Takeoff in stable mode?

[brucedjones]

I have finally squashed all the gremlins in my quad build (pics soon) and am slowly trying to learn how to fly it and build confidence. I dont have much experience with heli's other then friends indoor heli's and simulators. My main problem is really just the fear of crashing itself, which occurs an awful lot as my attempts at gentle takeoffs are ruined by ground effect.

So is it ok to try and takeoff in stable mode? or should I stick to accro mode, man up, and make sure everything is trimmed well.

PS the default PID values feel pretty responsive in accro mode, but I have no real reference to how the quad should feel

[Hamburger]

sure, I do it all the time.
You may start in stable/level mode and switch to acro when copter has reached a safe altitude. That way you can try acro and have time to switch back to stable mode for rescuing/recovering.

[cardboard]

When i started i could only fly in stable mode as ive never flown helis before ether. Never had any issue with taking off in stable mode.
My only advise is to give it a good blast of throttle to get it 1-2m off the ground in the first few seconds, there's nothing worse then only just being off the ground, fighting ground effect and bumping landing gear against terrain.
Failing that hand launch it in stable mode, I do this when theres no ground to take off from, long grass etc etc..... So hold it steady and power the rotors up, bring the throttle to a point where it'll hold altitude, give it a gentle nudge fwd as to not have it attack you, let go then regain two hands on your controller.
I wouldn't do this with a copter i don't trust but I'm very confident mine wont flip and and hurt me.
As a trick I can hover in a pluck it from the sky at the end of a flight to saves walking to pick it up.

80% of this flight was in stable mode including all of the take offs, landings and crashes
http://vimeo.com/31985786

[brucedjones]

Nice vid.

Encouraged by your comments I had a go with stable mode this afternoon. Holding the quad in my hand it feels like it wants to tilt off-level, and trying to take off from the ground as soon as the throttle approaches takeoff range it just starts to pitch up hard. I wasnt able to correct this.

So I went back to accro mode and had a play, finally managed to get off the ground fairly gracefully! The takeoff was followed by a nice little controlled flight, but in my excitement I stepped straight in dog sh*t. So accro mode appears to be working well which is nice, but no such luck with stable mode. Im going to try upgradeing to 1.9 to see if that makes a difference.

[cardboard]

it sounds like you havnt trimmed stable mode yet.

First trim in acro mode with your Tx trims so it is stable and doesnt drift about.

to calibrate ACC.
Copter must be stable and level at the ground.
Motors disarmed.
Full throttle up + full yaw left + full pitch backward

3. Now start motors and fly in stable mode.
Normally its better to start here as normal in acro mode and switch to stable mode while in the air.
Because if stable mode needs much trim, its easier to fly in acro mode.

Okay, so you are now with stable mode in the air and the copter drifts to the right and backwards.
Switch back to acro (easier to land) and land your copter.
Disarm motors.

4. Now trim the ACC mode.
Don’t touch your trims on the transmitter.
Give full throttle (must be >1900)
With the help of your roll and pitch stick you could now trim the ACC mode.
full PITCH forward/backward and full ROLL left/right (2 axis possibilities) will trim the level mode according to the neutral angle you want to change.
The status LED will blink to confirm each ticks.

So for instance, you have to move the pitch stick full forward about 4-5x.
That means from neutral to full and back to neutral, 4-5 times.
You will here the buzzer each time beep and see the led each time blink, when move full forward.
The same for the roll axis.

After that start your motors and do again 3. until your copter is complete in level in ACC mode.

If you want to reset the ACC trims, just do step 2. (ACC calibration)

[mr_rsv]

I've finally got my copter flying and i to am having the same problems with stable mode, when i switch it on the copter slopes right and pitches backward??

I've had trouble from the beginning as i wiped the Eprom and had to start from scratch' (DON'T ASK):
so is the problems in trims or do they start at the (default) 1.9 code im using?????
where do i find a ARDUINO CODE specific to my hardware?????
QUADX 900KV 200W TURNIGY MOTORS, PLUSH 18amp turnigy ESC ARIS v 3.0 - Original Nintendo Wii Motion Plus MP+
with LLC and BMA180 Acc
Any advice would be appreciated PLEASE....

[bill516]

If you have wiped the eprom and then re-loaded software it will revert to stock settings i.e what is set in the sketch. You need to set up as per the post above from Cardboard, although your Tx trims should remain the same, wont harm to recheck them with a quick flight in acro mode.

Re specific code there is none, you have to setup up the code to suit your hardware by commenting //, or un-commenting, removing slashes, for items in the config.h tab. Removing slashes enables that part of the code i.e.

#define I2C_SPEED 100000L //100kHz normal mode, this value must be used for a genuine WMP
//#define I2C_SPEED 400000L //400kHz fast mode, it works only with some WMP clones. Means that the I2C speed is set to 100Khz,

//#define I2C_SPEED 100000L //100kHz normal mode, this value must be used for a genuine WMP
#define I2C_SPEED 400000L //400kHz fast mode, it works only with some WMP clones. Means I2C set to 400Khz.

[PatrikE]

You need to calibrate ACC.
Do it with the Gui or with the sticks.(Full throttle up + full yaw left + full pitch backward)

If it drifts after that you need to trim the ACC mode.
Full throttle.
Adjust the acc with Pich and Roll.( Full throws)
Led will blink every trimstep.
take off and test.

Repeat untill it fly level

This is just the short version of cardboard's post.
http://www.multiwii.com/forum/posting.php?mode=reply&f=18&t=991#pr6598

Keep em flying..

/Patrik

[mr_rsv]

Ive tried all these things mentioned above and there not working (im about to purchase my 3rd set of props )
maybe i need to start with my code and gui settings to get it flying stable in stable mode!
Can anybody give me some advise what my code should be and GUI setup should look like??
Ive got PARIS v 3.0 - Original Nintendo Wii Motion Plus MP+
with LLC and BMA180 Acc, 18amp esc 900kv motors on quadX
Ive tried a few things in the GUI and nothing makes a difference, i can fly it okay in acro mode its quite stable like that' but
i want to get some thrills/altitude going and im going to need this stable feature to safe my craft

Also how do i stop it from changing altitude so much its very hard to keep it at constant height' does the stable mode help with this??
or can i add something to help this

would appreciate any advise cheers guy's

[cardboard]

still sounds like stable needs trimmed.
a few pointers to watch for when trimming stable mode...
if your tx end points are to low stable trim wont react and the led wont blink.
it takes allot of blinks to make a difference, i normally do lots of 10-20 blinks, means you can fine tune it a heap though. (if i remember correctly 1 blink consists of 3 very quick successive flashes, sorry copter is put away or id double check)
when i fist trimmed my tri i think it was near 100 blinks on one axes to level it out so it may take up to this much or more.
make sure you sensors are square and level, this will reduce the trim you have to account for.
only trim on axes at a time, it makes changes easy to spot.

and finnaly my cheats way of flying/trimming in level mode
if you DON'T plan on flying in acro mode this will have you in the air very quickly.
neutral Tx trims
turn on copter let arm
take off in level mode
use TX trims to trim level mode
have fun
drain battery
land-----all in level mode
this is how i flew for the first couple of months when acro didn't interest me at all. (aka i couldn't fly acro )

using the above method, if your copter is so badly out of trim after you've neutraled your tx trims its impossible to take off without major control inputs to correct you can use the following tips to help get it right.
(again all in level mode)
hold the copter in you hand and power it up
apply enough throttle that it is almost hovering in your grip and let it find its "level"
use TX trims until it gets to real level
once you eyeOmeter tells you it's basically level you should be able to easily fly it off the ground and tweak the last few clicks of trim in

[cardboard]

I just went through my HK account and ive gone through about 14 bags of props (70 individual ) in just under a year on my tri!!
some last minutes while others last weeks, just have lots spare.
Flying in cold weather doesn't help, I broke the most during winter when they were brittle and the ground was icey

[mr_rsv]

thanks for all ur help guys I'm flying in stable mode now,
It was a case of my misinterpretation of instructions
And not having trims set correctly so all throws can blink on stable
Mode calibration. Although its working now I'm not Impressed with how
It works, I think I can fly it best on accro! Yes it corrects the roll and pitch
Once you stop giving input, but it still keeps moving in direction at speed?
Though when I use accro my input corrections bring it to stop naturally
But I'm a begginer to say the least and I'll probly get fat from eating my own words to often

[cardboard]

The level mode is exactly that and no more. When the controls are released the copter levels its self.
wmp and nk are both accelerometers (linear and rotational) and as so can only detect acceleration, if the copter is going at a constant velocity the imu cannot tell this apart from being stationery.
I think your looking for gps position hold?? Check out the gps threads here for more info.
I like level mode as it is more like flying a fixxed wing aircraft but everyone likes something different

[mr_rsv]

I can probly get used to it with just the stable mode'
Eventually it stops drifting I think But what would be handy is the ability to
Maintain altitude without any extra/less control input.
I find I'm constantly up and down all the time with very litle input, again maybe it's just
More practice I need
Cheers

[cardboard]

ive heard of people using heli throttle curves to dampen the throttle curve around the hover point, similar to expo as far as i can tell.
Youll get the hang of hovering, took me a while to but once you learn the way your copter behaves it gets easier.
protip if your doing fast, low and aggressive flying you will be working the throttle stick allot

[luanlmd]

As also a beginner I can say acro mode is scary!
I fly acro just to make sure everything is ok, then I calibrate level mode and never more go back to acro.
I take off and land in level mode with no problems at all. (just try to take off a little fast to avoid ground effect as said before)
If I loose orientation (that happened often in the first flights) in mid air I can just leave the sticks alone and then throttle up to get away from a crash and figure out what to do!!!

[mr_rsv]

Thanks guys I shall try both tips
Once I straiten booms out and fit more props my copter had a duel at work with
A forklift and sadly lost' during show and tell.

[cardboard]

Allgood and happy flying,
I hope that poor forklift is ok though

[bear]

Hi all,

My quadX is using ADXL345 accelerometer with V1.9 code. I can takeoff it in acro mode.
But when I takeing off it in stable mode. Only the front or back side takeoff from ground.

Anybody have any ideas?

Many thanks for any assistance you can give.

Bear