500 Tomorrow, it flies.

[Tony]

You don't want to go towards the tail, you want to go out and make the slider travel more. Unfortunately there is not enough shaft to move it where it really needs to be, but you can move it out a little to help the issue some. Moving it in would decrease the right rudder pitch. But moving it out would increase the right rudder pitch.

 

[zenmetsu]

Ahh yes, you are correct. The linkages need to be shortened, or the hub moved out.

Even moving the hub out will not allow you to get things right, you will still be off-center when you have the needed pitch. The advantage is that you would have more travel range. Unfortunately, as you said, there is no room left on the shaft to move outwards.

Also, another problem that I have is that the GY401 does not have differential endpoint configuration. If left travel is shorter, I will have unused travel to the right. I could fix this in software by reprogramming my tail servo, but I don't know if I'd really care to piro to the left that fast.

On another note, instead of tearing down my heli to get to the travel pot on the gyro, i'm just going to reduce travel on my servos to keep them from bottoming out. Yay technology!

 

[Tony]

I have found that you really only need about 15% of the total pitch in the tail to fly. So losing a bit is not really that big of a deal. I'm going to have the 600 running about 360º per second. It's not fast at all, but it's fast enough to move the tail pretty quickly where I want it, and I have a lot of control with the rudder stick. Because of this, I don't run any expo on the tail. However I do run a dual rate for those times when I want even more travel. And with the DX8 having a 3 position switch, I can set two higher options to have on hand.

As stated in URI's maiden thread, it will take some time to get everything set correctly. But once you do, it will be one great heli.

 

[zenmetsu]

Good point. I'll scale back the servo travel... last thing I need is for the tail to bind. Heh.

Everything about this helicopter is intimidating. Even the fact that I get a nice shower of sparks from the inrush current to the ESC whenever I attach the battery... like I need any additional startling activity when I am apprehensive of the blades roaring to life right in my face as I am giving the thing juice

 

[Lee]

As stated, you'll never really need full throws on the rudder. Even doing piroflips i don't give full rudder.
You should hear the crack you get when plugging in a 12S system LOL Its like a fire cracker going off.

 

[Tony]

You would think they would put a small low voltage switch in these ESC's to keep that from happening. Just look at the ESC's on cars and trucks. They have this switch and there is no arcing. Much safer and your plugs last much longer

 

[Lee]

They do on a lot of them now. Gryphon BECs have a spark inhibiter

 

[zenmetsu]

You usually use a resistor to pre-charge the capacitors, then make full connection without resistor. This will eliminate the spark.

Using proper connectors is important as well. If you use connectors with a small contact area during initial connection, you will form carbon and eventually create a resistor of sorts during the initial connection.

Castle says that the spark is "good", and to an extent, they are right as it lets you know that your capacitors are still good. If there is no spark, you cannot tell that your caps are good. This is one of the drawbacks of putting inrush limiters into the circuit.

Anyways, just got back. Same thing, tail is now a good 5 degrees at neutral, but the tail still wants to swing off to the right. I had to use about the same amount of correction as before, and this tells me that the gyro is "seeing" a constant rate of rotation to the right and it is trying to correct the motion by applying left rudder input, forcing me to counter the gyro input. I put my rate mode gyro setting at 50%, flipped it off, and the tail only needed minimum correction. The gyro is seeing motion that isn't there, and my guess is that it is vibration related.

As far as vibration is concerned, the helicopter seems to be pretty smooth, and I do not hear the telltale sound of poor blade tracking. I am a bit apprehensive of putting my braincase in line with the spinning rotor, so I am going to have to find out how to test this.

Anyways, time to add more vibration protection to the gyro and try again.

 

[murankar]

My tail is set at center with the travel set to 120 (max), this is per jr's gyro setup. I also have no trim or sub trim. My pitch slider is centered and the blade grips are centered. My gyro will calibrate itself on the first flight and things are good.

Since your running the gy401 I am not sure what to say other than is it adjusted to the temperature prior to flight?

 

[zenmetsu]

The gyro should be at the correct temperature. I added additional foam for vibration isolation, so I will give it a shot to see if that had any impact.

Worst case, this heli will be grounded until I get my other gyro.

 

[zenmetsu]

OK, so adding foam + metal plate did not resolve the problem, the tail still drifted even with 100% gyro gain. I got the idea then that maybe the gyro didn't have enough tail to play with, especially since I didn't get any tail hunting at 100%.

So I bumped up the head speed... a LOT. The tail was then going nuts... nearly shook the helicopter apart. Had to drop gain back to 70% to get the shaking to stop, but then it seemed to hold pretty well. That is, until the motor sucked the last bit of life from the LiPo and it started spooling down about 10 seconds later.

I will have a better update after the recharge. I only have one pack at the moment, I need to make sure that this one is sufficient before buying another. At $100 a pop, I just can't afford to buy these like the little 850mAh 3s packs that I use on my 250.

One thing I do on my 250 is hit throttle hold after landing and go full collective to slow the blades down before I get to the helicopter to use the head stop button. Oh man, the sound this 500 made when I did that... wow.

 

[stokke]

Are we going to get any vid soon zenmetsu?

 

[zenmetsu]

Yeah, probably tonight. I ran into another vibration problem. The head appears to be very well balanced until I actually get it in the air, then it looks as if it is wobbling. I suspect that there is some tail wag at high speed and it is giving the appearance that the head is wobbling. I am changing my gyro mounting position and getting it further from the motor.

 

[zenmetsu]

Much better with a new gyro in this thing. Video coming up.

 

[zenmetsu]

ugh... lost net connection at 80% upload. Going to tether to my phone since upstream is 20mbit vs 1.1mbps on my dsl line

 

[zenmetsu]

Here is the video. I wanted to see what I would get for hovering time. Hopefully once the sun comes up tomorrow I will have a chance to open this thing up a bit and have some more fun. I had to keep her really low to the ground to stay in view of the camera, but I gave it a bit of quick rudder and cyclic input to see how the response was. Rudder input was under half deflection, so I image that thing thing will piro like a beast. When I gave it enough collective to get out of ground effect, the blades started making all sorts of fun noises.

Anyways, I had this gyro at 62%, and no wag that I could see. I will try getting it up around 70% and see if it cures the very slow drift that it has.

LiPo was warm after this, motor was quite a bit warmer, but not so hot that I couldn't keep my finger on it. I would say it probably was at 150F.


- - - Updated - - -

Looks like Spartan just released their FBL unit. Perfect timing I suppose.

 

[Lee]

Do you get any tail creep on the bench? Dial it out with sub trim if you do, that should stop the drift. Looks good though. Love the orange nose

 

[stokke]

Flying like a charm! Tail seems to hold perfect as well

Great job

 

[zenmetsu]

No tail creep on the bench. I think that it is just gain being really low. I'll adjust the tail mechanically just to see if it helps. Still a bit nervous with this thing, so I'm not going to try nose-in while indoors, lol. Going to give it a few more flights to make sure that there aren't any nasty surprises waiting for me before taking off the training gear.

 

[zenmetsu]

I adjusted my cut-off as well, from 3.2V to 3.4V so that my next flight doesn't devour the battery. Looking at the ESC data, I pulled 3Ah out of a 2950mAh pack. Oooops. The voltage really cratered at the end. The charger stated that it put 2866mAh back into the pack, so this is 97% depletion. No bueno.

Head speed was regulated quite well. ESC got up to about 120F, not as hot as I had expected.