GY611 Piro Doing A Funny

[Whirlybird]

Hi
I'm new to the 611, have used the 401 with no complaints. When I pull up into a 540 the piro rate starts out really slow and then speeds ups before the first full turn. Never saw this with the 401. Setup is like JK suggests, I think. Using F3C mode. Please help a 611 newbie.
Thanks :?:

[tnreefguy]

Sounds like the linkage is binding or it does not have enough throw. Check the piro rate in the program.

[Russ McC]

Assuming everything is set up correctly you are simply seeing a side affect of running the gyro in F3C mode, Jason likes F3C but try 3D, I think you will like it. 3D mode gives you the yaw rate you demand when you demand it, exactly what F3C mode does not do.

[DavidH]

I am in Birmingham. If you need some help. Let me know. My piro speeds are fairly constant using F3C mode. Piro rate for my setup depends on how far I deflect the rudder stick.

David

[Whirlybird]

Thanks for the replies. I don't think the linkage is binding but will recheck. That could cause this to happen. I'll try the 540 in the opposite direction to see if it's any different. I don't believe that this happens when I piro from a hover though. Will also try 3D mode next time. David, thanks for your offer to help, I may need it. BTW this is a brand new R50 Hyper heli.

[pilotError]

Definitely put it in 3D mode. The tail won't stop nearly as violently, and it'll give you the constant rate that your looking for.

Mike...

[Whirlybird]

I went out in the wind and cold (cold by Alabama standards) today and got in three flights on the R50. Something definitely going screwey with my setup on the tail. The hesitant start to the piro only occurs when going to the left, right is fine. It does same thing in hover as well as stall turn which is different than I thought. Piro in slow forward flight is fine to the right but it hesitates and whips around when going to the left. I really do not see any binding in the linkage. I can hold pressure against the rod and the 9256 doesn't even hesitate. I have equal throw in both directions. The only thing that looks different than my 401 setup is the servo arm on the 9256 is short, about 10mm from the servo arm screw and the ball. The reason for this is that the JK 611 setup says to use 110-120 % travel limit and a longer arm would make this impossible. You think I could have a bad 611 ?? This is weird.

[DavidH]

OK first. Jason has some good guidelines posted about the GY gyros on his website.
It is not bad information. 95% of the information he has posted was when he was flying for MA and flying Fury's. He was using different main blades, different tail ratios, different everything than what you have in the Raptor 50.
If the gyro is hesitant when going left. Something is definitely wrong with setup. The heli should really start to piro to the left than it would to the right. This is because the torque of the main rotor is wanting to piro it to the left.
What radio are you using?
Are you sure the linkage is not binding and free? Unhook the linkage from the ball on the servo. Then slide the linkage back and forth and make sure it moves easily and silky smooth.

Where are you reading the 110-120% travel limit?

If you want me to help on phone, give me a call. You can PM me for number.

David

[tnreefguy]

I would also check the enpoints in your radio. If they are unequal or set low that will also affect your piro rate.

[Whirlybird]

Hi
DavidH has kindly offered help by phone but I thought I would follow through on this thread. I checked again for binding, definitely no binding on the pushrod. Checked the settings on the 611, all default except for the LMTA and LMTB which are both 120% ( I did switch to 3D mode just to see). Flew it today and still hesitates in piro to the left, same in HH vs rate mode. In FF a left piro stalls at 90 degrees from start. Piro to the right no problem, very consistant. I jacked up the travel limit some in the left direction to see what happens but didn't really notice any difference. SO, pulled out my trusty 401/9254 and commenced to change out the 611. The only difference is that the 9254 has a longer arm than the 9256 (this may require some further testing). The 401/9254 did a much better job with the piro left. It would bring the tail around to the left in FF where the 611 would not. I am really wondering if maybe I have a bad 611/9256. I don't see why the shorter arm on the 9256 would have resulted in this problem. Remember the 611/9256 holds great in a hard punch and all other situations. It's just this left piro that is bad. I may go ahead and send the 611/9256 back for a check. Man I like that shiney sensor !
BTW I am running 1800 headspeed, the endpoints are at 103 both ways and the radio is a 9CHP with PCM receiver, 3-9252servos, TJ Pro Gov.

[Russ McC]

You talk about the travel limit being 120% with a shorter arm, well that should be fine as long as you are traveling to or very near the stop in both directions. The gyro will not travel past it’s set limit so if it is not to the stop you wont get the use of the full mechanical ability of the helis tail control. However none of this would make it hesitate before beginning it’s demanded yaw, it could or would affect it’s ability to piro in FF. It sees like you have a handle on this thing and if you can make a 401 work then the 611 should be the same basically so I also am leaning toward some defect, it would not be the first time, keep us posted.

[SteveL]

Did you check your delay settings on the 611. I know you said everything was defaul and default is 0 but it may be worth a look.

BTW what is the Verdict 3d or F3C?

What is a good starting gain EVO 2000 Headspeed. 92mm tail

[Whirlybird]

The delay setting was at default (0) . I switched to 3D mode but it did not improve the problem. WX has been bad and I have not been able to work with this issue. I will follow up with any info I find.

[edders]

I have the same exact problem on my raptor 50 only difference is I'm using 401 combo.
I'm going to try different tail blade sizes to see if that fixes the problem.

any other suggestions?


Edders

[3DME]

Are you setting the mechanical length of the tail puhrod in rate (normal) mode? This is an important step. I am not sure it would cause the problem you are having but it is worth a look. You will want to hover in HH mode (no wind is best) then switch to rate mode and see if the heli rotates in either direction. Also make sure you power up the heli in HH mode.

Mike