In Chris Rosser's latest video, he dives deep into testing a variety of 31mm props for tiny whoops, aiming to determine the best options available. The focus is on understanding how different props affect performance metrics like thrust, efficiency, and responsiveness.
Props on test
The props featured in this test include:
- Gemfan 128 triblade
- Gemfan 129s triblade
- T-Motor 12199 triblade
- HQ 31mm byblade
- HQ 31mm triblade
- HQ 31mm four-bladed prop
- HQ ultra light 31mm triblade
Test methods
Chris explains his approach to testing these tiny props, emphasizing the need for precision in measurement. He outlines how he collects thrust data and the various trade-offs that come into play when selecting the right prop. The aim is to scientifically assess each prop's performance, ensuring a thorough evaluation.
Test setup
The test setup features an RCM power 0802 27,000 KV motor, carefully aligned with an optical RPM sensor. Chris uses a separate BLHeli S 1 to 2S ESC to drive the motor, powered by a Molly Cell P45B lithium-ion battery. The setup includes sensitive 100G load cells for both torque and thrust measurements, showcasing the meticulous preparation involved in achieving accurate results.
Example test: SO CUTE!
To illustrate the testing process, Chris shares a quick example run, highlighting how data is collected and the rigour involved in the testing phase. The playful commentary adds a light-hearted touch, keeping viewers engaged while providing valuable insights into the testing procedure.
Test results: Motor Mass
After running the tests, Chris discusses the mass of each prop. Notably, the HQ 31mm X4 is significantly heavier compared to the ultra light HQ 31mm X3. This difference in weight affects the responsiveness of the whoop, with lighter props generally offering better acceleration and deceleration.
Thrust vs RPM
The thrust versus RPM chart reveals how each prop performs at various RPM levels. As expected, the 31mm byblade prop produces the least thrust, while the four-bladed prop generates the most. Interestingly, the T-Motor 12199 prop matches the thrust of the HQ 31mm X4, indicating its aggressive design and pitch.
Efficiency
Efficiency is a critical metric for many tiny whoop racers, and Chris highlights the slight differences between the props. The efficiency of tiny props tends to be lower compared to larger ones, with the HQ 31mm X2, Gemfan 128, and the HQ ultra light 31mm X3 performing relatively well. On the other hand, the older HQ models lag behind in this aspect.
Propwash
Chris introduces the concept of prop wash, discussing how certain props handle adverse flight conditions. He measures each prop's susceptibility to prop wash using the Advanced Ratio, which assesses the relationship between axial air flow velocity and tangential prop tip speed. Props with a high tip speed are less prone to stalling, making them preferable for smooth flight performance.
Best props!
In conclusion, Chris identifies the best performing props from his testing. The HQ ultra light 31mm X3 emerges as the top choice overall, balancing weight, thrust, and efficiency. For those seeking speed, the T-Motor 12199 is recommended, while the Gemfan 128 is highlighted for its smooth performance in prop wash conditions. Chris advises against using the older HQ models due to their heavier weight and lower efficiency.
FAQ
- What is the best prop for efficiency? The HQ 31mm X2 and Gemfan 128 triblade are among the top performers in terms of efficiency.
- Which prop is best for handling prop wash? The Gemfan 128 is noted for its ability to handle prop wash effectively.
- Are heavier props always worse? Generally, lighter props are more responsive, but the specific use case may dictate the choice.
- Where can I buy these props? Unmannedtech
For a deeper dive into the testing process and more detailed data, check out Chris Rosser's full video on his YouTube channel.
