450 Replacement Servos Trex 450

[Harford]

Can someone please recommend reliable good value replacement servos for my trusty old Trex 450 Pro FB, for both the cyclic and rudder. Currently has it's original Align DS410M and DS520.

Many thanks

 

[Matt]

I’ve got a Trex 450 Pro too and I’m using KST MS325’s on the cyclic and KST MS565 on the tail

 

[Harford]

Thank you for this. I have read that KST are excellent servos

 

[jacobcreek]

for good value kst 215mg(cyclics) and KST 515 mg(tail). Shop around ebay, gearbest,banggood etc.

 

[Tony]

What happened to the servos that were on it?

 

[Harford]

My issue is with the rudder servo. After intialisation the tail does not centre but moves hard towards the torque tube. It is in HH mode, but this is uncharacteristic (ie it would normally centre). In flight it needs constant rudder input. Mechanically, the tail set up moves freely, there is no binding/resistance. I appreciate this could be a gyro issue (GP780) but would prefer to see if a new tail servo made a difference. The heli is 8 years old with its original servos.

 

[Tony]

These are the servos that I have been using. So far, so good and they are fast.

Cyclic - ALZRC Devil 380 420 480 Parts DS452MG 450 CCPM Mini Digital Metal Servo
Tail - ALZRC DM1531T Medium Digital Metal Locked Rudder Servo for Devil 380 450 480 500 Pro

 

[Smoggie]

All good recommendations.. It would be worth your while doing a little trouble shooting before going and buying new servos though. Can you plug the suspect tail servo into the receiver directly (bypassing the gyro)?.. this would narrow down if it's the servo or the gyro that's causing the issue.

 

[Harford]

Thank you for all the recommendations and advice.

Absolutely agree about the trouble shooting. The tail mechanism moves freely (ie no binding). I suppose therefore it is either the gyro or the tail servo.The problem is sporadic which does not help the isolation process. I have had similar problems before on a Trex 500 FB with the same tail servo (DS520) and gyro (GP780).

Thank you for the suggestion about bypassing the gyro. I will try this.

 

[Tony]

I have had two 520's start acting funky. I ended up pulling them apart and cleaning the pot and it seemed to help for a while.

 

[Harford]

I remember you talking about this previously Tony. I am unsure of that procedure so if you were ever able to do a video on pot cleaning, I would be very keen to see it .

 

[Tony]

I think I can make that happen. I think I have an extra one laying around here somewhere lol.

 

[Harford]

Wonderful..

 

[Cyclone 7]

The KST D215MG v3 is an excellent servo and works well for both cyclic & tail. I don't do 3d however(more scale & sport flying) but 3D friends of mine reckon that is a good 450 servo, for 3D.

 

[Harford]

What I find difficult when looking at the KST range of servos is working out which one is most appropriate for the intended use. That's why it is good to have recommendations from those who have been down this track before.

 

[Admiral]

I look at the dimensions to make sure they will fit in the the voltage range that they can handle and the operating speed, with the KST D215 MG I use them on cyclic and tail they are plenty fast enough for the tail for a sports flyer, I would look at faster if I did anything extreme.

 

[Harford]

Thanks for this. The specs tend to show an operating voltage of 6.0 to 7.4v - guess I can assume they will still work at a lower voltage where I don't have an HV setup. Do you know what the practical difference is between a working frequency of 760us and 1520us ?