How do I legallly install winglets on a standard airworthiness certificate?

On Nov 20, 8:39*am, Scott Alexander
wrote:
A friend in my club built a pair of winglets for his Standard Cirrus.
His glider is expirmental, mine is not. *The total cost for him was
just a hundred dollars for supplies, and some free guidance from a
local IA/AP. *The finished product looks fantastic! *The mold came
from an American Spirit, which I believe is a copy of the Ventus. *And
the result is that his handling has improved quite a bit. *He did do
some adjustments on the toe-out angle to fine tune it which
supposively helped.

I would like to do the same thing with mine using the exact same
molds. *My Cirrus is a standard airworthiness certificate. *If I were
to do the factory winglet or the Maughmer winglet, the cost is between
3,000-5,000 when it's all said and done. *So that being said, this
option, looks very appealing.

Has anyone in this group dealt with the same sort of deal? *I would be
willing to change my standard airworthiness certificate over to an
expiremental if that is the best solution. *Any guidance is much
appreciated.

Thanks,
Scott

PS Happy Thanksgiving.

None of these winglets appear to have STCs so the installation in a
type certificated glider will be via 337/field approval (I doubt
you'll find an A&P who would claim adding a winglet is a "minor
alteration" although there could be corner cases...). Since likely you
need an A&P/IA to file a 337 and work with your local FSDO that is
where I'd start. OTOH if you can get a pair of winglets for $3k out
the door, all approved properly, then I'd take that route.

Darryl