Is there a better flight "time" difference in 3S vs 4S

G

gencode

Member
I asked a question before, and found out some good things with 4S faster spin speeds.
But my real question is more for flight time, mainly for photography so I have more air time to get some pics and keeping the weight down.
I wont fly in high winds so the only thing Im worried about is keeping it in the air.

So for photography of say buildings wouldn't 3S be better since its lighter and should give me more flight time because, again, since its lighter.

Also the lighter 3S should free more weight for more payload.

Or is that assumption incorrect?
 

kloner

kloner

Aerial DP
you can prop lower on motors to run 4s at lower amp draws than the 3s will while still maintaining the same watts. With that said your able to run less mah and same weight packs. on mine, i get the same weights, flight performance in wind with the smaller prop heli is better and it's a 4400 3s vs 3000 4s. Same flight times, essentially the same thing but less wobbles in wind. Also when i've done fast forward flight,,,,, the 3s amperage will go out of range. it is similar to why your tv runs on 110 volts but your air compressor uses 220 volt. Lets it be less stress on the systems and achieves the same watts...... Voltage x amp= watt the motors KV is huge in the "range" you get to play with prop wise. The most important part is proping and the ability to even buy the right props given weight, size, payloads, etc. Higher voltage means a motors kv= "rpm per volt" is increased
 

G

gencode

Member
Thanks, rather confusing to me but ill read this a few times.

Im running 10" only on the props with a 4S 2200
but i only get 10 min flight times, if that, so was thinking on paralleling two 4S so it should double my flight times, but then worried about too much weight.


kloner said:
you can prop lower on motors to run 4s at lower amp draws than the 3s will while still maintaining the same watts. With that said your able to run less mah and same weight packs. on mine, i get the same weights, flight performance in wind with the smaller prop heli is better and it's a 4400 3s vs 3000 4s. Same flight times, essentially the same thing but less wobbles in wind. Also when i've done fast forward flight,,,,, the 3s amperage will go out of range. it is similar to why your tv runs on 110 volts but your air compressor uses 220 volt. Lets it be less stress on the systems and achieves the same watts...... Voltage x amp= watt the motors KV is huge in the "range" you get to play with prop wise. The most important part is proping and the ability to even buy the right props given weight, size, payloads, etc. Higher voltage means a motors kv= "rpm per volt" is increased
Click to expand...
 

kloner

kloner

Aerial DP
if you just hover, changing to 8" props wouldn't change flight times a whole lot. if were talking flying, then it changes everything...... they all seem to hover the same watts per pound,,,,,,,,,,,, but flying per pound has a huge influence on flight times on what prop...... a 10" prop on 4s would hit 120 amp draws on my rig with my type of flying. it's never work esc's would be maxed, thing would handle horrible.... what am i saying would, they did cause i did it a while.

If you hovering in manual mode at half stick with the load you got and that setup, leave it alone. if it's not, we can help you make it fly better, same flight times though if your hovering and slowly flying around
 

T

Totality

Member
Kloner, I use 4S with 10" Graupner on a fully loaded DJI 920KV motor / DJI 30A ESC / Naza / X650 setup. Weighs about 2KG overall. Hovers at just over half stick in manual, but from what you say I should be using smaller props? Wouldn't this make it require more power to achieve the same lift if I put 9" on? I'm confused :(
 

DesJardins

DesJardins

Member
My understanding is that if your hovering in manual at over mid stick you can prop upsize, if your hovering in manual and under half throttle then you can prop downsize.
Feel free to correct me if I'm wrong.

With no FPV gear I feel the 10" props are over kill with my 3S packs and affected by wind too much.
 

kloner

kloner

Aerial DP
Your at the end of the watts your motors make. when you hit this end, you'd want 11" props for that motor/batt/prop/weight setup, problem is your making more watts there than your motors make

You really just need more motors then decide if you want big props spun slow or little props spun fast so you can pick a kv/size and prop combo


added info, a stock kit is designed to carry itself. When you load em down the main thing you want to change is the power, ie motors
 
Last edited by a moderator:

G

gencode

Member
Well all this is great info on the props, but really I guess I was wondering if I should run 2 3S or 2 4S with my current setup, almost 2KG, mostly slow flights because im trying to get some nice pictures of objects for my web site.

I was about to buy 2 batteries today but did not see any advantage of the 4S with the same man, but it sounds from this the 4S does have an advantage overall, except its heavier.


kloner said:
Your at the end of the watts your motors make. when you hit this end, you'd want 11" props for that motor/batt/prop/weight setup, problem is your making more watts there than your motors make

You really just need more motors then decide if you want big props spun slow or little props spun fast so you can pick a kv/size and prop combo


added info, a stock kit is designed to carry itself. When you load em down the main thing you want to change is the power, ie motors
Click to expand...
 

T

Totality

Member
kloner said:
Your at the end of the watts your motors make. when you hit this end, you'd want 11" props for that motor/batt/prop/weight setup, problem is your making more watts there than your motors make

You really just need more motors then decide if you want big props spun slow or little props spun fast so you can pick a kv/size and prop combo


added info, a stock kit is designed to carry itself. When you load em down the main thing you want to change is the power, ie motors
Click to expand...

Thanks Kloner. Was looking at upgrading the motors and using the stock DJI ones with another test build. What would be a good motor for using with Naza, DJI 30A, 4S batteries? I have a gimbal and GoPro mounted. Can move to 9" Graupner if preferred.
 

kloner

kloner

Aerial DP
gencode said:
Well all this is great info on the props, but really I guess I was wondering if I should run 2 3S or 2 4S with my current setup, almost 2KG, mostly slow flights because im trying to get some nice pictures of objects for my web site.

I was about to buy 2 batteries today but did not see any advantage of the 4S with the same man, but it sounds from this the 4S does have an advantage overall, except its heavier.
Click to expand...

you'll get more thrust with less amp draw. all that helps is the esc's as far as helping it electronicaly. if you were able to downsize props, it'd make her wobble less..... watts are still watts and that's what your seeing at the motors. i think the dji motors are 125 watt, that's 500 total is the weight is dead center it is evenly distributed but if it's off, a motor will try to carry it and get mad about it sooner or later.

Like i said, i fly a quad at 1.9 to 2.6k, it hovers at 20 amp x 16 volt=320 watt and nothings going up or down, just floating. if i floor it in atti and shoot up, 70 amps x 16 volts =1120 watts
 

G

gencode

Member
Just took a flight to get a better time, only get 4.2 minutes flight before blinking red :-(
New battery fully charged

kloner said:
you'll get more thrust with less amp draw. all that helps is the esc's as far as helping it electronicaly. if you were able to downsize props, it'd make her wobble less..... watts are still watts and that's what your seeing at the motors. i think the dji motors are 125 watt, that's 500 total is the weight is dead center it is evenly distributed but if it's off, a motor will try to carry it and get mad about it sooner or later.

Like i said, i fly a quad at 1.9 to 2.6k, it hovers at 20 amp x 16 volt=320 watt and nothings going up or down, just floating. if i floor it in atti and shoot up, 70 amps x 16 volts =1120 watts
Click to expand...
 


G

gencode

Member
No I have not, so it may not be 100% correct, I know I have at least another minute.

I dont have another way to test, Ill pick one up a tester, I have seen ones that seem to transmit to an attachment on the receiver if I can find it,

DesJardins said:
Even though the red light is flashing have you verified what the cell voltages are after the 4min?
Click to expand...
 

kloner

kloner

Aerial DP
telemetry.......

there is things like eagle tree logger to, goes inline and you download a file to see exactly whats up....
 





G

gencode

Member
Kloner, does this intercept the current fpv video and put the telemetry on real time? Or is this after the fact that you add on the PC?

Also does this work with the fatshark fpv?

kloner said:
telemetry.......

there is things like eagle tree logger to, goes inline and you download a file to see exactly whats up....
Click to expand...
 

DesJardins

DesJardins

Member
This allows you to test your battery packs and see what the actual voltage is reading as well as double as a warning alarm you can hear vs. just a blinking red light.
I'm wondering if your low voltage isn't correct in your software or a VU problem.

This would be a cheap way to test your cells and see if the pack is good/bad, see if the low voltage matches what the assistant software says & can always be used for an audible alarm while flying.

gencode said:
Des, I don't see how this is much different than the red light on the NAZA as long as its calibrated correctly, unless I'm missing something.
Click to expand...
 

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