Thrust from Quad

[Xander G]

Hi, I have read tonnes of forums and thought I had done the correct calculations for what I needed.

I have 4 NTM Prop Drive 26-28 1200KV short shaft motors, 30A Turnigy Plush ESC's, 1045 slow fly props and a 5000mAh 20C zippy lipo.

My quad weighs about 1500 grams and I thought this setup would generate enough thrust to fly it. I had done some rough calculations and figured each prop should produce around 1000grams of thrust.
My problem is the quad does not take off, it begins lifting but never detaches from the ground. I have the OpenPilot CC3D Lumineir flight controller with all my props in correct orientation with correct props.

I can get the Quad spinning in a circle on the ground and make it tilt at each prop so I am confident my setup is correctly configured and wired.

Does anybody see any glaring issues? Will this simply not produce enough thrust based on motors and props? Thanks for any help guys

 

[Mike]

Did you ever figure out what the issue is? I can tell you that my first build with my buddies was almost the same as what you have with some minor differences:

30A Turnigy Plush
28-26 (regular shaft - does not matter though)
CC3d
3S 2200 mAh batteries
8x4.5 props
HT-450 frame, then numerous generic ebay frames.

Are your batteries 2S or 3S?

Our copter got pretty darn heavy before we ever got a chance to do some good flying because we'd crashed and repaired/ reinforced arms with aluminum pieces from the hardware store. We were surely at the 2000g mark as far as weight goes. The thing was not very responsive in flight, but it flew.

The only issues I'm maybe seeing is if you're running 2S batteries, then you surely have a problem with not having enough volts. If you're running 3S or 4S then it could be your prop size is too big. What I always do when I buy motors from Hobby King is look at the "prop test data" in the details of the product page. For the 28x26, they tested with 8 inch props only, which tells me that 10 is not necessarily recommended for that motor. In fact, normally, if you're going with 10+ inch props, you should go low kv motors with 4S or bigger batteries.