Issue with SkyKing HCW 8500/8501 - RC Groups
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Oct 26, 2011, 11:46 PM
Power-line attraction pilot
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Issue with SkyKing HCW 8500/8501


It appears that my SkyKing has a mind of its own.

The throttle control no longer feels very proportional at all. Sometimes the helicopter wants to spin up its rotors full throttle when i have already put the throttle stick at zero position, other times it doesn't want to gain altitude unless i put the throttle at 100%. It seems generally unresponsive, specifically regarding throttle, and tends to shoot up high in the sky regardless what i do to try kill the power. Also, when first trying to spin up the rotors from a stand still, it almost seems like the heli races its blade to 1/3 to 1/2 full speed immediately. There is no such thing as slowly starting up the rotors....

What could be causing this issue? Perhaps with your further inquiry i can elaborate on my explanation. I am stumped here...
Last edited by caall99; Oct 28, 2011 at 09:36 AM.
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Oct 27, 2011, 09:44 AM
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Quote:
Originally Posted by caall99
It appears that my SkyKing has a mind of its own, and i am therefore renaming it to Sh*tKing and plan to spray paint exactly that on the side of the canopy.

The throttle control no longer feels very proportional at all. Sometimes the heli wants to spin up its rotors full throttle when i have already put the throttle stick at zero position, other times it doesn't want to gain altitude unless i put the throttle at 100%. It seems generally unresponsive, specifically regarding throttle, and tends to shoot up high in the sky regardless what i do to try kill the power. Also, when first trying to spin up the rotors from a stand still, it almost seems like the heli races its blade to 1/3 to 1/2 full speed immediately. There is no such thing as slowly starting up the rotors....

What could be causing this issue? Perhaps with your further inquiry i can elaborate on my explanation. I am stumped here...
Unfortunately those 3 channel helis are not hobby grade and are usually classified as disposable toys. They are rarely serviceable by the average owner but this type of heli is popular among many of the guys in the coaxial heli forum. Try posting your issue there and I bet you will find others there with that same heli or most likely its a clone of one of the other cheap China clone helis out there that they enjoy tinkering with.
Oct 27, 2011, 10:02 AM
Power-line attraction pilot
Thanks.

I'll request a move.
Oct 28, 2011, 12:59 PM
Power-line attraction pilot
Bump!
Nov 08, 2011, 03:19 PM
Power-line attraction pilot
Anybody have any input? i need to fix this trash heli...

Is this perhaps a transmitter problem? or the circuit board on the heli itself is fried? Thinking about dunking it all in 90% isopropyl alcohol... bad idea?
Last edited by caall99; Nov 08, 2011 at 03:51 PM.
Nov 08, 2011, 04:06 PM
Different fly 4 different guy
gordonzo's Avatar
Quote:
Originally Posted by caall99
Anybody have any input? i need to fix this trash heli...
I don't have this heli but I do have a large coax (MJX-T23).

If you had a hard crash or two it could be the pcb - any obvious loose wires or burn marks?

Is it lifting straight up with no spinning? That might rule out the motors.

Have you checked the easy stuff?

--> good batteries in the tx
--> heli battery is taking a full charge (11.1V battery should charge to 12.6V)
--> checked inside tx for loose/bad connection or wear on the throttle gimble

Good luck.
Nov 09, 2011, 04:54 AM
Oh no not another one
Quote:
Originally Posted by caall99
It appears that my SkyKing has a mind of its own.

The throttle control no longer feels very proportional at all. Sometimes the helicopter wants to spin up its rotors full throttle when i have already put the throttle stick at zero position, other times it doesn't want to gain altitude unless i put the throttle at 100%. It seems generally unresponsive, specifically regarding throttle, and tends to shoot up high in the sky regardless what i do to try kill the power. Also, when first trying to spin up the rotors from a stand still, it almost seems like the heli races its blade to 1/3 to 1/2 full speed immediately. There is no such thing as slowly starting up the rotors....

What could be causing this issue? Perhaps with your further inquiry i can elaborate on my explanation. I am stumped here...
This sounds to me like a loss of signal between the transmitter and receiver. First check that the transmitter batteries are all good and healthy. If they are much below 1.5v per cell then replace them. Then check the heli battery is charging to 4.2 volts per cell, i.e. 2S = 8.4v 3S = 12.6v. If the heli battery is weak it may not be supplying sufficient power to the receiver board to enable it to translate the received signal.

If all the batteries are 100% then I would suspect the board is U/S.
Nov 09, 2011, 09:06 AM
Power-line attraction pilot
Thanks for the responses guys.

I looked closely at my receiver board. No burn marks, damaged traces or components.

I have not yet cracked open the transmitter to look closely for any issues there. I received this skyking second hand from a friend in completely unflyable condition. I have since then shortened the rear boom, removed the crap LEDs, converted to a Mode 2 transmitter configuration (swapping pots around in transmitter) and replaced worn/broken parts. The issue i am describing in this thread has existed since day one, before i did any mods/repairs.

Do either of you have a SkyKing? if so, look closely at your receiver antenna and tell me if it is one continuous sheathed wire from end to end, or if there is a 1inch bit of insulation removed from it about 3 inches from the receiver with a globule of solder on it..

It almost looks like my friend severed the antenna in half and then tried to solder it back together, or perhaps that was the design from the factory, and the antenna is supposed to ground on the model somewhere (which wouldn't make any sense to me).

Any input? Could this contribute to my issues? If so, what type of wire should i use to repair the antenna?
Nov 09, 2011, 09:08 AM
Power-line attraction pilot
On another note, i still haven't performed my receiver alcohol dunk... is this a bad idea?
Nov 10, 2011, 11:11 AM
Power-line attraction pilot
More bumpage!
Nov 10, 2011, 04:29 PM
Different fly 4 different guy
gordonzo's Avatar
The alcohol cleaning may or may not have any effect. I have never had the need to try it - actually sounds a bit scary to me.

I am not sure what the effect is of a repaired antenna wire but that could be part of the problem. Something about impedance?

Bottom line is that the performance and quality of many of these big 3ch coaxial helis does not match up with their bling factor. They certainly are impressive to look at and hover but IME not really much more.

I tried a few big MJX 3ch coax's and although their quality was very good, they don't really fit, ie they are too big for indoors but not really capable of any significant outdoor flight. The only one i still have is the MJX-T23 which is a 3ch with servos which gives it some wind ability, but it is still a handfull if it you let it get sideways to the wind. Working on some minor mods for it now.
Dec 01, 2011, 05:02 AM
Registered User
A friend of a friend has just bought one of these as his FIRST helicopter (stupid really). Too frightened to fly it himself due to the size my friend has been trying it. It too loses transmitter signal and has destroyed roof tiles on two houses.

As a Heli repair man I will no doubt get the job of fixing it. If I get to the bottom of it I will let you know.
Dec 01, 2011, 05:02 AM
Registered User
opps dual post
Dec 07, 2011, 12:21 AM
Power-line attraction pilot
Please keep me updated. Mine is still not flyable.
Dec 26, 2015, 06:26 PM
Registered User

Power problem with HCW 8501


Can anyone help me I've flown a lot of smaller scale cheaper helicopters and my wife bought me the HCW 8501 off a friend of ours who bought it for her husband who never used it. I charged it up and the lights and everything worked fine. The next day took it out for my first flight and it started well. Hovered around a couple minutes and got used to it. The wind picked up and I started to lower it and when I got about 12 inches off the ground it blew over and the blades hit the ground. From that point it was unresponsive. It was not a bad crash at all and I would have never expected that to break it. I watched a guy on YouTube hold the blades against a wall going full speed and then out it right back in the air like nothing. Now that I've started looking into it some of the lights work but are extremely dim. I tested the battery and it is putting out the proper voltage up to the pcb. I'm lost from here. Can anyone tell me what needs to be replaced. Seems to me I need to change he pcb but I'm hoping it's just something stupid that I'm overlooking before I get to in depth. Any help greatly appreciated


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