Hey beerfan!
This is what I mean: http://www2.swaylocks.com/node/1028162
The trailing fin is forward swept, while the leading fin is trapezoidal:
Forward swept wings makes an airplane instable. Computer control (PID-controller) is needed to fly the aircraft.
Not sure if you will get the desired effect, but it’s worth the try! Don’t forget to post a review!
@ lawless: therfore I developed the finFoil application. It uses the NACA 4-digit 00 profile.
This is an interesting build method too! It is a fast way of foiling the fins. I hope the ride great, don’t forget to post a surf review!
Hi lawless! Yep ,there was no way that I would be able to foil foam or wood fins by hand properly. I thought that this way at least the finished product might retain some of the resemblence to a working foil. The problem with this method is that you are limited to straight fins.
Thank you for the glassing tip, in retrospect I should have hit up the fin building threads before glassing these. But it will be usefull for next time.
....show us YOUR fins , please , 'lawless' , and 'hans' !
cheers !
ben
Hans
Yep, the fin positioning will be the ultimate deciding factor me thinks. I would guess the forward swept keels would need to be pushed quite far back.
Thanks for checking this out!
i dont understand why it would limit u…i better have a go…lol
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i dont understand why it would limit u....i better have a go...lol
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Hey fongross
That line is in relation to hotwiring the foil.
There is no way that I can think of that one can hotwire a dolphin type fin (Where the leading and trailing edges are curved).
So now it was time to glass the leading edge. I used some left over CF tape.
I sprayed the CF tape with some spray adhesive. This was to try and reduce the fraying of the tape when cutting it into strips.
Once sprayed, i let the adhesive dry for a few mins, then cut into strips about 2cm wide:
Here is the entire set with CF tape on the leading edge:
I let the fins sit for a few days without applying epoxy to CF. I wanted to insure that the all solvent was gone fromthe spray-on adhesive befre lamination.
Lamination was pretty simple, I just used a small paint brush to apply RR KK to the glued on CF tape:
I applied generous amounts of epoxy to make sure there were no dry spots.
This particular tape has a very textured surface when laminated by hand, so to avoid this and avoid the extra hoatcoat that would have otherwise been required i wrapped each fin in cling film (saran wrap? for the US audience):
Now awaiting full cure.
Brilliant. Keep it coming.
hi retro
looks good , but any reason why you did this stage now ? [ I thought you might have done this stage AFTER cutting the fins to the finished size first , is all ...]
cheers !
ben
i'm thinking that if i use several templetes of decreasing size and place them in the fin (foam) as one would balkheads in a boat at the correct corresponding size to core length @ that section of fin ( maybe use balsa) . i will be able than hotwire in a good foil in a dolphin fin! only the templete will become part the fin build.
maybe....or it be shit....either way i'm keen try ....be a bit fun for minimal $ outlay
and its all your fault....you got me thinking about it with this thread..ha
[quote="$1"]
hi retro
looks good , but any reason why you did this stage now ? [ I thought you might have done this stage AFTER cutting the fins to the finished size first , is all ...]
cheers !
ben
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Hey Chip!
I attached the CF now so that when i go to cut the fins, I will get a clean cut of CF and the fin, there will be no extra work. If i were to attach the CF after cutting the fin, I'd have to tidy up the ends by sanding them. That would be messy and would probably end up looking shit.
What I am still trying to figure out is what to do with the exposed foam at the fin tips.
Would anyone have any ideas as to how to seal the the tips after the fins have been cut to size?
Hey fongross
Yeah, i get what youre saying. Theoretically the more templates you have the better approximation of the curves you'll get.
Well, when you are ready post up what you can.
After a hiatus of a few months, finally got around to finishing the dastardly fins…
So I’ve cut them down significantly, calculated the rough surface area to be 75 cm^2.
Test fitting on an EPS blank:
Got myself an IKEA lockable cabinet, also works as a handy, small work area. Here Im prepearing to seal the tops of the fins:
I used some home made glass roving. I used masking tape to keep the roving from sliding down:
After the resin cured, I shaped the roving into as smooth a shape as I could.
Here the fins being hotcoated after sanding:
Sorry, no pics of sanded hotcoat, was not too bad, only minor craters here and there.
The fins looked horrible though, when sanding the hotcoat I sanded into some carbon, creating a grey mess.
So I just sprayed the fins with white auto paint. (I masked of the carbon and the yellow tips):
After white, a few coats of clear and voila…finished:
Veeerrrryyy nice, I like
The fins have a home, just havent mooved in yet…
I’m going to put them on this 5’11 x ~20"
Its about 3" thick on both sides of the deck concave and I dunno…2 1/2" thick at the lowest point.
The tail is 14" wide and has 3 “barrles” running through it. The barrels are straight (i.e. do not follow the rocker)
I plan to run the fins with no toe or cant. My dilemma is: what combo to use for the fins?
The original idea was this set up.
Option #2
Option #3
Option #4
What are everyones thoughts on fin placement/combo?
the fins look great. the last pictures remind me of a airplane tail. like a stealth bomber or something. i’m looking forward to a ride report… What’s generally happening when you have a fin that has no rake? easier to turn? anyway, thanks for sharing…
I wouldn’t put the back fins far back, it looks to me that you have a lot of fin area.
I expect that putting th back fins far back would make it too stiff.
Unfortunately I cannot see the pic for Option 2.
But I’d give my vote to your original option.
Aren’t you going to use finboxes? That would be the safest bet for all the work you put into the board.
Hey Florian
Well from what I understand, these types of upright fins are believed to have less drag as compared to a raked fin of similar surface area. Most of the info I’ve read on the wavegrinder website. Well see what they feel like. I’ve never tried forward swept fins before. But I expect them to stall abruptly.