Motor help

[New2MultiRotors]

I'm waffling on these 2 motors. It's a large quad and I want it to primarily be an av machine so stability is the highest on my list. Which one of these 2 motors will give me that?

Will the higher kv rating translate into being able to correct for turbulence faster?

In which case am I better off going for slightly smaller prop? Or go with the biggest one allowed?

And what about pitch, high or low?

Sorry for sooooo many questions. I'm just trying to get everything right before I click the buy button and every time I think I got it straight I read more stuff online which makes the decision more confusing.


http://www.buddyrc.com/sunnysky-v2814-11-700kv-ii-brushless-motor.html


http://www.buddyrc.com/sunnysky-v3508-29-380kv.html

 

[Motopreserve]

I don't think you've given us all the info, sorry if I missed it. Is your estimate of 2600g including an estimate of the battery weight???

What maximum size props does the quad accept? Were you planning on 4S? Or 6S batteries?

 

[New2MultiRotors]

Sorry here's the info.

6S battery. I did some adjustment on equipment used and the auw will be 2045 or 2325, depending on the capacity of the battery I ultimately use. So say 2.4kg to be safe. Tarot 650 sport frame. Max prop size is 15"

Is it always a good idea to max out the prop size for an av type quad? And what about the pitch?

I don't think you've given us all the info, sorry if I missed it. Is your estimate of 2600g including an estimate of the battery weight???

What maximum size props does the quad accept? Were you planning on 4S? Or 6S batteries?

 

[New2MultiRotors]

As an aside, do you know if you can convert the 650 to a 680? I've read all you need is to buy the center board and 2 extra arms, and motor mounts. No desire to do it now, but curious if that was an option the future.

 

[Motopreserve]

If you're going for the 6S, only the 2nd linked motor is appropriate. Seems you'd be right about perfect on thrust with a 12" prop.

Not sure about the 650 to 680 swap. You'd have to check the length of the booms on both to see if it would save money over just buying the whole 680 kit.

Ideally, you don't want to max out the motor with the prop size. Better to keep it in a good efficiency range. You can see that on the far right of the spec sheet. The pitch of the prop will produce much less change than the length. I don't recall the formula - but I'm sure it's floating around here somewhere.

 

[New2MultiRotors]

Would there be a benefit in using a 5S battery and using the first (v2814) motor? The weight will be a little less what I originally stated. The 2814 seems to pull alot more thrust but less efficient.

If you're going for the 6S, only the 2nd linked motor is appropriate. Seems you'd be right about perfect on thrust with a 12" prop.

Not sure about the 650 to 680 swap. You'd have to check the length of the booms on both to see if it would save money over just buying the whole 680 kit.

Ideally, you don't want to max out the motor with the prop size. Better to keep it in a good efficiency range. You can see that on the far right of the spec sheet. The pitch of the prop will produce much less change than the length. I don't recall the formula - but I'm sure it's floating around here somewhere.

 

[Motopreserve]

Lack of efficiency will lead to less flight time. Any time you're losing power to heat - less time in the air, as well as potential wear and tear on a motor.

The only advantage to 5S might be cheaper batteries if it made sense design wise.

 

[New2MultiRotors]

What's your opinion on small vs larger props.?And I mean a small difference. Like 2-3". Would the slightly smaller props give u more stability because they could more quickly compensate for air turbulence? Or would the mass of larger props be a better option.

Lack of efficiency will lead to less flight time. Any time you're losing power to heat - less time in the air, as well as potential wear and tear on a motor.

The only advantage to 5S might be cheaper batteries if it made sense design wise.

 

[Motopreserve]

I think small props cut through wind better, and in my experience the are a bit more "zippy." But typically AV/P rigs go with a larger prop for the lift and the lower RPM. You don't really want zippy with aerial video

My rigs don't have huge props. 15" max on my biggest MR.

 

[eskil23]

Larger props, or at least heavier props, should give more stability because of the gyroscopic effect. But if it is stability you want you should go for a hexa or octo.