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Old Apr 07, 2012, 11:03 AM
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Joined Apr 2012
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Help!
Bmcx shifts left when flying

Hello,

When I am flying my bmcx it seems to always want to go left and will tip over (to the left) if starting from the ground slowly. It will also sometimes just drop when I am flying it (although it could be a low battery).

This only started happening after I replaced the blades and got a bigger battery...


What can I do to fix the problem?
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Old Apr 07, 2012, 02:25 PM
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Germantown, WI.
Joined Oct 2007
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Starting from the ground slowly always makes it tip left. It gets caught in it's own air current. The air under the blades has to go somewhere. A heavier battery just makes the condition worse, because you have less lift. The heavier battery will also make "coax death dive" more noticable. Turning at any kind of speed requires a certain amount of banking. But a coax can't bank very much. You get the death dive when the heli needs to bank more than it is able to. When that happens it loses the air under the rotors. More weight down low just makes this happen easier.
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Old Apr 07, 2012, 02:35 PM
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Joined Feb 2012
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Cmac......
Do you mean the mCPx??
Most CP helis tend to drift LEFT at lift-off, due to the tail countering torque...so it's normal to GENTLY apply a BIT of RIGHT CYCLIC right at lift-off.....It's also best to get out of ground effect as fast as possible --- don't "walk" the heli along the ground....lift off at least 12-18", then apply QUICK, SHORT cyclic corrections as necessary....
RE: dropping in flight.....if you DO have a mCPx, check to be SURE the main gear is pushed up SNUG on the main shaft, and that the "flat" on the gear is lined with the "flat" on the shaft....if you move the head up and down, there should be NO PLAY!
Of course, if the battery is approaching LVC (low-voltage cutoff) the heli will lose headspeed and shut down to avoid over-discharge (NOTE: Constantly flying to LVC WILL shorten battery life....time how long it takes a :normal" flight to bring on LVC....then shorten flights by ~:30 to 1:00.....
Did you replace the blades with stock or another brand/type??
Good Luck!
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Old Apr 07, 2012, 04:06 PM
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Quote:
Originally Posted by dasBlade300X View Post
Cmac......
Do you mean the mCPx??
Most CP helis tend to drift LEFT at lift-off, due to the tail countering torque...so it's normal to GENTLY apply a BIT of RIGHT CYCLIC right at lift-off.....It's also best to get out of ground effect as fast as possible --- don't "walk" the heli along the ground....lift off at least 12-18", then apply QUICK, SHORT cyclic corrections as necessary....
RE: dropping in flight.....if you DO have a mCPx, check to be SURE the main gear is pushed up SNUG on the main shaft, and that the "flat" on the gear is lined with the "flat" on the shaft....if you move the head up and down, there should be NO PLAY!
Of course, if the battery is approaching LVC (low-voltage cutoff) the heli will lose headspeed and shut down to avoid over-discharge (NOTE: Constantly flying to LVC WILL shorten battery life....time how long it takes a :normal" flight to bring on LVC....then shorten flights by ~:30 to 1:00.....
Did you replace the blades with stock or another brand/type??
Good Luck!
Thanks for everyone's help...

The box says blade mcx not mcpx. I replaced the blades with stock.

The thing is that now my heli flys to the left and does not hover without much movement anymore... Is there anything I an do?

Nice to know that it is normal that it tips left on take off....
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Old Apr 07, 2012, 05:14 PM
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Germantown, WI.
Joined Oct 2007
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Put a lighter battery back in, make sure your swashplate is level with the mainshaft, your servos have free movement in both directions and your anti-rotation pin is within the anti-rotation bracket.
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Old Apr 08, 2012, 11:44 AM
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Cmac......
Sorry.......I couldn't delete my post after I saw Balr14's response...
Mia culpa!!
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