Has anyone ever used carbon fiber r/c helicopter blades to make a keel fin?
Ian Sammis is doing it for both rudder and daggerboards on both his cat and tri multihulls.
PM him for more details.
Helicopter blades are generally much thicker than what you would want for a keel fin. The Heli blades that I have seen are 10% - 12% thick. An efficient keel fin should realistically be around 6% thick.
They will work, but you will pay a drag penalty for that much thickness. If you plan on racing and want to be competitive, you would not want to use those…
A few of us in our club looked into using them. As already stated, too fat of a section. Unless you have found some that are down at around 6%, I personally wouldnt bother. I can give everyone a tip on how to get them CHEAP or free though. Helicopter blades are normally sold in mathced and balanced sets. When someone breaks one, the other one is generally worth less than the material it is made out of. Find a flying club, or a hobby shop heavily involved with helicopters and they can normally find you a fist full in under a week for a buck or two.
I haven’t used the blades as such but i did use the stabilizer paddles cut and glued together as a rudder n my tri and they seem to work well. Just need it to stop tripping over it’s own feet now lol.
The heli blades on my tri ( Nightmare MKI ) are 15% but they work very well. I plan to make new ones that are 6-8% but I am sailing my IOM here ( Hawaii ) and on the mainland. Fla. regionals and next month’s Texas blowout so the tri’s have been put aside. I haven’t heard anything about the tri regatta.
i am in the process of building a 1.6 metre mono and will be using heli blades mainly because of the cost factor. I have seen carbon keels/rudders for sale for prices well over $200au but i can buy a new set of 650mm carbon heli blades for under $100 au including postage. ( i now wish i had kept a few blades from crashes when i was flying the damn things lol). will let every one know how it turns out both in this post and the stretch limo one metre post when it finally gets on the water [:D]
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