Attitude and GPS sudden ascent

[Explorocam]

KV = rpm per volt..... when you run 4s the props spin faster making more lift, problem is your most likely over rating the motors watts which is volts x amps. When a motor hits it's max watts, it pops like a fuse eventualy

I understand that the stock stuff is rated for 4s. Is this not the case? When I ran the 4s the motors remained pretty cool. Not really warm at all. Running 2 x 3s in parallel for 15 minutes got the motors pretty hot.

 

[kloner]

and around 120-140 watts. the 2814 i run are 350 watt motors

the 10" props on 4s with 900-1000kv motors will hit as high as 900 watts from what i've logged flying at 2 kilos. usually depending on cg and the crafts attitude, 2 of the motors usualy work harder than the other 2. if you split 900 by 4 you get 225 watts each motor, but 2 of em say 300w and the other 2 say 150w would seem about right.

 

[Explorocam]

and around 120-140 watts. the 2814 i run are 350 watt motors

the 10" props on 4s with 900-1000kv motors will hit as high as 900 watts from what i've logged flying at 2 kilos

I don't understand.

 

[kloner]

i can tell, that's the only reason i keep trying................

a motor, any motor is rated with a max watt. that is volts times watts (3s is 12, 4s is 16 just to keep the math easy) lets pretend a quad hovers at around 250 watts with proper props like 8" with 4s or 10" with 3s in your case, as you mentioned is written on the motor.

if you have a motor running 20 amps, 16 volts with 4s and 8" props, the same voltage going in the same motor but you change the prop to 10" and your overwight, your looking at a quad hovering at lets say 30 amps and 16 volts = 480 watts, sitting still. if we take the 480 watts and divide it equaly between 4 motors your running 120 watts a motor. tilt forward, amps start going up cause atti is keeping you from loosing altitude and the numbers go up higher and higher

this would be the same except split in 6 if a hex, higher numbers if more than 2kilos cause is all i know. but i log all this info during a flight and see in on screen flying fpv/ can download it later in a data recorder. without actualy seeing it on the craft we discuss is tough, but the numbers would be pretty close

 

[kloner]

this will screw you up a little, but the logger in this video is off by 50%, if it says 200 watts, it was 300 watts, if it said 10 amps, it was really drawing 15 amps, but heres an entire flight in atti with the osd info

but that's on a perfectly propped rig. when the props are too big and too many volts, they will make the numbers go ape crap. this is 2814 1000kv motors with 9"x5" props. the info on them is they run 11" to 12" props when we start talking about silly numbers written across stuff. Those numbers they show are a watts x aps thing that is predeterminned as an average for most craft, not for every single guy. some out of the box might be 1500 gram and nothing is added, then the next guys got a nex5, 3 way gimble, 3 servos, 3 batteries on it and it's gonna hve different number. For that there doing arm extensions so you can run 2814 750 kv motors with 12" props to carry the weight right

 

[Explorocam]

I have given some thought to using my 6 Cobra motors; 2217/20 = 960Kv. The motor is the same diameter but are taller than the DJI motors.

 

[kloner]

and way higher watt ratings. what does this thing weigh?

 

[Explorocam]

and way higher watt ratings. what does this thing weigh?

the motor or the hex?

Sorry for all the run around, I'm still trying wrap my head around all this motor size to prop size to voltage to amps thing.

 

[Explorocam]

The hex loaded with one 3s 5000mAh battery is 2.2Kg.
The Cobra motor is 77g.

 

[kloner]

so when you had 2 3s was like 2.6-2.7?

my motors are 100 grams

 

[kloner]

does it have the dji esc's?

 

[Explorocam]

if the hex was flying and you took it straight to a scale with batteries, camera and all, what is it?

The hex loaded with one 3s 5000mAh battery, FPV, GoPro and Transmitter with VTx battery is 2.2Kg. 2.2Kg is all loaded up.
Each flight battery is just shy of 400g, so if I run both in parallel just add 400g. Therefore the weight with two flight batteries is 2.6Kg.
It is running DJI ESCs 30amp and DJI motors [2212 920Kv].

 

[kloner]

your at the top end of the scale, that's for sure

bigger motors like you have cobra are perfect.

 

[Explorocam]

so when you had 2 3s was like 2.6-2.7?

my motors are 100 grams

With one battery 2.2Kg with two battery 2.6 (actually just shy of 2.6 about 2.58).

The Cobra motors are just shy of 77g might actually be 67 -70g.

 

[Explorocam]

I'm reluctant to use a couple of the motors as they suffered a crash on my quad. I have extra bearings and main shaft so I will ever so carefully balance them first and replace any bearings or shafts if need be. 4 of the motors are on my Open Pilot quad and 2 of them have not been used yet as the two were a Bday gift from my best friend.

 

[Explorocam]

If I use the Cobras I'll have to get these.
http://gothelirc.com/shopdisplayproducts.asp?Search=Yes&sppp=20

 

[Explorocam]

So I can continue to use the 10" props with the Cobras or should I go down to 9"?

I don't mind throwing the DJI motors on the quad, I'm planning getting 4 SimonK ESCs for the quad anyways.

 

[Explorocam]

your at the top end of the scale, that's for sure

bigger motors like you have cobra are perfect.

Hi Kloner,

I tested something today. Changed the 3s 5000mAh batter for a 3s 4000mAh battery (lighter) I also took the GoPro off and the FPV battery off. I essentially made the F550 260g lighter. Doing so did not make a discernible change in my sudden lift problem.

 

[kloner]

make us a video, get it close so we can hear what the motors do when it does it. Later today i'll try making a video of mine

you have to fly these, it isn't a flick the switch and sit back and watch the craft do everything unless your setup to. Right now, your obviously not setup right somewhere. my guess is motor damage, bet we can hear from onboard camera

mine are always the exact opposite, but this is how mine look, watch :16-:17 sec, when i hit my switch i automatically move the throttle stick, habit at this point. What i gotta do to be able to run 50mph forward.

Your is just opposite. Run 4s and risk it if it bothers you that much or get bigger motors that'll deal with the problem. if you had to have 3s, look at 1200kv motors, if you had to have 4s, look at the kv on your craft. You already did the test and got the result. only problem is the motors bolted on aren't rated for that kinda watts with 4s and 10" prop

 

[Explorocam]

Ok, here are two videos I just did showing the switch between Attitude and manual with throttle inputs to stop ascent and descent.