Foiler Design

[Doug Lord]

Originally Posted by Doran Oster

Hi Doug,

Pro/E can extrude foils with complex profiles and ever-changing crosssections. It can predict the weight of the foils but I don't have the chops or software to predict how much load these designs will support or how to optimize the design. How do the big kids do it? Is there a service for hire?

-d

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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:

[wind_apparent]

Originally Posted by bistros

Generally, blogs are free. The little one I'm maintaining for the build of my son's boat hasn't cost a cent.

In the academic world it is really important to publish your work - succeed or fail. The same thing holds true for non-educational endeavors, but sadly the nonsense legal fiction concept of "intellectual property" raises it's idiotic head and causes progress to slow, companies to fail and lawyers to get rich.

As you are talking about ground breaking and experimental work, publishing can bring positive constructive criticism and contribution from people all around the world. The quality and diversity of the skills necessary to get all the details right on a project of this scale is huge. Problem solving becomes easy when there are many sets of eyes looking for causes.

Saving the people that follow you from duplicating mistakes you have made and solved allows them to concentrate on improving the state of the art, not relearning lessons already past. This is why, good or bad, publishing is important.

The world would not be where it is today without open collaborative knowledge sharing through publication. It is entirely possible to be open and accept outside input without sacrificing commercial potential.

--
Bill

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.

[laurencet]

Originally Posted by wind_apparent

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.

[chabrenas]

...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.

[Paul Scott]

How true.

Like the Langley Aerodrome.

[wind_apparent]

Originally Posted by laurencet

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.

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.

[laurencet]

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.

[ancient kayaker]

Originally Posted by laurencet

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 ...

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.

[wind_apparent]

Originally Posted by ancient kayaker

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)

[Doug Lord]

Originally Posted by wind_apparent

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?

[wind_apparent]

Originally Posted by Doug Lord

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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....

[Doug Lord]

Best of Luck!

[Paul B]

Originally Posted by wind_apparent

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....

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...

[Karl Wittnebel]

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.

[MalSmith]

Originally Posted by Karl Wittnebel

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.