Sunday, April 25, 2010

Drag Queen

Up in West Hollywood where I work, there is no shortage of queens, but I thought it was high time to broaden the definition, Moth-style, in celebration of the prodigal mainfoil's return from the tank:

For reference, I post the Prowler numbers from Bill's earlier work with John Zseleczky, which was the most efficient foil in that paper (vs a Bladerider mainfoil) for 20fps and 18" immersion, 180lb load:

The two foils are the same area and span. Different 2D foil sections on lifting surfaces; struts should be the same shape but ended up different due to (my) operator error in building the thing. An old photo:

I feel good about these results; they confirm a lot of what I thought in the design stage and what I have sensed on the water, but could not state conclusively until now. I think it is good news for the class in general, because it shows if nothing else that there may be a way to get quite a bit more efficiency out of the boat.

I hope these data will serve as an impetus to anyone who might have been thinking about going completely flapless to get busy on a prototype, as the control system design isn't a particularly easy nut to crack! Sounds like J. Bethwaite et al may have something up their sleeves in this regard; should be interesting to see how our next iteration compares to their design. I have a date with the Shop Bot next weekend and hope to get a new system mocked up before July.

Major thanks to Bill Beaver for once again helping to shed some light on the behavior of these cool little boats.