Foiler Design

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Doran, I did the basic design for my foils including planform,selecting the foil loading and section but the engineering was done thru John Ilett and the guys who built the 40' Spitfire. They were engineered for the loads they anticipated when jumping.
The main foil is 3.5 sq.ft including 50% of the 45 degree angle dihedral tips and the rudder foil is 50% of the mainfoil area. I can write Mark Pivac in Australia if you'd like and see if he'd be interested and then put you in contact with him. Don't forget Tom and do you know Ray Velinga?
Pivac and team designed this:

 

I also pay nothing for my construction blog, but it has been a big help to my cause. Through my blog I was able to find a design partner, get materials sponsorship, and a part time job at a composites shop. It also gives people a way to see how things are going. When I start dragging my feet (all to often), I tend to get e-mails asking whats up? Always gets me out in the shop soon after. I see it as a way for my project to contribute to the future of foiling, because it shows how I solved a given problem and if it worked. Seeing as I don't exactly live in a sailing hotbed, and there isn't a foiler within 1000miles, I wouldn't have been able to get anywhere without seeing other boat building blogs, so its also a way for me to give back to the foiling community that has helped me in a big way. Should give it a go, I would tune in to it.

 

Hi Sam
Looks like alot of hardwork, getting plug just right can take hours. Just noticed a link about nida PP core. I have only used competitors products and have had a whole range of problems bonding to the PP core... Nothing seemed to stick apart from more PP/Glass. I'd carry out peel ply tests before you lay up your whole mould.
Ps keep up the goodwork.

 

...publishing also helps if you're ever likely to commercialise something derived from what you're doing, even in a very small way. Stops anyone patenting it later and chasing you for licence fees for something you did before they even thought of it.

 

How true.

Like the Langley Aerodrome.

 

I have done some bond testing, and its worked well so far. The Nidacore has a scrim face sheet that epoxy sticks to very well, the process is: Lay up inner skin, bag, cure, cover skin with thin layer thickened epoxy (microballoons,epoxy) apply Nidacore, bag, cure, lay up outer skin, bag cure, bog, fair, finish.

 

Sounds like you have it all in hand. I'm not sure i'd add the micoballons to the epoxy, great for making a light weight filler but not so great for gluing.
Are you laying up on your plug or making a female mould?
I came across the following video on youtube that shows an interesting way of laying up..
http://www.youtube.com/watch?v=mROBlWIu8q4
Personally i'd stick with the method your using, but thought you'd still find it interesting.

 

Depends on the strength of the material being glued - I'm not familiar with Nida Core. As always, test it before you do it ...

Nida Core is a polypropylene copolymer; I've not had success using epoxy on polymer materials in wet situations. The manufacturers provide NidaBond which might be a better adhesive for this material.

 

there is a scrim face sheet on the nidacore so that youy can laminate epoxy based substances to it. the manufacturer suggests the use of micro balloons to give the epoxy some body so that it doesn't all soak into the scrim sheet, this is the process they have used to make nidacore/carbon funny car bodies. (Note, I hope to soon have access to 3lb 1/4'' nomex overstock, plain and over expanded, so might use that instead, one of the reasons I've been dragging my feet a bit) Thre layup is just onto the male plugs, if the project works well I'll start making some proper female tools. (and a new lower volume, lower freeboard hull design)

 

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Any way to roughly estimate when you'll have the first boat ready to test?

 

I hope to launch by early summer, but that is best case. based on my current work load and family obligations it may take longer, it may take forever....

 

Best of Luck!

 

Since you so cordially answered the question it would be interesting for you to ask the questioner to reciprocate and explain his schedule to you...

 

I am designing a new lifting foil and I need to calculate the material stress, as I am pushing the limits pretty hard. I figured out how to estimate moment of inertia, but I don't know what distance to use from the neutral axis to the foil surface, mostly because I don't know how to find the neutral axis for the foil section I am using. Does anyone know how to compute this axis for an airfoil? Thanks in advance.

 

Karl,

You could probably approximate the section with composite shape made up of rectangular sections. The more sections, the more accurate it would be. If it was me, I would probably just eyeball it. The loading uncertainties (wave loads etc) probably don't justify using a figure with a high degree of accuracy.