500 Trex 500 Rudder Servo

[Tony]

In all honesty, 333 vs 200 will not make that much difference. And if you are not sure, just use the lower value to play it safe.

 

[Harford]

Jim,
Thank is a good question. I understand it is 1520/270 whereas the DS520 I have just removed is 1520/333. Is there something I should be doing to recognize this difference ?

 

[Harford]

Thank you Admiral. I had precisely that problem with the Align replacement torque tube gears. I solved it by reusing the umbrella gear which was not damaged with the replacement drive gear (the one which is driven by the autorotation gear) and umbrella gear combination. Hope that makes sense. It is running very smoothly now. I still think my problem is related to the gyro/rudder servo combination, whether it is set up or hardware.

 

[Harford]

I should add that I got the DS535 (new servo) rudder frequency of 270 from the BeastX servo list

 

[Harford]

However, the Spirit servo list and one other I have seen says it is 333.

 

[Harford]

I really don't want to give the impression I am giving up on my existing setup, but I really would appreciate some advice on an alternative to the GP780. My experience is with this hobby is that to solve issues you have to progressively and meticulously go through a system of elimination. I therefore want to try an alternative gyro. Is the Spartan Quark a good option ?

Many thanks

 

[Tony]

Yes, the Quark is a really good tail only gyro. Pair it with a good tail servo and your tail will be solid.

 

[Harford]

Thank you Tony

 

[Harford]

Are the DS520 and DS535 acceptable servos to combine with the Spartan Quark ?

 

[Tony]

Absolutley! The 520 is a little old and over time will develop an issue with a dirty pot, but it will work. I still use them on some of my helicopters.

 

[Harford]

Thanks Tony. I have resolved the issue I have had with the rudder servo jitter on the Trex 500. I replaced the DS520 with a DS535 but it was not a servo issue and the DS520 is back on the heli and working fine. I'll swap to the DS535 when the DS520 becomes a problem. The solution to the rudder servo jitter was thicker foam tape combined with the metal plate under the GP780.

 

[Tony]

Ah, some high frequency vibrations coming through to the gyro. Nice catch! And yes, the 520 will do great for quite a while. If requested enough, I will do a video on how to take apart a 520 and how to clean them to get them going again. It's involved to say the least.

 

[Harford]

The DS520 servo has a voltage range of 4.8V - 6.0V. The ESC for the heli has the BEC output voltage set at 5.5V (default setting) although it is possible to change this to 6.0V.
The DS535 servo has a voltage range of 6.0V to 8.4V. When I installed this servo on the heli for a short time, I did not alter the BEC output voltage to 6.0V. What affect would this have please - just for future reference, in the event the DS535 goes on the heli.

 

[Tony]

The higher the voltage the faster the servo. And going from 6 to 8.4 there is a tremendous increase in speed as a matter of fact. Below are the speeds and voltages of the 535.

• Torque:
  
  • @ 6.0V: 69.4 oz-in (5.0kg-cm)
    
  • @ 8.4V: 90.22 oz-in (6.5kg-cm)
• Speed:
  
  • @6.0V: 0.05sec/60°
    
  • @8.4V: 0.035sec/60°

 

[Harford]

So I understand that not changing the BEC output voltage to 6.0V means the DS535 is not operating at its' best but is not specifically detrimental.

 

[Tony]

That is correct. By raising just that little .5 volt will speed it up. If you can get a set of cyclic servos that can withstand 8.4v, you will get the most out of that tail servo. You will need another BEC that puts out higher voltages, but don't do it unless you have everything that can support it. Including the gyro and now that I think about it, I don't know if any of the tail only gyros can support that. Will have to look at the specs of the gyro to know.

 

[Harford]

Thanks for that. The plan I have is still to swap the GP780 out for the new Spartan Quark I have ordered. I can still leave the DS520 on the heli in the meantime, or swap this out for the DS535 and increase the BEC output setting to 6.0V. In addition to the point you raise about the tail gyros, I cannot go beyond 6.0V without swapping out the ESC and cyclic servos (and I really don't want to do this).

 

[Tony]

That is absolutely fine. the 520 is a fantastic servo and will be as stable as you can get that helicopter with what you have now.

 

[Harford]

Thanks Tony. At the end of the day, I just want to see if the heli flies better with the Quark on it rather than the GP780. It is flying ok now, just a small bit of movement in the tail - it has always been like that, as has my 450 Pro, also with a GP780. It is not a big issue - they are just not absolutely rock solid in the tail, unlike my DFC helis with the Microbeast Plus.