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Propel efficiency/performance test bench
Efficiency of powertrain is everything in multirotor building along with weight. Single propel thrust data is available everywhere. But I didn't find anywhere fact how two propels behaves on same axis (co-axial setup). Another propel is then in the first propel airflow. Two propels side by side could be calculated approximately as 1+1. Internet discussions says often that two propels on same axis is calculated as 1+(1*0.7). This test bench I used for testing that myth. My test results didn't fully support the myth. My results shows more like 1+(1*0.78 or 0.85). If lower prop runs faster then efficiency is better. Higher pitch (chinese wooden 1480) as lower prop made efficiency even lower if rotational speed was same on both props. Propels I used were APC 1455 MR and APC 1455 MRP.
Results: docs.google.com/spreadsheet/ccc?key=0AsH8A-9COlqudFlkUmx3...
Propel efficiency/performance test bench
Efficiency of powertrain is everything in multirotor building along with weight. Single propel thrust data is available everywhere. But I didn't find anywhere fact how two propels behaves on same axis (co-axial setup). Another propel is then in the first propel airflow. Two propels side by side could be calculated approximately as 1+1. Internet discussions says often that two propels on same axis is calculated as 1+(1*0.7). This test bench I used for testing that myth. My test results didn't fully support the myth. My results shows more like 1+(1*0.78 or 0.85). If lower prop runs faster then efficiency is better. Higher pitch (chinese wooden 1480) as lower prop made efficiency even lower if rotational speed was same on both props. Propels I used were APC 1455 MR and APC 1455 MRP.
Results: docs.google.com/spreadsheet/ccc?key=0AsH8A-9COlqudFlkUmx3...