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Nose hunts to the right?

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Nose hunts to the right?

Old 08-28-2012, 07:45 PM
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jester_s1
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Default Nose hunts to the right?

I had a primo heli day with my 450- virtually no wind, good light, nice temperature, and 4 batteries of flight with no mishaps. I'm still very much a newbie though so all I did was hover. I've noticed it before, but it really annoyed me tonight as everything else was going so well, but my nose constantly turns right. It does it enough that I've actually gotten nearly as comfortable hovering with the right side toward me as I am with the tail it. It happens as the load on the tail changes with control inputs on the main rotor, both cyclic and collective. I expect a little wag now and then because I'm running a .12 second tail servo, but it seems that it shouldn't only go right. I played with adding some left rudder trim which helped, but as I understand it that's not the right way to fix it. My setup is as follows:

Esky Belt CP
Solar Digital servos 17 oz/in .12 speed on everything
Telebee HH gyro
100% tail servo movement in the gyro, and about 85% gain is all I can run without wagging
Tail servo arm is at 90 degrees to the tail boom with the slider in the middle of it's travel when I plug it directly into the Rx with no rudder trim.

My hovering setup is at 80% throttle and about 6 degrees total collective. For kicks, I switched it to 100% throttle and that didn't affect it at all.
Old 08-28-2012, 10:21 PM
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madmorgan
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Default RE: Nose hunts to the right?



i would start with making sure the tail servo horn is at 90 on rate mode and the tail pitch slider is centered "good mechanical setup"  then check for vibes . maybe find a  better gyro, it could be the low speed servo but i believe if that was your problem it would be wagging alot. basically if you can take off in rate mode and the tail stays put its mechanically setup.  i tried that  rate mode take off before but shut it down before it left the ground as the hair stood straight on my neck lol. some people  will say that every heli does the nose drift  but i beg to differ as i see this happen with the gy48v gyros but dont see it with my quark, align 780, or the gy401's.

Old 08-29-2012, 07:36 AM
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jester_s1
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Default RE: Nose hunts to the right?

I'll check it out in rate mode then. But if I'm understanding you, it's that I don't have a good enough gyro and possibly not a good enough tail servo? It wags pretty hard if I go above 85% gain, so I know i'm not getting all of the good out of my gyro. It really did help with adding in some rudder trim on the transmitter but if that will cause other problems as I start doing aerobatics I'd rather fix it right at this point.
Old 08-29-2012, 10:03 AM
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Default RE: Nose hunts to the right?

getting the gyro set in hh mode is quite easy aslong as you have the mechanical end set up correctly (and the gyro and servo are up for the task). what you want to do is when you see wag is to start bringing the percent back down.  what i do usually if in a hover if there is no wag i will snap the tail to the left or right  for a split second and see what the tail does. so if it doesnt wag in hover i snap the tail  and watch for wag if it wags then i decrease more (by 1) until that calms down now if i start to see wag in the hover again i bring it back up and just suck it up as i would rather have a steady tail in hover and fwd flight .  never ever trim the tail  you want to ensure the horn is 90 degrees in rate using sub trim only,  another thing you can try if your getting a bit of vibe is to add another peice of 3m sticky or even sandwich a small metal plate between the 3m that helps with some known issues. 12ms timing on the servo could be the culprit though
Old 08-29-2012, 12:40 PM
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jester_s1
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Default RE: Nose hunts to the right?

I think I have the gyro set up like you're talking about. I'm the tiniest bump on the gain knob away from constant wag. It still wags every once in a while when I give it a lot of throttle to gain altitude, but otherwise it doesn't. The servo isn't 12 ms. It's .12 second transit time to go 60 degrees. Sorry for the confusion. It looks like the best tail servos make the same movement in .06, so mine is half as fast as the best ones.

I think I have all the vibrations eliminated as best this airframe can be. There's no noticeable shake at the landing gear or tail boom, and holding the heli while I check blade tracking gives me the slightest vibration in my hand once they are tracked right. I balance all of my blades for both weight and CG, have everything straight, I balanced my head with the flybar attached using a DuBro prop balancer, and I weighed my tail blades on a reloading scale.

You say not to ever trim the tail, but I'd like to know why. For hovering, trimming the tail gives me a better behaved machine that errs as much to the left as to the right reducing my workload somewhat. So is the fact that there is some rudder input at hover going to mess up other maneuvers?
Old 08-31-2012, 10:24 AM
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Goggles
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Default RE: Nose hunts to the right?

For hovering, trimming the tail gives me a better behaved machine that errs as much to the left as to the right
Mad is correct. you want it flying as perfect as you can mechanically with out the need for trim. Do you need to retrim at the start of every flight?

Now what you could do is after you trim, land and take note of where your control rod is and mark it (piece of tape on the boom, mark the control rod, mark the boom). Reset your trim back to 'O', unhook the ball link and either extend or shorten the link ends so they match up to your mark you made. Make sure your servo arm and control rod are at 90*, and as you already noted the servo should be faster.

So is the fact that there is some rudder input at hover going to mess up other maneuvers?
Lets so you want to fly from one end of the field to the other, you'll always have to be correcting (fighting) the heading to keep it straight. Or if your doing a tick tick, you'll always be fighting to keep it neat. If you do a flip, it'll want to go sideways on you if you don't correct enough with the rudder. The maneuvers are easier to do if your machine is well set up, you can concentrate on the maneuver instead of trying to fight the tail.
Old 09-08-2012, 08:41 PM
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Default RE: Nose hunts to the right?

Sorry I didn't notice the response Goggles until just now. For your first comment, as it sits, I have the servo arm at 90 to the tail boom, and the slider is at the middle of its travel. That's with the servo just plugged in to the receiver with no rudder trim in the Tx. When I set up the gyro, it stays the same with the throttle off. My understanding was that the mechanical setup was supposed to give the heading hold gyro the most travel in both directions that it can have so it is most able to do its thing?

For your second comment, the heli hovers better with 2 clicks of rudder trim. That actually makes it neutral and reduces my workload on the sticks. So with the trim in, I get a little bump left sometimes and a little bump right sometimes, which the gyro usually corrects on its own. The bigger bumps I have to fix myself but it's not nearly as bad as with 0 trim and the heli hunting 90 degrees on me every 20-30 seconds or so. So my question was is using the trim to make it hover better going to hurt other maneuvering?
Old 10-26-2012, 08:34 AM
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Default RE: Nose hunts to the right?

Set up with a few degrees right tail angle. Hover in rate mode and trim or mechanically move so it will hover and stay put in rate mode. This will now be neutral in HH mode. Do not trim in HH mode or your center will be affected. Trimming on the radio or moving the servo on the boom in rate mode does the same thing. I like to be neutral in rate mode, then when I switch to HH, the gyro knows where true center is. Even as the battery starts to die the center is the same. I had a Belt CP with a EFlite G-90(Telebee) and it worked fine with ESky tail servo.

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