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First flight... flipped over. Help?

#1
I've got an Electrohub kit with the RTFQuads pack. I flipped over immediately on my first flight. I verified that all the props are spinning in the correct direction and that the inputs to the board are connected to the right inputs on the receiver. What can I check next?
 

Craftydan

Hostage Taker of Quads
Moderator
Mentor
#3
A few pics of your setup might also help too. sometimes the obvious can't be explained in words ;)
 
#4
Thanks for the quick replies!

1) It's a spider quad (hoping to carry a GoPro but glad I didn't put it on yet!)
2) After I walked away from it for a bit, I realized that I only calibrated two of the ESC's while building it. Could that cause this? Is there a way to calibrate them now without desoldering them from the hub?
3) I connected it to the computer and checked out the software. I'm not exactly sure where to look for problems, but I did notice that when I manually tilt the quad, the two roll indicators appear to be showing opposite things? The one on top says I'm banking right but the one on the bottom says I'm banking left (the bottom one is correct in this case.) Is that expected? Am I just reading the indicators wrong?
4) For the props, I'm using the two different kind (standard and pusher) on the appropriate rotors... I think? Basically the leading edge of the rotor is always the higher edge. I think that's right.

Capture.PNG

WP_20150104_18_42_52_Raw.jpg

WP_20150104_18_43_04_Raw.jpg

(And my skill level is still pretty new. I've built three FT planes and I have a Bix2 and a UMX F4. Those all go fairly well. For quads I have a NanoQX that I've flown a ton but this is my first big quad and my first quad build.)
 
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Chamika

Junior Member
#5
Is the quad flip when you increase the throttle or after its airborne.If the quad flip when you increase the throttle it MAY BE because you have swapped the motor wires. Check the motor and corresponding motor out from the control board.

Also tighten your props well. In my first tri same thing happened. tri flipped over when I increase the throttle.The reason was a loose prop spinning on it's own.
 
#6
Double checked the motor wires and they are plugged into the right spots and oriented correctly.

The quad flipped IMMEDIATELY as I got off the ground. It probably never got more than 2 feet in the air. Interestingly it was missing a prop when it landed. I never found the spinner. I assumed that fell off as part of the crash, but maybe it was loose? I'm hoping that I'll either find the spinner when it's more light outside (tried this at twilight on the back patio) or that my local hobby shop will have a replacement. Otherwise I'll need to find somewhere to buy it online.

I'm going to recalibrate all the ESC. Realized that I'm dumb and I don't have to do any desoldering to do it :) So once that is done and I have a new prop spinner, my next test will be to really make sure they are all on tight and then try again.

Ok here's one question about the motors and the props... what order do things go onto the shaft? There is a little (mostly) flat disc, the prop and then the spinner. From bottom to top is it disc, prop, spinner? Or does that disc go on top of the prop?
 
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Quad

Senior Member
#7
Any thoughts on whether it is worth calibrating all of the ESCs at this point? I have better things to do with the next hour (have to disassemble a bit, desolder, resolder, etc) but maybe I should do it just to rule it out.
Did RTFQ calibrate the ESCs before sending them out?
 

johnmw

propulsion impromptu
#8
Double checked the motor wires and they are plugged into the right spots and oriented correctly.

The quad flipped IMMEDIATELY as I got off the ground. It probably never got more than 2 feet in the air. Interestingly it was missing a prop when it landed. I never found the spinner. I assumed that fell off as part of the crash, but maybe it was loose? I'm hoping that I'll either find the spinner when it's more light outside (tried this at twilight on the back patio) or that my local hobby shop will have a replacement. Otherwise I'll need to find somewhere to buy it online.
how did the flip motion when it happened, and which prop went missing.
it is possible these are related and that the loose prop causing the flip.

I'm going to recalibrate all the ESC. Realized that I'm dumb and I don't have to do any desoldering to do it :) So once that is done and I have a new prop spinner, my next test will be to really make sure they are all on tight and then try again.

Ok here's one question about the motors and the props... what order do things go onto the shaft? There is a little (mostly) flat disc, the prop and then the spinner. From bottom to top is it disc, prop, spinner? Or does that disc go on top of the prop?
From bottom to top: disc, prop, spinner

hth, GL.
 

Chamika

Junior Member
#9
Just Find a relevant size and relevant direction threaded nut from a hardware store. :)

There should be a way to calibrate all of your Esc's using your control board. I have no experience with a multiwii board.Use Google, there must be a tutorial for doing it.
 
#10
Not sure if the ESCs were calibrated out of the box but I just finished calibrating them now so that should be out of the equation.

Thanks for the tips on the prop installation order and also on just using a simple nut instead of a spinner. Home Depot is open for another 26 minutes. :) If I don't have something on my bench that fits, I might run over there.
 

makattack

Winter is coming
Moderator
Mentor
#12
Escs always have to be calibrated by the end user for all but the cheapest because they are specific to your receiver and transmitter throttle ranges. The calibration is of course to set the throttle range. This is in response to quads question.

Multiwii does have a special calibration mode, but you will have to flash it twice after editing config.h from the arduino ide from the source sketch, which you can download from rtfquads.
 
#13
I disconnected everything and calibrated them by plugging them one at a time into the throttle port on the receiver. I didn't want to mess with flashing the board (yet).

Great news! I used the nut that I had in my parts box to attach the fourth prop. I pulled the cars out of the garage and was able to hover a foot or two off the ground with no issues!!! Fantastic! So I guess I must have just lost a prop and that caused the flip. I guess that's a good lesson and a fairly easy fix.

Thanks so much for your help! You guys and the FliteTest crew are the only people I "know" in the hobby so getting support like this is what keeps me going.
 

Craftydan

Hostage Taker of Quads
Moderator
Mentor
#15
Good to hear! That's an easy problem to fix:

Nylock nuts.

You'll need a wrench to take them on/off (and you'll do that a lot replacing broken props, so keep the right size handy) but they'll never come off unintentionally again. If HomeDepot doesn't have them, lowes/ace/your local HW store will. You'll probably need an M5 nut (VERY common shaft size), but bring one of them along just to check.

Tighten them until you can't turn the prop on the shaft. Any looser and they'll slip in flight -- not a good thing.
 

makattack

Winter is coming
Moderator
Mentor
#16
3) I connected it to the computer and checked out the software. I'm not exactly sure where to look for problems, but I did notice that when I manually tilt the quad, the two roll indicators appear to be showing opposite things? The one on top says I'm banking right but the one on the bottom says I'm banking left (the bottom one is correct in this case.) Is that expected? Am I just reading the indicators wrong?

View attachment 37371
Glad to hear you got into the air with success!

I just remembered you had asked about this, and didn't think I saw anyone answer. That display is correct. The roll graphic shows your aircrafts orientation as if you were looking at it from the tail.

The artificial horizon (the two colored ball with the blue top half indicating the "sky" and the brown bottom half indicating "Earth") is supposed to be what you see if you were a pilot inside the plane looking at the analog equivalent. If you bank/roll to the right, you'll "see" the right side of the horizon rise up towards you.

http://en.wikipedia.org/wiki/Attitude_indicator
 

jhitesma

Some guy in the desert
Mentor
#17
Escs always have to be calibrated by the end user for all but the cheapest because they are specific to your receiver and transmitter throttle ranges. The calibration is of course to set the throttle range. This is in response to quads question.

Multiwii does have a special calibration mode, but you will have to flash it twice after editing config.h from the arduino ide from the source sketch, which you can download from rtfquads.
This is actually why it's best to calibrate through the FC and not calibrate them individually.

On a multi it's the FC sending the "throttle" signal to the ESC's not the RX. So the ESC's need to be calibrated to the range the FC is outputting not the range that the RX is outputting. The FC and RX in turn should be configured so the RX is outputting the range that the FC is expecting as inputs. (Which is done by setting up the endpoints/midpoint on the TX and then setting up the correct variables in MW to match - though usually with an adjustable TX you can leave the values in MW alone and just adjust the TX to what the FC is expecting.)
 
#18
Make sure you aren't trying to put the cap for flat centered props on it! In the RTFQuads package that I got, there was attachments for both types of props.
 
#19
Hmm thanks. Let me just get all of my dumb prop questions out of the way...

Is this the right one for the prop I'm using?
WP_20150106_08_55_36_Raw.jpg

So that goes on first...
WP_20150106_08_55_49_Raw.jpg

And then the little plastic piece fits into the prop and goes on like this:
WP_20150106_08_56_04_Raw.jpg

And then the spinner/nut goes on the top:
WP_20150106_08_56_19_Raw.jpg

Is that all correct?
 

Craftydan

Hostage Taker of Quads
Moderator
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#20
Almost -- washer goes between the nut and the prop, with any tapered edge on the nut side:

motor -> prop -> washer -> nut

so wrong order, but you are using all the right parts.
 
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