Tail servo on UNREGULATED LiFE?

[MeatRocket]

Who runs their tail servo on UNREGULATED LiFE @ 6.6v? I'd be interested in knowing what type of servo as well.

This question comes up because my DS620 tail servo burned up & I'm trying to figure out if it may have been due to over-voltage, or if it was just a dud. I've read some people on here are running it just fine. I've read others have used a step-down regulator with their tail servos.

[Discount_Bob]

I don't know about the 620, but I tried a 650 on straight life and it wouldn't hold after the first flight. I tossed on a step down, and I haven't had the issue anymore, so I assumed that was the problem.

However, I've read of lots of guys running straight 2s lips and having no issues. I think there are other factors in luck, setup, etc. that can affect the outcome.

[nynextel88]

About 30 flights or so and have a LiFe pack going straight into AR7200BX, align DS610 servos, DS650 on tail. No step-downs.

[JRAY]

I ran an unregulated LiFe on my 700 with a DS650, with no issue.

[Discount_Bob]

I think mine was a setup issue. I had the ball pretty far in on the servo horn to get the resolution I wanted in the vbar, so I know the poor servo was really working overtime.

[Hoosiermo1]

I run unregulated life on my 550 with ds620. Also on my 700e with a ds650. Lots of ppl on here do the same.
I have considered putting a couple diodes in line to drop it a hair, but it's not necessary.
They are designed for 6v (6v rx pack). A 6v nimh rx pack fully charged is 7.2. I see no harm here.

[mtuccio]

I run all my setups with DS650's unregulated. Never had an issue doing this to date.

[Phaedrus]

I have two 550s both with DS650 on the tail. Both running unregulated 2S LiFePO4 packs. Absolutely zero issues in over 100 flights on both.

[gehrbox]

Been running mine with ds620 straight life w/o issues

[MeatRocket]

I put another DS620 on it and (for my own paranoia) put an Align 2-way voltage step-down on it. It flies fine.

I did notice that it has an ever so slight clockwise rotation. Normally I would fix it with a little trim, but we're not supposed to do that with FBL. Could it be that I need to set tail blade endpoints again? I figured since it was the same model I wouldn't have to, but maybe I do? Could that be what's causing the drift?

[gehrbox]

Originally Posted by MeatRocket

I put another DS620 on it and (for my own paranoia) put an Align 2-way voltage step-down on it. It flies fine.

I did notice that it has an ever so slight clockwise rotation. Normally I would fix it with a little trim, but we're not supposed to do that with FBL. Could it be that I need to set tail blade endpoints again? I figured since it was the same model I wouldn't have to, but maybe I do? Could that be what's causing the drift?

Verify no subtrim?

What FBL controller are you using and what kind of tape or pad is it mounted to? We're is it mounted?

[MeatRocket]

Originally Posted by gehrbox

Verify no subtrim?

What FBL controller are you using and what kind of tape or pad is it mounted to? We're is it mounted?

I did have 4L subtrim. I might try increasing it a little. I'm using the 3GX on a single Futaba servo pad. Mounted on bottom rear bracket.

[gehrbox]

Originally Posted by MeatRocket

I did have 4L subtrim. I might try increasing it a little. I'm using the 3GX on a single Futaba servo pad. Mounted on bottom rear bracket.

You cannot use ANY trim or subtrim on a gyro controlled channel.

[MeatRocket]

Originally Posted by gehrbox

You cannot use ANY trim or subtrim on a gyro controlled channel.

I had subtrim on AIL Pitch & Elevator as well. I backed up my settings to SD card and then zeroed thos channels out. I'll test it tomorrow. If it's totally off, I'll go back to my saved settings.

[Hoosiermo1]

Most fbl controllers have a subtrim function built into setup on the controller itself. Is 3gx not the same? Hell, copter x and tarot have this function on zyx.

[gehrbox]

Originally Posted by MeatRocket

I had subtrim on AIL Pitch & Elevator as well. I backed up my settings to SD card and then zeroed thos channels out. I'll test it tomorrow. If it's totally off, I'll go back to my saved settings.

I did a little searching here on HF and found a reference (among several) that discusses subtrim on a 3gx to achieve 90 on the servos, but it specifies to only apply the subtrim while in DIR mode. If your subtrim was applied in DIR mode you are fine, but if you set it out of that mode it may be the cause of the issue. It's not something you apply to trim out flight, only used to achieve 90 on the servos during setup. You might want to check it out before your next flight. https://www.helifreak.com/showthread.php?t=415443

Here's another one saying the same thing https://www.helifreak.com/showthread.php?t=375834

I'm flying a beastx and subtrim on it is accomplished on the controller, not the transmitter. Looks like the 3gx is different, but still very specific about when it is acceptable to do it.

[koppterx]

you do not use subtrim when setting up tail on a 3gx. you rotate the arm to its optimum position and then adjust linkage to perfect geometry of the slider. a little error is not okay on cyclic because the servos interact. on the tail it doesn't matter.

the above applies pretty much to setting up any tail, it is not unique to 3gx. and as long as endpoints are set, sub trim offset isn't going to cause any ill effects.