Caution: Savox SB-2271SG Cyclic Servo Bench Test Results

[Rob Cherry]

Originally Posted by akamullen

Just tested with lots of pressure on the servos and moving sticks crazy fast for a good 20 seconds, NO brownout or lockout, NO blinking RX or sats.

I have the BEC PRO V3 set at 8V, hooked up to 6S. one power lead going to the beastX and one power lead going to the RX.

Which RX? your RX may have a much better 3.3V buffer than vbar, or the cheap RX I tried, that would be the key. But, MR MEL is right on too, I'm sure these servos draw upwards of 30A when they need to.

Maybe just try it with your setup and go?

[Chris Sexton]

Had unforcasted rain in my flight window today, I hope to beat on mine some tomorrow after work.

[Rob Cherry]

My next test will be a capacitor on the 3.3V lead that goes the satellites.

I did to string a few 4700uf capacitors in parallel and connect it to an open port on the vbar, but I've calculated that the servos will empty those capacitors in about 0.01 seconds, rendering them useless.

[MrMel]

Either use a buffer pack (if your BEC allows it) or a Fromeco DC up system.

[Chris Sexton]

As expected no issued at all on mine with an RX pack tonight.


Sent from my iPhone using Tapatalk

[Rollin_3z]

Yup, these servos are amp hogs, I should have put a buffer pack. I saw it glitch momentarily on bench. I put a small capacitor on vbar, but still not enough. I lost control for a brief second on the second piro flip, go full screen on video for full effect..lol


[ame]http://www.youtube.com/watch?v=rhlosmaDhk0&feature=g-all-u&context=G2e248dcFAAAAAAAAHAA[/ame]

[Chris Sexton]

Originally Posted by Rollin_3z

Yup, these servos are amp hogs, I should have put a buffer pack. I saw it glitch momentarily on bench. I put a small capacitor on vbar, but still not enough. I lost control for a brief second on the second piro flip, go full screen on video for full effect..lol


http://www.youtube.com/watch?v=rhlos...dcFAAAAAAAAHAA

Ouch man

Is the damage bad?

[kachur779]

ahh dude lol damn that was a bad day

[xfactor6]

Originally Posted by Rob Cherry

That's all fine and dandy, but I did that already.

I really love these servos, I'm ok with the fact that they draw power fast and furious, it results in uber sick response time. I've never seen a servo with this much torque and speed. I've been using the original outrage servos in my X5, 0.05 speed, these seem just as fast or even faster. They do have a tad bit of slop, but less slop than the stock X7 swash has. I'm waiting on my ABEC 5 replacement bearing, that should tighten things up around the swash area.

I currently get 4 flights from a 1300 2S RX pack. 2 is optimal to keep the voltage higher. This is a fair trade off for lightning quick servos, which I need.

can you give me a link to the bearing you put in the swash?

[Rollin_3z]

Originally Posted by cdsexton

Ouch man

Is the damage bad?

The frame survived, not one crack. One servo toasted, everything else was a right off

[Chris Sexton]

Originally Posted by Rollin_3z

The frame survived, not one crack. One servo toasted, everything else was a right off

[Rollin_3z]

Originally Posted by cdsexton

Ok, I just spent 1075.00 for another servo, 2 batts, blades and kit parts...lets see if I can get more than 3 test flights out of this rekit...

Can you imagine if this was a Outrage Goblin?

[Rob Cherry]

Man, sorry dude!

Another confirmation that vBar (with satellites), BEC and Savox 2271 DO NOT PLAY NICE.

[vr360]

It's the servos.

Luckily I have the Torqs!

[Rob Cherry]

Originally Posted by vr360

It's the servos.

Luckily I have the Torqs!

Because they are so friggen fast! I'll take 'em! Ninja tocs!



Actually, it's vbar, not the damn servos. We need BEC's to step up their game AND/OR vbar needs to increase the buffer on their 3.3V rail, both mini and fullsize failed and browned out!

To me, this is just more obvious evidence that all BEC's have a limitation, they will never replace the consistency or reliability of an RX pack. The are stepping the voltage at a certain frequency (hz), and now these new servos have surpassed the stepping frequency rate and draw more power, faster than the BEC can deliver. Beastx may have a larger 3.3V rail buffer, but that doesn't fix the BEC, only hides its problem.

[Rollin_3z]

Originally Posted by Rob Cherry

Man, sorry dude!

Another confirmation that vBar (with satellites), BEC and Savox 2271 DO NOT PLAY NICE.

Yeah you're right man...I just added a LiFe 6.6 pack and my sbec set at 6.0 volts. Plus a capacitor for good measure!

[Rob Cherry]

Originally Posted by Rollin_3z

Yeah you're right man...I just added a LiFe 6.6 pack and my sbec set at 6.0 volts. Plus a capacitor for good measure!

Looks like its ready to fly! (almost)

[joe1l]

Hey guys,

When i first got into this hobby i was using Hitec A9 because i wanted the telemetry feature. I noticed that i was having complete power shutdowns using same servos, bec etc others were using on the same helicopter...i couldnt understand what was going on. I ended buying a Futaba 8FG because i was starting to have suspicions that my Hitec electronics were behind the failures. One thing i knew was that the Hitec required voltage to be above 3.5v where Spectrum and Futaba could go as low as 2.7
I decided to do some bench testing at the time using 3 INOLAB 760MG servos. I did not mount the servos or anything i simply moved the sticks on the bench. I discovered that because of the telemetry the same exact servos using the same exact power source at same voltage would draw 30% to 50% more current when plugged in to an Optima9 RX vs my R6008HS RX. The difference between the two grew even greater as load increased.

I noticed that someone was using a DX8 and just wanted to point this out as Telemetry could be part of the reason why some people are having issues while others are not.

here is the link that pointed out the issue that luckily made me switch to Futaba!

[akamullen]

I'm not running Telemetry, but I am running DX8 spektrum, no problems here. I think this is a Vbar issue, not spektrum. My beastX with spektrum receiver is working fine with these servos. no lockouts or brownouts. I believe JC is running the same setup beastX, Spektrum, Bec Pro, on one of his with no problems.

[MrMel]

Originally Posted by akamullen

I'm not running Telemetry, but I am running DX8 spektrum, no problems here. I think this is a Vbar issue, not spektrum.

It's rather that bigger Spektrum receivers have bigger built in capacitors so they can hide the problem longer, but sooner or later they run out too.
Measure voltage drop on the processor and you can see you playing with fire.

VBar and others has smaller so its seen there faster.