View Full Version : 401 stopping different from left to right
If I rotate to the left and stop abruptly, teh tail stops very quickly and makes a fwap sound. Conversely, if I rotate to the right, the tail stops very softly, and if the command is abrupt enough, it will even bounce back, or overshoot, how ever you call it.
What can cause this? My 502 has left and right adjustments, and the 401 does not. I have tried lowering the gain, and it seems to help the left stop, but the right one gets so sloppy, it is almost scary. I bumped the delay up a bit, even though I am supposed to leave it on 0 for a digital servo, and it didn't help much that I could tell.
I am out of ideas, and appreciate any help.
Thanks,
Ivan
rob_jones
01-20-2006, 03:07 PM
Do you have the end points for the RUDDER channel in the transmitter set the same? With a 401, they control the piroutte rate (not servo travel). If each side is a different value, it will act like you described.
Yep, they are the same. The 10x makes them stay the same unless you unlock them to be adjusted differently, which I ahve not done.
Ivan
rob_jones
01-20-2006, 04:36 PM
Have you checked the LIMIT dial on the gyro case?
Take it out of heading hold, move the tail servo to either extreme of travel and adjust the dial until the pitch slider bottoms out, then back it off ever so slightly. Check the opposite direction to be sure it doesn't bind. If it does, back off the LIMIT until the binding stops.
If that's right, check for binding in the pitch mechanism. Also, be sure that all the torque compensation in the radio is turned OFF. Things like REVO MIX, Throttle to Rudder mix, etc.
The tail linkage is slop free and silky smooth.
The 10x doesn't have revo mix per se, it has a tail compensation curve, which I haven't ever played with, since i have been flying HH gyros since the time I got the 10x.
Also the limits are set, and the servo is at 90º to the pushrod when the tailrotor is in neutral position, which was determined by adjusting the linkage to get a steady tail in normal mode, while the subtrim was at 0 (and still is) and the trim is at 0 (and still is). As it is, the linkage moves very close to the same in either direction, and doesn't bind anywhere along the way.
I am confuzzled, to say the least.
thanks fo ryour suggestions, and I am open to more.
Ivan
svein
01-20-2006, 04:53 PM
Ahem.
commanding "left" yaw (i read that as CCW) it stops "bang" as it should, commanding "right" yaw (CW) it is soft.
If my guess is correct, when you command it to decrease pitch (on the tail rotor) for piro, the stop is sudden, when you command it to yaw by increasing pitch, the stop is soft.
This wouldn't by any chance be a Raptor 30/50, with the tail rotor grips being mounted backwards? (this will give an asynchronous behaviour). No, not the blades. The blade GRIPS.
//Svein
flyinfool
01-20-2006, 09:55 PM
The way that you are set up you are only using half of the athority that the tail has to offer. This will cause issues like what you are having.
The way that I set up my 401's is to have the servo arm at 90* when the travel of the tail pitch slider is centered.
You should then be able to adjust the limit to just touch on both ends of travel.
This will allow the gyro to use all available travel in the tail to control the tail.
It will also allow a higher limit setting to allow a more full use of the range of servo travel and resolution.
If you set it up this way the heli will do wild piros in normal mode.
If you wish to be able to use normal mode (and I do) adjust the trim for a straight hover. Yes your trim will be way off center and the servo arm will not be anywhere near 90* to the pushrod.
This is how a rappy 30/50 needs to be set up with a 401 to get full use of the tail.
I have been told by many that this method is all wet, after I fly they ask how come their 401 can't do that. :arggg:
There may be other ways to accomplish this but I have not found one that is better in the air or easier to set up.
The way that I set up my 401's is to have the servo arm at 90* when the travel of the tail pitch slider is centered.
You should then be able to adjust the limit to just touch on both ends of travel.
This is how I have it set up. the tail on the sceadu has a bit of offset built in when the travel is centered. The servo arm is at 90º, in the middle of the travel, and the limit is set to allow the pitch slider to touch and then back it off just a hair, so the servo doesn't buzz. There is a bit more clearance one way than the other, but I would say less than .030".
I did have the same trouble in my Vigor with the 502, but it was rectified with the delay settings and etc which are adjustable independantly with that gyro. This leads me to be suspicious of what I might be doing wrong with my setups. :dontknow
flyinfool
01-20-2006, 11:28 PM
I would still set it up to every bit of travel available in both directions.
I am not familiar with the Sceadu yet.
Do you know what your tail ratio is? Tail RPM?
Some helies have low tail rpm which results in weak tail authority.
A 502 or 601/611 will control the tail better than a 401.
With a Raptor 50 SE and Stinger 50, I was able to get my 401 to hold as good as a 601 just by increasing the tail rpm.
I am not sure what the tail ratio is on this machine. I bought it used and it has upgraded gears, and I believe it includes a speed up gear for the tail.
Good news though, I found a tail boom support that had the hole elongated, and letting the tail boom flex a bit. I am hoping the weather breaks tomorrow so I can test fly it. If that doesn't cure it. I guess I will just turn right all the time. It will make me fit in with the planks that way. :mrgreen:
flyinfool
01-21-2006, 07:31 PM
Ouch, You never want to fit in with the planks.
Update:
I fixed the boom supports, re checked the tail geometery, and everything is A OK with the setup, but it still does it.
I went from plastic blades to NHP carbons, to see if the stiffer blades make a difference.
It may be that I just have to live with it.
A bit of an update on the tail.
It seems that I can get better performance by addig a touch of differential in the system.
I have set it up to have a bit fister travel one way than the other, and still use all the travel, I did this in my center bellcrank (moved the servo to the front end) and it has helped drastically. I think if I were to take the time to tweak it, I could, infact, get it to be perfect. As it is now, it will stop without bouncing one way, but it doesn't slap, and the other way it will still slap, but it doesn't sound like the heli is falling apart in the air.
You were on to something about not worring about a "square setup" Flyingfool.