Air's multicopter project

[Airwolf]

I have a problem.

FC (HK KK V2) is flashed with the latest Tricopter firmware, and I can arm it without problems, but left and right motor won't run when throttle is applied. Instead they're buzzing and beeping (just like when one of the wires is disconnected or like it would be jammed by something). Of course electrical connections are OK, ESCs are OK (throttle position is set), and motors spin freely. Also yaw servo doesn't work (it has a signal and power but it won't move). Tail motor runs OK. Rx-FC-ESCs are connected OK I think (Rx Ch1 (Ailerons in Tx) is connected to AILE port on FC, Rx Ch2 (Elevator in Tx) is connected to ELEV port on FC, Rx Ch3 (Throttle in Tx) is connected to THRO port on FC and Rx Ch4 (Rudder in Tx) is connected to RUDD port on FC).

Tx mixers etc are turned off (and Tx it's in acro mode). Any ideas what can be wrong?

 

[Airwolf]

It was electrical problem (I've connected one of the wire from left ESC to right motor end vice versa - silly me - it's not a good idea to build these things when very tires...). Everything is fine now. My TriCopter needs some final touches and it will be ready to it's maiden flight. I'll post some pics later...

 

[colorex]

HAHAHA Well, good to hear it works now. Keep us posted.

 

[ananas1301]

Yeah I know that! In late evening you sometime do very simple mistakes and then say after it "What a stupid mistake".
Everyones had that

What about some picture right now?
Anyway, I hope it flies well and you have fun with it

 

[Airwolf]

Later I will try to hid the ESCs and wires inside the hull, but for now it looks as it looks...

 

[ananas1301]

nice build you did there!

I like how you mounted the servo. that won´t move a lot, I think.

Now lets be patient about how it flies

 

[Airwolf]

Yeah, it's tightly mounted on the arm. Only thing I'll change is leading servo wire under the servo.

After first flights I'll break it down and rebuild the hull (I already have some ideas how to improve it).

 

[FlyingMonkey]

Are you using the cat as your auto-stabilization system?

 

[John Campbell]

Looks like you have a Quality Assurance Inspector.... Did he find a problem with the motor, or cause one. My chief inspector looks exactly like yours.

​

He is usually a little more active, he is just getting ready for bed

John

Yeah, it's Chip. He helps me alot with my hobby LOL



He usually sits by me watching what I'm doing, only sometimes he touches some parts carefully with his paw... only a few times I've got to stop him fhrom eating my foamies

 

[Airwolf]

Update: it's flying, and it's flying well (careful calibration of ESCs and stick positions is a key)... But it crashes constantly - using propsavers on DT750s was a failed idea... These motors have so much torque vs so much drag caused by 11x4,7 props, that even tightly mounted propsavers fly away (and tricopter doesn't really fly well with only two props). I'll replace gws 11x4,7 props with apc 10x5 props mounted directly on motor shafts. Another idea would be using medium thread locker on propsavers, but I don't have any laying around at the moment...

 

[ananas1301]

So why exactly do propsarvers not properly work? I though that they would just allow the prop to fold away a little in case of crash....

I didn´t really get your explanation there...

 

[FlyingMonkey]

ananas, I think you're confusing prop savers with folding props.

A folding prop wouldn't work, because when you are not moving the motor, the props would fold down on either side of the arm, and would get caught when you tried to spin the motor up.

Prop savers, usually a mount that uses a rubber band of some sort to hold a propeller onto it, are not effective because they are too flexible. They would have too much give in the rubber band to be effective when doing rapid throttle changes required for multi rotor flight.

 

[ananas1301]

ananas, I think you're confusing prop savers with folding props.

A folding prop wouldn't work, because when you are not moving the motor, the props would fold down on either side of the arm, and would get caught when you tried to spin the motor up.

Prop savers, usually a mount that uses a rubber band of some sort to hold a propeller onto it, are not effective because they are too flexible. They would have too much give in the rubber band to be effective when doing rapid throttle changes required for multi rotor flight.

I know the difference between folding props and propsavers. Like folding props are the ones mostly used on sailers to reduce the drag by the prop itself.

Propsavers are those rubber bands that hold the prop in place and therefore the prop is not held into position in a crash. The motors would stop running (because you are fine enough to turn throttle down with a crash) and what then?

I just didn´t really get what really happened with propsaver in airwolfs post. I thought that I´d go for propsavers as well to reduce the amount of broken props per battery

EDIT: After rereading your second part I got it! The rubber band is to flexible and when the tri needs to stabilise with quick change in "rotor"speed that results in a too uneffective way and cause the tri to crash eventually. That was what I was asking for. Thanks

 

[colorex]

What about making prop protectors like the Avatar gunship? Like, around the props with, dunno, fiberglass or something?

 

[Airwolf]

I bought:
Propsavers: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=8241
Props: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=18777

First of all - above propsavers are not compatible with those props (I've got to drill the bottom of the props for a good fitting).

Second - it's barely possible to get the props perfectly centered on the propsavers (I think that some of them have minor quality issues as sometimes it's not the case and some prop-propsaver pairs work better than others).

Third - I tightened the propsaver screws all the way down as hard as I could (a little more and I would strip the thread). As soon as I try some more aggresive maneuvers - props fly away randomly from motors (together with attached propsaver!). Or propsaver is screwed down all the way to motor bell, causing prop to fly away (happens on counter-clockwise motor only). Propsavers act just like a big nuts. I don't think that vibration "unscrewing" propsaver screws is a case here (I've checked them before every attempt, everything seemed tight and secure and still - one of them flew away in mid-flight). Perhaps some thread locker between motor shaft and propsaver would help but I'm going to put the props directly on the motor shaft or I'll buy regular prop spinners (I don't really care about "saving the props" as I have lots of them)...

What about making prop protectors like the Avatar gunship? Like, around the props with, dunno, fiberglass or something?

Yeah I think that would made sense for indoor flying... But for outdoor... Props are cheap and readly available on every corner (at least in Warsaw - I everyday drive in front of the big hobby shop (which is also going to be Hobby King's reseller in Poland soon - though I'm not very enthusiastic about it) so I don't think I'll ever suffer 'prop shortage' and when I'm done with 'escaping propsaver' problem it doesn't really seem I'm going to crash the tricopter alot (it's pretty stable and easy to fly)...

 

[Airwolf]

I've replaced propsavers with props mounted directly on shafts (it seem 10x5 props are a bit too small though). Problems with props flying gone away... But it still didn't saved me from crashing and this time it was pretty bad (two arms bent, yaw mechanism needs fixing, one prop in pieces). It was totally controllable in flight but I lost orientation, and only reasonable thing to do was to bring it down when it was still over the lawn...

 

[ananas1301]

I've replaced propsavers with props mounted directly on shafts (it seem 10x5 props are a bit too small though). Problems with props flying gone away... But it still didn't saved me from crashing and this time it was pretty bad (two arms bent, yaw mechanism needs fixing, one prop in pieces). It was totally controllable in flight but I lost orientation, and only reasonable thing to do was to bring it down when it was still over the lawn...

So from you experience up to now would you say that it isn´t like learning to start flying at all again but it is quite a challenge to do? When you say that it is totally controllable, you mean, with not much control input, but you still gotta correct a little on the axis?

I am just asking as I wanna know what to do when my Tricopter is ready to be flown.

 

[John Campbell]

I've replaced propsavers with props mounted directly on shafts (it seem 10x5 props are a bit too small though). Problems with props flying gone away... But it still didn't saved me from crashing and this time it was pretty bad (two arms bent, yaw mechanism needs fixing, one prop in pieces). It was totally controllable in flight but I lost orientation, and only reasonable thing to do was to bring it down when it was still over the lawn...

I don't think I like the idea of prop savers on a quadcopter... One breaks when it isn't supposed do and you are down. Probably in many pieces I will definitely have mine hard mounted.

 

[Burg]

I don't think I like the idea of prop savers on a quadcopter... One breaks when it isn't supposed do and you are down. Probably in many pieces I will definitely have mine hard mounted.

Definitely +1 on this one ..
The torque with 750kv-1000kv motors and larg(er) props could break the rubber o-rings.
It will happen once for sure and you'll crash.

When you mount such a motor and prop on a plane you wouldn't use a prop saver eighter IMO.
Just go for the collet shaft adapter or even better, get the DT750's with APC/GWS 10", 11" or 12" depending on the quad size.

 

[Airwolf]

So from you experience up to now would you say that it isn´t like learning to start flying at all again but it is quite a challenge to do? When you say that it is totally controllable, you mean, with not much control input, but you still gotta correct a little on the axis?

I am just asking as I wanna know what to do when my Tricopter is ready to be flown.

I mean it's pretty stable, responds as expected (very little control input is needed). But it's nothing like flying an airplane and it needs more space (at least for beginner) that one would think so I won't try to fly it near my house again. And another thing - very important thing - mark one of the arms (rear one) with something (like LEDs) (yaw mechanism is barely visible from several meters).