KST 215 at 7.4V- What about the Tail Servo?

[dwdw910]

For people running the KST servos at 7.4V.... what did you do for the tail servo?

Will the KST DS 515 fit the rudder mount location on the TREX 450. I cant find any information if its a mini servo or not.

Any help on how you got the cyclics at 7.4V and what you did with the tail only able to handle 6.0V


Thanks

[boykster]

The KST 515 will fit just fine, it's what I use. The HV version can handle up to 8.4v

http://tarot-rc-heli.com/KST-SERVOS-515MG

[paedbo]

I tied all the cyclic servos to the external bec. I then ran my FBL controller and tail servo from the esc internal bec.

If your good you can pull the pins on the servo connectors Then just leave 1 pin on the signal wire and connect that to your receiver/fbl. The other two wires you run to the external bec. The tail you just leave alone and plug it into the fbl/receiver.

[RedOctobyr]

The 515 is a mini servo, it would fit either the Sport or Pro. As was said, the version here can handle 8.4V, I don't know if there are others:

http://www.alofthobbies.com/ds515mg.html

If you wanted to save about $20 and 15g, you could just run another 215MG on the tail. I'm using one at 6V, I think it works great. It's a tiny bit faster than the 515MG at 6V, though less torque, of course. But it's already about the top-end of torque for micro servos, and more than many 450's have on their tail. The extra torque of the 515 might not really be required? It certainly can't hurt, of course

You can use step-down diodes to lower the voltage for the tail, if required. Apparently different types of diodes have different voltage drops. I've heard 0.9V is a fairly-common drop, IIRC. I bought some recently that claim 1.6V (I needed to get from 6V, to anything under 5V). I believe you can multiples in series if required.

[dwdw910]

Good info guys... thanks..

I assume everyone here would agree that KST servos are worth the time and investment?

Thanks for the help.

[boykster]

I've had nothing but good experience with my kst servos. Have the 215s as cyclic and 515 on tail now. I've also had good luck with the turnigy tgy306 on cyclic (clone of 215) and just picked up a tgy616 which is a 515 clone for tail on a new build. Haven't flown with it yet - that new build is waiting for a couple of parts

[RedOctobyr]

I put a 215MG on my tail a year ago. Has 450+ flights on it, at 6V, it's performed great. It started twitching/jittering while on the ground a few weeks ago. It was basically an isolated incident, but I'm in the process of getting it replaced. I don't want it failing or jerking around in the air.

After buying that 1, last summer I put 3 on my cyclics. Those had some issues. Sometimes wouldn't initialize (1 or 2 might act unplugged until I cycled power), and I got a few random big jerks in the air, then a few big twitches/swings on the ground. Based on some info that came out after I returned them, it's possible they were suffering from a lack of insulation in the cases, allowing a board to intermittently short against the aluminum case. I don't know. Aloft Hobbies is an excellent vendor, I will say without reserve.

I went to MKS on my cyclic, didn't want to risk a crash. Kept the good 215MG on my tail to see how it did. The recent jittering might have been a fluke, but I feel better replacing it. Given the # of flights on it, I can't complain.

This isn't mean to knock them, merely to share experience. Many others have had only good luck. I bought all mine right after they were released, perhaps they were going through some startup issues.

I wouldn't steer people away from them. And I'd be more comfortable buying the KST from Aloft, than I would buying the Turnigy from HK. If you have a problem, HK isn't the greatest, but Aloft has been excellent.

[dwdw910]

I see... Was your KST servo the open case design?

There is some talk going around that KST has now insulated the board and that the case is now sealed versus having that opening in it.

I think I will email the vendor first to make sure that I'm getting the sealed case 215MG.

I'll be hoping it'll be the newest version.

Thanks for the input- I'll do a thread about the KST 215 on the cyclic and KST 515 on the tail- All at 7.4V.

I'm really hoping to get a servo that performs well without a painful price.

The Hitec 5065MG are good... but they are pretty slow for hard 3D.

The DS 415 are a little better... but they have a ton of slop that I can feel in the air.

DS 95 are the bomb... but too pricey for me.

The DS 92+ are not supposed to work with my CC BEC

So hopefully the KST will be just right :-)

[RedOctobyr]

I got a replacement 215MG last week (they'd just come off backorder, so I know it was a very recent shipment from the supplier, if not recent build). It did have a sealed case, which is good (I just put tape over the openings in my others). But it did not have insulation on the board, unfortunately. I added some electrical tape and reassembled, just took a few minutes.

I did put it on a servo tester and let it cycle for maybe 20 minutes, just to run it for a bit before relying on it. No issues.

Performance is very good. I compared them (visually, on the bench, no load) with the DS92A+ I ended up going to on my cyclics, I couldn't see a speed difference. I couldn't justify DS95 either, but the 92A+ were my next choice, after having some issues with the KSTs last year.

Despite the MKS being twice the price, the gears in the KSTs I bought last year were smoother than the MKS (the new one is also very good)

[dwdw910]

Ok cool.. I will be sure to check then for insulation. :-)

[boykster]

Ditto on the insulation check - one of my TGY clones would occasionally jitter on the bench or mid-flight - popped it open and it wasn't insulated. I check all my servos now, forgot to mention that in my earlier posts. Post insulation, I've had ZERO issues with either KST or TGY clones

[dwdw910]

Originally Posted by boykster

Ditto on the insulation check - one of my TGY clones would occasionally jitter on the bench or mid-flight - popped it open and it wasn't insulated. I check all my servos now, forgot to mention that in my earlier posts. Post insulation, I've had ZERO issues with either KST or TGY clones

Good to hear... I'm going to give them a try :-)

I'm pretty impressed with their stats at 7.4V... Hoping that I can insulate them and make them last well :-)

Thanks again for the input.

[Trexwilly]

The DS215s stats even at 6V are very impressive, just an option, but you don't "need" to run them a 7.4. If I was going to use the DS215, or the TGY S306G on a HV setup, then DS515 would be a good option. At least on paper it's stats blow away most of the "dedicated rudder servos" .

[paedbo]

At5.2v 215mg was the only servo I had that could handle my clone 250's tail because of slop. I was sold on it after that. 250 tails are very tempermental!

[dwdw910]

That's interesting about the 250... I heard everyone wanting a great tail servo.. So that's good to hear.

I'm really interested to run the servos at 7.4V-- not just for the torque and speed --

But as an experiment with the 3GX. I've noticed it does better and better with more power and it can handle much more than that.

I like to turn up the flight controls, acceleration and dampening... and love high roll rates.

With 5065MG servos- there's no difference between the roll rates at 70 or 100- the servos are too slow to go any faster.

[Trexwilly]

Well the DS215 will be a huge improvement to the HS5065, they are so much more durable. And the speed and torque too!

I had a love hate with the HS5065, they performed good, but crashed terrible.

[dwdw910]

Cool. I really hope so.

Yea the 5065 is really tight and makes the DFC shine. Super precise and stable.

But it really is slow. .11 is being really generous it seems.

The KST at 7.4 are .05 lol... That's fast. I've seen demo videos of them online too and they sound great and do indeed wink wink much faster than my 5065.

[Trexwilly]

I am super happy with the 115, I have a set of the 215s in my cart, but need a heli to put them on... 450L

[lcc014]

Originally Posted by boykster

Ditto on the insulation check - one of my TGY clones would occasionally jitter on the bench or mid-flight - popped it open and it wasn't insulated. I check all my servos now, forgot to mention that in my earlier posts. Post insulation, I've had ZERO issues with either KST or TGY clones

A question about KST 215 and TGY clone servo, are they having the same frequency specification: 1520us/333Hz ? I am thinking of replacing my KST215 MG with TGY in my 250 because I keep getting minor tail wag when doing right aileron. I checked the mechanical part of tail assembly, pitch slider, bearing, belt tension, tail shaft (new), tail grip bearings (fairly new) all good. The only thing left is the servo itself.

Thanks.

[boykster]

Originally Posted by lcc014

A question about KST 215 and TGY clone servo, are they having the same frequency specification: 1520us/333Hz ?

Yes - I run my TGY-306 servos exactly the same as the KST 215's - 1520us/333Hz