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; 03/04/1010:52 AM.
Mike Shappell www.themanshed.com TMS-20 Builder G-Cat 5.7 - Current Boat NACRA 5.2 - early 70's
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 03/04/1005:55 PM03/04/1005:55 PM
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; 03/04/1005:56 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 03/04/1010:59 PM03/04/1010:59 PM
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.
Last edited by TheManShed; 03/04/1011:04 PM.
Mike Shappell www.themanshed.com TMS-20 Builder G-Cat 5.7 - Current Boat NACRA 5.2 - early 70's
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.
Last edited by TheManShed; 03/04/1011:50 PM.
Mike Shappell www.themanshed.com TMS-20 Builder G-Cat 5.7 - Current Boat NACRA 5.2 - early 70's
Marking bulkheads. I picked up this laser on a sidewalk sale at Harbor Freight last year it was good deal and figured I’d use it some time. I was going to use plum bobs to mark the hull then remembered the laser stuffed away in the cabinet.
Last edited by TheManShed; 03/06/1001:55 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