New to RC heli wobbling problem

[drewex]

Hi all, i just got my rc heli, as a first timer, i tried to of course to do a lift of after practising for a while. I did realize that i after getting the propeller fast enough, the heli starts wobbling, which i can tell the propeller is not balanced. Not sure how to adjust what to adjust. I know im probably not clear enough with my explaining but i'm really new.

[Aztek1701]

Hello Drewex,

Welcome

I'll try to help a bit but your description of whats wrong is a bit vague so to nail down the problem could be a bit tricky lol.

There are a few reasons why a heli "wobbles"

1. The blades are out of balance.
2. Something is bent. Most likely the mainshaft could also be something else.
3. The blades arent going fast enough so you are getting a resonant vibration that will go away on its own.

Lets take these in no particular order but before I do, I need to ask .. what kind of heli is it, was it pre built, have you tipped it over while the rotor is turning (propellors fit on the front of planes lol ), what direction does the wobble happen.. Left to right or up and down and finally, when does it happen... before it flys or once its flying?.

Now down to reasons..

1. Blades out of balance.. This could be true but if the heli is "ready to fly" they usually balance the blades. To check.. Take em off and then bolt em back together. Now place the blade set on something raised and flat.. (A couple of VHS video boxes on end should do.) using the bolt as a pivot so make a see saw (think they are called teeter totters in the US). If one blade drops, you need to make it balance by adding a little tape to the high blade.

2. Something bent. Im betting this is whats going on, and you dont need to be able to see a bend to have it affect the heli. If youve tipped your heli over at any point while its running there is a good chance youve bent the main shaft that takes the power from the motor up to the rotor head. The way to check this is to remove it and roll it on a piece of glass. If its bent it will be obvious. Unfortunately this does mean a fairly big strip down of the machine so if your not confident with it, take it to your local hobby shop and see if they will help you.

3. If there is a wobble as the heli spins up.. this is totally normal and there isnt a great deal you can do about it. Ive also seen models like fixed pitch humminbirds wobble in flight because the blades are quite slow.

Hope this helps... Good luck with it ... Azzy

[drewex]

First of all im sorry missing info. My heli is venom night ranger 2 RTF.

The blades are unbalanced your right. Today i spin the main rotor full speed while i was holding it, after stopping it i took off the flybar paddles. At that moment i realized the propellers were badly balanced. The rotation bar and flybar control tray was falling towards one way which i can feel the weight of the propellers when try to balance it myself. Im not sure if this does count as a miss balance but as much as my physics tell it is miss balanced.
I am having some problem following the vhs tape idea to check the balance.

The heli did come with small weights. Should i use them to balance the flybars.

I dont even know if im on the right track. :P kinda sad actually. I bet some knows where to look for some basic and detailed instructions how these thing should work or wrong.

[drewex]

I just tried the weights and no luck the the main rotor is falling towards one of the flybar sides. Any suggestions.I'll try to use the flybars as weight balancing. Ill put one closer one farder. If this is wrong to do please tell me. stop me hehehe.

[Aztek1701]

Hiya,

Okay lets try to explain how to balance the blades a bit better.

1. Remove the blades from the helicopter.
2. Try to get a longish bolt that will go through the blade mounting hole. Find 2 nuts that fit this bolt and 2 washers that work with the nuts.
3. Screw one of the nuts part of the way up the screw and put a washer on. Then put a blade on, then put the other blade on so that the leading (straight) edges form a straight line from the tip of one blade to the tip of the other.. Id draw it for you in text but the editor isnt up to it.

Fit the other washer and nut and tighten the assembly up just enough that the blades keep that straight line.

4. Get your supports (VHS boxes or whatever you like) and put them on end close together. Closer than the length of the screw thats holding the blades together.

5. Now stick the blade assembly on top of the boxes and it will look vaguely like a traditional balancing scale.

6. No let go of everthing and wait and watch... One of the blades will fall... This is the heavy blade.

7. You need to add small ammounts of tape (pvc tape is best) to the high blade until it balances.

If the assembly doesnt move youve either built the rig wrong or the blades are in balance and the mainshaft is bent lol.

If your still stuck Im sure if you look on youtube there will be a video of how to do it. Gimme a shout and I'll try to help you find one.

Good Luck ... Azzy

[drewex]

i found some youtube videos good idea to check it from there. I'll do some testing tonight.

[drewex]

after adjust the blades, i started to practise. after 1 2 hour trials, i messed up i couldnt stop the power before crashing and broke one of the blades. Now try im tryin to super glue it. I dont have my spares yet they are on the way. Thanks for the help tho. You were really helpful.

[drewex]

After getting my propeller fixed and balanced, i wanted to give it another try. Well not sure if its because of the propeller being fixed with super glue or its just having something else weird i still have the wobbling and the chopping noise. Now i recorded the chopper high speed run while im holding it. The sound recording isnt that good but maybe it can give you some clue.
http://www.youtube.com/watch?v=b5Begskb81Y

Let me know what you think. Thanks