I guess someone listened to my warning, now on there site under these servos in the specs you see the "Voltage can not higher than 7.2V, 2S lipo is not supported"... The changed it today.

http://www.himodel.com/radios/XQ-Pow...vo_S4020D.html

A new thread I've started... https://www.flyinggiants.com/forums/...splay.php?f=29 Lots of info.

Also HK has Aluminum Futaba servo arms for like $3.50 I just bought a ton, they look great! AND THE PRICE IS CRAZY!

http://www.hobbyking.com/hobbyking/s...dproduct=14850

http://www.hobbyking.com/hobbyking/s...dproduct=14849

I wasn't going to say anything and keep them all to my self but thats just no me! LOL

Yakman did you get your servos yet?

Well, my servos should be here this week hopefully. They are in the U.S but they have to make it through customs.

Servo has made it to my in town sorting facility I should have some results tomorrow.

Update, I got my XQ-S4020D servos in and my initial impressions are good (not great) and I'm talkin overall, I have to do some more test. Expect my full pre-review with video's tonight. The two negatives that I have seen by running them and opening them up are, More grease needed on the gears, and no silicon RTV on the wires to help with vibrations... More to come later.

T.J.

Yes I have mine as well.

Originally Posted by T3beatz

Update, I got my XQ-S4020D servos in and my initial impressions are good (not great) and I'm talkin overall, I have to do some more test. Expect my full pre-review with video's tonight. The two negatives that I have seen by running them and opening them up are, More grease needed on the gears, and no silicon RTV on the wires to help with vibrations... More to come later.

T.J.

so its better to buy them and open them and put more grease (what kind is the best ??)
also the centering of the servos ???

waiting for the video ... but for 27 us ...and hv ....its very good deal exept if you have to sugest something else with these futures and close to that amount of money ....
keep the good work!!!!!!

OK guys here we go, Got the initial test done and some video. This is the XQ-S4020D, Price Range $27.15 - $34.00

The torque of these servo is very good, the Dynamic torque at peak was 13.9lbs which is 222.4oz/in
The stall torque was well over what was listed, I nearly broke my rig pulling on the servo with the arm stalled. I was able to pull over 29lbs before the servo arm budged (from my view, they must check for very little movement) I got to around 33lbs before I gave up not wanting to break anything. 29lbs is 464oz/in of holding torque (I do have video of this along with some readings with my watt meter)

At around the 29lb mark the servo was reading about 2.37 amps... I highly doubt at any time the servo will be pushed to that level. The no load reading was variable while moving fast, about .3 amps, when moving slow it was more like .7 (weird) the video is on the bottom if you stop it at 2.04 you can see the amp readings, MAX (on the bottom) and Realtime (on top).

The gears did need a little grease to be added, all gears were metal and yes they seem to be all titanium gears, I'm not an expert on metals but I have seen a few titanium gears and these seem to match.

The resolution is good but not great, with each click of the trim on my A9 the servo arm did move. I do think the servos will be smooth enough for most normal day to day 3d and precision flying.

so to sum things up, I would give this servo a 4 out of 5 (on the bench).
5 for price
4 for resolution
5 for torque
3.5 for grease
2 for no RTV on the wires, and the main board is not fixed, by screw are glued down. (don't know how it is with the bottom servo case though, the soldering looks ok)
5 for gears
4 for looks and packaging. (I don't really care) It came in a plastic bag with the accessories in a separate little baggy.
as long as the servo performs well I can care less, but some guys like all the extras. But the servo it self makes up for this, it looks to be more of an expensive servo than it is.
The case is very robust, if you look at the picture from the bottom you can see that the aluminum is not very thin it's about 3mm thick and very durable. You can also see how the aluminum is contacting the motor by cuffing it to help dissipate the heat. As I worked the servo the aluminum would heat up a little during long run times or when I was stalling the servo a lot.
4 for minor gear play. (not enough to complain about) but some anally retentive guys may...

Am I missing something?

Oh, and for the guys who want to do multiple servos per surface there was no servo jump upon power up with the A9 and 6ch RX, so I assume the 7 and 9ch RX would be the same.

Next to put it in my plane to see how it holds up on the rudder of my 30cc gasser, then on to the 50cc Yak.

here is the first video...

XQ-S4020D Servo Test (4 min 0 sec)

and here is the second...

XQ S4020D Servo Stall Torque Test with amp readings. (2 min 15 sec)

Originally Posted by GEORGE0310

so its better to buy them and open them and put more grease (what kind is the best ??)
also the centering of the servos ???

waiting for the video ... but for 27 us ...and hv ....its very good deal exept if you have to sugest something else with these futures and close to that amount of money ....
keep the good work!!!!!!

The XQ-S4020D is not HV you can run it at 7.2V and thats it. The XQ-S4120D is the HV version that you can run an unregulated lipo on it.

As far as grease you can get some Hitec servo grease, I think its like 7-8 dollars for a tube... but I'm sure there are many other options out there that you can just get from the local hardware or car parts store.

I am pretty sure that the little slop you have is the servo arm on the shaft. I have never had a Dudro go on snug on a shaft. Always got some slop on them because of fit.

Oh, no its not the servo arm on the shaft, I checked that... that dubro arm is on there tight, it is the correct spline type but it goes on snug, even after pulling over 33lbs on that arm it is still tight. The slop is not much, the centering is not effected by it. Also the gear train is smooth, if you push the arm around when the servo is not powered it will continue to spin when let go.

Cool!

Yakman what do you think about the servos?

How about a resolution test? If you set your radio to one trip step per trim click, is every step actuated?

ie jr's test

JR Comparison Test (2 min 53 sec)