H0ndaJunkie

Ok guys, I've got 2 TRex's, each with Futaba GY401s, and I share a Futaba T6EXHP tranmitter between the two. Both helis also have a Hitex HS-50 servo on the tail.

My problem is that I can't seem to get rid of the tail wag completely. It's not terrible.....it rotates on the rudder axis and stops smoothly, but it still wags a little even after playing with remote gain and delay settings. I have my heading hold gain set to +65.

Can someone who has the same setup, or at least the same gyro and servo, tell me the settings that they have on thier 401? Where is your gain set, and where is your delay set. Thanks!

H0ndaJunkie

I just took one of my Rexes outside to see if I could beat the wag. No matter what I did, the wag did not go away. When I'm testing, I'm just lifting a foot or two off the groumd, checking for wag, and setting her back down again. Do I really need to be in idle-up to test properly, or not?

PsychoRookie

I do not know much about hs-50's, I am assuming that it is an analog. Try a digital tail servo, the 401 is much better suited for a digital Servo which will make it much more responsive.

The Rookie

VinceHerman

Just a note - HS 50 servos on the tail are at risk for splitting the case apart. Put some large diameter shrink wrap around them (tape might do)
How much did you reduce the gain to, trying to get rid of the wag?

H0ndaJunkie

Well, on my Tx, the positive numbers are AVCS mode, and negative numbers are normal mode.

I originally started the gain at about +80, and kept adjusting back until I got to 0. It didn't make much of a difference, it only served to speed up or slow down the wag. I also tried adjusting the delay on the gyro. I went from 0 all the way to 100, and tried the different setting in conjunction with different gain settings, but it was no good.

I don't really know what else to do, and I don't have the money right now for a digital servo to replace the HS-50. Other people use the 401 with this servo I know, so I wonder why they don't have the same problem. :-(

N11634

I had a similar problem on mine. Unhook your control rod from the servo and feel if there seems to be a very minor bind in the middle of the travel. This is caused by the eyelets that go from the slider and the blade grips being too tight and having a spring effect around center. Loosen the screws on the back a tiny bit on the eyelets and see if that solves the problem. I chased this for a week straight before I found the problem. It makes it hard for the servo to center when hovering and bounces back and forth over the "hump" in the travel....Thus creating a slow wag at any gain value.

I'm assuming you have the plastic tail slider, on the CNC slider, the eyelets are hinged and you shouldn't have that problem with it.

H0ndaJunkie

Why you say "eyelets", do you mean the ball links that are screwed onto the tail slider assemply, as shown in the photo?

BarracudaHockey

My Feedback: (11)

Wag is caused by too much gain, either in the radio or mechanical. Mechanical gain can be raised by moving out on the servo arm or reduced by moving in.

My 401 on my rex with a 9650 digital servo is 32 percent in HH mode with a hole that I had to drill as close as I could get to the spline of the servo.

With an hs50 make sure DS mode is off (if you have been running with it on just throw that servo in the trash and start over) and that you have some delay set on the 401.

Also make sure that your linkage is as silky smooth as you can make it and if its going through the fin brace, I enlarged that hole as well and squirted some triflow on the rod where it passes through there.

H0ndaJunkie

My DS mode is off........I was careful to make sure of that, since Futaba is very explicit with their warnings on the dangers of using an analog servo in digital mode.

I moved my linkage ball closer to the servo spline, like you said, by drilling another hole. Of course, now the servo has to travel much further to move the tail assembly the same amount as before. That doesn't seem like a good thing though....why is that better?

I'm sure I probably eventually need to get one of the 9650 servos like you have, but I don't have the money right now.

I don't use the fin brace to guide my tail linkage. I changed out the regular bent-wire linkage on the servo end, with a stainless ball and link. I also have stainless balls all over the heli, so my linkage seems to be as smooth as it could possibly be. I used my ball link tool to loosen all of the links a little too, just to be sure nothing is binding.

I'll give her a test flight this afternoon, and let you know what happens.

Barracuda, you said your gain is set to 32% in heading hold mode. Considering that positive numbers from 0-100 on my transmitter is all heading-hold mode, approximately where on a scale of 1-100 would your 32% be on my transmitters scale?

BarracudaHockey

My Feedback: (11)

When you move the linkage in on the servo don't forget to adjust the limit on the gyro, the closer the gyro is to 100 the better it will perform and the servo will get less stress. I'm speaking of 0 to 100 on my Futaba 9c so if you are using a gyro menu, then they would be the same.

H0ndaJunkie

gotcha......wow, 32% seems so low. Is that just because you're an accomplished pilot and don't need as much gyro interaction, or is that really where you found you had to set the gain to get proper gyro performance?

I did adjust my limit back to 100%, which does give my slider it's necessary travel. I did take it outside for just a minute, and gave it a quick hover-test. The wag did seem a lot better at 60% gain, and 50% on the delay, but it still wasn't right. of course, considering the gain setting you use, my gain could certainly be way to high now.

I think after lunch I'll try your 30% gain setting, and see what happens. If it doesn't help, I'll mess with the delay setting a bit in conjunction with the gain.

I'm seeing results though, so that's encouraging. Thanks!

BarracudaHockey

My Feedback: (11)

A note on gyro gain. Only run as much as you need, otherwise the gyro will fight you in manuvers. The way I set my gyro gain is to make the helicopter fly sideways as fast as I can and run enough gain to hold it. Any more is a waste and more wear and tear on the servo thereby decreasing its life.

H0ndaJunkie

I also notice that my headspeed doesn't appear to be anywhere near what it should be at idle-up......I don't know exactly what it is, because I don't have a tach.

I'm currently running the Align 430L 3550kv motor, with a 25A ESC and the 11 tooth pinion gear. Would I be safe to go up to a 13 tooth pinion with this motor?

UKgroucho

You (probably) just hit the nail on the head.
If your HS is too low then the tail WILL wag...

H0ndaJunkie

I tinkered with the heli again today. I must have lifted off, hovered for a few seconds, set it down, and then re-adjusted 15 times.

My ball link on my servo is as close to the spline as I can get it. All of the tail linkage feels nice and smooth too. I tried setting the heading hold gain to almost every setting possible, and even tried adjusting the delay setting on the gyro, in conjunction with the gain, but it still hunts.

I just don't get it. []

It's not a bad hunt, it's perfectly flyable, as it only moved between 1/2 and 3/4 of an inch, but I expected to see a rock steady tail with this popular gyro.

Maybe this is as good, as I'm going to be able to get it?

I have the gyro mounted upside down, underneath, where the tail boom meets the frame......is this an ok way to mount it?

H0ndaJunkie

Well, after several days of testing, tinkering and reading, I was finally able to nail the problem down.

It was the HS-50 servo. I don't know why, but no matter what I tried, I couldn't get rid of that wag, so I said screw it and pulled the servo off. I replaced it with a very standard, slightly slower Futaba servo......one that came with my 6EXHP radio setup. I set my gain back to 60%, set the delay to almost 75% and took the Rex out to give it a try. Imagine that......it cured the problem.

My tail was rock steady, but still responsive. Perfect.

Why on earth would I need to use a slower servo to acheive the results I was looking for?!?! Everyone seems to like the HS-50s, but considering that my other Rex has the same problem, and it also has an HS-50, I'm not sure about them anymore.

clive45

Probably find the old servo had to much slop and the gyro was continuously correcting or the servo had bad centering, the pot may be bad etc.
Anyhow you are now flying with a solid tail. And you have learned a bit about gyro's and servos

H0ndaJunkie

Well, originally built the two standard T-Rex's......One HDE, and one CDE. Then I sold the CDE Rex to a really cool guy from this forum who lives in Norway.

I switched the HDE tail servo over to the standard futaba one, and it has been fine since. It flies great with a rock steady tail.

Since then, I've upgraded the HDE frame to the Microheli CF CCPM frame, and made the following upgrades:

Neumotors 1107 motor
Parkflyer 6V BEC
Castle Creations Phoenix 35
JR 770 PCM receiver
Gorilla gear landing gear
3 HS-56s
Futaba 9650 on tail
Microheli Delrin CNC main gear
Microheli CNC front tail gear and CNC pulley
Microheli complete CNC head
Microheli complete pro tail
4S Maxamps 2200mah LiPo

So, I've upgraded that one just a little! hehe

But now, because of all of the old plastic parts left over from the HDE, I've begun bulding a another heli! It's a modified HDE. I bought the brand new Align HDE CF frame, that still has the mechanic pitch lever, but it's all CF and alum. The other components are going to be really cheap items; Telebee gyro, HS-55s, JR 700 PPM reciever, 450TH motor, Align 25A ESC, stuff like that. Since I spent so much money on the other one, I'm now scared to fly it just incase I break something. So this "new" built-from-parts heli will be my knock-around-heli! LOL

Trust me, I'm not looking for that much performance out of it, especially not with that crap gyro, but at least I can try some new moves without worrying about it so much, know what I mean?

So to answer your question, yes I have learned a lot......a whole lot in fact. :-)

plane766

Is Align headlock gyro a good choice or go for GY-201? Thanks

RickP

My Feedback: (2)

I've got your set up but with a hs-56 servo. Rock solid. Sorry to read about all of the problems.
RickP

H0ndaJunkie

It's ok, my first post is way old now.......my heli has a 9650 on the tail now.....and it looks like this now: