Recently at OpenROV Headquarters, we did some tests on the efficiency of various propellers which we thought might be good alternatives the to E-Flight Delta-V 15 ducted fan props we have been using so far. The original selection of the Delta-V 15 was really made primarily because it fit (mechanically) very nicely with the motor we had selected, and it "looks about right", but the only hydrodynamic analysis we did was pretty crude. We decided to get a little bit more scientific...
For this first set of tests, we selected two propellers to compare to the Delta-V 15:
The objective of these tests would be to measure the efficiency of the selected props by comparing the thrust they produced when spun by one of the brushless motors we use for OpenROV and comparing that to how much current was consumed in order to achieve that. To measure thrust, we used the open-source test stand that Colin Ho designed and built several months ago.
We plan to do more thorough testing soon (which will also have a much more thorough write-up), but in the mean time, we thought it would be good to show some initial results. Bottom line: the Graupner 2308.65 gave us a more then 200% increase in thrust/current efficiency!
This means that among other things, simply by changing props, we'll enjoy:
- Much longer battery life
- Less thermal issues from the ESCs
- Thinner tether or lower voltage necessary to send power over the tether (future ambition)
- Less noise generated by the ROV (probably)
- Less fatigue on the battery tube (as a result of to opening it less to change batteries)