Monday, January 18, 2010

new foil

I re-designed the foil with a bigger bulb, so that the socket could be 25mm deep. The bulb looks a bit fat, but in theory it should work. I wish I could use CFD to sort this out propperly, but bloody ANSYS are too on top of their licensing.

anyway that can get cut out tomorrow, if anyone has any comments about the shape please let me know before then!

deck goes on tonight hopefully. making pretty good ground, a good 1/3rd of the list is ticked off.

Wednesday, January 13, 2010


well, practically. i stuck the wingbars on with string.

stood back and admired my work. (you'll notice that i stuck them on once before, made holes in the hull, then decided they were too far forward and moved them back. not like me to be that conservative, but i realised that i got my numbers wrong, upon measuring a Mach 2, and i probably should have put the centreboard case about 85mm further forward. im happy with how its sitting now. mast step is 985 from the bow, front of centreboard is 1585.) anyway, standing there planning how i was going to paint it, i realised there were still a few jobs to do. made a list.
The list nearly fitted on the foil alignment template, so thats a good sign. i reckon if i tick a few of these jobs off each day i should be done in like 3 or 4 weeks. start work in a week.

Thursday, January 7, 2010


Foils and deck done. the laminates came up really nice. the araldite 3600 resin that Ive been using becomes so high modulus when you bake it (80 - 100 deg) that you'd almost say its prepreg. Foil came out at 1.8 kg and the deck at about the same, with a further 250 grams for the bulkheads. so the vacuum did the trick. The only problem is that the socket in the foil looks a bit too shallow, (by like 10mm, massively too shallow!) so if thats the case i might re-do just the horizontal with a much bigger bulb, and cut the tab on the strut a bit longer. Will try and make what ive got work first. I put 2 tubes down the strut this time, in case i want to do a swept horizontal with a split flap at some point. I really should have put some high build primer down in the mould first, as Andrew at CG composites suggested, because im going to have to go over everything with some black bog to patch up all the tiny holes in the weave that the vacuum leaves behind.

Anyway lots to do, tomorrow the bulkheads go in and I need to make some little angles so that the deck can stick to something. I really have no idea how people would normally stick a deck on a moth. If anyone has a suggestion let me know! also the gantry mould is ready for the CNC machine to cut out. opted for a box gantry over tubes because then I could avoid buying tube, and use the materials I have already that are leftover from the deck. quite like the design of it though so it should be fine. function over form!

ps. if anyone would like some free moth bits, i have some now redundant lowriding foils, need some care admittedly, some moulds for a NACA 66014 strut and an old repaired carbon strut that is about 1.3m long. and my old gantry.