Knuckle H Quad Motor Issue

[Justin]

So I purchased 4 28-26 1200kv motors for my new Knuckle H Quad. I am using 8x4.5 props, 30 amp ESCs and 3S 2200mAh 30C Turnigy batteries. I will run them in parallel if necessary. I am worried if the kv is too low for my quad. The motors haven't arrived yet, but they are almost here. I need to know what kv motors I need for this Knuckle H Quad. Motor - http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=25084
Please help. The motors will have to be returned if not worthy.

 

[Tritium]

Try them Justin. They should work. Just make sure your craft hovers somewhere near 1/2 throttle. If it takes more throttle then just use a little bigger prop and you will be good to go.

Thurmond

 

[Justin]

Well here is the problem. Hobby King's policy is that returns will not be accepted after use. The Knuckle H Quad was designed for an 8 inch prop and it can't take much more.

 

[xuzme720]

Yes. You have room to go up in prop size on those motors so if it seems a little underpowered you have a cheap solution. If needed, you can extend the boom a little to allow the larger props...

 

[Tritium]

I'll tell you what Justin. If it doesn't work then I will buy those motors from you for other projects as long as they haven't been crashed (that is how sure I am they will work fine). Props can have the tips within 1/2 inch of each other without issues. The decision is yours of course. I also recommend keeping posting in your original thread instead of this one (it keeps information neater for future readers to have it all in one thread.

Thurmond

 

[Justin]

Thank you for your opinion. I found this motor that might just do the trick (if the one I'm ordering doesn't work). http://hobbyking.com/hobbyking/store/__35673__NTM_Prop_Drive_28_26_1350KV_302W_USA_Warehouse_.html The reason why I started this thread was because the last one was about batteries, and I now need advice on motors. It was just that "bare minimum" post you posted that gave me a scare.

 

[Tritium]

The suggestion to extend your booms for bigger props is a cheap and easy solution.
A couple of extra inches of length and some new props and you are out less than 1 NTM motor.

Thurmond

 

[xuzme720]

Thank you for your opinion. I found this motor that might just do the trick (if the one I'm ordering doesn't work). http://hobbyking.com/hobbyking/store/__35673__NTM_Prop_Drive_28_26_1350KV_302W_USA_Warehouse_.html The reason why I started this thread was because the last one was about batteries, and I now need advice on motors. It was just that "bare minimum" post you posted that gave me a scare.

The bare minimum was just referring to available lift. It might be just fine when it's built as the knuckle is pretty light. No worries as you can definitely use those motors.

 

[Justin]

well would the 1380 kv motors be better, because I can order them from the U.S. warehouse and return the others for full price. I want some flexibility for this quad.

 

[xuzme720]

No, the 1200's actually give you more flexibility since you can put larger props on them for more lifting power. You only need to make the booms a couple inches longer and the1/2" boom material is cheap at the local hardware store.
We all second guess ourselves sometimes, but in this case, your first guess was the right one.

 

[Justin]

Thank you for helping me reassure myself. Is it necessary for me to extend the booms? I think they sit about 12" apart. I'll go check right now!

 

[Justin]

Okay, I'm back. I measured 11" from center of motor mount to center of motor mount. With 9 inch props, 4.5" each, there are two inches of free room, which is okay. But if I wanted more stability, I would extend the booms, which would probably be good for me since this is my first quad. Right?

 

[xuzme720]

You'll only need to extend the booms if you want to go larger on the props or, if you want a touch more stability. It is probably a good idea to go ahead and grab some extra sets of props as you will break some learning how to fly. Possibly some booms, less likely but still possible, so get a stick or 2 of the 1/2" wood from the local Lowe's or Home Depot to have some on hand. Then you are back in the air much faster than having to go get more material or waiting on a shipment. Remember Chinese New Years is coming up and everything is going to take awhile once that happens!

 

[Justin]

I just noticed a problem. The motors are not rated for 9" props and a 4S might blast them (not using one yet). I don't know what a three cell will do to it. That watt meter requires soldering, and I do not have soldering equipment. Will I fry something with a 9" prop? If I am talking bogus, then what pitch would you recommend for the 9" prop?

 

[Justin]

Speaking about 4 cells, I could use them with the 8"x4.5 props for heavy lifting. That way I would get what I wanted in the first place, a multirotor that can switch from a 3S to a 4S for lifting purposes. Before I mess up, I ordered and now own a AR6210 receiver with a 6" remote receiver extension. I was thinking about putting one next to the control board and one in between the rear or front motors on the boom. I was thinking though, that the wires sandwiched between the top and bottom plates would cause interference. Do wires create interference too (too as in electronics)?

 

[Tomtom]

Hi Justin.

If you really want to change your motors, I recommend you the ones I currently have with my H-quad. A lot of power comes out of those little guys which is more than sufficient

 

[Justin]

I would rather stick to the ones I ordered, but thank you for your suggestion. Does 100 kv make a big difference? If yours are more than sufficient, then mine will be sufficient Keep note that I can run it on a four cell for more power.

 

[Tomtom]

Actually, thrust is the key here. If you stick with your 1200Kv motors, you have to size your props accordingly, for instance 9x4,5 minimum.

1000Kv seems too light to me though.

 

[Justin]

I just got home and found the package waiting on my doorstep. If I open those motors, there is no going back. The funny thing is, is that the motors were rated for both 7" and 8", not nine. In my last post I accidentally put 1000kv, sorry it was 100kv (from your motor to my motor).

 

[Tritium]

They will handle 9" props. I know from experience.

Thurmond