My thanks to John Churchill for the inspiration and design discussions to build the windvane. John, refined the Pardey design and showed me how to incorporate ball bearings in the control wheel and upper support strut. The vane, control wheel, upper support strut and counterweight weigh 13 lb. 6 oz. without paint. The wing is structural and has a NACA 0015 airfoil. The windvane image is prior to painting.
Thanks John.
Fair Winds,
Rod
S/V IDUNA
Looks really good Rod! Have you had a chance to try it out?
Rick
Aistear, BCC #7
Rick:
We are hoping to find a weather window when my shipmate is in town to mount the unit.?We have?had?our share of rain this year.?Our backstay has two antenna insulators, hence I need to replace the backstay. We plan to haul the boat for two months to finish her, starting 1 July. Historically, there is not much wind?on the Chesapeake in July and August.??It will be our luck?for the weather to give us good winds in July?and August.??We are hoping to finish the refit?with this?haulout then sail Sept.,?Oct., Nov., and perhaps Dec.?
I just finished?modifying the trim tab to change it to a 80-90% balance trim tab. This will be installed during the haulout.
Once we start sailing I can give a report about the performance of the windvane. Based on the engineering calculations, the unit should work just fine. In 10 knots of wind, 85 F air temperature, the NACA 0015 wing generates 0.9 lb of lift at a 5 degree angle of attack. The torque from the control wheel is 0.7 ft-lb. With the 80-90% balance trim tab, we are hoping the unit has good light air performance. We consider the unit a prototype. The lift calculations where?done by a NASA program - mathematical modeled wind tunnel - fun stuff. I will have more details available when I find time to put together a website for IDUNA.
Fair Winds,
Rod
S/V IDUNA