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Old Oct 31, 2012, 06:15 PM
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Joined Oct 2012
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Help!
Heli just gets out of control

hey everybody ,
i dont know if its the right forum to post this but i am kinda desperate to look for a solution so
i have recently bought a rc heli
here's the one i bought
http://www.gadgetbox.co.uk/Product/R...ed/p-6266.html
now the problem i am having is that the heli crashed really badly and its lower gearwheel was seperated
i tried to fix it and now i have tighten it , but now it wont rise at all , it will just come backward when ever i try to pull up the throttle.
before it the heli was flying pretty fine.
could it be that i have tighten the lower gear wheel too much?
and one thing more the gear wheel is kinda touching the helibody something that is surely not suppose to happen.
any advice cause i am not going to touch it until i get some hints from an expert like you people
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Last edited by samj89; Oct 31, 2012 at 06:33 PM.
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Old Nov 01, 2012, 03:25 AM
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Letchworth, Great Britain (UK)
Joined Jul 2004
11,439 Posts
Welcome to the forum

I'm not familiar with that particular model, but in most coaxial helis the lower large gear wheel is connected to the inner shaft (running in bearings inside the outer shaft), to which the top pair of rotors are mounted. The upper gear wheel is connected to the outer shaft, to which the lower pair of rotors are mounted. Each gear wheel is driven by a pinion on its motor.

When that kind of model doesn't lift, or doesn't respond properly, it's often because one or both of the drive-trains has some slip in it somewhere. So you need to check that the gearwheel or rotors are not slipping, by holding each pair in turn and seeing if you can twist them on their shaft. Also check if the pinion is slipping on the motor shaft -- it's sometimes just a tight fit assisted by a drop of Loctite or similar -- and check if it's meshing properly with its main gear.

Also, I don't know if it's possible to mount the main blades the wrong way round on that model. If one or both of them are wrong (the blunt edge should face the direction they're moving) you'll get less lift and lack of tail control.
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Old Nov 01, 2012, 08:25 PM
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Joined Oct 2012
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thanks for the reply,
i checked for the slip on pinion on motors and there doesnt seem to be any
i also checked for slip on gearwheels and well there seems to be a slip on outershaft (it seems to even move freely without the movement of gear or bladed) which is connected to the lower pair of rotors but again i am a complete noob so i dont even know if i am even checking it properly .
what would you suggest me to do ?
should i try to repair it myself or should i take to someone who can actually repair it ?
i am more than willing to fix it myself ,only if i can find a good help somewhere
i ll try to upload the vid of the heli too , so it would be more clear to you
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Old Nov 01, 2012, 08:35 PM
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Germantown, WI.
Joined Oct 2007
21,378 Posts
Try spinning each rotor. They should turn very easily.

Hold each main gear and try to turn the rotor. They should not be able to turn.

This type of heli is usually disposable. They are not built to be repaired, so you may have some problems.
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Old Nov 02, 2012, 03:05 AM
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Letchworth, Great Britain (UK)
Joined Jul 2004
11,439 Posts
Sounds like either the gear is loose on the outer shaft, or the hub that holds the lower blades is loose on the outer shaft. If it's the gear, you may be out of luck because those are often bonded to the shaft, and trying to re-glue them (thin cyano) reportedly is not always a success.

If its the hub, you may be able to do something about it because they're usually fixed to the outer shaft with a tiny grub-screw that goes through the gear into a small hole in the outer shaft. You may be able to tighten that so that the hub doesn't slip on the shaft.
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Old Nov 02, 2012, 07:39 AM
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Quote:
Originally Posted by Balr14 View Post
Try spinning each rotor. They should turn very easily.

Hold each main gear and try to turn the rotor. They should not be able to turn.

This type of heli is usually disposable. They are not built to be repaired, so you may have some problems.
hey , thanks for the help , well i tried to rotate the rotors while holding the main gears and
the lower rotor which is connected to the upper main gear seems to move even when i am holding the gear
so i guess that is the problem.
and yes its a pretty cheep heli. (bought it for 70$) but still i havent had a single decent flight with it so i am going to do all to fix it .
all the help or tips you can give me to fix it is much appreciated cause its my first heli and i dnt know much
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Old Nov 02, 2012, 08:21 AM
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well the lower rotor is now now not moving when i hold the gear , the problem was that the screws on that rotor was not properly fitted, that prob fixed but now still the heli wnt lift , i have made a video of the behavior of the heli and it seems like the upper rotor is not spinning as much as the lower rotor.
i have also checked and it seems that when the upper rotor is not moving , its corresponding lower gear is also not moving so i should assume that there is no slip between gear and upper rotor?
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Old Nov 02, 2012, 08:44 AM
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heli wicked behaviour

rc heli wicked behaviour (0 min 21 sec)
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Old Nov 02, 2012, 08:50 AM
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http://www.youtube.com/watch?v=8ZcbB...eature=mh_lolz

in this you can see the upper rotor doesnt move where as the lower rotor is moving
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Old Nov 02, 2012, 09:14 AM
Cranky old fart
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Germantown, WI.
Joined Oct 2007
21,378 Posts
The tail motor isn't turning. Check the board. Either the connections are bad and need resoldering or you blew out an FET. Both are very common problems with this type of heli, especially after a crash. I'd move the battery further forward, too. The upper and lower rotor not moving at the same speed doesn't mean much until you get it in the air.
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Old Nov 02, 2012, 09:35 AM
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Quote:
Originally Posted by Balr14 View Post
The tail motor isn't turning. Check the board. Either the connections are bad and need resoldering or you blew out an FET. Both are very common problems with this type of heli, especially after a crash. I'd move the battery further forward, too. The upper and lower rotor not moving at the same speed doesn't mean much until you get it in the air.
thanks for the quick reply,
the tail motor is turning when i use the navigation stick on the controller , so i ll think that it isnt dead, right?
so any thoughts?
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Old Nov 02, 2012, 10:24 AM
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hey sorry for bothering but as far as i have learned in a couple of days , the tail motor is linked with changing the direction of heli. isnt it?
or is it the tail motor has any thing to do with heli lift off?
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Old Nov 02, 2012, 12:41 PM
Cranky old fart
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Germantown, WI.
Joined Oct 2007
21,378 Posts
Your videos show the heli sliding backward rather quickly, which is controlled by the tail motor. That makes any other meaningful diagnosis rather difficult since you need to get it up in the air about waist high to eliminate any ground effects. If the heli isn't yawing, it doesn't need both main rotors to turn to control yaw. If it's up in the air and one rotor isn't turning very fast and the heli is yawing, then you have a problem.
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Old Nov 16, 2012, 07:28 AM
Semper Fragosus
United States, IL, Lindenhurst
Joined May 2012
133 Posts
suggest you get a different heli

As one of the previous posts pointed out many of these cheap helis are pretty much disposable and nto designed to be fixed. You can pick up a used Eflite Blade MSR with transmitter on RC Groups, or other sites or ebay for probably about what you paid for your heli and they are fairly well made, light enough that if you cut down on the throttle when you get into a bad situation, you probably aren't going to have any significant damage, parts are readily available and it is a good way to start learning even if it is somewhat smaller than yours. I know, I know - but I just spent all I wanted to invest in RC heli's - you'll get over that quickly or your birds will be grounded. Everybody crashes, everybody needs to make repairs.
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