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booboo_yvr · 03-10-2013, 01:41 PM

Hi,
I hope this is the right place to post this?

I gave up on my first build, a HK450.. at least for now, until I can figure out where all the vibration is coming from. Some of the forum posts I've read says can be a number of things.

In the end I found an Align 450 V2 Pro on sale, and bought it. I finished building it few days ago, and very little if any vibration. Went to fly it yesterday. There seems to be two problems:

1) The heli slowly rotates counter-clockwise. It's not a fast out of control spin. So I believe the gyro is set to the correct direction. Is this a problem with the gyro gain? or should I just adjust the sub-trim or trim? Some of the videos/posts I've read seems to indicate to leave the sub-trim alone.

2) The heli also banks to the left (when I use the rudder to counter the spin). The banking is slow so I can correct it with the stick. Is this because my swash plate isn't 100% level? or is this a tracking issue?

Thanks for any sugestions and help! I won't be able to try much out until I get my landing skids fixed/replaced. It broke on one of the hard landings.

BooBoo

neverland · 03-11-2013, 02:18 AM

your problem with the drifting tail might be that the tail servo needs to be moved on the boom. the conventional method of setting up is to set the servo position so theres no drift in rate mode, then switch to head hold and it should hold, things like gain being correct too.

banking to the left when hovering tail in is normal, due to the tail rotor pushing air the other way. you just have to learn to counteract it i'm afraid

booboo_yvr · 03-12-2013, 02:33 PM

Thanks!
I'll try adjusting the tail servo.
I thought the gyro would have "fix" any mechanical errors.

neverland · 03-13-2013, 12:27 AM

hi, in theory, but the gyro cannot work properly if the mechanical pitch range isnt available to it. if the tail blade pitch slider hits the stop either side before the the necessary blade pitch is reached, theres nothing the gyro can do. thats why you move the servo position, so the range available to the gyro is correct. you generally start by setting the tail slider so its about 1 /3 of the way from the boom side when the servo horn is at 90 degrees, in rate mode. this gives approximately enough 'basic' pitch to counteract the main blades and alows the gyro enough range to do its thing.

PassinThru · 03-14-2013, 12:00 AM

Quote:

Originally Posted by booboo_yvr

Thanks!
I'll try adjusting the tail servo.
I thought the gyro would have "fix" any mechanical errors.

It may be that you don't have the tail shaft slider adjusted properly.
It's not so much the servo you have to adjust as the distance between the ball links so that at a centred stick and servo, the tail blades are biting toward the boom just a few degrees - enough to counter the CCW torque created by the main blades when doing a stable hover. Then, as Neverland suggests, adjusting the travel of the tail shaft slider so that the slider moves within its physical limits without binding (tail servo buzzes) at the blade shaft or at the boom tail assembly. This adjustment will have to be made using the instructions for whatever gyro you're using. Good luck.

steve54 · 03-14-2013, 12:27 AM

Soo, Mine did the same thing with the slow rotation and i did everything you could think of in the gyro (3GX) to get it to stop,I spent 100 dollars on a MKS tail servo and i was only able to make it sparadic and the tail hold was week. It was the tail servo horn, i was using the stock align ex shaped servo horn with the ball on the closest hole to the center and it wasnt enough resolution so i used a different horn so i could get the ball right next to the center of the servo. I wasnt able to figure this out untill i upgraded to the V bar, it gave me possible solutions within the sofware and has a live vibration sensor so u can spool up on the bench to check if your tail bairing are bad, or remove your tail to check the main bearings. PM me if you still r having the problem, I just fixed it today on my 45oV2 upgraded to DFC

RookieAv8r · 03-15-2013, 12:19 AM

I just got through building my HK450 with a Micro BeastX set up as the tail gyro and I am experiencing the same thing. I will readjust the tail slider tomorrow and give it a try. The drifting left problem though has me puzzled. If I try to counter with aileron, the heli will almost tip over before it corrects the drift. Trying to counter with left rudder does not seem to be much help either.

Charlie

booboo_yvr · 03-16-2013, 10:00 PM

Hi,
I think i know what my problem is

I had ordered some cheap tail blades from HK, and I thought I'll probably destroy the ones from the kit pretty quickly. So I put the HK blades on. At first they looked liked the same size. But after a closer inspection the HK blade's surface area is much smaller. Plus they're not really shaped like a wing; it's more like a long diamond if I was to take a cross-section.

But it's been raining here in Vancouver. So I haven't been able to try going back to the original blades yet.

03-10-2013, 01:41 PM	#1 (permalink)
booboo_yvr Registered Users Join Date: Feb 2013	Q: Newbie trying to setup Trex 450 Hi, I hope this is the right place to post this? I gave up on my first build, a HK450.. at least for now, until I can figure out where all the vibration is coming from. Some of the forum posts I've read says can be a number of things. In the end I found an Align 450 V2 Pro on sale, and bought it. I finished building it few days ago, and very little if any vibration. Went to fly it yesterday. There seems to be two problems: 1) The heli slowly rotates counter-clockwise. It's not a fast out of control spin. So I believe the gyro is set to the correct direction. Is this a problem with the gyro gain? or should I just adjust the sub-trim or trim? Some of the videos/posts I've read seems to indicate to leave the sub-trim alone. 2) The heli also banks to the left (when I use the rudder to counter the spin). The banking is slow so I can correct it with the stick. Is this because my swash plate isn't 100% level? or is this a tracking issue? Thanks for any sugestions and help! I won't be able to try much out until I get my landing skids fixed/replaced. It broke on one of the hard landings. BooBoo

03-14-2013, 12:27 AM	#6 (permalink)
steve54 Registered Users Join Date: Aug 2012	Mine too Soo, Mine did the same thing with the slow rotation and i did everything you could think of in the gyro (3GX) to get it to stop,I spent 100 dollars on a MKS tail servo and i was only able to make it sparadic and the tail hold was week. It was the tail servo horn, i was using the stock align ex shaped servo horn with the ball on the closest hole to the center and it wasnt enough resolution so i used a different horn so i could get the ball right next to the center of the servo. I wasnt able to figure this out untill i upgraded to the V bar, it gave me possible solutions within the sofware and has a live vibration sensor so u can spool up on the bench to check if your tail bairing are bad, or remove your tail to check the main bearings. PM me if you still r having the problem, I just fixed it today on my 45oV2 upgraded to DFC

03-15-2013, 12:19 AM	#7 (permalink)
RookieAv8r Registered Users Join Date: Feb 2013	Same thing here I just got through building my HK450 with a Micro BeastX set up as the tail gyro and I am experiencing the same thing. I will readjust the tail slider tomorrow and give it a try. The drifting left problem though has me puzzled. If I try to counter with aileron, the heli will almost tip over before it corrects the drift. Trying to counter with left rudder does not seem to be much help either. Charlie

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03-11-2013, 02:18 AM	#2 (permalink)
neverland Registered Users My HF Map location Join Date: Jul 2010	your problem with the drifting tail might be that the tail servo needs to be moved on the boom. the conventional method of setting up is to set the servo position so theres no drift in rate mode, then switch to head hold and it should hold, things like gain being correct too. banking to the left when hovering tail in is normal, due to the tail rotor pushing air the other way. you just have to learn to counteract it i'm afraid

03-12-2013, 02:33 PM	#3 (permalink)
booboo_yvr Registered Users Thread Starter Join Date: Feb 2013	Thanks! I'll try adjusting the tail servo. I thought the gyro would have "fix" any mechanical errors.

03-13-2013, 12:27 AM	#4 (permalink)
neverland Registered Users My HF Map location Join Date: Jul 2010	hi, in theory, but the gyro cannot work properly if the mechanical pitch range isnt available to it. if the tail blade pitch slider hits the stop either side before the the necessary blade pitch is reached, theres nothing the gyro can do. thats why you move the servo position, so the range available to the gyro is correct. you generally start by setting the tail slider so its about 1 /3 of the way from the boom side when the servo horn is at 90 degrees, in rate mode. this gives approximately enough 'basic' pitch to counteract the main blades and alows the gyro enough range to do its thing.

03-16-2013, 10:00 PM	#8 (permalink)
booboo_yvr Registered Users Thread Starter Join Date: Feb 2013	Hi, I think i know what my problem is I had ordered some cheap tail blades from HK, and I thought I'll probably destroy the ones from the kit pretty quickly. So I put the HK blades on. At first they looked liked the same size. But after a closer inspection the HK blade's surface area is much smaller. Plus they're not really shaped like a wing; it's more like a long diamond if I was to take a cross-section. But it's been raining here in Vancouver. So I haven't been able to try going back to the original blades yet.

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