Hello Dear Friends
I've build an Hexacopter based on Tarot 680Pro frame.
The problem Is that It doesn't take off at all (80% throttle until it actually start trying to)
I've calibrate the Remote (via Mission Planner) and the Esc's and It looks like It doesn't have sufficient power.
The Electronics Specs of it are:
6* Afro ESC 30Amp Esc's (SimonK firmware) - I didn't try to reconfigure it
HML 650 Carbon Fiber Folding Legs
APM 2.6 Firmware 3.2 Controller
Some lite FPV+Telemetry+MinimOSD+3 AA Battries.
Total weight about 2.8Kg
What Can be the problem for it can't lift itself at all?!?
Thank you very much
Best Regards
Yochai
Replies
I agree the issue is the motor. I have Tarot 4006 620kv motors on my 680 with 1355 props and dual 3s 4000mAh Lipos, so quite heavy and it just fly well about 20-30min.
I have the same frame setup on 4s. Your motors are too low KV for 4s, they just won't spin fast enough to give you the thrust you need for that copter (you would need 6s for those motors on that frame (but you would need to calc your power usage if doing that to make sure your other components are up to the task). If sticking with 4s then its new motors I'm afraid. 1355 props are the standard for this frame. Mine with a 3 axis gopro/gimbal and 2 x 4s 5Ah LiPos has AUW of 4.3Kg - I have no idea how you get your AUW so light. In any case I am running SunnySky x4108s 690kv motors and get a hover at around 40% throttle on 1355 Tarot CF props. eCalc is f=definitely your friend on calculating the thrust and power/efficiency curves though. Good luck. I'll be interested to see how you get on.
Be certain that the props are not mounted upside down. This is a common error and has led to bushels of pulled hair. Behaviour may be more or less what you describe.
If you can make your own large center plate by yourself, still useful original PCB for wiring.
Or, replace six carbon tube for long one.
Then you may be able to use your big motor and larger propeller.
340KV + 13"props + 4s do not fly :D
I suggest you put 16" props, if necessary just alternate mounting your motors one arm- top another bottom, this way you can fit 15"-16" props on hat frame no prob.
You're definitely using the wrong battery for that motor and prop size. A motor that low of kV must use a 6S battery or larger battery.
Right now eCalc shows your build hovering at ~80% throttle (definitely bad). Switching to a 6S battery brings hoover to ~56% throttle, but this adds a lot of weight.
Really you want this to be closer to 40% throttle if you're planning on adding more payload weight (i.e. camera + gimbal), but it's not critical.
If you want to stay with the 4S battery (I'd encourage this), I'd then suggest using the Turnigy 4225-610. This will give you hover at 40% throttle while saving you a lot of weight between battery and motors while offering a flight time around 20min.
Thank you Phillip
If I'll replace to Turnigy 4225-610 motors (with the current 4S 6000mAh & 30A ESC's & 1355 inch prop's)
Would I be able to add a 2KG payload (or even 4KG?)
What flight time should I expect?
I'm using 2814-710 motors driving Graupner 11x5s on a simiIar frame. I'm cheap, so I got RCTimer ones, even if it's sporting a $3k thermaI camera, but one can find them from Cobra, T-Motor, KDE and more.
The bird weights 2.1 Kg and has attached a ~ 1 Kg 11.000 mAh 4S pack giving 20 minutes of soIid fIight.
I didn't test, but a 2Kg payIoad is possibIe, with dismaI fIight time - expect 5-6 min most - but care shouId be taken about pack C-rating. 4Kg is a no-no unIess trying a 10-second beerIift :)
Based on a weight of 2.8kg with your current setup, just changing the motors will reduce this to 2.3kg.
Single 6000mAh 4S battery
With no payload (AUW 2.3kg): Hover = 20min @ 41% throttle
1.0kg payload (AUW 3.3kg): Hover = 11min @ 50% throttle
2.0kg payload (AUW 4.3kg): Hover = 8min @ 60% throttle
3.0kg payload (AUW 5.3kg): Hover = 5min @ 68% throttle
4.0kg payload (AUW 6.3kg): Hover = 4min @ 76% throttle
For comparison, if you use two batteries in parallel:
2x 6000mAh 4S battery in parallel (4S2P)
With no payload (AUW 3kg): Hover = 26min @ 48% throttle
1.0kg payload (AUW 4kg): Hover = 17min @ 57% throttle
2.0kg payload (AUW 5kg): Hover = 12min @ 65% throttle
3.0kg payload (AUW 6kg): Hover = 9min @ 72% throttle
As you can see, weight makes a huge difference in flight time. People who are flying for 40min+ do everything possible to reduce weight.
I would discourage any set-up that requires more than 60% throttle to take off.
Flight times may be slightly better if you spend a lot of time moving forward at a moderate-low speed while maintaining altitude.
These numbers were generated by eCalc.ch
Please ask eCalc for your setup.
5008-340KV has 700W by single motor that is too much power for the 2.8Kg hexacopter.
And also there will be synchronization issue by mismatch of ESC, motor and battery.
It will easy by change of 5008-340KV(700W) to 300W class motors.
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