I'm new here and have a new Quadrotor. Your Input is appreciated.

[HawK86uk]

Hey everyone!

I've been watching alot of the FliteTest videos on YT and thought I'd head over to the forum and a) introduce myself b) ask for input on my setup and methods.

So, me, I've never flown anything RC wise other than the small toy helo's that you can get for £30. As a present a friend got me a kit Quad. I've taken it on a couple of smashing adventures (for it, not so much for me!). I'm a beginner in pretty much every sense of the word but eager to learn and have some fun. I'm UK based so if anyone has any UK rules I should be aware of, let me know.

My Quad is:
Carbonfibre 1 piece frame (not sure what brand). I've ordered a turnigy plastic spare frame (detachable arms in case they break? Consider me SOLD!)
2200kv Motors, I don't believe they're branded.
5045 Triblade Propellers (I've read and it sounds i may want to switch to 5030 until I'm a bit more capable). About as large as my quad will take in terms of diameter.
KK2.1.5 Control board.
Skywing 10a SW10a ESCs
2200 mah 11v 30c 3S1P Battery.

TxRx I'm not sure on (Not at home so can't check).

I've set everything up where I can (person that bought the quad did alot of the construction so where knowledge is lacking that's why, but I'm trying to learn).

I'm finding on take off that it likes to flip end over. I've played with the P & I Gain a little but not had much luck. It also Yaw's on the ground if I accelerate (sounds like it's not balanced / trimmed?).

I'm running the Quad X set up on the KK with the most recent firmware, I've set the accelerometers up on a flat surface and I've matched all the inputs on the KK down to 0 Trim (or as close as possible). Rotors are spinning right direction and have leading edge of the rotor facing the spin, in line with the KK QX set up.

Does anyone have any suggestions as to what it may be? Any tips for both fixing this and general starter tips are helpful. I've tried giving it a little more power for lift off but there's only so many broken props I can take.

A couple of other questions, on a small quad like mine does dual or tri bladed rotor make much of a difference?
I know the tri should generate a higher static pressure but have a lower efficiency at speed with the dual being generally more stable I think? Can anyone give me anything on this without going into crazy depth?

Motors... I have 4x2200KV motors that came with the kit. I don't really know why they need to be 2200kv other than, smaller props = higher revolutions to maintain lift, but 2200 seems REALLY high. Can anyone give me a quick cheat sheet method of working out what KV I need?

That said, hello again and hopefully I'll be sharing more than my flipping great adventures with you before long! Pun intended! :black_eyed:

 

[cranialrectosis]

Welcome to FliteTest!

I run 2300kv motors on my small copters. For your sized copter, you are right where you want to be.

Instaflip, where the copter never takes off just flips upside down and ruins rotors, is VERY common. There are a number of things that can cause it. The most common is having the ESCs connected to the KK2 incorrectly. The ESC for motor 1 as detailed by the KK2 motor direction diagram must connect to M1 on the KK2. Motor 2 to M2, motor 3 to M3 and motor 4 to M4. It is common for people to mistakenly swap two of these and the result is always instaflip.

Check those connections against the KK2 motor direction diagram and pinnouts closely or post a high res detailed photo of how your ESCs connect to the KK2 and we can help you get them right.

Pinouts:
http://1elevenblog.files.wordpress.com/2013/01/kk2pinout.png

Motor direction diagram:
http://www.fpvhub.com/index.php?topic=12760.0


Other causes of instaflip are a reversed channel on the transmitter, rotated flight controller, upside down props, loose props that can spin without the motor spinning etc... The most common is swapped ESC signal wires to the KK2.

Triblades cause more vibration and give you more thrust. For me, the vibration increased more than thrust and I found triblades to provide less flight time. Triblades look cool and I have a hex with them but they require more maintenance and are more PITA than they are worth.

 

[HawK86uk]

Hi Cranial.

Thanks for the tips. I've checked everything and looks like all the ESCs are fine. I've re-run the set up and it seems more stable now.. Sort of.. I've had to invert my rudder and my forward / back motion on my controller (they're now inverted on the controller but the KK seems to agree when i push the left stick right, that it's rudder right and not left and my right stick forward, it's no longer trying to travel backwards).

The controller software says it's backwards but as long as KK is happy with it, I'm happy with it. It's a Fly-Sky FS-CT6B, FYI.

The one thing that I can't shake now is, when there's any kind of lift, it yaws right, and no amount of trim is fixing it... I've got some props coming tomorrow so I can bang those on in the hopes the dual 5030 props work better than the tri 5045 but I can't think that would affect rudder.

Again, any suggestions are welcome. I'm looking to get this right before I take off, I don't want yaw throwing me off and accidentally sending it into a tree because it's orientation has changed. lol

 

[HawK86uk]

So, after a bit of research and a lot of learning (how lift and torque is generated and balanced on a quad) it was pretty clear cut what the issue was. I got new rotors today (ordered them a couple of days ago). Fitted and flys nice and stable. Need to set my P & I etc. but it's not spinning like a Catherine Wheel!

Thanks :-D

P.S. I still don't understand how the rotor generates torque.. I'm guessing it's the air resistance on the pitch of the rotors?

 

[Balu]

Sit on a rotating chair, put the arms out to the side and move them sideways in the same direction. The chair will rotate in the opposite direction. This is a result of the change of you arms' moment of force / torque.

The motors on your quad do something similar. They speed up or slow down, resulting in a reaction of the quad, just like the chair.

 

[Craftydan]

If you want to feel it for yourself . . .

- Take off your props.
- power up your quad, hold it in your hand (you took the props off, right?).
- while holding in one hand, move the yaw stick. you should feel the quad try to twist in your hand.
- try moving the quad in the yaw axis -- if the control board is working right, you should feel it resist your motion.

Just the weight of the spinning motor requires torque to keep spinning. I've even been able to catch that I miswired motor doing this (three turning CW, one turrning CCW) before I even checked the individual motor's direction -- powered up to make sure the ESCs were working and felt the torque . . . hmmm . . . something's not right.

A prop's grab on the air makes it stronger, but the energy burned just spinning the motor is enough to generate the torque.