Author Topic: Foil Boom  (Read 19834 times)

Keys Sup

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Foil Boom
« on: November 04, 2019, 12:14:57 PM »

Looks like a standard windsurf boom with harness lines. Interesting.

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Re: Foil Boom
« Reply #1 on: November 04, 2019, 02:17:11 PM »
That is obviously incredible riding.  On the other hand, the smallest, lightest all carbon booms are over 4 lbs.  That is more than a 5 meter Swing and almost twice as heavy as a Swing 2.8.  I don't see that as the answer.

Keys Sup

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Re: Foil Boom
« Reply #2 on: November 04, 2019, 08:54:52 PM »
Agree too much weight. Is it me or does the Duotone boom feel heavy.

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Re: Foil Boom
« Reply #3 on: November 05, 2019, 12:24:26 AM »
The Duotone boom is 1.8 lbs which is still a lot of weight.  Hot Sail's approach of two micro boom handles is bound to be lighter but I can't tell if they are held away from the strut with something structural.  That would be the way to go. 

PonoBill

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Re: Foil Boom
« Reply #4 on: November 05, 2019, 07:48:46 AM »
I cut the weight of my duotone boom to under a pound (about 400g) for even the 5M: fixed carbon shaft and lightened leading edge boom end. Ken Winner told me he thinks some of my issues with the 5M being hard to handle stem from the lightening job I did on the boom end (lots of big holes) but I tested a stock one vs. my old school hot rod version and couldn't detect any difference in deflection with 50 pounds hanging on the boom two feet from the end. If I pushed it closer to failure I'm sure I'd see some, but I don't have any spares to sacrifice in finding out what that might be.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

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Re: Foil Boom
« Reply #5 on: November 06, 2019, 01:05:15 AM »
A modular system would be easy, cheap and awesome.  The strut itself is plenty rigid.  The problem is that we have too much play in the handles themselves.  Attaching something stiff to something sloppy doesn't solve the problem.
 Sew a nicely reinforced and contoured plate sleeve to the strut and mount removable handles to it.  Better yet, mount a short slider track (or two smaller tracks) and you have variable handle positions and riders can add or remove handles within that range.  This would be much more rigid, super light, very portable and entirely customizable.  Tons of handles exist or have a mold done (its cheap).  My ideal would be two slightly longerer handles (a hand and a half would do it) similar to the longer handle below but without the hard angle and with boom wrap. 

« Last Edit: November 06, 2019, 04:07:57 AM by Admin »

Keys Sup

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Re: Foil Boom
« Reply #6 on: November 06, 2019, 07:34:24 PM »
Pono 400 grams is great. I do not have an extra paddle shaft so started looking at carbon tubes and they all weigh more than that. I imagine you use a shorter extension than Duotone.
Does anyone have the specs on the 3.0 Duotone boom? Trying to build a boom with shortest extension possible.

PonoBill

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Re: Foil Boom
« Reply #7 on: November 07, 2019, 09:33:57 PM »
My 5M boom is fixed length. I used a KeNalu shaft which is tapered almost perfectly to fit both the front and rear boom ends. My 3/4M boom is heavier, I don't remember how much. It has an extension and spacer, both of which add weight. Still used a KeNalu shaft but I got a telescoping CF tube for the extension and used a chunk of KeNalu shaft for the spacer instead of taking a chance on drilling holes for spring pins.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

Keys Sup

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Re: Foil Boom
« Reply #8 on: November 08, 2019, 09:27:31 AM »
So with the fixed length you have it set at 169cm and just loosen the outhaul to get 165cm? Or just fixed at 167cm?
There are some cheaper carbon paddles with 16" of adjustment that might work.

PonoBill

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Re: Foil Boom
« Reply #9 on: November 08, 2019, 01:19:05 PM »
It's fixed at 174 but I have a sliding loop that attaches the clew to the boom, then I just outhaul to the length I want. So I can bag it to 168 or even more if I wanted or over-flatten it to 173 if I need to manage the wing in gusts. My 3/4 boom has an adjustable outhaul from Sailworks that works like a slalom windsurfing outhaul (in fact that's what it was before I cut it all up). One of their kits will make two duotone booms since they are made for double-sided booms. I stole the idea from Ken Winner and Julie Schreyer. The problem with adjustable paddle shafts is they are thick and heavy. Usually, they're a lot of layers of fiberglass with a few layers of carbon on top. They can handle having holes drilled in them or other stuff done to support adjustability, but they're heavy. Not as heavy as aluminum, but close. The KeNalu 100 flex carbon shafts are super light, and crazy strong as long as you don't scratch them up or do anything that compromises the carbon. I think an adjustment hole would just kill them, even close to the end where there is the least stress.

I'm pretty sure Lane still sells them as components. Not cheap, but neither are plain carbon tubes that don't have the taper that makes these work like they are made for the purpose
« Last Edit: November 08, 2019, 01:26:51 PM by PonoBill »
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

Keys Sup

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Re: Foil Boom
« Reply #10 on: November 08, 2019, 06:24:54 PM »
Thanks Bill.
Price is more or less the same as carbon tubes.
I still have a sailworks adjustable outhual that I never used.

PonoBill

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Re: Foil Boom
« Reply #11 on: November 08, 2019, 09:32:58 PM »
If you get one, cut it to length by cutting the small end. the big end is doubled up carbon to add strength to the blade end. All you really need to do is drill the rivet out of the boom ends and take them off, Check the fit of the big end into the boom end. You might need a few wraps of aluminum tape to make it tight. Hot glue it in place. Same for the small end. Done.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

Keys Sup

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Re: Foil Boom
« Reply #12 on: November 09, 2019, 04:55:00 AM »
Great!
I like to over think things. Would making the boom end going to bladder out of 1/8" Divinycell wrapped in Carbon worth the time to shave off some weight? Could probably make plug for outhaul.

Dwight (DW)

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Re: Foil Boom
« Reply #13 on: November 09, 2019, 05:42:29 AM »
Shaving a little weight wonít make anyone a winging ninja and it wonít make the wing fly any different. Either you like it, or you donít. If not, try another brand. Save the money youíll waste on carbon and use it for the exchange.

PonoBill

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Re: Foil Boom
« Reply #14 on: November 09, 2019, 06:10:25 AM »
I doubt it. I considered making a boom end out of thin aluminum. I build a lot of very light aluminum parts, so it wouldn't be much of a challenge. I could certainly reduce the weight of the boom end by more than 50 percent. I build things like aluminum shelf brackets for my motorhome and other goofy projects that weigh a few grams but support 250 pounds--the general design would work well for this. But rationality overcame me and I just butchered one of my existing boom ends.

I reduced the weight of the boom end with some old school hotrod drilling using small holesaws. The thicker girder webs on the plastic is where most of the rigidity is so I took out quite a bit of the plastic in between and also cross-drilled the heavy connector. Dan Gavere did a lot more removal than I did and his is still holding together, but I'd be a little concerned about flex if I went much further. As it is, Ken Winner expressed some doubts about the idea, so I tested the ability to resist flex with a stock boom and my lightened one using a loop of line to the upper fixing point and letting the blade rest on the edge of my workbench. I added weight to the shaft a foot from the boom end and found no measurable (using my primitive rig) difference between stock and lightened.

The lighter boom makes the wing much nicer to use. I don't think it adds anything to solving the fundamental stability problem with the larger duotones but a lighter wing is simply easier to handle in most conditions.

A pretty short jump from here to a boom end.
« Last Edit: November 09, 2019, 07:14:29 AM by PonoBill »
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.