Hello, folks :-)

What diameter, thickness, and metal do I need to build wings for my Nacra 450? I'd think 6061-T6 would be the alloy.

Also, any suggestions about building are welcome. I don't know much about bending the tubing. Heard of somebody kinking very small 3/4" tubing with one of those 'bow-and-arrow' benders. Have heard the kind that move the die around in an arc are better.

If anybody has some pics or drawings, that would be nice too.

Cheers,
Danno

I looked into building wings for my H-18. The bigger part of the fabrication job was the fittings. I just found a used pair via the internet but haven't recieved them yet. I remember that the main tube is 1 1/2" OD. The tube thickness depends on the design (bracing). Best bet is if someone has a set of NACRA wings that you can measure and get a pattern off of. A local metal fabricating shop will be able to bend the tubing without kinks and weld it if needed.
Put some feelers out on the internet for a used set and wait a while, you may get lucky.

Hello.

I am on a similar quest.

Found a great resource at the hobie cat site. Go to the fx-1 link,..in there is a link to 'rack'.

You will find someone already went where we want to go.

There are 3 designs. One of the 3 designs are the standard Magnum wing. The other 2 are quite innovative and modern.

I am attaching a PDF file of the link.

Edit Line; Ok, for some reason this site will not take a .pdf file,.....so go to
http://www.hobiecat.com/sailing/models_fxone.html

and under OPTIONS you will see a link to WINGS and view the racks,....real nice too.



regards,

Bruce
St Croix
I-17 normal

Thanks, guys :-)

I'm attaching a pic of somebody's wings I found awhile back. And my beams are 6' apart, so it seems I'd need around 12' for a single piece to be bent for the main support. If so, that would mean it couldn't go UPS. Could I make it from (2) 6' pieces and have it welded in the middle after bending?

Danno

Here's a pic of the beam and my tentative plan for wing fittings.

I'm considering setting my wings tubing right on top of the beam from outboard edge of the hull to maybe an inch or so past the inboard hull, enough leave space to run a bolt up through the bottom of the beam, leaving a couple inches sticking out the top. Thread a nut down these 2 inches next to the beam. Drill through both sides of the inboard end of the wing, slide the hole over the beam bolt sticking up, washer and nut to secure.

For the outboard fastening point, I'd drill a hole in the top side beam on either side of the wing tubing near the outboard hull. Slide 2 bolts up from inside the beam. Finish by placing a strap across the wing tubing onto the 2 bolts and secure with a couple nuts and washers. Sort of like a U bolt without the bottom part of the U.

A second method would be to replace the existing 2 beam bolts with longer bolts, threaded on both ends. One end into the hull, washer and nut over the top end to secure the beam but with a couple inches of threaded bolt left sticking up. Slide appropriately drilled wing tubing over the top and secure with washers and nuts.

But this last way I'm concerned about putting extra stress on the beam-to-hull bolts in the event of dragging the downside wing in the water. The first way would put the same stress on the beam but would avoid the hull bolts.

Does anybody have an idea of how strong these wing tubing bolts need to be? Most of the designs I've seen look no stronger than either of these methods. I'm concerned about the 3-4' arm created for torque when the wing plunges into the water at 15 knots.

The wing tubing would be parallel to the beam, then bend up just past the outboard bolts at maybe 45 degrees, then bend back to parallel at butt height. No extra smaller support like in the firt guy's pic.

Cheers,
Dan

Here's a sketch of my idea. I've added an optional brace to run from the inboard beam to the seat, if needed.

I've never seen the brace beam on the top before but I think doing it that way will create to much load on them. I have the Mystere wings and an abrupt hit from an unbalanced body will break that weld where the small pipe attaches to the larger. Prindle sold a set of wings that went into a kit to reinforce the end cap area without the smaller pipe for the 18-2 and 19 maybe performance has them for the Nacra type tubing ....

MB:

Thanks for the input. I don't even know if a diagonal brace would be needed. Maybe moving it to outboard end would work better. Have it run diagonally from where the tubing leaves the hull to the very outer end of the seat. That way it would be in compression instead of tension. See the attachment.

Take care,
Danno

Someone sold wings that went into NACRA beams. Check out a older Murrys catalog or contact NACRA. I remember that they had no braces. Like any wing, there is a weight limit. (I'm not sure skipper and crew from Team Bulk can sit on the H-18 Magnum wings).

I see your trying also to put the beam on top of the hull you coul inadvertantly crack the deck.There is as DVL has stated a sleeve system that you can get or copy for the Nacra tube beams,its similar to the ones in the prindle catalog ...there is no minor strut type tube.

Hmm...

I've seen the Murray's catalog before. Several months ago when I last started thinking about this project, I called Performance Cat. Indeed they did say there is a bushing or sleeve to fit inside the beam, into which the wing tubing would fit. But I also remember them saying something about it not working because of the bolts. I've just looked at the online nacra manual dated 1991, which shows straps holding the beam to the hull of whatever model they used. But a later catalog online shows a newer version of whatever to have the same type of through-the-beam bolts I have. So it's probably a good time to have a chat with them again.

I imagine it would be hard to make a sleeve with my bolts going through the middle of the beam. Do you have any suggestions?

Also, with the wing tubing on top of the beam, how would this cause stress to crack the deck? Downward force would be spread along the beam. Upward force on the inboard fitting would be taken by the beam, since it's connected only to the beam. Upward force on the 2 outboard bolts would be transferred likewise to the beam.

Cheers,
Danno

First of all, here is one link about wing construction for the Moth sailboat. They are using aluminium tubing and building carbon fiber sleeves and connections. It might be the easiest way to build one if you do not have access to a metal workshop

http://www.moth.asn.au/download/building_moth_hardware.pdf

There are some problems bending aluminium tube or pipe 90 degree. It can be done but it requires a special tooling and be certain to check with the metal shop that they have actually done that because aluminium tubing will crack if you are trying to bend it at 90 degrees. Even with the proper machine, you will limited with the bend radius because the 6061-T6 aluminium is already heat treated

As far as the brace is concern, I would go with a bigger diameter tubing instead of a brace. If you still think that the brace is required, use a smaller diameter pipe insteat of a plate, it is going to be almost as efficient and much safer. BTW the brace should be located on the bend closest to the catamaran, the other one near the seat is pretty much useless.

Don't forget that aluminium looses almost 40% of it's strength after welding so if you decide to go with a welded construction, you should put the brace to help with the strength of the welds or go with a bigger diameter tubing.

One last option is to use aluminium pipe elbows instead of 90 degrees bend and have the wings welded.

Unless you buld it with the Moth procedure, the wings are almost certain to be heavier than stock wings

As far as size of the tubing, If you want to trapeze out of your wing, you will need to have at least a 2" outside diamter for comfort. Anything above 3" of outside diameter is going to be too heavy. You can build using two diameter of tubing, one for the longitudinal tubes, one for the crossbar.

Charles Leblanc

I really like the system shown on that Mystere 6.0 picture you posted. The wings stay put and can fold up easily for trailering. As an added measure of safety, you could run a third "trapeze" line from the mast to the middle of the wing for support.

One of the drawbacks to wings is having the leeward side hit waves or drive into the water if you fly a hull too high. I hear tale of an open Worrell boat that had wings that were supported by cables from the mast such that when one would go down (if the sailors sat on it) the other would raise up to 90 degrees or so.

I too like the Msytere 6.0 design......Does the short support pipe line up to the end cap of the crossbeams? Wouldn't you want something other than bare pipe rubbing on that end cap?
And Jake, on the open Worrell design you heard about, would that mean that both wings couldn't be "deployed" and used simultaneously? OR perhaps there was a way to "disable" the support cable that lifted the leeward wing?
Greg

I would imagine that you could only use one wing at a time - why would you need both?

Jake,

Cruisers.

Lounge Chairs.

4 babes on a boat.

need more than one wing deployed

Don't forget it's a great place to set up the wet-bar!!!!

Greg

your right I looked at your diagram incorrectly.you are putting the major tube on top,why not do it like the mystere and put it in front of the forebeam just inside the hull and in back of the rear beam again just inside the hull. these beams are then throughbolted together. The smaller support struts are then angled inward and attached with the (outside) beam to hull bolts.The seat actually should not sit as parallel as the deck but slightly angled upward (5degrees).The same tang as the hobie 18 can be used to attach the smaller strut.Remember to cut an angle in the pipe of the smaller strut so it sits flush on top of the tang when the wings are deployed.The wings are the best for cruising and short course sailing but they are back breakers in the ocean in some distance racing.

MB:

Main objections I have to the Mystere wings posted are the wing tubing to beam connection bolt and the smaller angle brace. Mainly ignorance on both accounts. I don't know how big of a bolt would be needed and don't know if a bushing fitted inside the tubes through which the bolt would go is needed.

Also didn't want to hassle with that smaller welded tubing and its fitting when deployed.

If I didn't need anything fancy to get these fittings to work, I'd be fine with it.

Charles:

Thanks for the input. Good idea to check about the shop. I would think making a larger radius bend would be safe for a 90. But not sure what radius.

Thanks,
Danno

PS: I looked at the moth wings link. After looking at the diagrams for 10 minutes, I still don't understand them.

About the Moth wing,

The moth are a very narrow and short monohull, Something like 10' long and 1' beam.

Feel free to look at the moth site for the current design

http://www.moth.asn.au/

There is one example of a wing on the title page

Basically, what they do is that they build their wings with straight aluminium tubes and they build carbon fiber sleeves and connection instead of bending or welding the tubes.

BTW when you will be shopping for your aluminium, there is Aluminium Pipe and Aluminium tube (also named hollow structural section). The diameter is usually different for the same nominal size: Tube is rated with the outside diameter, pipe is rated with their indide diameter but for pipe it changes with the dirrerent sizes.

Elbows are only available for the Pipe but you can use an elbow on a tube is the actual (measured) size is the same.

For example: A 4" pipe is usually 4.5" of outside diameter. A 4" pipe is actually 4" of outside diameter. The elbow will be 4.5" because the elbows are always built on the pipe size.

Finally, Tube is usually available with thinner wall setions than pipe.


Charles