Shaking Violently at when throttling up...

[expertzx]

Sucessfully started my YS50 with the settings of the main and idle needle according to instructions. But when I start to increase the throttle, the chopper shakes violently. So violent if I continue, the chopper would probably fly apart in pieces. What's causing this? Could the engine be running too rich causing this problem? Don't have alot of experiences with glow engines so any suggestions will be helpful.

[Azlum]

Your blade grips could be too tight, not allowing the blades to find their "happy spot" during spool up.

Other than that... I dunno :dontknow

[erniefritz]

i 2nd that. when you fold your blades out before your 1st flight , you may not be perfectly straight , during spool up the blades use the centrifugal force to straighten out but before that the chopper shakes , if your blade grips are too tight the blades can't straighten out causing violent shaking... your blade grips should be tight enough so they don't flop around or fold up when you apply throttle but can be moved by hand to fold up or straighten out during spool up...

[WayneBrown]

you on grass or pavement? try from grass and run up quicker to get the blades 'out'.

[LITHIUMSTATIC]

Being to loose can cause this too.

Extend your blades out as straight as you can get them. Next hold your heli firmly on it's side and give it a firm shake towards the ground. You want them to just start to fall. After you get them set so they do this give them a slight turn tighter.....maybe another 1/8 of a turn. That's how I set my blade tightness and it works great for me.

[expertzx]

I'll try that. I was thinking more along the lines that I did something wrong with the clutch assembly, but if it's just the blades I"ll be happy its such an easy solution.

[UncleBen]

If the blades are straight then it could be the flybar paddles not being equal length apart from each other. Just double check to see if they are the same on either side.

[expertzx]

This is what is happening. As I increase the throttle, the blades turn without any vibration. But as I increase the throttle, the helicopter starts to go in a circle while on the ground and I have no control of the tail rotor at all. It's just rotating in a small circle on the ground. As I cut power, thats when the helicopter starts to shake uncontrollably.

:dontknow

[tcast305]

Have you checked to make sure your gyro is set correctly? If your heli starts to piro on the floor you might have your gyro set incorrectly, ie you need to set it from NOR to REV or from REV to NOR (on the gyro itself, not your TX).


Thanks.

[Mercuriell]

You have your gyro reversed or your main blades too loose. Push the rudder stick to the left and watch the servo - kick the tail of the heli to the left also and it should move the servo the same way.

[expertzx]

well according to the gyro instructions, when u move the nose of the chopper to the right, the servo should move to the left. Mine does that. So I'm assuming that the gyro is set correctly. It's in HH mode as well at 72% gain.

Got the main blades just right and it's still doing it. Will try and reverse the gyro and see what happens.

Mercurriell, since you did a video on the clutch installation, is there anythign I couldve done wrong in the clutch assembly causing this problem? Somebody in person mentioned that I might not have the clutch aligned properly causing this problem.

[HeliSat]

Wait a second ... there are are two directions you need to check:

(1). Firstly is the direction of the stick. It sounds like you have this one sorted. You should also check the tail rotor and visualise the thrust generated by the pitch on the tail rotor. By this I mean, when you give left rudder stick, the thrust from the tail rotor will push the tail right -- therefore the nose will turn left.

(2). Check the direction of the gyro. This is very different from (1). With everything powered up, grab the boom of you heli and push it to the left, you should see the tail rotors pitch try correct this by providing right thrust & vise-versa. This is the problem I think you have -- you have this one reversed and when the heli starts to spin on the ground, the gyro is unable to stop this because its corrections are the wrong direction. For example, when you spool up the blades (clockwise), this will cause the airframe of the heli to want to twist (counterclockwise). Normally the gyro will correct for this by providing right thrust, but in your case it is providing left thrust and there is your perpetual problem. If your running a GY401, it is the second switch marked "DIR".

I hope that makes sense :D

[Mercuriell]

well according to the gyro instructions, when u move the nose of the chopper to the right, the servo should move to the left. Mine does that. So I'm assuming that the gyro is set correctly. It's in HH mode as well at 72% gain.

Got the main blades just right and it's still doing it. Will try and reverse the gyro and see what happens.

Mercurriell, since you did a video on the clutch installation, is there anythign I couldve done wrong in the clutch assembly causing this problem? Somebody in person mentioned that I might not have the clutch aligned properly causing this problem.

I don't think it's the clutch - work through HeliSat's instructions carefully - sure it's the gyro - you've checked your rotor blade tightness - stiff enough not to fall when you hold the heli on its side and give it a gentle shake ?

[Azlum]

Dont assume the gyro is NOT reversed due to setting it the way the manual describes.... I also followed the manual's description of which way the servo should move when the heli is rotated... and it was WRONG! I had to reverse my gyro on my first spool up... and then I had to reverse my rudder servo on my second spool up!

[HeliSat]

If your unsure ... you should get a local club member to help you.

Remember .. spare parts are a little hard to come by at the moment!!

[Russ McC]

(1). Firstly is the direction of the stick. It sounds like you have this one sorted. You should also check the tail rotor and visualise the thrust generated by the pitch on the tail rotor. By this I mean, when you give left rudder stick, the thrust from the tail rotor will push the tail right -- therefore the nose will turn left.

(2). Check the direction of the gyro. This is very different from (1). With everything powered up, grab the boom of you heli and push it to the left, you should see the tail rotors pitch try correct this by providing right thrust & vise-versa. This is the problem I think you have -- you have this one reversed and when the heli starts to spin on the ground, the gyro is unable to stop this because its corrections are the wrong direction. For example, when you spool up the blades (clockwise), this will cause the airframe of the heli to want to twist (counterclockwise). Normally the gyro will correct for this by providing right thrust, but in your case it is providing left thrust and there is your perpetual problem. If your running a GY401, it is the second switch marked "DIR".


You all need to ignore any manual telling you and check it at the source of the thrust just as HeliSat describes. You must understand the direction of rotation and then it acts just like a prop so it is easy to see witch way it will pull the tail when tail pitch is increased by either the stick and or the gyro. Now with that said the manual may be right and you may have installed the tail blade grips flipped over, this will reverse the gyro and the stick, triple check this stuff and you will get it right the first time. Most of us have screwed this up at some point and if you avoided damaging the tail drive then you got off easy. If you get this fixed and ever get it up to speed the shaking will stop assuming the blades and paddles are installed in the correct direction, yes I have done this to and it will shake so bad it will not get to speed and it can be difficult to spot after you thought you installed them right!

[expertzx]

Checking that now. How frustrating, this stuff never happened to me when I built my Trex 600 electric. :dontknow

[expertzx]

Well it turns out the problem had a very simple solution. Didn't even notice that I had one of the main rotor blades BACKWARDS, causing all this headache.

:bomb:

So now it hovers, but now I have another question. I'm running the engine with the intial settings on the main and idle needles. The engine is running really rich, probably too much. There is a vibration in the heli now, could the engine runing so rich cause this problem?

[Russ McC]

Your welcome, funny how that can screw it all up, you probably did no damage, its probably just to rich, if the engine is stumbling it will shake, one of the main keys to your heli flying well is engine tuning, it can make all the difference.