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450 Class Electric Helicopters 450 Class Electric Helicopters manufactured by Align, Tarot, SYMA, Airhog, Chaos, HK and similar.


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Old 05-17-2009, 09:30 PM   #1
uniquexme
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Default tail still blowing out

guys, recently i have done the 8degree tail blade at center stick as my tail blow out when there is strong wind, together with the chinese tail mod. But i dunno y recently, my tail is getting worst, i have damaged 2 sets of CF blades, 2pcs of 65MG servo.

here's what i did :
- tail pitch slider at about 8degrees, so that it hover nicely in rate mode
- Chinese tail weight mod (i put a pair of 450 ball link tru the bolt where it lock the tail blade)

here's the outcome :
tail blow out about 90degree yesterday. it was funny. like in a tic-toc, for the 1st few tic-toc its ok, but when u are at the 3rd tic-toc, the tail blow out alot, about 90degree, which i managed to recover safely about 5 times, then i add more gain and more limit on the 401, but then it blow out again, this time, i wasn't able to recover, and it crash on the tarmac, i got so fed up that i didn't even check what was damage, but basically the whole head flew off... damn... making me not feel like flying it anymore..

may i ask what are the signs of damaged gyro?
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Old 05-17-2009, 11:24 PM   #2
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What tail servo are you using?
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Old 05-17-2009, 11:52 PM   #3
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Is there any other helis you could swap gyros with to test? I personally wouldn't suspect the gyro being the problem (only as a last resort).

Have you tried just setting it up with the slider centered (Finless' recommendation)? Maybe you're limiting the throw on one side too much, causing the occasional blow-out? I setup my 401 with the slider centered with great results.

Also, what tail servo and distance out on the horn?
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Old 05-18-2009, 12:54 AM   #4
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You only have X amount of throw each way regardless of where it is when it's not flying. In a hover it is at X deg of pitch in HH, doesn't matter if it goes there in rate mode too, you have the same amount each way regardless or what mode you're in and how you set it up.

I find gyros work better when they have been set up in rate mode.

If it were me and I was looking for a problem like described, I would be making sure the tail moves free and that the tail servo has enough power to do the job, take the link off the tail servo, put in rate mode, check to see it has power each way and isn't weak at all.

And if that all checked out I would be looking at elec gremlins like static build up in the tail and things like that, or maybe even a cyclic servo acting up making it seem like the tail, or maybe or more than likely your belt is slipping but only under high stress maneuvers, if you keep flying it the problem will get worse and you'll be sure of what is wrong.

Do you put oil on any surfaces? It needs it. Grease too.
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Old 05-18-2009, 01:19 AM   #5
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What tail servo are you using?
m using 9257 step down to 5V.
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Old 05-18-2009, 01:35 AM   #6
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Originally Posted by ken22golf View Post
Is there any other helis you could swap gyros with to test? I personally wouldn't suspect the gyro being the problem (only as a last resort).

Have you tried just setting it up with the slider centered (Finless' recommendation)? Maybe you're limiting the throw on one side too much, causing the occasional blow-out? I setup my 401 with the slider centered with great results.

Also, what tail servo and distance out on the horn?
i have no other gyro to test.... yeah, previously i was using finless method, but then when it gets windy, and i do fast flips or tictoc, it blow out, swing away... so thats where i found here that the tail needs to be set in rate mode.... when i 1st set this new way, its ok, but as time goes by, problem still coming back... i did the chinese tail mod, last few flights, and problem comes back again...

i think i m gonna set back finless center tail pitch slider. the distance of horn, i think i m using the 2nd last.
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Old 05-18-2009, 01:50 AM   #7
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Originally Posted by Lota Fun R View Post
You only have X amount of throw each way regardless of where it is when it's not flying. In a hover it is at X deg of pitch in HH, doesn't matter if it goes there in rate mode too, you have the same amount each way regardless or what mode you're in and how you set it up.

I find gyros work better when they have been set up in rate mode.

If it were me and I was looking for a problem like described, I would be making sure the tail moves free and that the tail servo has enough power to do the job, take the link off the tail servo, put in rate mode, check to see it has power each way and isn't weak at all.

And if that all checked out I would be looking at elec gremlins like static build up in the tail and things like that, or maybe even a cyclic servo acting up making it seem like the tail, or maybe or more than likely your belt is slipping but only under high stress maneuvers, if you keep flying it the problem will get worse and you'll be sure of what is wrong.

Do you put oil on any surfaces? It needs it. Grease too.
same amount of throw each way??? i dun get it... when we set in rate mode, it tends to be more towards the tail case. so which means we have a longer distance towards the tail blade holder... i try adjusting the limit pot, until the slider is almost touching the tail case, so the other way we still have a gap, and i just leave it there... BUT when i see the amount on the gyro, its about somewhere between 70-90... do think this might be the cause? if i were to increase somemore, for sure the servo will be binding one way... whats the gyro gain in DX7 for this setup? do u think the chinese weight mod might be the problem?
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Old 05-18-2009, 04:08 AM   #8
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It doesn't matter.

If you hover in HH mode it's the same as if you hover in Rate mode, as long as it stays put it's the same thing, it IS the same thing.

It only goes over so far and that's it. Doesn't matter what mode it is, it's the same, the tail only goes so far in any mode/direction.

IT IS THE SAME...........
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Old 05-18-2009, 06:23 AM   #9
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Quote:
Originally Posted by uniquexme View Post
i try adjusting the limit pot, until the slider is almost touching the tail case, so the other way we still have a gap, and i just leave it there... BUT when i see the amount on the gyro, its about somewhere between 70-90... do think this might be the cause? if i were to increase somemore, for sure the servo will be binding one way...
You compromised pitch slider range in HH mode for stability in rate mode -- and guess what, you didn't have enough pitch slider range in HH mode. To avoid tail blowouts in HH mode, you need the gyro to have authority over the full pitch slider range. That means that when the rudder servo is centered and the arm is at 90 degrees, the tail pitch slider must be in the physical center of its travel range.

If your limit pot isn't somewhere between 80 and 100, strongly consider changing your servo horn length.
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Old 05-18-2009, 07:12 AM   #10
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I think it is a headspeed issue.

As you get into your third tic toc your headspeed is slowing down a lot probably. When that happens you won't have any authority for the tail to hold... this leads to a blow out.

What motor, pinion, headspeed and throttle curve?

Either increase your headspeed by flying 100% throttle or using a larger pinion.

Or you can get a more powerful motor.

As long as your slider moves the entire range then it isn't anything with the gyro or servo.
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Old 05-18-2009, 03:05 PM   #11
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Quote:
Originally Posted by Lota Fun R View Post
You only have X amount of throw each way regardless of where it is when it's not flying. In a hover it is at X deg of pitch in HH, doesn't matter if it goes there in rate mode too, you have the same amount each way regardless or what mode you're in and how you set it up.
.
If he sets up in rate mode without separate endpoint adjustments and adjusts the limit setting to prevent binding, he will lower his amount of throw on the other side. With it properly set up in rate mode it shouldn't be a problem, but I would still prefer to center the slider to get the max pitch range with the 401.

For me, I found the sweet spot for the 401/S9257 to be on the second hole out on the star wheel. It put me at like 85% limit setting with the pitch slider centered. The tail was holding perfect for me. (And I almost never get to fly in less than 15-20 mph winds on the coast)

Like airjawed mentioned, any gyro will blow out if the heli bogs down and a higher and more constant HS will greatly help your tail control.
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Old 05-18-2009, 04:12 PM   #12
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Very strange, as I have found 9257 and 401 to be perfect mates on my tail. Its rock steady.

I use the middle hole and the round servohorn.
The travel adjust on the gyro channel to 70-71%.

I have adjusted the limit so I have the full range without any binding.
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Old 05-18-2009, 05:41 PM   #13
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If your limit is at 70%, you'd probably get better performance with a shorter servo horn and a higher limit. Below 80% gain, you lose some precision and you reduce the effective servo torque, resulting in slower, less accurate tail adjustments.
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Old 05-18-2009, 06:28 PM   #14
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Redo your gyro/tail setup.

I don't know if you have the new or old version of the gyro but in the new version you can get full slider pitch and a rate mode hover as well. The directions that came with the gyro should be followed.

Really though even with a poorly setup gyro the tail should hold. What is your headspeed? Motor pinion and throttle curve?
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Old 05-18-2009, 07:53 PM   #15
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Quote:
Originally Posted by airjawed View Post
I think it is a headspeed issue.

As you get into your third tic toc your headspeed is slowing down a lot probably. When that happens you won't have any authority for the tail to hold... this leads to a blow out.

What motor, pinion, headspeed and throttle curve?

Either increase your headspeed by flying 100% throttle or using a larger pinion.

Or you can get a more powerful motor.

As long as your slider moves the entire range then it isn't anything with the gyro or servo.
i m using scorpion 2221-8 with 13T pinion. Headspeed, i dun have the gadget to measure it... throttle curve in idle is 100-95-90-95-100, normal mode 0-40-60-80-80
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Old 05-18-2009, 08:01 PM   #16
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i fix my heli last nite... this time i remove the chinese weight mod, and use back the old finless setup, tail pitch slider in center... i guess that blow out is even less than my current setup.... well, maybe i did something wrong here....

refering back to setting in rate mode, i have actually use the pitch gauge to check, and indeed its 8degrees when it hover nicely in this mode... BUT the travel is really less in one direction compared to the other... so i adjust the travel adjust in my DX7 and come up with about 37%, while the other way i leave at 100%, so for sure this setting, it will piro faster in one direction...

but no matter which setup i did, i found that when i do a left side-in tic toc, the tail tend to sway a little to the right.. the gain in my DX7 is about 73-75%, which of course is slightly over it as when u make a turn, u will hear the buzzing sound of rudder servo.....

I think Finless is still debating on this rate mode setting... anyway, will try again later this evening to see how it goes... at least i crash less with this setting.... thanks guys..
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Old 05-18-2009, 10:33 PM   #17
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I would leave the weight mod on, the 9257 isn't rated very high for torque.
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Old 05-18-2009, 10:45 PM   #18
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Quote:
Originally Posted by uniquexme View Post
i fix my heli last nite... this time i remove the chinese weight mod, and use back the old finless setup, tail pitch slider in center... i guess that blow out is even less than my current setup.... well, maybe i did something wrong here....

refering back to setting in rate mode, i have actually use the pitch gauge to check, and indeed its 8degrees when it hover nicely in this mode... BUT the travel is really less in one direction compared to the other... so i adjust the travel adjust in my DX7 and come up with about 37%, while the other way i leave at 100%, so for sure this setting, it will piro faster in one direction...

but no matter which setup i did, i found that when i do a left side-in tic toc, the tail tend to sway a little to the right.. the gain in my DX7 is about 73-75%, which of course is slightly over it as when u make a turn, u will hear the buzzing sound of rudder servo.....

I think Finless is still debating on this rate mode setting... anyway, will try again later this evening to see how it goes... at least i crash less with this setting.... thanks guys..
Travel adjust in the rudder channel is for adjusting maximum piro rate. It is not for reducing the servo travel.

I think maybe you need to learn more about radio and gyro setup.

How are your batteries?
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