T-rex 500 Tail wag!

[Highlights]

Ok so I know there is alot of info on this matter. I have not yet been able to find a really definitive answer yet though.

So here goes:

I am working a few bugs out on my new T-rex 500. I am running stock motor 13t pinion and 2500mah packs. I have the Futaba gy611 giro . I am experiencing tail wag. Sprice and I have tried uping the head speed. Lowering the gain until we had adverse hunting and weather vaining. We are back at 35% on gain and I have 80% head speed on a dished curve. Do I have to worry about the Align esc with built in Bec. Could this be the source of my issues and the tail wag????? Forward flight is fine but the wag is really not lending to precision locked in feeling. What do you think?
Thanks in advance,
Mark

[sprice50]

Mark is not running governor mode. He is running 85% throttle straight across in normal mode from half stick onwards. We have tried to adjust the gain one percent at a time and gone from hunting to weather vaning.

I have a 611 gyro on my trex 600 so am familiar with the gyro.

PS he did forward flight and co-ordinated turns on his second flight and lands easy on the mat!

Thanks for the help.

[Highlights]

Shaun man , thanks for chiming in here. I am not the electronics GU -----RU that you are. Your explanation is a tad more refined and people may get the gyst of what is going on here.

[Animal Jesky]

Mark,

How far is the ball on the servo arm? I'm running a 9257 tail servo on my heli using the 6 star futaba horn and the 3rd outermost hole. Check to see where you are.

Andrew

[Highlights]

Andrew,

I am running the Futaba BLS 251 coreless brushless. It too is the star arm ( only the adjacent arms have been filed off) I am running the ball link off of the innnermost hole. Basically right at the base of the arm at the servo shaft.

................. you have a theory?

[3DBatixkid]

As andrew said, move the ball out and try that. Also, take the servo arm off servo and make sure everything moves freely. Lastly, take your tail blades off and check that the bolts holding the grips on are tight, and that there is no binding in the tail.

[sprice50]

	Quote: Originally Posted by 3DBatixkid
	As andrew said, move the ball out and try that. Also, take the servo arm off servo and make sure everything moves freely. Lastly, take your tail blades off and check that the bolts holding the grips on are tight, and that there is no binding in the tail.

I don't think he needs to move the ball out at all. Mark already gets full travel, but we could give it a try.

I think the suggestion re binding is key here. That is likely the issue as we went from being loose to hunting. Mark, I think you should take some time to get the 'tilt' setup in the tail servo so that the pushrod is straight down the bottom of the boom. I'm putting my money on that. Definately something I didn't check for was binding and he has a curve in the pushrod setup.

Thanks for the help 3Dbatix

[Highlights]

Already there Shaun man. Re configured the rod and ready to role Tuesday after noon.

keep your fingers crossed.

[sprice50]

I'm pretty sure it will fix it. Wish I was off work earlier!

[Highlights]

Alright..........well that didn't help. The pushrod is perfectly straight and I moved the ball link out


My next option is to turn the voltage down to 5.0 amps on the bec.


Any one know how to deal with the belt tension on this model? The tail boom fits into it's slots and the belt is tight. There doesn't seem to be any way to lessen the tension at this point. I can see once the belt stretches with a few flights that it will be able to be snugged up. For the time being though it seems to be pretty tight. Even at that though it does seem fine . Everything turns simply enough.

**** This is not the first model I have built. I am a perfectionist and I can certainly say that this is an extremely tidy build. There isn't much to overlook. I am stumped however.

Any thoughts?

[sprice50]

Let's wait for the next installment from the Highlights show. I think the turning the voltage down to 5V on the BEC may do it as my 611 runs a voltage reg at 5.1V between the gyro and the S9256. That said yours is the brushless.... lets do a quick google.

http://www.futaba-rc.com/servos/brushlessservos.html

Yup... that's it! My suspition earlier is right I think. They do not give a 6.0V rating for the 251 brushlesss servo, only rated for 4.8V. as you have been running it at 5.5V this is likely causing some issues.

[SHANERC]

I had this problem once and it was push rod binding on mine, I have been watching this thread
and thinking about the steps you have already covered and the only thing left is a bad servo(?)
just a thought, I am just tossing ideas out, maybe borrow one so there is no cost till you make for sure. heck, I would let you use my tail servo if needed. keep us informed GOOD_LUCK

[SHANERC]

Sprice I posted before I seen your last post, this info sounds if you have hit the nail on the head

[Highlights]

Let's hope so guys. I will reset for 5.0 volts and give it a go tomorro. I would hate to think that the flashy corless brand new brushless mega exotic servo (lolol) is bad


fingers crossed yet again!

[sprice50]

When it works... I owe you a couple less beers