Hi all,

Just got done with a test flight with the a new Eflite G110 gyro on board my otherwise stock CPP...the results were a bit disappointing, to say the least. Hopefully you guys can steer me in the right direction...you always do!!

When I first spun up the blades, before it left the ground, it was doing counter clockwise (left turns) spins. So, I stopped it, and put in a bunch more right sub trim in the rudder, about 60% to the right. Still, not enough, ended up going all the way right on the sub trim, and was still at full right trim, and barely enough to hold it from spining to the left. I began with about (approximate on the pot) 70% gryo setting...figuring that was too much, I dialed it down to about 40%, to see what happened. At that setting, I was able to dial the trim back down, but I had very little gyro going on, the tail was extremely loose, all over the place, little or no rudder control by the gyro...

Do I have a tail motor taking a crap here? Or do I have some other setting, like throttle curve, or pitch curve way off? The bottom line is, the more gyro I put in, the more right rudder I need, to the point of running out of right rudder trim, and still not having a very stable tail...

Any suggestions are more than welcome, I am thinking very seriously about putting in my newly purchased tail motor, and see how that affects it...

Also, anyone have any tips on securing a loose tail rotor gearbox on the tailboom? Mine is shifting around every time I have a bit of a hard landing, I tried a little bit of super glue, but it quickly gave way?

Thanks so much all,

Glenn

Try and turn the gain pot on your 3 in 1 controller all the way down counter clockwise and then center your sub trims in your transmitter and you rudder trim. Adjust the proportional to obtain netural. I would start with the G-90 gyro setting on about 80 percent and slowly adjust down until tail quits wagging.

Hi DVI,

Thanks for the tips, I have not adjusted the gain pot on the 3 in 1, the CPP manual said to adjust the proportional to full counter clockwise, to disable the 3 in 1 gyro and mixer, and don't bother with the gain... maybe that info is wrong...

It's sure worth a shot, because I don't really think it's the motor, because the very last time I flew, the motor seemed to be doing a pretty good job...

Let me make sure I follow you correctly, full counter on the gain on the 3 in 1, center trims, and then adjust the proportional on the 3 in 1 to get it close to a neutral setting with a starting pot setting on the gyro at about 80%?

Cool...that sounds like a great place to start, I have seen other inconsistencies in the Eflite manual as well, I guess they can make mistakes like anyone...

Another quirk, sort of, is the manual states to switch the normal/reverse switch to reverse...but mine is set at normal, and it seems to be fine?

I installed a new motor anyways, just to rule that out as a possiblility...I have heard that the motors are very short lived, some reporting as few as 5-10 flights before failure?

Thanks so very much for the insight, I will be applying these changes tomorrow evening, and we'll see how it goes!

Glenn

Is the gyro set to standard not digital? I just did a quick read of the manual and when you add right rudder does the tail speed up and when you add left rudder does the tail slow down. With the main motor unplugged you can do a quick test. Rapidly rotate the helicopter to the left then the tail should speed up and when you rotate it to the right it should slow down.

Nick

Doc,
Think you have it backwards the gain is your gyro sensitivitly and with the G90 should be turned all the way to the counterclockwise position, the Proportional is your tail RPMs if your helo's nose is moving to the left it is because you do not have enough RPMS to the tail to hold it steady. You need to turn it clockwise until it will hold. This is pretty time consuming to really get it dialed in. What I do on my gyros is start at full bring it down enough like DVI said until the tail stops wagging. 40% is pretty low most of my gyros are all in the neighborhood of 70-75% to hold pretty rock steady in a hover.
When I had my CP Pro this thread proved invaluable to me and I had a copy of it printed out and kept with my manual. http://www.rcuniverse.com/forum/m_31...19/key_/tm.htm (post 469)
There is a condensed version/PDF of everything you actually need on the last page. It goes through the complete set-up of the CP and basically only a minor difference between the Pro and that is the bell hiller head. Hope this helps! Gene

Hey Nick,

I did actually check the servo setting, and it's set to standard, not digital. I have my reverse switch set to normal, but it seems to be working the way it should. I did actually do the tail rotor tests, as you suggested, and all seems OK with those as well...

I think DVI and Gene are onto something, and I DO believe there is a misprint in the CPP manual regarding the setup of the G90 gyro...

I am going to test some tonight, and I'll post my findings this evening for you guys...

Thanks so much for your input!

Glenn

Hey Gene and DVI,

I think what you guys are saying makes perfect sense, after all, the proportional is controlling the main to tail rotor speed relationship, correct? I think that there is a major misprint in the CPP manual for installing the heading lock gyro...I am about 90% certain that it said full CCW on the proportional, (to disable the gyro, so they say...) and don't mess with the gyro, which, thinking about it, makes no sense....

I will post the manual's instuctions verbatim later on in a post, once I double check my hunch that there is a misprint...

In a few hours, when it slows down here in the shop, I'm going to apply the settings that you guys suggested, and I'll be sure to post the results later on tonight...

I can't thank you guys enough, God Bless...

Glenn

I think when I set up a gyro on the pro before I turned the gain all the way down. Then in standard rate mode adjusted the proportional potentiometer. Then when the main and tail were balanced I switched to HH mode. I did it a long time ago and I can't remember what I did. Come tuesday I should get my gyro hooked up and test it out.

Nick

SUCCESS!!

You guys hit the nail on the head! I did exactly what you said, and that is to go fully CCW on the gyro gain, and center the trims, and then adjust the rudder basically using the proportional. It did take me a while, for sure, about 2 hours and 3 battery packs, but the effort was so worth it!! This thing flies like a dream now, I have NEVER been able to hover that steadily before! I can almost keep it stationary in a hover now...so cool! Don't know what I would do without you guys!

I do have another issue though...which I am sure you can advise me on... That is, now that it's flying extremely well, I am noticing that I'm having some "revolution mixing" issues, when I throttle it up, the nose takes a left turn...from not enough right rudder being applied to compensate for the main rotor blade/motor torque. My DX6i has revo mixing, but the manual states that it is only to be used with non-heading lock gryos? Also, is this phenomenon unavoidable on a motor driven tail heli?
I can live with it, it's not a big issue at all, just wondering since it is flying so well otherwise. The DX6i manual also states that the revo mix won't compensate for the initial torque reaction...

Now, just to set the record straight, and hopefully prevent someone else from the same pitfall that I fell into...here's the exact wording of the CP Pro manual regarding the 3 in 1 settings when installing a G90 gyro (in bold type, I might add);

"In order to ensure proper operation and the best possible performance of the heading lock gyro, it will be necessary to disable the standard rate gyro and mixer in the 3 in 1 control unit. This is accomplished by turning the proportional mix trimmer pot on the 3 in 1 to the lowest, most counterclockwise position (-). No adjustment of the gyro gain trimmer pot on the 3 in 1 control unit is necessary. "

That bogus info can be found on the top of page 43 in the CP Pro manual...I think Eflite better issue a supplement to the manual for the CP Pro on that one!

THANKS AGAIN !!!

Can't wait to fly this thing tomorrow, I am charging up now!

Glenn

Congrats on the success. I read somewhere that adding revo to a HH gyro messes the information up or something. I will try to find that info, but it could take awhile. Does adding more gain help that at all or would the tail start wagging? You could upgrade to a more powerful tail motor or better tail blade.

Nick

Hey Nick,

Thanks for the info, and the congrats, it finally feels like I am starting to be able to enjoy flying this bird, rather than the white knuckle wait-for-that-bladestike drama that accompanied flying there for a while! Yeah, that would be nice to know why you can't use revo mixing with a heading lock gyro...don't go to too much trouble finding it, I am sure there is a good reason for not being able to use it.

I'll tell you, at first I was struggling to find the right combination of gyro, and proportional...got way off track, and went back to zero on the trims, and just got it as close as I could with the proportional. One thing that was throwing me way off was the torque reaction and the ground effect/rotor wash when I was first setting it up, I was trying to tune it in without actually FLYING the heli....then I got more used to the torque reaction, and was more able to compensate on lift off. As it is set now, it will, on a fairly slow take off, twist about 75 degrees to the left, but once in the air, it's fine...if I take off fast, I don't get much of this phenomenon. It's like it just needs a rudder boost when powering up...the whole purpose of revo mixing I suppose. But I am also keeping in mind the manual for the DX6i, that states that it will not correct for initial torque reaction...to quote the manual "the initial acceleration and deceleration swings should be overlooked"

I'm going to keep fine tuning it, for sure. One thing that I didn't get, was any twitching of the tail, even when I was way up there, close to 100%...about all that I had up that high was VERY little rudder control, the rudder was so dampened that it had almost no reaction to input of the stick...I have it at what looks to be about 75% now, I may bump it up a bit higher, and see if the torque reaction is decreased any.

Don't get me wrong, I'm nitpicking here, this thing flies like a dream compared to when I first flew it out of the box...I am really starting to love to fly it now!

I should be able to get 3 packs in today later at the shop, it's far too windy today to to anything ouside...I just got done with 3 packs inside on the CX2, I am still a bit rusty on orientation, and nose in manuvers with the CX2...I need more sim and CX2 time to help supplement my CP Pro basics...

Take care, and thanks so much!

Glenn

Glen, Glad you got it going! When I got my CP Pro to where I really liked it I sold it! lol I did not get that nose turn on start up but my throttle curve was fairly smooth and the gyro would hold it. I did however also have a tail esc and Micro heli dual motor mod on mine. Best of Luck on your Pro, not a bad bird by any means just takes alot of work and $ to get it going really nice. Gene

Turning the proportional all the way down is not bogus info. The proportional setting of the 3 in 1 is the same as revo mixing in a radio, it will add rudder commands as power increases to offset the increased torque. In HH mode the gyro will see these rudder commands as heading changes and will drift. I've got the proportional pot turned all the way down and my G90 holds just fine. It is normal to have to adjust the rudder trim to stop drifting as stated in the G90 manual.

If the gyro is having trouble holding the tail it's also possible your tail motor is on the way out.