Questions about prop/motor combo (1780kV on SF props :/)

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Mr.ChronoM
Posts: 5
Joined: Sun Sep 11, 2011 8:25 pm

Questions about prop/motor combo (1780kV on SF props :/)

Post by Mr.ChronoM »

Hi !

I'm very new to RC flying and came up with the idea of building a quad after playing around with Arduino's for a while. After reading information for about 2 months I finally got all my parts delivered and managed to get a quad that almost works. The mistake I made, was to order some parts after reading just a few articles. So now I probably have a combination that won't fly at all...

My Setup
  • 4 x E-Power GC GT2210 1780Kv 55g Brushless Motor
  • 8 x Counter Rotating Blades SF 8x4,5
  • 4 x Hobbyking SS Series 18-20A ESC
  • 1 x WMP Clone
  • 1 x Sparkfun 5DOF
  • 1 x ZIPPY Flightmax 4000mAh 3S1P 20C
  • 1 x HK Eco6-5A charger

What I got working
After doing some code changed to get the Arduino 2009 and my clone WMP working, I got my quad to show all the expected information in the GUI. The remote seems to be working find, the gyro and accelero is read. ESCs are starting up and the engine run idle when I start the quad up (Had to calibrate the ESCs individually). So far so good.

What isn't working
I simply isn't lifting of the ground. When I slowly raise the throttle I can only get my quad to spin around a bit on the floor (Props are turning correct direction). Even at full throttle it is just making lots of noise :). At this point I'm guessing that my motor and prop combination is (completely) wrong and that it will never fly on those.

  • Could someone tell me if I'm guessing correctly ?
    1780Kv motor on 11.1V is +/- 18000rpm on SF props. That doesn't sound right, but is the described behavior normal ?
  • What should I replace ? The motors, the Props or both ?
  • If my guessing is incorrect, do you have an idea ?

Big thanks in advance !
Kevin

mr.rc-cam
Posts: 457
Joined: Wed Jul 27, 2011 11:36 pm

Re: Questions about prop/motor combo (1780kV on SF props :/)

Post by mr.rc-cam »

You should post the Quads motor to motor distance and the AUW. For most models the 4000mAH battery is quite heavy; Sometimes smaller batteries will offer the same flight time with better agility. I think the high KV motors were not the usual choice, but maybe someone will chime in and offer some advice about them.

When I slowly raise the throttle I can only get my quad to spin around a bit on the floor (Props are turning correct direction).

Assuming the ESC's are calibrated correctly, that sounds like you don't have the motors or props setup correctly.

Each prop should have raised text on it that identifies its specs (prop size and if it is reversed pitch). Install the props so the text faces towards the sky. Then post a drawing that shows the location of each motor and label them so that we can review the rotation and the prop type (normal/reversed pitch) at each motor location.

Mr.ChronoM
Posts: 5
Joined: Sun Sep 11, 2011 8:25 pm

Re: Questions about prop/motor combo (1780kV on SF props :/)

Post by Mr.ChronoM »

These are the props I bought http://www.giantcod.co.uk/0845-inch-cou ... 06231.html.
They are labelled 8A and 8B and they are facing upward. I can feel the air pushing up on 2 props and down on the other 2. The quad is not spinning, it just moved a bit on the floor.

I created a frame from 100cm alu, cut in 2 pieces. So the engine space is around 40cm. I wired everything from the MultiWii diagram Motor 3 CW, Motor 9 CW, Motor 10 CCW, Motor 11 CCW

mr.rc-cam
Posts: 457
Joined: Wed Jul 27, 2011 11:36 pm

Re: Questions about prop/motor combo (1780kV on SF props :/)

Post by mr.rc-cam »

I can feel the air pushing up on 2 props and down on the other 2.

That is not the effect you should see. As mentioned, please post a simple drawing showing the requested motor/prop details; we may be able to see why it does not hover.

I created a frame from 100cm alu, cut in 2 pieces. So the engine space is around 40cm.

What is the Quad's AUW with the 4000mAH pack installed?

tovrin
Posts: 705
Joined: Tue Sep 20, 2011 4:08 pm

Re: Questions about prop/motor combo (1780kV on SF props :/)

Post by tovrin »

Image

all air should be pushing down, your motors should be spinning in the direction as such indicated in the picture above.

this creates a counter rotational effect that is part of the stability, if I'm saying that right.

edit:/
also i note that you state purchasing 4 of the same props (counter rotating) you need 2 of each rotating and counter.

mr.rc-cam
Posts: 457
Joined: Wed Jul 27, 2011 11:36 pm

Re: Questions about prop/motor combo (1780kV on SF props :/)

Post by mr.rc-cam »

also i note that you state purchasing 4 of the same props (counter rotating) you need 2 of each rotating and counter.

He appears to have Gaui style 8A/8B props, so he has two of each type. I have edited the drawing to show the standard Gaui 8A/8B prop positions. Once props/motors are installed as shown then hold the model in your hand (be careful!) while moving the Tx's sticks around to confirm correct thrust and pitch/roll/yaw movement. I expect that if the motors and props are setup as shown his model will lift off the ground.

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Attachments
Motor/Prop Details.
Motor/Prop Details.

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