mCPx: Known issues, fixes, information rollup

[AlphaKilo]

Thanks for that. I'm getting it. I'm well dialed in, now, I think. Can actually hover for short periods in the box. All about zeroing the lateral rates w/cyclic, in increments of collective and it lift straight up into ground effect almost by itself.

Mine lifts from the right front.

[smoothb10]

In my opinion and experience ( 9 years flying rc helis) the stock setting are horrible for getting into a nice stable hover. What I suggest is leave the travel adjust alone it only adjusts the amount of servo travel for a particular servo or group of servos ( I keep mine at the stock MCPX settings). After you level the swash and set 0 pitch at mid stick set your throttle curve for normal to 0, 100, 100, 100, 100 and idle up to 100,100,100,100,100. The stock expo makes the stick real mushy at center and while hovering. I adjusted my exp to 20 but will adjust it more as weather allows me to do more testing out side. For me these adjustments makes my mcpx feel like my trex 450 FBL and real easy to keep a nice stable height and hover

[AlphaKilo]

Yep, need a DX6i. The DX4e doesn't have expo. IAC, got the new rotor head and swash plate on last night, but discovered I no longer have a tail rotor blade. Off the the store this AM.

[Liduno]

Originally Posted by AlphaKilo

Yep, need a DX6i. The DX4e doesn't have expo. IAC, got the new rotor head and swash plate on last night, but discovered I no longer have a tail rotor blade. Off the the store this AM.

The dx4e does have an option to activate or deactivate expo, I will see if i can find the directions that casey posted.

[Liduno]

Here we go

Originally Posted by caseyjholmes
DX4e and DX5e Expo Activation and Deactivation
Disconnect the battery from the aircraft before
activating the Expo feature in your transmitter.

Once Expo is activated, it will remain activated for use through subsequent power cycles of the transmitter.
Once Expo is deactivated, it will remain deactivated until it is activated again.

DX4e (Modes 1 and 2)
Activate and Deactivate Expo
1. Put the ACT switch in the down position
(ON) and the Rate switch in the down
position (LO).

2. Push and hold the trainer (bind) button
and move and hold the two sticks (as
described below for activation (A) or
deactivation (B)), while powering on
the transmitter.

Here are the stick positions for A and B above.
A: Left stick: upper left. Right stick: upper left
B: Left stick: upper left. Right stick: lower right

3. Release the trainer switch and the
control sticks only after a series of
tones sound (ascending tones for
activation, descending tones for
deactivation).
__________________

[AlphaKilo]

OK, thank you. I'm learning. Now what? This is a non-adjustable exponential control? Of all 4 channels. I suppose it means a lighter touch on the....or heavier?

I don't know what it means.

[Liduno]

Originally Posted by AlphaKilo

OK, thank you. I'm learning. Now what? This is a non-adjustable exponential control? Of all 4 channels. I suppose it means a lighter touch on the....or heavier?

I don't know what it means.

Activating the expo makes it less sensitive to stick movement.

[stevec]

Check this all expo questions answered by Finless Bob...

http://video.helifreak.com/?subpath=...me=expo101.wmv

Cheers
Steve

[AlphaKilo]

Thanks, I had seen some of these in the mCPx bible section. Is there a URL for all these videos in one place? I think I need to watch all his stuff.

[AlphaKilo]

Ah, here it is...Finless Bob's Tech Room

https://www.helifreak.com/forumdisplay.php?f=60

[fstclyz]

Great info. I didn't know that was available. Thx

Originally Posted by AlphaKilo

Ah, here it is...Finless Bob's Tech Room

https://www.helifreak.com/forumdisplay.php?f=60

[3DnOC]

[
Several BNF helis seemed to have been shipped with a significant amount of negative pitch at mid stick. Use pitch sub-trim on your TX to achieve 0 pitch at mid-stick. ]

Yes, I noticed that on a v2 I just got. After sub trim adjustment 0 pitch is at half stick now.

[Tasteles]

WHen mine originally shipped, the pitch was fine, however it had a little forward elevator on it. level was good except for the elevator.

[xv-townboy]

Originally Posted by 3DnOC

[
Several BNF helis seemed to have been shipped with a significant amount of negative pitch at mid stick. Use pitch sub-trim on your TX to achieve 0 pitch at mid-stick. ]

Yes, I noticed that on a v2 I just got. After sub trim adjustment 0 pitch is at half stick now.

Much better to mechanically do this in TH mode

[oldrich]

Hi Everyone

I have been watching this thread for weeks. You folks have some really good ideas, I mean that. I found that the rotor head had way too much slop in the swashplate and as well the blade grip and upper head. I got Micro-Heli CNC parts to replace all of the stock stuff. Mechanically set up all for 0 pitch at TH mid stick, Ah yes but I found their using their .075" brass washers on the head it still had slop from side to side. I opened the hole in the center of some teflon washers to fit over the the feathering shaft. I assembled all so the teflon washers were between the sleped side if the brass washers and the inner blade grip bearing, that made all smooth moving and free of bind.

I then set up my DX6I per the factory manuel, all settings. With it set up that way it takes about 75% stick and a super high head speed. That made mine not possible to hover. I then reset the transmitter pitch curve to start at 65% and at full stick be 100%, boy did that help. The head speed came way down and the Heli is now stable!!! I played around with this and the Throttle curve is max set at 85% both normal and stunt modes. I believe that if you were to look at it from a scale version of a real flybarless heli I think that a lower head speel is should be the way to set up the McpX and it sure seems to work that way. Just thought I'd share that, maybe I am all wrong but it seems to work for me. From what I can see the V2 board has a different current (amps) protection. That seems to be really all, the board needs position or vector sensing along with the gyros to really work.

oldrich

ywbc75d@hotmail.com

[uh1medic]

I have a similar post in the main MCPX forum, but i'll pose my question here as well:

I have been experiencing servo/3-in-1 issues recently. I will put in a fresh battery and begin normal flight. 30 seconds or so into flight one or two of my servos will max out causing a death roll which is unrecoverable. These servos will remain in full throw and refractory to input until I unplug the battery. Once I plug back in the battery, all is back to normal. I have already cleaned the servo wipes and inspected all connections without any issues found. I have also rebound my DX6i.

Please let me know if you have experienced similar and have found the solution. Tomorrow I will investigate the main motor. I have owned this little guy for about a month and am just getting the hang of forward flight around the pasture. What a blast!

I will say that I am a little concerned with my abilities to troubleshoot something that is so small and has consolidated electronics. I am very hesitant to purchase a new 3-in-1 at the tune of $80 plus new servos at $15 each. I do understand that this is an expensive hobby, and I have over the years forked considerable dough over to my LHS for other non-airborne models. I just want to avoid having to purchase the equivelant of a new bird every month to be able to enjoy flying.

[GmeisteR]

Originally Posted by lenrev

ISSUE
Can probably add that the main gear and shaft are a press fit and the gear will shift until there is about 1/16-inch gap between top of gear and the frame.

SYMPTOMS
Heli won't lift and vibration occurs at high RPM (blades appear out of track).

FIX

Remove landing skids and hold opposite end of main shaft while pressing the main gear until there is approximately 1/16" of the main shaft end protruding out of the main gear.

I just read this and have this problem I'm hoping it fixes my problem of the vibration at 3/4 pitch...also should add at the bottom of the main shaft if you look closely there is a flat portion that fits into the flat edge on the bottom of the main gear itself..mine was rotated and not seated properly.

[oldrich]

Hi uh1medic

When you say the heli goes into a death do you mean that the right or left servo is pulling the swashplate down??? My heli does that, not all of the time, usually the right servo as viewed from the back. I believe it is from noise (electrical) caused by the main rotor motor. Using an oscillicope I see a bunch of junk riding on the logic when the main spools up. Personialy I want to try a brushless conversion, If I can setup one with a programable ESC and run it in governor mode. That will allow me to run a lower head speed than is recommended per the manuel setup. Anyone what can be used??? I know that the RX is pretty imune to noise, but not the logic on the heli-board. Also are you sure there is no endplay in the mainshaft? Also check your swashplate for excessive bearing play. I have discussed all of this with HH and got nothing I feel that was a good answere. I must say though they try hard but they don't have the full support of the Manufacturer, that was my opinion after discussing problems with HH.

Thanks to All

oldrich

[GmeisteR]

Originally Posted by GmeisteR

I just read this and have this problem I'm hoping it fixes my problem of the vibration at 3/4 pitch...also should add at the bottom of the main shaft if you look closely there is a flat portion that fits into the flat edge on the bottom of the main gear itself..mine was rotated and not seated properly.

THIS FIXES the issue !!!

[AlphaKilo]

Since I have the metal head, I turn the heli over and place the head button on a desk. Then with both thumbs I can press the gear back up the shaft.

If it is on the flat part. This is a every time, pre-flight test. Mine won't fly without that drive shaft absolutely tight in vertical.

Also, I just check the gear lash on my 250. It's correct. Gears are only suppose to mesh 2/3 of the teeth depth. Not correct on mCPx. Very hard to correct.