Following yesterdays excellent ideas thrown around on how to simplify setting/dousing spis.
Here is another topic thrown around. Drag reduction from cables. The drag from the cables in the rigging is not large, so this is a minor component on speed compared to the loose nut on the tiller. Still, here is a small discussion on drag reduction in rigging as posted by Tom Speer on the landyacht forum.
Freely rotating cable fairings have been tried many times in the past, without much success. There are several physical constraints on the problem that make it very difficult.
The aerodynamic center must be behind the axis of rotation for the fairing to be statically stable. The distance between the axis of rotation and the aerodynamic center must be great enough to overcome friction and to provide a natural frequency high enough to track wind gusts. The center mass of the fairing must be ahead of the axis of rotation to be dynamically stable against flutter. One would like the cable to be located near the thickest part of the section, or else the fairing will have excessively large frontal area. Different parts of the fairing must be able to rotate independently because of the change in apparent wind angle with height.
I suspect the fairings need to have tails attached in order to meet all these requirements. This makes the fairings heavier and more fragile. Not to mention adding additional wetted area.
A simple flat plate with its leading edge against the cable, possibly with ballast extending ahead of the cable, may prove to be the best design. Simply preventing the formation of the Karman vortex street using the splitter plate can result in a significant reduction in drag.
Landyachts operate at far higher speeds than F16s so drag is much more critical. But I thought I would throw this idea out here and see what happened.
