ideal material to use with this machine, as the extreme pressure flattened the mold’s smallest elements, i.e. the two little upper stabilizers.
Project 01aProject 01a
Despite the disgusting scalp-like texture of the resulting piece (I am not exaggerating, I have never been so disgusted by a tablecloth in my life), the level of precision that the industrial vacuum affords definitely amazed me. The composite came out strong, flexible and quite light, and I could then simply cut the excesses of cloth/composite (this enterprise was actually way harder than it sounds - the composite is so strong that cutting it made the mechanical saw overheat every two minutes, so it took me a full hour to do it... and the smell is just awful). The final piece might not be the most gracious ‘paper’ plane that one has seen, as it can do nothing but some clumsy barrel rolls before crashing, but I was still amazed by the great material qualities that composite can offer for such a piece calling for both lightness and strength.