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face992 · 05-02-2010, 02:53 PM

Hi,

I got a problem with my cog. Beside im tailheavy, I have to trim the heli to the right, obviously the cog is too far at the left. My swashplate was leveled perfectly with a leveling-tool. Where is this caused from, the silencer? Am I the only one with this problem or do you have to trim to? Thanks in advance for your answers.

Best regards, Max

nitro burner · 05-02-2010, 04:03 PM

You can check your fly bar paddles that may help. But yes you have to trim for flight even if the swashplate was leveled perfectly you also have to work out the interactions aswell. Your CG can be changed by moving your electronics and battery around at half a tank. Hope this helps

face992 · 05-02-2010, 04:10 PM

Yes thanks, I'll try to adjust it again. But why do I have to trim to the right? Is this normal?

Stillakid · 05-02-2010, 05:22 PM

Quote:

Originally Posted by face992

Yes thanks, I'll try to adjust it again. But why do I have to trim to the right? Is this normal?

The tail roor pushes the heli to the left so right trim is ok. Heli's don't hover exactly vertical.

face992 · 05-03-2010, 02:43 AM

I know, but you shouldn't need trim because of this. If I dont trim my heli, it tips over to the left and would fly away in this direction. This isnt sth caused by the tail rotor I think...

IrishT · 05-03-2010, 09:43 AM

You can test for lateral CG by holding the flybar inline with the boom, and seeing which way the heli leans. If it leans to the left, then you've narrowed down the problem to a lateral CG problem.

There are issues if you use trim to correct for CG problems. If you trim it to be fine when upright, you'll be twice as bad inverted. This goes for both fore/aft CG and lateral CG.

face992 · 05-03-2010, 09:58 AM

Yes, thats why it bothers me. Assumend that it is a lateral CG-problem, what could I do against it? All my electronics are pretty much placed on the long axis or so much that the shouldnt affect the CG. Only thing I could probably do is to place the elevator servo on the other side... Any ideas?

MartinS819 · 05-03-2010, 11:46 PM

Are you talking about the heli banking to the left or drifting to the left? If you set your heli up perfectly, with a perfectly level swash, it will never fly level. With so much thrust from the tail to counteract the torque, the heli will drift left. All helis with a tail rotor will hover with a slight tilt toward the direction of the tail's thrust.

If it is banking left, weed out any interactions you might have. Also check your trims for each flight mode. If they aren't set to common, you could inadvertently be setting trims when you switch flight modes, or come out of T-hold. Also check to make sure you didn't have any trim when you did your setup.

Hope this helps,
Martin

05-02-2010, 02:53 PM	#1 (permalink)
face992 Registered Users Join Date: Nov 2009	T700N Center of Gravity... Hi, I got a problem with my cog. Beside im tailheavy, I have to trim the heli to the right, obviously the cog is too far at the left. My swashplate was leveled perfectly with a leveling-tool. Where is this caused from, the silencer? Am I the only one with this problem or do you have to trim to? Thanks in advance for your answers. Best regards, Max

05-02-2010, 04:03 PM	#2 (permalink)
nitro burner Registered Users My HF Map location Join Date: Jun 2004	You can check your fly bar paddles that may help. But yes you have to trim for flight even if the swashplate was leveled perfectly you also have to work out the interactions aswell. Your CG can be changed by moving your electronics and battery around at half a tank. Hope this helps __________________ T-Rex 450 Pro FBL ZYX,T-Rex 700 Nitro FBL BEASTX,T-Rex 700 Nitro FBL BEASTX Spektrum DX8,AMA#849731 Last edited by nitro burner; 05-02-2010 at 06:05 PM..

05-03-2010, 11:46 PM	#8 (permalink)
MartinS819 Registered Users My HF Map location Join Date: Nov 2006	Are you talking about the heli banking to the left or drifting to the left? If you set your heli up perfectly, with a perfectly level swash, it will never fly level. With so much thrust from the tail to counteract the torque, the heli will drift left. All helis with a tail rotor will hover with a slight tilt toward the direction of the tail's thrust. If it is banking left, weed out any interactions you might have. Also check your trims for each flight mode. If they aren't set to common, you could inadvertently be setting trims when you switch flight modes, or come out of T-hold. Also check to make sure you didn't have any trim when you did your setup. Hope this helps, Martin __________________ See my artwork: http://martins819.deviantart.com

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05-02-2010, 04:10 PM	#3 (permalink)
face992 Registered Users Thread Starter Join Date: Nov 2009	Yes thanks, I'll try to adjust it again. But why do I have to trim to the right? Is this normal?

05-03-2010, 02:43 AM	#5 (permalink)
face992 Registered Users Thread Starter Join Date: Nov 2009	I know, but you shouldn't need trim because of this. If I dont trim my heli, it tips over to the left and would fly away in this direction. This isnt sth caused by the tail rotor I think...

05-03-2010, 09:43 AM	#6 (permalink)
IrishT Registered Users Join Date: Feb 2008	You can test for lateral CG by holding the flybar inline with the boom, and seeing which way the heli leans. If it leans to the left, then you've narrowed down the problem to a lateral CG problem. There are issues if you use trim to correct for CG problems. If you trim it to be fine when upright, you'll be twice as bad inverted. This goes for both fore/aft CG and lateral CG.

05-03-2010, 09:58 AM	#7 (permalink)
face992 Registered Users Thread Starter Join Date: Nov 2009	Yes, thats why it bothers me. Assumend that it is a lateral CG-problem, what could I do against it? All my electronics are pretty much placed on the long axis or so much that the shouldnt affect the CG. Only thing I could probably do is to place the elevator servo on the other side... Any ideas?

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