It might be better to put it on training gear, and try spooling up. Sometimes when the heli is fixed to the bench it will fight itself. I believe the tail is notoriously difficult to get right on the 250. The unit looks gigantic on the poor little 250 too!

ahhhh!!! figured it out! the collar on the shaft isn't marked, and between my two rotor heads there's a good 1/4in difference, and they both leave the reduced end of the shaft inside the bearing. so i fixed up a shaft and played with the rotor heads until i finally got a good test, it wobbles a little when its starting up, but nothing to bad really, ran really nice and smooth once it was going, and didn't have that high end jitter on the servos like before. i could tell the gyro was playing with the servos a bit but nothing crazy like before, i'm going to make training gear for it and test fly it tomorrow!

so i'm really glad i bought two kits, otherwise i would've been up a creek i'll make another video tomorrow of my little test fly.

Good to hear you are making progress. If the wobble does continue in flight then the most likely thing is the cyclic gain is too high. Do you know what each of the pots do yet. ehirobo said they were gains, but not about which gain each pot sets.

haha alright, i couldn't help myself, made up a pair of bamboo skewer, charged my batteries, and headed to the basement. went through a battery to get to trust myself with getting it up above the ground effect in my tiny workshop. seemed like the tail was holding decently well, i made a little video for you guys so you can get the first peek at the cx-3x2000 flying

and i'm not sure if i'm running into the dreaded 250 tail delima, but i'm having a tricky time getting the tail to hold like normally, it might be the gyro being on really low gain, but i kinda have to hold the tail just a bit to keep it from swinging from the torque. i put the helicopter on "beginner" so that might be the problem, it felt really sloshy and like i had to chase the cyclic with big stick movements. i'll try putting it into a higher rate setting tomorrow, because i really need to get some work done today, lol

copterx 250 fbl with cx-3x2000 gyro, first test flight (0 min 27 sec)

Thanks for the video. Looks good. The tail was very soft on the CX-3X1000 when set to beginner. You needed to get to the middle setting or the next one up to get it a lot better, but agility will be increased as well, so be careful.

haha oh yeah, if you knew me you wouldn't worry about me being careful, everything gets tested, checked, re-tested, re-checked, re-re-tested, re-re-checked but i'm going to try bumping it up tomorrow, i'll probably do another video once i get it to my liking and have it hovering nicely. then after that i think its good to loose the trainer and take her outside for a real maiden video!

put the heli into "soft 3D" mode today and test hovered it in the basement a little bit, i liked it a lot, enough to take it outside! here's the video of it flying outside. the gyro holds well if i dial in the tail on the sub trim, but it seems to move around every time a turn it on? i actually flew it for about 3 minutes and it did a lot better than it did in the video. still gotta work on the tail.. lol stupid 250 size

2nd test hover with cx-3x2000 gyro (0 min 39 sec)

Sounds like your tail is in rate mode.

Even if you use rate mode, trim settings may be forgotten when you reboot the gyro, depending on what kind of coffee the programmer had when he wrote the code. Never rule out bugs.

Originally Posted by mr.michael.2468

put the heli into "soft 3D" mode today and test hovered it in the basement a little bit, i liked it a lot, enough to take it outside! here's the video of it flying outside. the gyro holds well if i dial in the tail on the sub trim, but it seems to move around every time a turn it on?

Make sure your TX sub-trims are all set to give zero in the "monitor" tab in the software with the sticks centred.

Don't use any TX trim - since the gyro will see the trim as the new neutral each time you power it up, and you'll end up adding more trim. You might use TX trim when flying the heli for the first time, but after landing adjust the linkages or servo trim in the CX so that your TX trims return to zero.

You can either set the tail up with the slider centred at neutral, and then only fly in HH mode, or set up the tail in rate mode. Adjust the trim in rate mode by altering the pushrod length, and then use servo trim in the CX to make any fine adjustments after that. I'm not sure which works better on the 250 - centring the slider, or rate mode setup, but I use rate mode setup on my 450's.

What's all that white stuff in your yard?

If you have changed your subtrim on the tail, make sure you reset the failsafe, as well. With some gyros, it's important that the failsafe and stick neutral positions are the same.

hmmm good point, so i need to set it in the gyro menu or do it mechanically... gotcha, that would explain why it was like it was resetting even when i changed the trim. i'll have to play with it a little, good thing i got a bunch of people hear who know what they're doing

The cx3x1000 had a blue LED for HH and a red LED for rate mode, likely the new one is the same way.

Try to turn the gain on your radio past 50% (or below if you're above) and see if the LED turns blue. This way you should see no drift and should not need trim. Generally older gyros needed to be turned on in HH mode to read the center correctly, then could be switched to rate mode if that's what you wanted. Seems this FBL unit has that bug too. This is how you know if the guys who program the gyros fly RC helicopters.

hey i took the advice for the HH mode, i originally bumped the rates to 40%, but CX is backwards, 0% is highest HH mode, so to make it "more HH" you have to go further below 50%. i ended up at about 30% as the highest i wanted to go without getting any shakes. the gyro does a great job while hovering, but as soon as i took it out and buzzed it up and down the tail would like give while a was giving it more throttle and then it would "stick" at the new height, then when i'd drop it the tail would swing the other way and "stick" at the new hovering position, i'm sure this is just another programming issue, even the mcpx can handle this --somewhat-- any advice on this one? other than this issue i was really happy with it, even with the analog servos it centers nicely, very stable and easy to hover, yet very smooth on the controls.

by "buzz" i mean like throttle it up hard and then dropping it and catching it, i would think it should be able to figure out when the throttle is increasing and decreasing?

The gain at 50% is zero and further from 50% it increases to either heading hold or rate mode, whichever direction you go towards. I think this is only for spektrum radios, though, as far as I remember, my RDS8000 is designed to display a range of -100% to 100%.

As far as the yawing on collective goes, there are quite a few things you can do (and mess up pretty bad along the way), so write everything down.

There is a "revo" setting, otherwise known as collective-tail pre-compensation. It's hiding somewhere in the advanced menu. Try set it to zero. Also try to fly with your back turned to the wind and see the tail feels sluggish, this will help you diagnose why it's mushy. Sometimes tail can stay put and not wag, but it will have a lot of "give" that you can only see in wind. Try to play with the tail servo arm length. You can also go in the advanced menu increase the "I" gain a little and decrease the "D" and see what that does. Set your servo endpoints correctly too, this will give your tail servo more travel.

Keep in mind, that I'm talking from my cx3x1000 experience.

One question I have. Have you played with the quad and airplane menus? Can I see some screenshots?

One more question. If you hold the cyclic stick to one side and then center it, how many seconds does the swashplate take to come back to level?