I've been performing some flight tests using two batteries and I'm just not getting what i was expecting. I am hoping other Y6 users can chime in with their battery/flight times, and see if i'm really off.. or if this is what is expected. Lastly, most importantly.. what can I do to increase flight time? It would be a goal of mine to achieve 20minutes.
Battery 1: Turnigy nano-tech 5000mah 3S 25~50C Lipo Pack
Approx 8minutes.
Batttery 2: ZIPPY Flightmax 5800mAh 3S1P 30C
Approx 10 minutes.
Using 850kv 3DR blue motors. Long Range Telemetry module. Dragonlink for Radio. Carrying Tarot 2D gimbal (+200g) no camera for these tests.
Attached images of flight times and VCC/volt data.
Replies
Hi Raph,
It's normal that Y6 has a rather bad flight time. My spec,
Y6 with Sunnysky 800kv
Turnigy 4S 5000mah or Zippy 2x 4S 3000mah
APC 11x4.7 props
AUW 2.92kg
HBK low voltage lipo buzzer default at 3.3V
Flight time btw 7min to 8mins. A Y6 compare to Hexa, has 20% efficiency lost, which i think is quite a lot.
And in the ecalculator, the "6" is for Hexa, minus the calculated flight time by 20% and you will get pretty accurate result, at least in my case it's very very very accurate.
I am sensing a apples to oranges batch of comparisons here.
For the most part a quad or a hex is always going to be 10 to 20 percent more efficient than an "equivalent" Y6 because of the intrinsic inefficiencies of the Coax configuration.
But, individual tuning of each of the components, motors, props and weight is significantly more important than any of that.
Generally the bigger the prop diameter the better the efficiency (assuming your motor can operate most efficiently at the resulting hover motor rpm speed).
And, bigger prop diameters decrease stability and responsiveness, so it is a trade off.
If you want the longest flight times the new Big (and really expensive) 100KV T-Motors with 29" props will give you great flight times, but you probably won't be happy in gusty winds.
Guessing this really isn't an option, but the reality is that motor, battery cells, total vehicle weight and prop need to be carefully matched for optimal flight times, usually figured with hover throttle at about or less than 50% for best efficiency.
Raph,
These are fairly standard flight times with 200g as your payload. Keep in mind, we found a 1200 gram max payload for the Y6 is as much as you can lift safely. Payload would include anything that is not the airframe, motors, props, escs, PDB, RC Rx, or APM components. You could carry a 1000 gram battery max with your 200g gimbal and be right near the maximum recommended payload weight. Once you know your camera gear weight, you can use the remaining weight to fit as big of a lipo as possible if you wanted. The prop configuration (10/11) was chosen because it showed the greatest efficiency between all of the other prop combos that we tested. It was to my surprise that a pitch differential made little difference, but a 10% increase in prop diameter on the lower prop required the least power to fly in any given configuration-
I think 8 minutes with a 5000mah batter is very reasonable with a Y6. I have a quad and get about 10-11 minutes flight time with my 5000mah battery and I have the alarm set at 10.5 volts.
If you're getting 8 minutes (.133 hours) with a 5ah battery then you are pulling about 5/.133=37.5 amps or 6.25 amps per motor which sounds about right. I didn't take into account the Peukert number but this would lower the estimate.
I get about 10 minutes taking 6000mAh out of my 8000mAh 3s bats, mine is about 2500grams with graupner 11x5 props.
Hi Raph
First I have to say that I believe any X2 config is inefficient. Only reason I would use it is, if you need redundancy.
why i don't like it is simple. The prop inside the stream of air is not doing the work it should but adds the full weight for motor, esc and cables to the config. Only way to go around that is to add a bigger prop to the bottom motor. You have to test that as you get no reliable number for power consume and thrust rate of such a setup. if you want to fly 20 min, make it a Tricopter.... you loose all redundancy... but gain quite a bit in weight you remove... so flight time.
Important is the prop you swing... there are huge differences to prop size/pitch, how efficient the motors power consume will be compared to lift. Slow flyer are best at 50% throttle and suck over 80%. E-type on the other hand get good over 70%. Depending how you fly and what pos is hover for your gear, choose your prop. Balance each prop, get good props!
All will add to make your craft fly smoother.... if you don't reach 20 min on indoor hover, you should rethink your concept... depending on weather... we tested a quad and hex in a good 25 knots wind on loiter.. the quad had 50% flight time drop due to heavy wind corrections... so how you measure... will change your results in flight time.
Cheers
J
@Ralp or Wessie, have you tried running the numbers through ecalc to see if it is close? Im not sure how well a Y6 vs hex compare for efficiency. http://www.ecalc.ch/xcoptercalc.htm?ecalc&lang=en
What is your thrt value at when your are hovering? you might be able to go up a prop size to increase your hover time (but decrease your max thrt time) ecalc can give you an idea how this changes. Just be sure you do not exceed your speed control, motor, or battery current limit.
If you do change your prop size, don't forget to redo your PIDs and hover point.
last attachment.
5800-vcc-volt.JPG
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