sails

Prototyping our first wingsail

Submitted by mac
on Sat, 03/26/2011 - 15:28

This week we have taken our freshly built hot wire foam cutter for a ride and we have produced our first wingsail prototype. The sail was not intended to be actually used on the boat, but more as an exercise to check out if the building technique we had in mind was a viable option or not.

The technology we chose for our prototype is very simple: the mast (aluminum) and two "skeleton rods" going through it (carbon fibre) are reused for each wingsail, while different wings (foam) can be slid onto the mast (the skeleton rods can in turn be slid through the wing to keep it in place). The wing is done by gluing together the two halves of it. Each half is done by attaching the corresponding airfoil at each end of a foam block and sliding the wire along these guides. See the complete gallery/how-to for a step-by-step explanation.

The Magellan wire cutter

Submitted by mac
on Tue, 03/22/2011 - 15:45

For prototyping our wingsails we decided to use polystyrene: it's cheap, easy and quick to work with. Moreover, there is a concrete chance that even our final wingsail will have a foam core (although not polystyrene).

Given that foam will be with us for quite a bit of our adventure, and since the Magellan Machine headquarters are located in El Cheapo, we decided to build our own hot wire foam cutter.

On the internet there are several how-to's for building them (apparently El Cheapo is the silicon valley of RC planes enthusiasts), but all of the designs I saw had a couple of characteristics I did not want to deal with.

A first round of considerations on wingsail design

Submitted by mac
on Fri, 03/11/2011 - 00:21

One of the main outcomes of the research on wingsails performed so far has been a new "mantra" that I now repeat myself every time I start working on the project:

« The Magellan Machine is all about reliability, not performance. »

It might sound silly, but aerodynamics is all about performance optimisation and it is easy (at least for me) to be carried away by the idea of a custom-built, 50-knots-capable, hydrofoils-suspended, twin-winged, all-composite, custom-built trimaran. Yet, all we need is "just" a sturdy and reliable boat able to sail on its own for months: our goal - after all - is to build the first robot to circumnavigate the planet, not the fastest.

Early ideas on our first wingsail

Submitted by mac
on Sat, 03/05/2011 - 13:51

As the new hull proceeds under the skilled hands of Erl, it's time for me to begin moving on the sail for our second milestone. Here's a little breakdown of my thought so far. Comments and feedbacks (even negative ones!) are more than welcome, of course.

A wingsail instead of a traditional sail

There are many reasons behind our choices. Some of them are admittedly speculative: