!! im sorry, i did a mistak by scaling, dont know how to change the pull
liion 2s 3000mah is 95g (not 68g)
the 2s 1500mah is 90g (not 100g)


10a 2s esc / 16x16 f4 / hyperbola v1 frame / noisy dys 1306 4000kv / swift micro / gf5125x3 / xm+ / 470uf 35v / nano32

i will shorten the cam wire, add a vtx and thats it, no topplate...

the build is 100g, i need a more accurate scale.
i didnt build as light as possible, up to 20g could be saved on the same parts, at extrem weight focused building.

this build is no longrange quad at all but its a cruiser and as flighttimes/flightdistances are a imprtant discipline for longrange, i thought i post it inhere.




how good can you imagine flighttimes and battery matches?
the deal would be to cruise at a low throttle level, forward-hoovering about 30kph.

to try is:
a 450gnb 2s 80c
a (2cells of sorted out 4s) tattu r-line 1500mah in the past 90c
a liion samsung 10c 18650 3000mah

what will give the best flighttime? until voltage drop under 3v for lipo and for liion under 2,75v
(what should i choose for the liion, 2,75v a good value?? dont know the rest capacity% in comparison)


this wont be true scientific, just for fun. share your ideas of flighttime, who will get close with knowledge and some luck? which battery should be choosen? will this settup be nice in anyway?

next to the poll what flighttime is your imagination on the best matching battery?

Hi Hugnosed,

Very interesting build. I look forward to see how this turns out.

Where did you get the 2S 18650 3000 mAh pack that weighs 70 grams ??  That would be 35 grams per cell or less when allowing for the wiring harness.

If you have a link, please share.

All of the 18650 3000 mAh cells that I have found weigh about 45-50 grams per cell; plus the wiring harness.

Thanks.

the weight of 68g is sure but probably the capacity is wrong im sorry
need to do research, the two cells was a gift by buddy

(29-Jan-2021, 04:55 PM)hugnosed_bat Wrote: the weight of 68g is sure but probably the capacity is wrong  im sorry
need to do research, the two cells was a gift by buddy

Hi Hugnosed,

No worries. I am just always looking for better batteries; You know, the high capacity, low weight kind     

I’m going with the li-ion batt...
(3000/1000)*(4.1*2) = 24.6 watts (for li-ion)

(1500/1000)*(4.2*2) = 12.6 watts (for tattu)

(450/1000)*(4.2*2) = 3.78 watts (for GNB) (not a LR battery...)

The li-ion batt has almost twice the power as the tattu, But is 30 grams less (Edit 5 grams more... )
Edit: the li-ion weight was wrong...

im sorry corrected in the post but i cant change the pull or dont know how.

the liion is 95g
ant the lipo weight is also wrong its not 100g its 90g


"Samsung INR18650-30Q" i guess these are it, but not sure anymore. these would be 5c not 10c. i will update when i have the exact model

I think a lightweight 5" build could really cover some ground, especially on 2S with Li-ions!

Are you sure about that pack weight for the 18650 cells? Most 3000mAh cells are 45-50g each. Edit: I see you answered all of this while I was typing. I'll update my numbers below.

Some eCalc numbers:
GNB 2S 450mAh: 10.7 min hover, 3 min mixed flight, 1.4 km range, 7.3 thrust:weight @ 130G AUW
Tattu r-line 2S 1500mAh: 20.4 min hover, 7.5 min mixed flight, 3.2 km range, 5.0 thrust:weight @ 190g AUW <- Over 10A at max throttle, may blow ESC
2S 18650 3000mAh: 45.2 min hover, 18.2 min mixed flight, 7.1 km range, 4.1 thrust:weight  @ 193g AUW
2S 21700 4000mAh: 42.8 min hover, 21.4 min mixed flight, 7.4 km range, 3.1 thrust:weight @ 240g AUW <- diminishing returns with the larger LiIons

If you switch to some APC E props, they're crazy efficient and could easily bump this to a 10km+ build:
https://www.racedayquads.com/collections...rop-4-pack
https://www.racedayquads.com/collections...rop-4-pack

2S 18650 with the APC 5.1x5.0: 
55 min hover, 19 min mixed flight, 12.3 km range, 4.7 thrust:weight  @ 193g AUW <- Over 10A at max throttle, may blow ESC. Definitely set throttle limit in BF.

2S 18650 with the APC 5x4:
56 min hover, 20 min mixed flight, 11.8 km range, 4.5 thrust:weight  @ 193g AUW

thanks for the ecalc math


so it looks like wont do a hoover try xD on the liion xD battery

does ecalc provide a particular flightspeed, efficiency sweet spot?


the esc burst is 15a, its about 3 years old, its a cheapo eachine esc: wont die xD i have a few of them
i dont expect differences about throttle increasement above 75% about throttle authority

(29-Jan-2021, 06:57 PM)hugnosed_bat Wrote: does ecalc provide a particular flightspeed, efficiency sweet spot?

With the 2S 18650: max efficiency at 12-15 mph cruise, 3.7A/motor current draw (~15A total). I guess that's the downside of big, slow, efficient props - slow cruise speed.

crazy more efficiency on the apc props :-o
intresting the higher pitched prop is more efficiency.

tiny reallife try today, haha what a result xD
7degrees outside

started with the liion, in case i wont fly after... 24seconds tha battery passes 3.5v. another 25s the voltage passes 3v. the liion doesnt provide nearly the c-rate in cold conditions, this let me believe even in warm conditions the battery wont be able to provide the capacity bevor voltage drops under 2,5v per cell.
i believe liion with their low power is the wrong battery for this settup. 2s2p 6000mah would make the battery way to heavy, need that 70g liion xD doesnt exist :-)

i flew 11miutes on the 1500mah battery, the voltage recovered to 3,6v per cell, lets see what mah it used by recharge :-)

i had spare transmitter battery, 900mah 2s 25c, i flew 4minutes until it started to rain. there was still capacity and no drop under 3.3v

both flights was with a few powerless flips and rolls, sort of cruising and mixed flights.

(29-Jan-2021, 05:14 PM)V-22 Wrote: I think a lightweight 5" build could really cover some ground, especially on 2S with Li-ions!

Are you sure about that pack weight for the 18650 cells? Most 3000mAh cells are 45-50g each. Edit: I see you answered all of this while I was typing. I'll update my numbers below.

Some eCalc numbers:
GNB 2S 450mAh: 10.7 min hover, 3 min mixed flight, 1.4 km range, 7.3 thrust:weight @ 130G AUW
Tattu r-line 2S 1500mAh: 20.4 min hover, 7.5 min mixed flight, 3.2 km range, 5.0 thrust:weight @ 190g AUW <- Over 10A at max throttle, may blow ESC
2S 18650 3000mAh: 45.2 min hover, 18.2 min mixed flight, 7.1 km range, 4.1 thrust:weight  @ 193g AUW
2S 21700 4000mAh: 42.8 min hover, 21.4 min mixed flight, 7.4 km range, 3.1 thrust:weight @ 240g AUW <- diminishing returns with the larger LiIons

If you switch to some APC E props, they're crazy efficient and could easily bump this to a 10km+ build:
https://www.racedayquads.com/collections...rop-4-pack
https://www.racedayquads.com/collections...rop-4-pack

2S 18650 with the APC 5.1x5.0: 
55 min hover, 19 min mixed flight, 12.3 km range, 4.7 thrust:weight  @ 193g AUW <- Over 10A at max throttle, may blow ESC. Definitely set throttle limit in BF.

2S 18650 with the APC 5x4:
56 min hover, 20 min mixed flight, 11.8 km range, 4.5 thrust:weight  @ 193g AUW

You need to look at it from power/watts and efficiency perspective.

Typical 600g 5" 6S, slow crusing is only 4.5g/W.
If you use 4S, or small battery goes up to 5g/W. Maybe 6g/W. On oldschool 5", 15min flight time is almost impossible.

But talking ultralight.
We have 250g limit. Assume 400g thrust cruising.
So, find best motor + prop @100g thrust.
Sunnysky 2304 is 20g and can do 13.5g/W on 8043 prop.
https://sunnyskyusa.com/collections/prem...y-x2304-v3

400g thrust, 250g hover (eff even higher, so W lower)
@10g/W = 40W, 25W*
@13.5g/W = 33W, 19W*
Our power use should be somewhere in this range.

The hyper efficient 2304 motors and 8" prop. 13.5g/W.
A Gaoneng 1100mah HV 4S = 800Wmin @80% capacity.
800/33 = 24min cruising and 800/19= 42min hover

But, we cant build a 8" under 250g, and this battery.
But if 5", we hit 10g/W: 800/40= 20min cruising, and 800/25= 32min hover. I think thats realistic

i will giv my settup a try on gf4023x3 with the 1500mah battery, what direction will the efficiency turn out?