Hi y'all,
Just finished building my first multicopter and got the first opportunity today to try and get it in the air. But no such luck, it appears as if there's not enough power to get the quad airborne. Increasing throttle to max just gives enough power to hop a a few centimeters off the ground.
I'm using a Crius AIOP FC and got a 'pre-selected parts' beginner's kit from RCTimer so I had the least chance of mismatching stuff. It's an RM450 V2 frame with 2212/930KV brushless outrunners and 30A ESC's - here's the complete setup.
It's using RCTimers 2200mAh 15C batteries which were the highest capacity they had available, but I'm thinking they just don't have what it takes. I did use the online RC calc to check but is wasn't possible to fill in exact matches to my kit so I'm unsure about the results.
Before I waste a bunch of money on better batteries that might not have any effect, any idea's? All help is appreciated.
[Problem] Not taking off, just hops - SOLVED
[Problem] Not taking off, just hops - SOLVED
Last edited by Tizzy on Sat Sep 01, 2012 1:12 pm, edited 1 time in total.
Re: [Problem] Not taking off, just hops
how much does your copter weigh?
what size props are you using?
the 15c battery is likely to be an issue, my 20c battery gets hot, my 40c does not.
make sure all sensors are turned off during initial tests, you want to be operating on gyro alone. for now.
what size props are you using?
the 15c battery is likely to be an issue, my 20c battery gets hot, my 40c does not.
make sure all sensors are turned off during initial tests, you want to be operating on gyro alone. for now.
Re: [Problem] Not taking off, just hops
in addition to Tovrin's comments ...
1. Check to make sure the props are on correctly. Embossed printing on top, blade orientation and rotation per the FAQ.
2. Recalibrate the ESC's per the FAQ. This is an important step.
3. In config.h, change MAXTHROTTLE to 1950.
4. Install a freshly charged 30c or higher rated 3S/2200mAH pack. Your 15c will be ruined after a few short flights; It may already be on its last legs. BTW, I recommend a 2200mAH / 40c for your model.
1. Check to make sure the props are on correctly. Embossed printing on top, blade orientation and rotation per the FAQ.
2. Recalibrate the ESC's per the FAQ. This is an important step.
3. In config.h, change MAXTHROTTLE to 1950.
4. Install a freshly charged 30c or higher rated 3S/2200mAH pack. Your 15c will be ruined after a few short flights; It may already be on its last legs. BTW, I recommend a 2200mAH / 40c for your model.
Re: [Problem] Not taking off, just hops
v.i.b.r.a.t.i.o.n.s..... (had this problem, crius aiop, unbalanced prop and bad-centered prop adapter)
verify with "heavy" lpf (20hz,10hz), if it take off, it's a vibration prob, if not, it's something else ^^
but, dont fly with 20/10 lpf.....
the mpu6050 of crius is very sensitive, and too many vibs will produce a lot of "on-off-full-power-on-esc-off" jittering (you can see it in multiwiiconf, esc pwm go crazy). ESCs wont handle this and keep power low
good centered prop adapter, balanced motor, balanced prop and ~98/188hz lpf should do the job (arducopter with apm2 for example, use a 98hz lpf on its mpu6050, if you you try megapirateng on crius, dont forget to verifiy lpf too)
verify with "heavy" lpf (20hz,10hz), if it take off, it's a vibration prob, if not, it's something else ^^
but, dont fly with 20/10 lpf.....
the mpu6050 of crius is very sensitive, and too many vibs will produce a lot of "on-off-full-power-on-esc-off" jittering (you can see it in multiwiiconf, esc pwm go crazy). ESCs wont handle this and keep power low
good centered prop adapter, balanced motor, balanced prop and ~98/188hz lpf should do the job (arducopter with apm2 for example, use a 98hz lpf on its mpu6050, if you you try megapirateng on crius, dont forget to verifiy lpf too)
Re: [Problem] Not taking off, just hops
Thanks people for quite a few interesting options to try out. One thing I'm not sure how to do though is balance a motor, how does that work?
Edit
- Hopter currently weighs less than 1 kilo
- I calibrated the ESC's using a combi cable connected directly to the receiver whereby all the ESC's are connected and calibrated at once
- The hopter tilts in the right direction when I use roll or pitch or yaw so I'm pretty sure they's on right. I did also verify that they werent on in reverse (ie CW & CCW) and the hopper actually didnt move at all. As for upside down, it's pretty self evident on close inspection if they are on wrong.
- config.h was already set to 1950
- I've ordered new batteries which are specced to 35C. It'll be a while before they arrive though
Edit2
I recalibrated the ESC's one by one. I didn't have time to take it to the park so just a quick test in the backyard (which has way too much concrete) and I can happily report we have liftoff. I set it down immediately but it jumped on full throttle as if something had bit it so that's a major improvement. Back in the shop I did a quick check on throttle response and noticed one of the motors consistently lagging so not out of the woods yet. But I would say this one is solved. Much obliged for all the input guys and I'll most likely be back soon
Edit
- Hopter currently weighs less than 1 kilo
- I calibrated the ESC's using a combi cable connected directly to the receiver whereby all the ESC's are connected and calibrated at once
- The hopter tilts in the right direction when I use roll or pitch or yaw so I'm pretty sure they's on right. I did also verify that they werent on in reverse (ie CW & CCW) and the hopper actually didnt move at all. As for upside down, it's pretty self evident on close inspection if they are on wrong.
- config.h was already set to 1950
- I've ordered new batteries which are specced to 35C. It'll be a while before they arrive though
Edit2
I recalibrated the ESC's one by one. I didn't have time to take it to the park so just a quick test in the backyard (which has way too much concrete) and I can happily report we have liftoff. I set it down immediately but it jumped on full throttle as if something had bit it so that's a major improvement. Back in the shop I did a quick check on throttle response and noticed one of the motors consistently lagging so not out of the woods yet. But I would say this one is solved. Much obliged for all the input guys and I'll most likely be back soon
Re: [Problem] Not taking off, just hops
Went out for the first actual flight this morning since the very short test day before yesterday and actually I'm a happy chappy even though bost first and second flight ended in disaster.
I take off to close to the edge of the clearing and 30sec into the first flight it gets into some trees, crashes to the ground and brakes a leg right at the landing joint.
Good thing? It hit the tree about 10meters up, so that's a major improvement as far as the hopping goes 
Second flight I learn from the first and take it to the middle of the field. There's quite a bit of wind and it takes a few tries before I get the hang of hovering at a certain height. As the minutes (which feel like seconds) go by it gets harder to control and the end of it is a hard landing whereby one of the motors comes right off. Closer inspection shows all the screws have gone. Probably due to vibrations and lack of locktite Good thing? I got to see it working properly and even switched from acro to level to baro to mag. And could see the result of each!
Okay so it resonated up and down a bit but it did so keeping itself pointed in the right direction and pretty much level. I didn't get to try RTH out but was happy to see the GPS unit got a fix in seconds!
Done flying for now and won't have time for a few days either but in all honesty, all in all, I'm a happy happy chappy!
Oh yes, I used Q-bond to fix the broken leg and boy is that the best buy ever!
I take off to close to the edge of the clearing and 30sec into the first flight it gets into some trees, crashes to the ground and brakes a leg right at the landing joint.
Good thing? It hit the tree about 10meters up, so that's a major improvement as far as the hopping goes Second flight I learn from the first and take it to the middle of the field. There's quite a bit of wind and it takes a few tries before I get the hang of hovering at a certain height. As the minutes (which feel like seconds) go by it gets harder to control and the end of it is a hard landing whereby one of the motors comes right off. Closer inspection shows all the screws have gone. Probably due to vibrations and lack of locktite
Good thing? I got to see it working properly and even switched from acro to level to baro to mag. And could see the result of each! Okay so it resonated up and down a bit but it did so keeping itself pointed in the right direction and pretty much level. I didn't get to try RTH out but was happy to see the GPS unit got a fix in seconds!
Done flying for now and won't have time for a few days either but in all honesty, all in all, I'm a happy happy chappy!
Oh yes, I used Q-bond to fix the broken leg and boy is that the best buy ever!
Re: [Problem] Not taking off, just hops - SOLVED
glad to hear your on the right track, it wasnt that long ago i was in a similar boat about to quit this project because i couldnt get a good flight in.
i dont have GPS yet, so i cant comment on that, but use blue loctite and keep everything tight to reduce vibration. use a suitable LPF if you cant get rid of the vibration completely.
i dont have GPS yet, so i cant comment on that, but use blue loctite and keep everything tight to reduce vibration. use a suitable LPF if you cant get rid of the vibration completely.
Re: [Problem] Not taking off, just hops - SOLVED
tovrin wrote:glad to hear your on the right track, it wasnt that long ago i was in a similar boat about to quit this project because i couldnt get a good flight in.
i dont have GPS yet, so i cant comment on that, but use blue loctite and keep everything tight to reduce vibration. use a suitable LPF if you cant get rid of the vibration completely.
Got my 3rd flight in today and can happily share that the quad flies! It appears though that the 2200 15c batteries are indeed way underpowered for the job and within a minute or two the quad starts showing an ever increasing height oscillation and has trouble staying up on roll or pitch. Within 3 or 4 minutes it's reduced to a hopper that can hardly clear the ground.
I still had a few 1300mAh batteries from my ARdrone times which are 30C and they actually last longer and give more power (ie better throttle response) than the 2200's! Connecting 2 actually gives almost 5 minutes of actual control but obviously the quad needs tuning and control is perhaps too big a word. In fact, without level, mag and baro active it's almost impossible not to crash as the quad is extremely sensitive to the controls and has a tendency to rocket off in whatever direction I twitch the sticks. But with these power problems there's no point in trying to tune anything so I'll be waiting for my replacement 2450 30c's before I can get started with any serious flying (although reading your post again it's seems prudent to reduce the LPF just to be safe before I do anything else, I'll get back on that).
About the batteries, I went for the smallest size and weight which I thought would have enough juice to sustain at least 60% of max amps for a few minutes, but I'm thinking maybe I should order some bigger ones. Tricky though as bigger also means heavier, any recommendations?
Anyways, I've indeed locktite'd the motors and frame so that should be fine for a while. How do I get them loose though, is it enough to put some heat on it with a heat gun?
Re: [Problem] Not taking off, just hops - SOLVED
my experience is loctite blue comes off pretty easily with a wrench but holds great otherwise.
as far as your very sensitive flgiht characteristics, i believe you will want to lower your EXPO rates within the gui, start with your pitch and roll expo, turn them WAY down, and then slowly turn them back up as you fly and learn how it reacts.
the expo rates basically make your stick adjustments less dramatic, so you can make easy flight changes without the copter jerking hard one way or another off a slgiht move of the stick.
when you get good and want to play batman in the air, you will turn them back up!
good luck and happy flights!
as far as your very sensitive flgiht characteristics, i believe you will want to lower your EXPO rates within the gui, start with your pitch and roll expo, turn them WAY down, and then slowly turn them back up as you fly and learn how it reacts.
the expo rates basically make your stick adjustments less dramatic, so you can make easy flight changes without the copter jerking hard one way or another off a slgiht move of the stick.
when you get good and want to play batman in the air, you will turn them back up!
good luck and happy flights!
Re: [Problem] Not taking off, just hops - SOLVED
That's a great tip on the Expo rate, thanks. New batteries havent arrived yet and the weather looks to be turning so it might be a while before I can try it out but I'll definitely post back on progress.