We went out for a brief tow test today to check adjustments to side foils and to compare performance of original T-foil rudder to newly fabricated larger T-foil rudder.
The attached plot compares the speeds and loads with each rudder T-foil. The speeds are not identical in each case, and other factors such as the tow angle and acceleration may have varied between runs. However, there is some indication that the “new” foil requires a larger towing force at 20-21 knots.
Jamie put the logger components in a new box (orange, on top) that is even smaller than the old box (silver, on bottom). Right now he is running a program on the Android phone to record the temperature to make sure that the electronics will not overheat in their new closer quarters.
The graph shows the temperature recorded by a Nexus S phone, using software that we wrote to log its battery temperature. (The PC either has no non-CPU temperature sensors or they are not visible to the OS.) The phone battery temperature is typically a few degrees higher than the ambient temperature. While the temperature did not fully stabilize during the 2.5 hour test, it appeared to be leveling […more]
