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| Medusa Products MR-028-040-3400 | |||||||||||||||||||||||||||||||||||||||||
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| Firstly my thanks to Medusa Products for supplying this motor for testing. The Medusa MR-028-040-3400 is a new motor onto the brushless market. It is quite heavy at 100g and therefore at the top of the weight class for the T-Rex. With it's 3400kv rating I chose an 11T pinion for the purposes of testing. Fitting the motor was very straight forward with no large heatsinks to get in the way of positioning the motor. Having fitted the 11T I did a short test flight to check headspeed and basic running of the motor before subjecting it to test conditions. Running the Align Carbon Blades and with the governor set to 95% the headspeed was 2750 RPM, which produced a very responsive T-Rex and blistering climb rate. This is certainly going to be a good motor for 3D based on it's ability to deliver headspeed. Thoughts of the AON 2815-3500 immediately sprung to mind. For the purposes of the test I would need to govern that headspeed down to the 2450 RPM that the wood blades can cope with. This meant governing the motor back to 87% throttle. The Phoenix 35 kept the Medusa under nice control using the governor mode throughout the flights.I'm going to run two separate bench tests for the Medusa, one test using stock wood blades and the other with the Align Carbon Fiber 325mm blades. Both tests will follow the standard format as below. The tests were conducted in an ambient 22 degrees centigrade, 72 degrees Fahrenheit. The pitch range on the T-Rex being from +/- 10 degrees. Due to the Tanic 2220mah starting to struggle with the loadings placed on it I have now changed to using the new Kokam 3S 2000mah gen4 pack. This pack holds it's voltage far better than the Tanic and has a greater capacity for delivering the amps required in these tests. |
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| Graphs from the 315mm Wood blade test : | |||||||||||||||||||||||||||||||||||||||||
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| The Medusa recorded the following maximum values : 25.6 amps 12.6 volts 263 watts The recorded minimum voltage was 9.8 volts during the 30 second full throttle/pitch. The motor temp at the end of the test was 70 degrees centigrade, 158 degrees Fahrenheit. The lithium pack reached a max temperature of 40 degrees centigrade, 104 degrees Fahrenheit. For the duration of the test I had fitted the Align heatsink as this motor can climb to 87 degrees without it, whilst this is within specification the motor benefits from the extra cooling. During the 30 second climbout the headspeed dropped from 2450RPM to 2260RPM, a 190RPM drop in overall headspeed over a full 30 seconds of full pitch. This is an AON 2815-3500 beating performance and by quite a considerable margin. However, there is a price to pay for this performance as can be seen in the amp draw figures. The Medusa motor pulled a maximum current of 25.6 amps, this will certainly impact flight times but is the price to be paid for that huge performance. This put to one side the Medusa takes the lead as the most powerful motor on test so far and it is evident in it's flight performance with both wood and carbon blades. Where this motor stands out is in much the same areas as the AON, headspeed being one and brute force the other. With SAB Carbon blades and a 2750 RPM headspeed the climb rate is nothing short of ballistic. It's going to be interesting doing the Align Carbon Blade test as this motors figures put it at it's most efficient close to the 30A range, the T-Rex will be around this baseline with the carbon blades. In order to get a more efficient run from the motor and to see if I could improve the wood blade test I installed a 10T pinion and re-ran the tests. This time the max headspeed I could attain was 2300RPM at 100% throttle which is below where I normally like to start but hopefully this more efficient run would mean a lower overall drop in RPM on the head at full pitch. Temperature was an ambient 22 degrees centigrade for this test. The test conclusively proved that a 10/t pinion was not going to enhance performance and the overall RPM drop in the full pitch test was considerably higher. Align Carbon blades are the next test. Graphs for Align Carbon Blades : |
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| The Medusa recorded the following maximum values : 33..4 amps 12.6 volts 324 watts The recorded minimum voltage was 9.1 volts during the 30 second full throttle/pitch. The motor temp at the end of the test was 69 degrees centigrade, 156 degrees Fahrenheit. The lithium pack reached a max temperature of 54 degrees centigrade, 129 degrees Fahrenheit. For the duration of the test I had fitted the Align heatsink as this motor can climb to 87 degrees without it, whilst this is within specification the motor benefits from the extra cooling. During the 30 second climbout the headspeed dropped from 2450RPM to 2100RPM, a 350RPM drop in overall headspeed over a full 30 seconds of full pitch. The results from this test were somewhat jaw dropping in terms of the amp draw and watts produced by the motor. This certainly is one very powerful motor but there is a price to pay in terms of current draw and flight time, although see below for mitigating circumstances. Fortunately the Kokam coped with the 33.4 amp peak and in fact came off the machine relatively cold considering the stress it had just been put under. If you intend to run the carbon blades with this motor then don't even think about going for a budget lithium pack, it won't cope and your ESC will shut down. After some further checking I discovered that for the above carbon blade test the top pitch range was actually 11.5 degrees rather than my normal 10, which does account for the abnormally high current draw in this test. However, given the extra 1.5 degrees of pitch the Medusa motor still managed to hold 2100RPM, which is extremely good considering that extra load it was under. I'm not sure how this deviation in pitch range occured but rather than re-test I am going to leave this data as it stands. Conclusion There is no doubt that this is the most powerful motor I have tested. No other motor has come close to breaking 300 watts power output. The motor has bags of headspeed to offer on an 11T pinion and power to spare behind that headspeed. The only concern would be slightly high amp draw, most 3S packs won't cope with that level of current draw. Plus, flight times will be reduced as a result. If you want to run 3S and just want all out power without worrying about flight times, then this is the motor for you. Due to my changing lipo for this test and that the test machine has had a rebuild I re-tested the AON to allow for changes, just to confirm which motor has the most power. The Medusa was confirmed as being well ahead of the AON at the end of the re-test. One point to note is the AON did draw more current than it's previous test (due to the extra pitch noted above) and hit a maximum of 23amps, on average it was 3 amps adrift of the Medusa, which isn't a huge margin in terms of flight time impact. One way of minimising this amp draw is to reduce the maximum pitch range and make up for it in more headspeed, which should allow for a more efficient run whilst still delivering excellent performance. If you have this motor rate it yourself using the TRex Tuning rating system : |
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