600 Derek's Align Trex 600e Pro DFC

[Derek]

I'll mess with that and see if I can get it to help. The guy at the LHS told me that I needed to raise the pitch precomp. I raised it a bit and then a bit more and nothing seemed to help so I put it back where it was.

Update...

I just read and then re-read the precomp selections. I think I understand it now. I thought the pitch precomp had something to do with the actual pitch of the helicopter. It actually has to do with the tail pitch. Thanks Kev! I will work on this today. The weather is gorgeous and I have two flight packs charged.

 

[Graham Lawrie]

Is this to counteract the torque of the main rotors?

 

[Derek]

Is this to counteract the torque of the main rotors?

That actually raises a question for me....when I give hard positive collective, the tail kicks to the right about a foot to a foot and a half. Now, since the main rotor is spinning clockwise, if the tail was kicking because of the torque of the main rotor, wouldn't the tail kick to the left?

 

[Derek]

Grahams comment made me think. The main rotor turns clockwise. In a hard collective pump, the tail would kick to the left. My 600 was kicking to the right. After a bit of further thought, I decided to disable the governor and just try the Fixed End Points. So, I changed that and made some minor changes in the Ikon. Went for a test flight and the tail is super solid. Just awesome!

So...I'm curious....any idea as to why the tail would kick to the right, against the torque of the main rotor???

 

[murankar]

If it is pre comp then it is high, lower it. If its not pre comp then I don't know what to tel you.

Sent from my LG-E980 using Forum Runner

 

[pvolcko]

No, the counter torque will be in the opposite direction of the main rotors. So clockwise rotors means the tail wants to spin counter clockwise. That's why the tail rotor blows air out to the right to keep it in check, to counter act the main rotor torque.

I was just about to caution against making pre-comp changes at this point, then i read the rest of your last post. My tail kick out issues have always ended up being either governor issues or motor/ESC setup issues.

On the 550X: CC 120HV ESC and stock eflight motor, I ended up having to select 8khz PWM rate and low advance timing params in order to get the thing to behave propertly. Without that I ended up getting motor stalls and all sorts of oddness. I believe I also selected low gov gain in the ESC and setup some rpms for SetRPM governor mode. All was good. No tail pre-comp needed.

On the TRex 700: CC 120HV ESC and a Scorpion motor (can't recall the model off the top), the tail kick out I was seeing ended up being governor gain issues. I had to use a low gain setting in order to eliminate tail kicks on this model. Later I wired in a phase sensor to feed into the Ikon and use it's governor instead of the ESC gov. I ended up using a very small amount of pitch pre-comp to eliminate some very slight tail kick (maybe 3 inches of movement).

In general, if you're seeing big kick outs (6+ inches) you need to look at gov gain and/or ESC/Motor setup params before anything else. Pitch pre-comp (revo mix on the AR7200BX) should only be used for adjusting out small kicks.

Gob 500: CC Edge 100 ESC, stock Quantum motor, Ikon gov: never had any tail issues with this, at least at 2000+ RPM. 1800RPM setting results in some tail fluctuations on tic tocs. Rock solid from the first flight.

Gob 700: I don't fly this all that much. I'm still working out the settings a bit, but no tail hold issues. Had this almost a year now and I think I've flown it 5 times. So sad.

 

[Derek]

ok, that makes sense, Paul! I had to read it twice to absorb what you were saying. If you consider the tail of the helicopter at 6 o'clock (tail in hovering) and I'd give a hard collective pump, the tail would jump to about 4 o'clock. it was quite a large kick.

I do have an RPM sensor on my 600 so that the Governor on the Ikon can be used, instead of the Castle HV 80. I guess that would be worth a shot, if I'm wanting to run the Governor. Honestly, for my flying style, I don't think the Governor is really mandatory. I was, and still am, wanting to run the Governor on my 600 because it's something new that I'd like to learn. I'm not a hard smack pilot but maybe some day...who knows.

Prior to disabling the Governor, I did have Low Governor Gain selected (even though Align recommends "Medium") and I did have my own set RPM's set at 1850, 2050, and 2200. Would that be too low or too high?

 

[pvolcko]

Those rpm settings should be okay. I wouldn't count on the low headspeed setting not kicking out. But the 2000+ setting should be good. Since you know the no gov mode is solid then you should be able to get the gov mode a lot closer. Do some test flights with increased gov gain on each flight. See if it helps. Put it on the setting that is closest to right. Don't be afraid to try the custom setting to select values between the three preset values.

What are your pwm and advance timing settings?

 

[Derek]

The PWM is set to 12Khz. It has an "*" after that. I'm assuming that means it's the default setting. As far as the Advanced Timing, the only "timing" option that I see is under the "Motor" tab and that's set to "Normal 5", also with an "*".

 

[Derek]

If it is pre comp then it is high, lower it. If its not pre comp then I don't know what to tel you.

Sent from my LG-E980 using Forum Runner

I had added a bit of precomp, at one time, but I had also heard from several people, Paul included, that the tail should be setup with as little precomp as possible. So, I put the precomp back to 0 shortly after I had changed it.

 

[pvolcko]

A little pre-comp may well end up being necessary. But it should be as little as possible and only after having ironed out any gov and motor/esc settings issues. If the tail was solid with gov turned off, then motor/ESC settings are likely just fine. That leaves governor settings to sort out. Get it as close as you can with the gov gain first, then try pre-comp to fine tune it.

 

[murankar]

I know from my experience is that everything should be solid prior to adding in a governor. The gov will flake out a poorly setup tail and will cause a bunch of chasing that won't go away. That's because you are going to be chasing the wrong things.


Next with my ZYX-S any pre comp added or subtracted should not exceed 10 or 12 points. Typically if any was needed then 5 points was what youtubers recommended. I think 5 was the magic number for that devise.

Sent from my LG-E980 using Forum Runner

 

[Derek]

A little pre-comp may well end up being necessary. But it should be as little as possible and only after having ironed out any gov and motor/esc settings issues. If the tail was solid with gov turned off, then motor/ESC settings are likely just fine. That leaves governor settings to sort out. Get it as close as you can with the gov gain first, then try pre-comp to fine tune it.

Yeah, the tail is quite solid with no Governor. I'm actually a bit afraid to enable the Governor again, and start messing with it, because a few people here seemed to think that the Governor gain was partly to blame for the stripped teeth on the torque tube and front drive umbrella gears....twice. I could be wrong, I dunno. Perhaps I "accidentally" got the torque tube gears meshed properly (even though I thought I had it done properly before....twice.) I will try to get someone to come out to the field with me next time with the video camera. I'll try to get a flight with the Gov off and on.

I know from my experience is that everything should be solid prior to adding in a governor. The gov will flake out a poorly setup tail and will cause a bunch of chasing that won't go away. That's because you are going to be chasing the wrong things.


Next with my ZYX-S any pre comp added or subtracted should not exceed 10 or 12 points. Typically if any was needed then 5 points was what youtubers recommended. I think 5 was the magic number for that devise.

Sent from my LG-E980 using Forum Runner

ok, thanks Matthias