Question about motors and props

B

BBr0

Member

Old Man

Old Man

Active Member
Might want to look at the motor specifications again. You want to use far too much prop with the motor selected. I don't know you could even fit 17" props on a T-650.

Spec:
KV(RPM/V): 490
Lipo cells: 4-6s
Max Surge Watts(W): 300
Working current: 12 amps
Max.current(10s): 17 amps
No Load Current: 0.45 amp
Intemal Resistance: 0.104 ohm
Number of Poles: 22
Dimensions(Dia.xL): 47.5 x 25 mm
Shaft: 6 mm
Prop: 12 x 3 - 14 x 5
Weight: 98 g
 

Pumpkinguy

Pumpkinguy

Member
If you know what camera you are using, figure out total weight of every single component. Frame, FC, motors, esc, gimbal, camera, landing gear to name a few. Add it all up and post here. Then we can recommend motor/prop combo.
Or better yet, I can teach you to figure it out yourself. Unlike most other areas of life, bigger is not better when it comes to multi's. It's about balance.
 

Old Man

Old Man

Active Member
We don't know that a camera was part of the equipment list. The mention of "building my first quad" is a little ambiguous. Is this your first MR, first build, or both? The T-650 is a good frame so in that respect you have a good start.

Looking at the dimensions of the 650 it appears the size is measured from the outside ends of the arms. Motor centers are set back about an inch from the ends. You have a 650mm frame, which works out to ~25.59". Because of the motor set back that works out to roughly 23.59" motor center to motor center. Let's subtract 17" (inside propeller blades) from the motor wheel base and see that what we have left between the propeller tips in the middle to mount everything is ~6.59". I suppose it could be done but you won't be able to mount a battery on the top plates and have to be ultra careful in positioning equipment and wires to keep everything clear of the propellers. Most of accessory mounting will have to be performed at a level below the top plate which would establish a need for some creativity.

So is the 650 using 17" props something you absolutely must have or could you scale things down a little bit?
 

B

BBr0

Member
Thanks for the response. I guess I am a little uncertain on what I need my goal is to have a quad that could fly for around 20-25mins.

Here is the full setup I have been considering:

Tarot 650 Frame
qbrain 25A ESC
Turnigy Multistar 4822-490Kv
16.5 or 17.5 CF props
Go Pro
DJI Naza v2 w/ GPS
Some Receiver (not sure yet)
Possibly two batteries in parallel (no sure yet though/ wither 3s or 4s)

Any thoughts or suggestions, and or criticisms ?
 

B

BBr0

Member
Heres a breakdown of the options I am considering for motor, again my goal is to achieve efficiency while flying and have a longer flight time:

4010-485kv
http://www.rc-calc.com/c/xg5cbd
http://hobbyking.com/hobbyking/store...ong_Leads.html

4010-580kv
http://www.rc-calc.com/c/RyQOc4
http://hobbyking.com/hobbyking/store...ong_Leads.html

4822-570kv
http://www.rc-calc.com/c/7hb1a9
http://hobbyking.com/hobbyking/store...Outrunner.html

4822-490kv (same as chuenwe)
http://www.rc-calc.com/c/Jc2K76
http://hobbyking.com/hobbyking/store...Outrunner.html
 

Old Man

Old Man

Active Member
In both of the lower kV calcs you listed the estimated flight time is less than half your goal. The calcs were established using 17" props and the manufacturer specs for you chosen motor don't go there. Perhaps the amp loading goes too high with props larger than manufacturer maximums. If that was the case then larger ESC's would be required and power drain would increase. Look for a motor that clearly lists 17" propellers as acceptable in their spec sheets. ECalc is not 100% accurate btw.


Sent from my iPhone using Tapatalk
 

B

BBr0

Member
I see thanks... I am considering scaling back to 15 in props with the 570kv motors possibly. Any suggestions, what are your thoughts on Turnigy motors?
 


eskil23

eskil23

Wikipedia Photographer
BBr0 said:
I see thanks... I am considering scaling back to 15 in props with the 570kv motors possibly. Any suggestions, what are your thoughts on Turnigy motors?
Click to expand...
For what I've learned, you don't want to use smaler props, you want to use bigger motors. Larger props are always more efficient than smaller, and lower kv motors are more efficient than higher kv motors.
 


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