Thursday, August 7, 2008

Get Smart! CONTROL vs. KAOS

Would you believe?

I think this television show (and now, movie) is a metaphor for my moth escapades. During today's sail the main foil rod pulled out of the tapped barrel in the flap, so I had no ability to generate negative flap angle. Normally a recipe for disastrous stacks, but fortunately the wind was only 10-14 knots. I managed to sail about 2 miles on a broad reach controlling ride height by my fore and aft weight placement. Surprisingly, everything went fine. I suppose that the AoA of the main foil with zero flap angle is just about right for these conditions. Of course, with more wind and more speed the ability to generate a negative flap angle is required. So back to the shop to re-engineer the mechanism.

My push rod is a 1/16" diameter stainless steel rod I bought from McMaster Carr. I used a tap and die set to cut threads in the rod and in a piece of brass that I embedded in the bottom of the flap. I do have another piece of 1/16" ss rod so I may just replace the rod with a newly treaded one. However, something tells me that it's the brass threading that has stripped out and that will require opening up the carbon on the bottom of the flap to remove the old brass and insert a newly tapped piece.

I understand that BR uses a 2.4 mm rod, and I may bump up my rod to the 0.094" diameter (the English equivalent) but then I need to buy a new tap and die for that size rod....

It's hard reigning in chaos!

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