450 Servo Flip?

Rob Lancaster

Active Member
I can't find the original thread so well just start here.
As mentioned before my aileron servo did a flip. That is to say it started to move in the opposite direction then it was suppose to.. It went from a +70 to -70 (swash settings) and I have to reverse the servo to get it back the way it was.

As I was playing with the numbers in the TX, I also switched around the cyclic servo plugs. Just to check the servo operation in a different plug locations. Their all fine except I noticed the aileron servo would sometimes continue to move after I stop moving the sticks.. Sometimes it would continue going a little in the same direction and sometimes it would move back the other way a little... remember, this is the same servo that did the flip... That explains the crummy hovering capability.

I thought while I have a never used identical AR8000 RX,, I'd would switch it out with the original. Again just to see what happens. I rebound it and it worked exactly the same way, the problem remained.

OK, here it comes!
I was trying different settings with the TX when I noticed no combo of settings would make the servo work right except the one mentioned above. So I set it back the way it was. Oh man! that didn't work either.. All the servos were still going the wrong way... I checked it and checked it again. It seems like what ever I try to set with the TX, it's not getting to the RX properly.

Any whoooo,,, I put the original RX back in and rebound it again. I plugged in the servos again and again the servos were moving all wrong. What dah heck is this?! Time to go to bed and think it through...

Ok it's tomorrow and guess what??
I turn on the TX and check the settings. The setting are the same. (aileron reversed -70 swash = backwards)… All the servos are now working right! I didn't do nothing, just turn on the TX/RX...

Ok guys, what do you think? I'd love your input on this very interesting problem...

Here's what I think.....
I'll bet I have two problems. First, I have a bad aileron servo, (drifting)…
Next I have a major software issue with the TX... To have a servo all by it's self switch direction really freaks me out.
I informed Horizon and they said to send it in for inspection. I was hoping I wouldn't have to send the TX back but I think I have no choice at this point.
Thanks guys!
Rster...
 

Tony

Staff member
I didn't read anything on what you are using as far as gyro. Is this on a flybar helicopter? If so, when you are setting up the cyclic, you use the servo reverse function to get the servos moving together and then use the swash mix to reverse if needed. I think that is what you did, but it wasn't clear.

But it does sound like you have a bad servo. What servos are you using?
 

murankar

Staff member
Its an ar8000.

This looks like a standard rx for a fly bar head. If it is follow tony's advice. Or you could go watch the 45 minute video of tony setting up his exi or HK 450 helicopter. That will explain what need to be done and in the order in which you need to do it.


Start with a new model from scratch. The first thing is to get all the servos moving in the right direction. This is where reversing the direction comes in. The reason is due to the orientation of the servo. At least on servo may need reversed. At this point all your doing is getting the one servo that's not right to move correctly in relation to the others. It does not matter what the sticks are doing right now. Up on collective could be moving the swash down. That's fine at this point.


Now if you do have a reversed travel of the swash then go into the swash travel and reverse your numbers. If they are positive then make them negative or vise versa.

Now you should be good to go for your initial servo setup. I hope this makes sense. If not the watch the video.
 

Rob Lancaster

Active Member
Oh hey, I guess I should've included the type of aircraft and the electronics on board...
Got me a HK450GT clone, (flybar head) DX8 TX with a AR8000 RX , TM1000 telemetry , single axis Spartan Quark gyro, 3 HiTec HS-65MG cyclic servos, Futaba S9257 tail servo, Scorpion HK-2520 3500kv motor , Hobbywing Platinum V4 60 amp ESC, LED nav light controller and locator beeper; WHEW!...….. Did I leave anything out? Oh yeah, the battery is a Glacier 2200 mAh 30C 3s...……..

Tony, your right about that the aileron servo is bad . Can you tell me what could be failing in the servo that would makes it drift like that?
And what would you recommend for a good digital replacement?

And yes, yes! Tony's video of the 450s flybar head setup is one of my favorites.. know it well, LOL.... I always watch it when ever I need to reset the head for what ever reason. Plenty reasons when your running an HK450GT head...

Any whoooo,, I want to reiterate what the problem is...
It's not the head setup. When I was programming the new ESC with the P-BOX, the P-BOX fried. After I got a replacement I programmed the ESC no sweat. BUT! It was then I noticed the aileron servo was reversed. I never went any where near those setting in the TX.

To get the servo to move properly (+70 swash, normal direction with the servo).. This is where it was. Now I have to reset to -70 swash and reverse the aileron servo only. Do you guy's see what I'm trying to say? I know these things only happen to me, ha!

Heck I'm going to continue playing with the numbers just to further my training with these flying computers. This stuff is truly fascinating!

Remember, time to upgrade the cyclic servos so what do you guys say? I'll bet you got all kinds of killer ideas. Just like with the ESC and motor; WOW!!
Rster...
 

murankar

Staff member
This is a possibility, maybe when you tried the program box the system passed voltage to the servo. As a result the circuit in the servo went bad. That's just a guess.

If your getting drift and wackiness then the electronics went bad.

Or the servo went bad as you were programming the esc and that's what killed your program box
 

Rob Lancaster

Active Member
Yeah, that's what I was think'n too.. Oh the possibilities, ha!
That aileron servo defiantly is malfunctioning. I figure all the cyclic servos are getting there with age and after all they have been through a few minor crashes too, so it's time for some of these.... Good enough for my skill level I'm sure... Hitec HS-5065MG Micro Digital Metal Gear Servo [HRC35065S] | Cars & Trucks

About the mysterious servo flip...
I've been through it and through it, I can't find any inconsistency with the TX's firmware. After I get the new servos, I'll put them in and reset the whole head and see what happens next. I'll bet she flies pretty good... Who knows what happened to the numbers. Sometimes, stuff like this can get by my Dyslexia of a sort. All I know is I'll try to be more observant in the future.
But then again? "See what I mean"??

Onward!
Rster...
 

murankar

Staff member
If this is a 450 let some KST servos. They are very cost friendly, powerful and fast. In had a set, dog uses them on a few helis and on an sure a few others have used them on here. They are generally found on eBay by a seller called Garrt RC I believe, I think its the guy who sells the devil line of goblin clones.
 

Tony

Staff member
I agree with URI, get KST servos. Hose Hitec, although good for what they are, are a little over priced. Even the ALZRC servos that I"m running are awesome and very fast and powerful. Just food for thought.
 

Tony

Staff member
A coreless motor is just a different armature type. Instead of having the entire armature turn, they have basically taken the windings and the windings are now the armature. There is a sleeve on the outside with the magnet on the inside. These are still brushed motors so they will still wear out. But, are a little quieter and more efficient than standard brushed motors.

Coreless-Servo-Motor-250pics.jpg
 

murankar

Staff member
In a bit shell they removed the core of the motor. This allows the servo to accelerate and stop a lot quicker. There is less mass to move and stop.

In the model it gives the feeling of being more connected.

For us mere mortals on the sticks we won't notice the difference. If you had a choice just do what Bert kammerer does, brushless. He is not much of a scoreless dude and still beats the snot out of the turkey leg. Goblin that is.
 
Top Bottom