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revisited

Based on the build described in my previous ' part 4' blog, the performance of the on the lake was less than impressive so I decided to rework the plumbing. The solenoid valve based solution worked, but the water flow was restricted by the small bore of the valves. Using two valves to divert water from the ESC cooling to the monitors also meant that one or other of the valves was always energised resulting in unnecessary battery drain. To overcome these limitations, a diverter valve was constructed based on a 10mm compression fitting from the local plumbing store. A central rotor was turned on the lathe and then cross drilled to produce a three port valve which is actuated using a small servo. I wasn't sure that this would work without leaking, but with an o-ring fitted on the rotor shaft it seems to be OK. At one extreme of the servo rotation, water is routed from the pickup scoop to cool the ESC and motor. At the other extreme of travel, water is routed from the pickup to the monitor pump. An RC switch connected to the same Rx channel as the valve servo switches the monitor pump on when the valve is routing water to the pump. The pump was also upgraded. I have tried a variety of pumps sourced on-line, most of which did not have adequate performance. The pump now in use is an aftermarket windscreen washer pump which seems to work OK. To make it easier to install in the model, a ply chassis was constructed to hold the valve, pump and the RC switch. The chassis also provides a locating box for the LiPo. Out on the lake this afternoon, I was able to get a few photos of the monitors in operation. The performance is much improved.

4 years ago by Graham93