[quote=southstars2012]Now in terms of the custom wings we built, here were the key parameters of our design:
- Seat style: we went broadly with a Hobie Comfort seat style
- Beam/hull supports: we went with M32-style supports, as revintage pointed out. These are similar to Hobie 18SX wing supports in terms of overall load distribution (a compression/downwards load on the beam end + a tension/upwards load 6-12'' inwards from the beam end). The M32 style seemed easier to make, and sturdier overall vs. the slim support strut tabs and attachments on the Hobie 18SX wings (though admittedly the later are battle-proven). A critical consideration in favor of both styles was the ability to swing the wings up (at dock or if beating upwind in heavy airs where we wouldn't want the leeward wing dragging).
- Mast wire support: to distribute loads further, we reused old trapeze wires to support the wings from the top in two places (near the front beam, and and about 2/3 between the front beam and the aft beam). We tried to distribute the loads about 50:50 between the beam/hull supports and mast wire support. Perhaps we should have put more load on the mast, because we still broke one of the rear beam connection points... (but were able to jury rig it and continue using the wing, though more gingerly)
- Fore-aft support: we had none. That is not uncommon (see M32 wings, and early H18SX wings for example), and felt ok for our use case (one time race). But I would agree that for long duration uses/cycles it would help to support the wings fore-aft. Hobie later added this to the H18SX with a small strut going from about 6''-12'' behind the rear beam and then going forward to the primary wing support strut ([url=https://www.flickr.com/photos/38912672@N05/5979684079/]see picture here[/url])
- Primary support struts: these are the large posts that go from the beam to the wing itself, and incur most of the loads. The main decision here is whether to go straight (as we did, also mostly on the M32) or with a curved beam (as on Hobies). A curved beam enables a fully-flat seat, while the straight struts mean the seat is always inclined (and more so if you're lifting a hull). While flat may be best for beer can sailing, the inclined seat felts very safe (little change of you falling backwards out of the seat!).[/quote]
No HTML tags allowed (except inside [code][/code] tags)
