LATEST MODS

A bad mCPX brushed tail motor prevented the test flight of a brushless mCPX. So I had to get creative with the stuff I had on hand. No store to run to at 12AM. Here’s the result. A Hobby King AP-03 brushless motor and a Blade 120SR tail boom.

Worked really well too with a XP 3A ESC flashed with BLHeli tail code.

Mated a Hobby King AP-03 Brushless Motor to a 120SR tail boom and motor mount.

7/9/2012 Update:

I saw that there are some people who do view my post…and so perhaps some more thoughts on using the HobbyKing AP-03 motor is needed.

It works good…but obviously you gotta mod a mount for it.

I like that it’s relatively cheap from Hobby King ($15). The negative thing is, the shaft size is 1.5mm. Which means you gotta bore out that size on the prop you wanna use. I like the RRC 65mm Tail rotor blade because it has a larger center hub so you can enlarge the default 1mm hole to fit the 1.5mm shaft. Also, with the AP-03 as it comes from HobbyKing, you have to reverse the shaft. It’s easy to do with a drill press and a small socket. I’ll try and do a post on it if there’s demand. I also recommend you get a 1.5mm to 1mm replacement shaft and replace the shaft that comes on the AP-03 motor. That way, you don’t need to bore out holds on the tail prop. Fabricating a tail mount may be too much work, so if you don’t have the motor laying around to use…I’d just grab a Oversky HP03T motor and be done with it. :D

1/16/2013 Update:

I have flown the mCPX with this tail more, as well as crashed it more. And everything is still great. Had to replace one broken Plantronics tail rotor. Other than that, solid so far. I replaced the 1.5mm shaft with a 1mm shaft from Astroid-Designs so now changing props is not a hassle.

Every now and then, I see a flurry of post about v911 RX that refuses to reconnect or rebind to the transmitter. Often times, this occurs following a crash. The symptom is upon plugging in the battery, the RX LED immediately turns solid without blinking, or sometimes, it does a series of rapid blink and then turns solid much quicker than normal.

A number of us learn that the cylindrical crystal that is responsible for the timing of the circuit has gone bad. Replacing it usually fixes the issue. I’ve had this happen on three RX already, and solding on a new one have fixed the issue all three times. So it’s worth a shot instead of throwing the RX away.

For the repair, you need a working 16mhz crystal. You can purchase some on eBay or DigiKey. Or grab one from a non repairable, broken RX board.

The ones I got from Ebay is actually smaller than the original. Whether it’s more dedicate and prone to getting damage as a result, I can’t say yet. Time will tell.

Here’s the two side by side. The original on the left and the Ebay version on the right.

Comparision of the stock v911 16MHz crystal versus the replacement one.

It was easy for me to solder on the new crystal from EBay. And it works like a charm. Here it is soldered to the same location on the v911 RX. It doesn’t dangle past the RX edge like the original one. Just need to glue it down to secure it in place.

Replacement 16MHz cylindrical crystal soldered in the proper location on the v911 RX.

I purchased 50 of them, so let me know if you need one in a pinch.