Jun 7, 2013

Polyhedral, 'Quintus M' & Artemis Foiling 45

Update: Good timing for this post I made earlier today, as Artemis has announced they will continue to campaign, also they published additional 45 foiling pics from this week like this above. More info on Artemis program here --
When Artemis decided they needed to fly, they did it in just one month, and with a rather ""simple"" commando like solution on a set of foils for the 45.
First set of Oracle L foils for the 45 and their 72, are even simpler to built but we saw some awful unstable rides with them, so what it took my attention from Artemis 45 Foiling project was how stable they were flying even in day one.

It seemed so 'easy' and I said to myself :" I can build a set like that".. and also others, as the F20c flying project guys did. A stepped or Polyhedral foil/wing, a known concept in aerodynamics (from WII Corsair, to RC Gliders and more).

Basically a Dihedral angle gives you more roll stability, negative anhedral angle gives you manoeuvrability as used by Strike fighters.
Diehedral angles graphic left  by aerosente.com/tom-martins-flightline/page/4/

So simple & known, but also I guessed someone must be using this conf right now beyond being common knowledge in a current advanced design Glider, as I remember all being high aspect ratio and flexible wings, but didn't recall a 'stepped' one.

Yesterday while drawing a cad of the foil I found what I was looking for: 'The Quintus M' (Image above), an Open Class World Champ 2012 after being launched in 2011, designed & built by Schempp-Hirht http://www.schempp-hirth.com/index.php?id=221&L=1  .

I also was trying to get a solution for two part assembly foil, for better handling/functionality and after seeing the video below, of course... everything is already invented, check how they assemble the tip of the wing at  0:40.

So how come in one month you can have a super steady foiling from scratch? While other projects took years, and lot of struggle to even get airborne?

Well, I hope we can have an answer soon with a Q&A I'm working for. As I always talk about the big picture, and for real technical details you know I rely only on the best

in the business.. Melvin, Fischer, Drummond, Redondo and many others , just check the Interview  Design labels to find some juicy technical stuff.

In the meantime I will try to refine my foil for Ralph Moolenaar from Marine CFD to make some tests. I like to race but I also want to fly, and being a builder it is a nice challenge, the F20c guys are having some serious fun. 

Below Artemis AC45 Foiling and Quintus M Luanch video.

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