Newbie problems... Quad keeps flying backwards and motor power problems...Please help!

Tito1990

Tito1990

Member
Hello everybody.

Little introduction: I'm Rico, 24 years old and from the Netherlands. I've had several quads. The first was a 30$ quad which only lasted a week or so. Second was the Parrot AR2.0 (sucks) 3rd was the Phantom 1. Currently owning a Yuneec Q500+ and a budget FPV build quad that has given me some problems.

Yesterday and today I've build the quad. Everything seems to be going well. Tried to lift off. Then found out there were some problems.

Setup:
2300kv motors,
HK blue-line(right?) 12a ESC
KK2 mini board.

1. The motor will not properly start up (all four of them) when they fire up they idle fine. Little power is good. Full power all the motors flutter really bad, giving less performance than mid-power.

2. When I try to gently lift off the quad respons to all movement. After I try to raise it (or even keep the situation the same) the quad wants to fly backwards. When I try to hover fast after liftoff I can get the quad going forward. But then it fly's back again even after full forward stick input.

What I already did: ESC calibration (don't know for sure if done correctly), Multiple ACC calibrations. Checked stick input, Checked ACC calibrations (last line says 670/680 which seems to be normal) All sensors read OK. Occasionally I get a sensor error when starting up. Checked motor layout. Props spin right directions, I was in self leveling mode. Tried the fixed-wing and delta-wing on mij transmitter.

See the youtube links for the problem:

Motor flutter:
(yeah, don't test quads with props on... Learned the hard way as you can see at my wrist.)

Fire-up and drifting:

Thanks in advance.

Oh... I'm sorry for posting in the wrong section! Can anybody move it?
 
Last edited:
GJH105775

GJH105775

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Thoughts on the first video:
Have you tried to balance the props? It sounds like the props are unbalanced, and possibly flexing too.

Thoughts on the second video:
Looks like you need to make some adjustments to the auto level settings, and later maybe flash with Steveis (is not your problem, but will be a great improvement on many things)



As for the correct forum to post in, first build, or build discussion would have been better, maybe Neil will move it if he sees fit.
 
Tito1990

Tito1990

Member
Thanks! It helped!

The quad flipped once because I missed a rotation setup on one motor. The quad flew out of my hand in a basket and cut my wrist. Probably bent a prop then because I've installed a second pair and I can get full power now (btw, the power in these little things is amazing!).

Also I moved the KK2 mini to the top and the battery in the center. I can now play with the setting more easily. However the FCB is quiet vulnerable. Just flew it again and I guess is was a balance issue. Before the battery was on top moved more to the rear, probably disturbing balance. I managed to fly about a meter and land on my bed.

I'm now considering what to do... Battery back on top (in the centre) and having a hard time tuning it with the screen and buttons, or leaving it for now and hoping that the battery on top again later doesn't affect balance and settings so much. I've seen more quads with the battery on the back btw.

Tomorrow is going to be it's maiden flight. I'm anxious to get it flying!
 
Tito1990

Tito1990

Member
Yeah. Have had it before the balance plug is catching the props. But I'm going to use the balance lead for everything FPV related.

It's quiet amazing seeing that a slight imbalance in 1 prop can cause severe problems. It was actually reducing power at more than half throttle. Not even enough to hover.

Also I found out the pitch and roll adjustment needed to be set a lot higher. I set it to 20 but it only gently drifts at 100. So there's probably the balance solution.
 
Tito1990

Tito1990

Member
You make me curious! I'm guessing 20k rpm? My Yuneec is like a big American v8 with its 14" props. Lol.
 
GJH105775

GJH105775

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It also will be slower at times, if the quad was not apposed by gravity or air resistance, and the props somehow still worked the 4.7 pitch means that they would move 4.7 inches per revolution. Imagine the speed of that haha.
 
Tito1990

Tito1990

Member
Somehow when I fired it up for the testflight the motors where stuttering again. Haven't given it some attention because i'm in Egypt at the moment. Going to try to figure it out next week.
 
GJH105775

GJH105775

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Take the props off and have it spin at about 30% throttle. Touch your finger to the top of the prop mount. Do they wobble?
 
Tito1990

Tito1990

Member
Ok. Got back from Egypt. I fired the motors without props and they didn't wobble. Installed new props (again) and still no power. I disconnected the ESC one by one and then revving them. Found out that ESC 3 is giving me problems. Thats also the ESC feeding my receiver. I don't think that's a coincidence, so I'm guessing that's the problem.
How do you guys feed the receiver? One ESC that's powering the kk2 mini isn't showing problems... Should I just hook up the remaining 3 ESC to increase the power to the receiver? 'Cause I think that'll be the problem. It's just a 5v output right?
 

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Tito1990

Tito1990

Member
Well, Switched the 5v BEC for the receiver from esc 3 to 4. Problem is still there on ESC 3. When disconnected it again fires up full throttle. So the problem is either the motor or the ESC (or the power towards those two). Going to check my soldering now.

The startup problems are also gone with the ESC plugged out.

Here's a crappy video showing the esc disconnected, and then connected again.

 
GJH105775

GJH105775

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Moderator
The receiver gets it's power from the FC when you plug it in to the different channels, and the FC gets it's power from the ESCs.
 
Tito1990

Tito1990

Member
That would indeed be the normal way of feeding the receiver. However, the kk2.0 mini doesn't have that option.

I've now routed 2 BEC to the receiver and I can get full power now! Yay! And the startup problems are gone.

But somehow the reaction time is very bad now, going to look into that further now.
 
Tito1990

Tito1990

Member
I bought the mini on accident lol. Wouldn't recommend it to anyone building a normal 220-250 or bigger quad. It's too small. Buttons and screen are also smaller. Resolution of the lcd is very good. It does fit the Chinese frames. Further is it just the same as the it's big brother. But it's missing some pins which are not that nessecary (like the receiver feed)

Bad responding is now also sorted. It was a low battery in the transmitter. I've now moved the kk fc back to the lower part. Hooked everything up and got it flying indoors. Charged the lipo's and fixing the cheap FPV goggle now. Tomorrow we will see how good I'm at flying a non gps quad.
 
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