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Re: The Man Shed News [Re: TheManShed] #204825
03/04/10 12:55 AM
03/04/10 12:55 AM
Joined: Feb 2009
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Palm Beach County
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Slow work but I start to see some shape.

Attached Files
P1010001.JPG (264 downloads)
P1010004.JPG (261 downloads)

Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

-- Have You Seen This? --
Re: The Man Shed News [Re: TheManShed] #204826
03/04/10 01:56 AM
03/04/10 01:56 AM
Joined: Sep 2007
Posts: 757
japan
erice Offline
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japan
i was under the impression that lifting boards worked best when their section was an aero-foil style asymmetrical wing type

ie not symmetrical

somewhere on SA is a pic of the end bmwo's banana boards that showed a fat, high-lift, wing section

your build description for curved boards doesn't seem to mention a lifting section...???

straight boards can be angled to provide lift, but apparently they don't work well across a broad range of speeds so aren't used much

symmetrical curved boards aren't going to provide any lift are they???




Last edited by erice; 03/04/10 02:13 AM.

eric e
1982 nacra 5.2 - 2158
2009 weta tri - 294
Re: The Man Shed News [Re: erice] #204845
03/04/10 10:34 AM
03/04/10 10:34 AM
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Palm Beach County
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Still looking for information any technical-engineering data would be welcomed. Are the boards on the A-Cats Asymmetrical?

I think it was pointed out in the commentary from the AC that curved boards is a way to improve performance so there is going to be development in the whole concept of curved boards in an engineering aspect.

Until then the old way of build and test will have to do. On the prototype I think I like Jake's idea of making a trunk that will accept both type of boards. Then I can tell which is best.

Last edited by TheManShed; 03/04/10 10:52 AM.

Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

Re: The Man Shed News [Re: TheManShed] #204870
03/04/10 04:22 PM
03/04/10 04:22 PM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
Carpal Tunnel
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Originally Posted by TheManShed
Still looking for information any technical-engineering data would be welcomed. Are the boards on the A-Cats Asymmetrical?

I think it was pointed out in the commentary from the AC that curved boards is a way to improve performance so there is going to be development in the whole concept of curved boards in an engineering aspect.

Until then the old way of build and test will have to do. On the prototype I think I like Jake's idea of making a trunk that will accept both type of boards. Then I can tell which is best.


I believe the Flyer boards are symmetrical. Sym. sections do generate lift as a function of their angle of attack...most aerobatic airplanes have a symmetrical wing section and they fly just fine. An asymmetrical foil doesn't generate lift as well when inverted (which is why most aerobatic planes have a fully symmetrical wing). You do depend on your daggerboards to provide lift on both sides depending upon which tack you are on. However, the marstrom curved daggerboards, which have also proven to be pretty quick, are asymmetrical and conceptually mostly rely on the leeward board to provide the lateral resistance for sailing upwind.


Jake Kohl
Re: The Man Shed News [Re: Jake] #204884
03/04/10 05:55 PM
03/04/10 05:55 PM
Joined: Apr 2002
Posts: 805
Gainesville, FL 32607 USA
dacarls Offline
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So far as I KNOW in A-class, only the commercial Marstrom boards are assymetric. All others appear to be symmetrical, but there is discussion/controversy whether they can/should be canted forward to provide a positive angle of attack. Also there are several opinions on location: fore, mid or aft between front and rear crossbars.
IMHO, None of this is clear to the builders/experimenters. But you are allowed to buy a new A-boat for $US 25,000 based on your best guess!

Last edited by dacarls; 03/04/10 05:56 PM.

Dacarls:
A-class USA 196, USA 21, H18, H16
"Nothing that's any good works by itself. You got to make the damn thing work"- Thomas Edison
Re: The Man Shed News [Re: dacarls] #204901
03/04/10 10:59 PM
03/04/10 10:59 PM
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Palm Beach County
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Busy day I have the connecting beam plug fared and ready for epoxy & glass. Guess what starting to look like a hull need to match, fit, and build bulkheads.

Attached Files
P1010023.JPG (145 downloads)
ready for epoxy and glass
P1010028.JPG (143 downloads)
P1010033.JPG (144 downloads)
Last edited by TheManShed; 03/04/10 11:04 PM.

Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

Re: The Man Shed News [Re: TheManShed] #204902
03/04/10 11:01 PM
03/04/10 11:01 PM
Joined: Feb 2009
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Palm Beach County
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few more...

Attached Files
P1010035.JPG (143 downloads)
P1010041.JPG (143 downloads)
P1010043.JPG (143 downloads)

Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

Re: The Man Shed News [Re: TheManShed] #204903
03/04/10 11:12 PM
03/04/10 11:12 PM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
Carpal Tunnel
Jake  Offline
Carpal Tunnel

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Posts: 12,310
South Carolina
lookin' great Mike!

I'm having trouble picturing the final shape of your beam you're molding...why does it appear to have such an irregular shape?


Jake Kohl
Re: The Man Shed News [Re: Jake] #204904
03/04/10 11:37 PM
03/04/10 11:37 PM
Joined: Feb 2009
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Palm Beach County
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The beam is going to be an elliptical shape. I had some engineering done on the shape it is stronger then a circle or teardrop mast section shape. The beam will be low profile and will fit in a sleeve by design it will take care of twist so no pin is needed. Plus it is different and blends with the boat nicely; the designed connecting beams were funky. That is one reason I had more freeboard designed in the ama's to meet the beams better. I may build a channel and cut a groove in it to slide a tramp boltrope inside like a mast.

Attached Files
P1010114.JPG (127 downloads)
Last edited by TheManShed; 03/04/10 11:50 PM.

Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

Re: The Man Shed News [Re: TheManShed] #204915
03/05/10 08:12 AM
03/05/10 08:12 AM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
Carpal Tunnel
Jake  Offline
Carpal Tunnel

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Posts: 12,310
South Carolina
OK - I got it now. Thanks. It's also more aerodynamic too!


Jake Kohl
Re: The Man Shed News [Re: Jake] #204982
03/05/10 04:39 PM
03/05/10 04:39 PM
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Palm Beach County
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I figured it would help reduce beam slap from the waves.


Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

Re: The Man Shed News [Re: TheManShed] #205005
03/06/10 01:51 PM
03/06/10 01:51 PM
Joined: Feb 2009
Posts: 678
Palm Beach County
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Marking bulkheads.
I picked up this laser on a sidewalk sale at Harbor Freight last year it was good deal and figured Id use it some time. I was going to use plum bobs to mark the hull then remembered the laser stuffed away in the cabinet.

Attached Files
P1010003.JPG (64 downloads)
Still makes me made I was shorted on peel ply.
P1010013.JPG (64 downloads)
Dueling tape measures may the best one win.
P1010011.JPG (63 downloads)
All that for lines?
Last edited by TheManShed; 03/06/10 01:55 PM. Reason: The laser did not burn the lines it was a sharpie

Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

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