Anyone tried KST DS245S servos?

[CBR240]

Anyone know these or have an opinion on how they would work for a TREX 250 collective servo?

I've been using KST DS113MG servos for TREX 250s collective servos for a while, and I am happy with them. At slightly less than $10 each, they seem a good deal for a decent collective servo, and at 12g are not too bad weight wise:
http://www.alofthobbies.com/kst-ds113mg-servo.html

But I just noticed these DS245S servos:

KST DS245S SERVO - 2.2KG (30.5 OZ IN), .09/SEC - ONLY 9 GRAMS!
http://www.alofthobbies.com/kst-ds245s.html
They are 23.5 mm wide, so seem like they would fit fine. Just narrower and not as tall.
Specs look pretty good:

Servo Type Digital
Gear Type Metal
Stall Torque 2.2Kg.cm@6V, 1.25Kg.cm@3.8V
Speed .09sec/60°@6V, .12sec/60°@3.8V
Voltage Rating 3.8V to 9V, Working Frequence: 1520us/333Hz, 900us-2100us, 7mm coreless motor
Dimensions 23.5 mm wide x 8 mm thick x 20 mm high
Weight 9 g / 0.31 oz

Are a bit expensive at $30.25 each. But at 9g, that's 3g less each than what I am currently using. Would be 9g off my collective, which I'd welcome. I really like the DS215MG for my 450 collective servos, so as you can see I am biased towards KST servos, and these DS245S look like possible mini 215s for my 250s.

Anyone tried these? Or see a reason not to try them for TREX 250 collective servos? The specs look pretty good for a 250 collective servo don't they? They are an airplane "wing" servo, but I don't see why they wouldn't work for a 250 collective servo.

[gimbleguy]

i've been using the Emax ES09MD on my 250, it's been going well. I enquired about those servos and the guy there didn't recommend them to be used on the trex 250. Apparently they don't fit well. It would of been nice to have them. I prefer metal casing, than plastic.

[CBR240]

Thanks for your input gimbleguy. The specs on those Emax ES09MD looks good, and at a good price. But they weigh a bit more than the 113s I am using now, and ... I want it all. A strong fast servo at light weight Maybe I can't have that?

DS245S - "Apparently they don't fit well", rats, I was really liking these. I may have to order a few and see what can be done. Worst case, they wind up being over kill servos for a foam fixed wing plane or something like that. $30 servos on a $3 plane Well, we'll find something.

[gimbleguy]

Originally Posted by CBR240

Thanks for your input gimbleguy. The specs on those Emax ES09MD looks good, and at a good price. But they weigh a bit more than the 113s I am using now, and ... I want it all. A strong fast servo at light weight Maybe I can't have that?

DS245S - "Apparently they don't fit well", rats, I was really liking these. I may have to order a few and see what can be done. Worst case, they wind up being over kill servos for a foam fixed wing plane or something like that. $30 servos on a $3 plane Well, we'll find something.

If you can test the ds245s, to see if they fit the 250 frame. That would be good.

[rob221]

I have used these kst servos they fit fine and seem to be nice and fast have only 3 flights on them so far will post again when I have a few more and let you know how they go

[CBR240]

rob221 - thanks for the information. And please do let us know how they work out for you after more flights.

I ordered some 245s just to see if I could get them to fit, so that's good news. I don't really need to swap out collective servos on either of my 250s right now, so might be a while before I actually try them, but I'll post back here when I do.

[gimbleguy]

Originally Posted by CBR240

rob221 - thanks for the information. And please do let us know how they work out for you after more flights.

I ordered some 245s just to see if I could get them to fit, so that's good news. I don't really need to swap out collective servos on either of my 250s right now, so might be a while before I actually try them, but I'll post back here when I do.

Please post some pics, when you install them on your 250. It would be interesting to see how the look on a 250.

[CBR240]

^^^ be glad to. Any excuse to post pictures of my Helicopters.

Rob221 is way ahead of me here. He might already have pictures of them installed.

[Griff1]

wonders will never cease, a 9gram servo that actually weighs 9grams, bit late now with Lynx releasing a new frame that takes 6 gram servos but better late than never.

I see these being ideal for an Oxy3, x2, or 300x though.

They look nice too.

[mutna]

Originally Posted by Griff1

wonders will never cease, a 9gram servo that actually weighs 9grams, bit late now with Lynx releasing a new frame that takes 6 gram servos but better late than never.

I see these being ideal for an Oxy3, x2, or 300x though.

They look nice too.

What new frame???? Have lynx released a new Trex 250 frame???

[Griff1]

Lynx are working on a frame at the moment, I don't yet know whether it'll just be new uppers sized for the new lynx 6 gram servos or a full frame. Servos are due any day now so the frame shouldn't be far behind.

[mutna]

Awesome, many thanks.

[gimbleguy]

Originally Posted by Griff1

Lynx are working on a frame at the moment, I don't yet know whether it'll just be new uppers sized for the new lynx 6 gram servos or a full frame. Servos are due any day now so the frame shouldn't be far behind.

about time, we've been waiting for lynx to come up with some upgrades. Hopefully a metal tail pitch slider would also be in the works?

[Griff1]

Luca decided that with the pending release of the Ubrain and high spec sub micro servos that it was finally possible to "upgrade" a 250 and achieve some real benefits as apposed to just making it heavier still.

I'm not sure this is gonna open the flood gates on upgrades but we can hope.

Originally Posted by ininverno

Fornthe 250 we have news.. let me explain.. are preatty important.. long ago we start made upgrade design but heli already heavy become a stone. Than I stop all design x 250 cause I start to be preatty good to smell when a project is good or is not.. days pass.. we was focused on 180x and suddenly 2 important thinks uppen.. 1 MSH distribution definition and the new U Brain.. 2 metal gear super fast servo coming for 180x.. this 2 important factors before not availables help me to take a new and challange project direction.. made a new super light weight frame for t rex 250 .. belive or not will be ready soon.. once the servo and u brain available.. ttyl.. stay tuned

Luca Invernizzi
Lynx Heli Innovations
Oxy Heli

[CBR240]

^^^^ Interesting on the Linx frame and servos. I'm glad to see the 250 getting the attention. We (my son and I) really like them.

Back to the DS245S servos. They arrived Saturday, and I did install them last night. Not quite done so no test flight. Will probably have to wait till the weekend.

Did have to make a few mods to get them in. But so far they are looking good, and save me about 12g over my KST 113 servos. I'll write more when I have time.

The subject is the nearest heli (left). My TREX 250 DFC Pro.


DS245S installed, but not finished. I used the yellow back drop, to show how much "light" comes through now.

[CBR240]

A few more notes.

1) As you can see in the last picture above, the DS245S are not as "tall" as most, so when mounting the servos on the outside of the frame (front collective) the arms are in closer, which makes the linkages more upright. So I need to shorten the linkages a little. Also my DFC linkage on one side was bent in my last flight (mild tip over on emergency "landing", thought I lost a left front collective servo, which I did, but it's the FBL not the servo ).

2) The servo arm mount (spline?) is not as tall as most. With the balls mounted on the inside of the servo horn, they will touch the top of the servo case if screwed all the way down. I have them not screwed too tight for now, but think I need to cut down some small washers to go under there.

3) It did take a little filing of the frame to get the front collective servos in. They would drop right in, except for the servo wire.

4) The wires on these are shorter than any others I have tried. Right now I have them running outside the frame, which I find unacceptable. yea, it's true, so I'll have to add extensions (weight) or put on longer wires.

[gimbleguy]

Originally Posted by CBR240

A few more notes.

1) As you can see in the last picture above, the DS245S are not as "tall" as most, so when mounting the servos on the outside of the frame (front collective) the arms are in closer, which makes the linkages more upright. So I need to shorten the linkages a little. Also my DFC linkage on one side was bent in my last flight (mild tip over on emergency "landing", thought I lost a left front collective servo, which I did, but it's the FBL not the servo ).

2) The servo arm mount (spline?) is not as tall as most. With the balls mounted on the inside of the servo horn, they will touch the top of the servo case if screwed all the way down. I have them not screwed too tight for now, but think I need to cut down some small washers to go under there.

3) It did take a little filing of the frame to get the front collective servos in. They would drop right in, except for the servo wire.

4) The wires on these are shorter than any others I have tried. Right now I have them running outside the frame, which I find unacceptable. yea, it's true, so I'll have to add extensions (weight) or put on longer wires.

thank you for the pics, and the installation tips. So the guy was right I guess, it's not an easy install or fit.

[CBR240]

^^^^ yea, these aren't just "drop in". I'll see over time if they are worth the effort (and cost) to me. Which, BTW ...

I manged to get the install and configuration finished. But it was raining hard today, so I just hovered a pack on my screen porch. Seems solid, and the weight loss is apparent . Good so far, but I will not have a meaningful test until spare time, and clear weather happen to occur at the same time.
And don't be expecting an expert report from me, as I'm not a hard 3D guy, more of a "sport flyer" who does an occasional flip or loop.

[CBR240]

Had a chance to really fly the DS245S servos this weekend. They flew very good, but the heli was quite tail heavy. I had a DS215MG, which is a 20g servo, on the tail boom. Since I had some extra DS245S, I decided to try one of those on the tail. 20 g replaced with 9g.

Pictures:






I am very surprised, but the DS245S is going great on the tail. Overall, I am very pleased. It's lost over 20g of servo weight, and the 245S fly excellent so far (even on the tail). The drop in weight is very apparent, and I have to say it now flies better than any 250 I've had yet.

I'll see how they hold up to the next 50 or so flights and report back, but I LIKE THEM A LOT so far.

[myxiplx]

Aren't the Align servos about the same weight as these but a little faster? My DS410 servo spec looks very similar.