low thrust with 2205 motors on Mini Guinea

[timshotts]

I'm rebuilding my mini guinea with 2205 2300kv motors and 30amp ESCs, and Gemfan 6040 props. https://www.aliexpress.com/item/32694789418.html?spm=a2g0s.9042311.0.0.6f794c4diGmOPg https://usa.banggood.com/Sonicmodel...p-1649079.html?rmmds=myorder&cur_warehouse=CN and https://usa.banggood.com/1-Pair-Gem...p-1320274.html?rmmds=myorder&cur_warehouse=CN which look like the same thing as https://hobbyking.com/en_us/brushle...941&indexName=hbk_live_magento_en_us_products and https://hobbyking.com/en_us/hobbyking-30a-2-4s-esc-3a-ubec.html. I'm only getting about 750g combined thrust out of them. So far, I've bypassed the y-harness and mounted a 850mah 3S 70C battery under each nacelle in case my y-harness was dropping the voltage too much despite it's 0.2 ohm resistance. I took some extra XT30 connectors and make a triple parallel connector to hook three 850mah 3S 70C batteries together that then attached to my y-connector so see if my batteries just couldn't supply the current and it made no difference. I reset and recalibrated my ESCs. Nothing I do is getting me close to the 1200g of thust I am expecting. I don't have a wattmeter and I have checked the direction of the props, and even measured their thrust reversed - It's about half if anyone is wondering. Does anyone have experience with any of the items I'm using? I'm not sure what else I can do to troubleshoot this. Thanks in advance.

 

[Bifi.baarlo]

0,2 Ohm is too much, 20A X 0,2Ohm is 4Volt.

 

[Ketchup]

Have you made sure that your tx is giving you full range? Maybe you could calibrate your tx sticks (at least you can on spektrum). If you are flying spektrum then go to the page that tells you how much controls you are using and make sure that throttle goes from -100 to 100.

 

[timshotts]

0,2 Ohm is too much, 20A X 0,2Ohm is 4Volt.

I agree, so I double checked the resistance this morning with a similar length of wire (about 18"). I think my multi-meter is incapable of measuring a resistance lower than .2 and was showing an incorrect value.

Have you made sure that your tx is giving you full range? Maybe you could calibrate your tx sticks (at least you can on spektrum). If you are flying spektrum then go to the page that tells you how much controls you are using and make sure that throttle goes from -100 to 100.

I re-calibrated my throttle again and tried with a different receiver and new model profile, but it's still not providing the thrust I'm looking for.

Thank you both for your suggestions. I suspect that the 18awg y-harness insufficient even if it's *OK*, so I have some 14awg wire that should be arriving any day.

 

[Bifi.baarlo]

I agree, so I double checked the resistance this morning with a similar length of wire (about 18"). I think my multi-meter is incapable of measuring a resistance lower than .2 and was showing an incorrect value.



I re-calibrated my throttle again and tried with a different receiver and new model profile, but it's still not providing the thrust I'm looking for.

Thank you both for your suggestions. I suspect that the 18awg y-harness insufficient even if it's *OK*, so I have some 14awg wire that should be arriving any day.

18 awg is enough, if the wiring is not getting warm, than that is not the problem. I have few planes with 2205 motors.

 

[FTcello1869]

Specs on HK website that you specified call 5045 prop. A 6030 (even at reduced pitch) will reduce your thrust.
Specs:
RPM/V: 2300kv
Voltage: 2~4s LiPoly (7.4~14.8v)
Output: <290W
Max Current: 21A
Suggested prop: 5045
Thrust: 800g (5045 prop/4s)
Efficiency: <3.0 g/W
ESC: 30A
Shaft: M5 CW
Motor Mount Holes: M3 x 16/19mm
Dimensions: 27.9 × 17.5mm
Weight: 28g

 

[timshotts]

I unhooked everything, and tested it outside the airframe, calibrating the throttle separately for each ESC instead of together (which I suspect was part of the issue with these ESCs...) and tested each motor individually (590g thrust), and together, with and without the y-harness (530g thrust with the harness and 590g without). Ketchup, I think you were right. Somehow the ESCs were not calibrating correctly when they were hooked up at the same time. Bifi.baarlo the y-harness is restricting the top-end power and getting warm, but no warmer that the battery, but you're right, not enough that would be causing significant drop in power. It's pretty close to the Hot-Rod STOL Guinea I was hoping for.

Thank you both for your help with the troubleshooting.

Here's a video of the STOL Guinea with 1806 motors and a 10mph wind.