AH-64_d

My CX2 has anew habit of falling from the sky after 2 min of flight. Bought new batteries and a battery status checker - the batterieswere OK.I removed the motor fuses and flew again with the same result. This was the third flight that ended in 2 minutes with a power failure. On the assumption that something else was getting hot and dying, I took off its front cowl and ran it up on the bench with the intent of using an IR thermometer to find what gets hot. The 4 in 1 and the motors stayed within normal range - 10 degree rise for 4 in 1 and 20 degree rise for the motors. To make matters worse, it did not fail. The only possibly odd thing was that the light would go from green to red and stay red when I ran the throttle all the way up.The red usually kicks on in flight when I bump the throttle to return to the LZ from the far end of the yard, so even that does not seem too odd. I have sparebrushes, spare motors, and a spare 4 in 1, but other than just swapping things out, I do not have a good idea of what is most likely wrong. Any suggestions?

Thanks in advance, AH-64 D

Coyote64

The reason for the led going from green to red is that the transmitter is losing its bind with the reciever which would indeed explain the cxfalls down goes boom lol

Check the transmitter batteries, rebind heli and last if all else fails, open the transmitter casing and see if the ariel wire has come off the external ariel as mine had done once, if this is the case the range is drastically reduced. As you said on the test bench this did not happen which suggests to me that on the test bench was the only time that range waas not a factor as your transmitter was really close. Try doing the experiment again but leave the heli on the bench and increase the distance between to prove it is a range fault

AH-64_d

Thanks Coyote64.  Rebinding seems to have fixed it.  

Best regards, AH-64 D 

Coyote64

Good good, my pleasure mate happy flying

AH-64_d

It turns out that rebinding did not resolve the problem.  When the weather improved, I flew it long it enough to have it settle to earth within a few minutes.  Both rotors lose power, so it is not one bad motor, as was the case with a recent MCX thread, but I am going to put new motors on it and if that fails, it will be time to swap out the 4 in 1.  Its present motors are first generation Xtremes.  The replacements will be second generation Xtremes.  I have been shy to use them because their magnets are so strong that they do not spin freely even when properly broken in.  I am not used to that, but figure I have nothing to lose if the choices are new motors or new 4 in 1.

regards, AH-64 D

AH-64_d

Today, I finally changed the motors and found that it still settled to earth in a few moments. Then I stuffed a used 4 in 1 into it only to get the same behavior. My next thought was the transmitter, so I spun up my MCX using that transmitter and had no problems. Just to be sure, I bound the CX2 to a DX5e transmitter and got the same loss of power, settle to earth behavior. The green light would go to red after the rotors slowed. Since every mechanical bit moves freely with no binding and the battery cell voltages are still above 4V when the rotors spin down, it would seem that I am lucky enough to have two bad 4 in 1 units. My LHS will likely be closed for Independence Day, so buying a new 4 in 1 will have to wait a bit.

dream_mas

Man, sry to hear all that... sounds like you have done all the trouble shooting though...
I would think that it has to be the 4 in 1, but who knows...
Just a thought, check the antenna lead on the receiver possibly the receiver itself could be bad...

on the bright side, it sounds like you will have enough extra parts to get another frame and build a second bird...

Good luck and keep us updated please!

CX2 4 life baby!

~Dream

AH-64_d

This may take awhile. LHS only had used 4 in 1 units. No new units in stock. Usual internet sources are also out of stock and do not expect more for a few weeks. This is beginning to look like the end of a product cycle, when parts get scarce. Hope it simply reflects good flight weather with resultant increased demand for parts.

AH-64_d

Good thing there were no 4 in 1 units in stock - The problem was a bad battery and not the 4 in 1. Before I tried a new battery, I bound the CX2 to a DX5E and failed to notice that the rudder servo was now driving hard over due to trim differences in the 2 transmitters...I was bench testing rather than flying. The out of trim servo sucked current like a tick and quickly ran down the new battery causing me to think that the problem was a bad 4 in 1. Lessons learned - 1) Battery voltage when the battery is not under load is not a good indicator of battery health. 2) Reduced flight times indicate a battery problem or high current drain. 3) When binding to a new transmitter, check trims and servo movement.

Coyote64

Oh well at least its fixed now, happy days