When the hull is finally completed with a well suited power system, it is very important to follow these next few steps. More often then not, the first run for any hull usually is not the best, as you may think. Taking the next couple minutes to read the rest of this page will become very valuable.
Motor ESC LiPo Battery Temp Check – 45 second test.
After choosing the most conservative prop for a given setup, charging the packs and placing the hull in the water, run it for 45 seconds. After the 45 second period, bring the hull in and note the temperature of the ESC, motor, and cells. If all components are well under 140F/60C, run the hull for 90 seconds. Keep increasing the run time by 45 seconds if all components are under 140F/60C. If the temperature exceeds the safe limit, one has either exceeded the maximum allowable run time or is using too large of a prop or a combination of both. Reduce prop size or run time.
In the process described above, determine your total run time that will drain 80% capacity of your LiPo’s. Each time you run the hull for the 45 second period and reach about 3-4 minutes, it would be a good idea to record how many mAh is placed back in to the LiPo Battery. For example – If you were to get a 4 minute 15 seconds run time and replace 4000mAh from a 5000mAh battery, this should be considered your maximum run time. 80% of the batteries capacity has been drained. This is to ensure Long LiPo life while getting the better part of a batteries discharge curve.
Moving to a Larger Prop
Once you know how long of a run time you are getting from your LiPo’s and your motor is well under 60C(140F) in temperature, it is safe to move up in prop size from the original conservative prop. It is recommended to increase prop diameter in increments of no more than 2mm at a time. When you make the next run with your newly selected prop it is recommended to start the 45 second test(as above) to ensure the prop is still safe for your components. In doing so it is required to re-evaluate the maximum run time of your hull by either cell capacity limitations (as above) or thermal limitations. Continue these steps until the best suited prop is found.
It may turn out using the 45 second test that certain screws have been loosened, hatch tape is slowly peeling off, hardware have been adjusted ect. During each temperature check, it is a very good idea to check over as many screws as possible. Try to rotate the can of the motor to make certain it is snug and the motor mount screws have not been loosened. Check all hardware to be certain each component has not been adjusted from the run. Inspect the drive line for excessive temperatures caused by insufficient oiling/grease. Look over the thrust bearing and prop shaft to insure it is secured and working the way it should be.
Following these simple rules will greatly increase the odds for a successful 1st or 100th run.