Still there, still playing...

Hi there,

THAT was a long time ago ... I started playing with CFD and must admit it's quite some work, but fun ! After fiddling with 3D, I am now playing with XFOIL, to compare some foil shapes.

I put up a little excel sheet to transform the xfoil variables into somthing standard. I also read on the net that the Ncrit variable should be put to around 3 to have a water behaviour of the turbulence. If you have any other advice, I'm interested of coarse.

Meanwhile, I'm nearly done installing a little room where I hope I'll be playing around with epoxy soon. We saw a very usefull Youtube vid http://www.youtube.com/watch?v=mROBlWIu8q4 of the beaver hull bluiding and it opened my eyes a bit. I'll have to build a team too and we'll probably just copy all the rest... One thing I didn't understand is why they put a layer of aramid under the nomex ; you know ?

Stay tuned, post a comment, happy christmas.

Simulating ...

Hi there,

I'm working at simulations of the structure to fully understand the stresses it undergoes and be able to build it as light as possible. This is going to take some more time 'cause it isn't easy to simulate laminates and apply realistic pressure loads.

I'm also planing to do some CFD on the foils measured in this paper (don't miss it if you're on the same path as me ...) :

http://www.moth-sailing.org/download/CSYSPaperFeb09.pdf

I don't really know how to build the foils yet and that is an important point, so if you've got ideas or good references to share, please do !

Voilà, see ya.

Hull version 1

I had a look at the existing boats and asked myself why the hull shape and invented some answers. Maybe their not wrong ! But mainly the hull shape I came up with is very simple (I do imagine myself trying to build it). It's not as if it was a very important part of the boat. I'll do the foils last, when I'm finished reading all the stuff I found on the net and some books...

Stay tuned; give me your impressions, definitly if you have a clue.

Stations : every 1 foot

Waterlines : every 4 inches

Buttocks : every 2 inches
Draft is 0.16m at 126kg displacement (yes; I'm heavy)

Here we go!

Build an international moth instead of sparing for years to buy one, well that sound's a good idea. I live next to the Geneva lake (switzerland) where wind is quite a valuable thing and should be used when there is some. But there are already some flying moths around and they seam to be multiplying; they can't all be wrong.
I found quite some info on the web which is great as I'm starting from scrap. I'll put what I can online, as it might be usefull for the next amature builders. Maybe wait until I confirm the boat floats before coping...

Step 1: draw a hull out of a mix of the "Geko" and the "Hungry Beaver" both found on the internet. I downloaded the freeware "Delftship" to end up with the lineplans.
Step 2: do some simulations and calculations on where to put the carbone (that's my job so I'll manage).
Step 3: find out how to effectively stick the whole thing together. Quite ambisiously I would like to take some ideas form the "mach2".
Step 4: rent a garage of celar and get itchy.
Step 5: cry and throw it all away... (never)

I'll put my version 1 lineplan online as soon as.

Make comments give advice, I need you !