E-sky Belt CP CX

sude · Posted: Sat Dec 18, 2010 12:34 am Post subject: E-sky Belt CP CX

Hi, I just bought myself a E-sky Belt CP CX. When I run up the motor to about 30% the whole heli shakes like a mad doggie! However when I open her a bit more it smooths out. Is this normal or do I have a major imbalance problem some where? Could it be the blades?

Would appreciate any help. Thanks

pjdog · Posted: Sat Dec 18, 2010 1:36 am Post subject:

Hi sude:

Something is out of balance. Like a car tire that will shake at 50 mph but smooths out a 70 mph. RC Helicopters must be balanced. First start with the main blades. Then try to run it up again. Your blades should track one another also. Plus the flybars must be centered. The whole rotor needs to be in turn with itself.

Tombo, jump in here and help this fellow out.

Jack
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tombo242 · Posted: Sat Dec 18, 2010 1:37 am Post subject:

Hi sude,

Many helis do this, the blades have to be slack enough to 'self center' as the rotor(s) speed up. This often means that at the start the blades kick out of alignment and the heli shakes, then at around 1/3 throttle are spinning fast enough to align correctly and the shaking stops.

Your blades should be tight enough not to drop when the heli is held horizontally, but loose enough to drop by the same amount each if you give it a sharp upwards jerk.

Tom.
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silhouette015 · Posted: Sat Dec 18, 2010 3:36 am Post subject:

I think the main blade is out of balance for the heli to shake that violently. Happens to me when I was still flying my T-REX.

Mark the two blades at the end with markers, differnet colors each. Spin up the blade at low speed at eye level and you will see each blade spinning. They should both be spinning on the same plane.

Scott · Extreme 3D Joined: 11 Nov 2010 Posts: 340

My 400 did that the 1`s few times it was spooled up, but now
it doesn`t do it. Go figure......The blade tracking is not perfect tho.
Need to get it outside to adjust it, where there`s more room,
but the weather is not good. Crying or Very sad

Good Luck Sude,
Scott

sude · Posted: Sat Dec 18, 2010 8:54 am Post subject:

Hi Everyone,

Many thanks for the response. Tried Tombo242 's tip but did not fix the problem. Fly-bar etc are all ok. I am now thinking of removing the blades to check their weights etc.. and do a static balance. Lets' see whether that will sort things out.

pjdog · Posted: Sat Dec 18, 2010 9:42 am Post subject:

Try spinning up the rotor head without the blades on. If you still get a vibration you'll know it's not the main rotor blades.

jack
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sude · Posted: Sun Dec 19, 2010 11:07 am Post subject:

Hi Jack,

Yes I spun the heli without the blades and there were no vibes. Therefore I took the main blades out and checked the individual weight which is ok. Also the static balance of both blades ok too. Would out of tracking blades cause the heli to vibrate? I do not have a pitch guage at present and I have to eye ball the blades whilst they are spinning to check the tracking.

Your feed back is much appreciated

pjdog · Posted: Sun Dec 19, 2010 2:01 pm Post subject:

You will need a blade balancer. It's a must for helicopters and while your at it get a pitch gage. You should have a swash levelr too. Got to have the tools to survive.

Jack
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sude · Posted: Mon Dec 20, 2010 11:43 am Post subject:

Hi Jack,

Thanks for your help. I know I need to get those tools but unfortunately we do not have hobby shops as such in Sri Lanka. Any thing to with rc and flying was banned due to the war situ we had for the past 30 years! Only now the restrictions are being lifted very gradually.

Now to cut a long story short, I managed to hover the heli for a short time before gravity pulled it to the ground! Crying or Very sad

I really do not know exactly what happened and I am trying to analyze the mistake. The chopper was only about two feet off the ground and it was drifting towards a drain and I think I cut the throttle too fast. Had the training skids on as well. I saw the training skid hit the grass and in the next instance the heli was an instant kit.! The rotor blade hit the tail boom. On inspection the damage was not serious, only a bent tail boom and feathering shaft and surprisingly no damage to the blades. The heat shrink covering was slightly torn on the blade that hit the tail boom. I still have to check the main shaft though.

Now my question is how did the blade hit the tail boom? With the blades spinning and the stick pulled right back the the rotor does not come any where near the tail boom to make contact. Therefore I cannot understand how the blade(s) hit the tail boom. One thing I notice is that there is no support from the tail boom to the main frame. In other words the tail boom is fixed only at its' mount on the main frame. Could this design error have caused the tail to flex upward when the heli hit the ground?

Sorry for the long explanation. Any feed back will be greatly appreciated

Thanks / Sude

pjdog · Posted: Tue Dec 21, 2010 1:39 am Post subject:

Hello sude:

Welcome to the mysteries of RC helicopters. I have had several tail boom strikes. A couple broke the tail boom in two. My guess is that the blades and possibly the tail boom flex when they hit the ground. It all happens so fast the we can not see it happen only the result of it happening. This is why most helicopter fliers are know a builders. We are repairing all the time. But that is also the fun of the hobby. I do much more repairing than flying.

That’s a hardship not being able to get to a local hobby shop. I guess all your supplies and models must come by mail. But lots of modelers are in the same boat.

I don't know what material your main rotor blades are made of. I only use wood main blades (Woodies). They will break before doing serious damage to my helicopter. Well most the time anyway.

Do you have a simulator. That's almost a must. It's far cheaper to crash a simulator model then your own model. If you don't have a Simulator and a training TX for the simulator look into it. Clearview is a good simulator and not expensive. I don't know how that would work in your location but if you can work on this forum you should be able to use Clearview simulator.

Sorry you crashed. I hate it when I mess up one of my toys. Order parts and repair.

Jack
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chopper54 · Posted: Tue Dec 21, 2010 3:44 am Post subject: post subject

hi sude
i think tail boom strike are the curse of the noobie. when i first got a cp heli i was always bashing the boom. as your hovering improves your boom strikes become less frequent.

sude · Posted: Tue Dec 21, 2010 9:02 am Post subject:

Hi Friends,

Thanks for the words of encouragement. It is great to be able to share ones fortunes and mis-fortunes on friendly forums such as this one. By the way this is my first go on a forum as well.

As you said Jack building/repairing is the most fun part in this hobby. When I was into planes I had one which was repaired umpteen times that it was named the 'Glue Pot'! Yes I should try a simulator. My Tx has a PS2 port named trainer but did not have a cable in the box. Will troll the net to see where I can get one or better a schematic so I could build my own. Most of the time I make my own (the easy ones) because of the lack of model shops.
Thanks for your help Jack.

Hi Chopper54, good to know every one goes through the same learning curve! Oh by the way you and I are the same vintage.

Cheers.

Sude

chopper54 · Posted: Wed Dec 22, 2010 3:37 am Post subject: post subject

hi sude
the only problem with being our vintage is keeping hold of those tiny screws that hold everything together. i saw a tip posted that suggests using an old white t-shirt under the heli when building as it catches any dropped bits and makes them easier to find.
even so i think we are among the younger members here.
you can learn plenty on this forum there is always help at hand when you need it.

tombo242 · Posted: Wed Dec 22, 2010 8:18 am Post subject:

Hi Folks,

Just stepping in with an amendment here. A white towel is better than a tee shirt. The bobbles catch the little bits before they start to roll. They have been known to clear a smooth tee shirt, but not bobbley towel.

The ultimate is the do the job on the floor where the bits have no further to fall. OK for you youngsters but not so easy for us 70+ westerners though.

Tom.
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