Embla down again

[mattks]

After getting a nice new canopy from one of my friends at my club and flying my embla successfully for 3 weeks this time round it is down again. Aileron servo burnt out again. So far this is the 3rd aileron servo gone. First 2 resulted in minor crashes costing me skids. This time as I was lifting of noticed it was not feeling right so shut it down. Went to check, aileron servo dead again.

All links/swash/head running smooth no binding

My setup is as follows
Stock motor
Futaba subs receiver
Futaba cgy750
Futaba 3156mg on pitch and cyclics
Forget the futaba tail servo I have
Kontronik koby 55 esc
Using Hyperion 3s 2600's

The bec delivering 5,5v on full battery and no load

Anything you guys can think off that I should check? Ty?

Below I a pic of my custom canopy




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[gratefulfrog]

Hi!

I have had similar problems with small Futaba servos on flybarless cyclic. Although my problems were with the tiny 3114 analog servos, I kept having burn outs and finally Futaba admitted that those servos were not suited for helis. The Futaba note for your servos says :

"Using any voltage higher than 6.0 volts or applying high load to the servo will shorten its life."

I think that means, "Don't use these servos on helis."

I would suggest upgrading to a heavier duty servo, like the Savox digital ones, or MKS, something with a metal case to better dissipate the heat. Change them all for higher end, tougher servos.

I now use: Savox SH-0261MG on flybarless cyclic and have no problems. I run my electric circuit at 6V via a separate BEC since all that digital stuff seems to draw quite a bit of current and my ESC's linear bec was getting really hot. I'm not sure about the need for a separate BEC with your Kontronic Koby. You might want to write to their support line and ask the question. Kontronic always replies quite quickly, but be sure to make your question clear :-)

Let us know what you go for!
Ciao,
Bob

[mattks]

Thanks for the reply Gratefullfrog. Will see what servos are readily available. Would not have expected this from Futaba. Will let you know want I end up with.

[gratefulfrog]

Originally Posted by mattks

Thanks for the reply Gratefullfrog. Will see what servos are readily available. Would not have expected this from Futaba. Will let you know want I end up with.

That's exactly what I thought: that Futaba was not such a "perfect" place either. In fact, I now believe that you have to be very careful when you select a servo, and really understand what you need and what the servo you select is intended for. So, in other words, I realized that Futaba were not "to blame" but that I simply didn't understand what I needed, and what all the requirements of going flybarless are.

Flybarless implies gyro controlled servos, meaning that the servos will be moving much much MUCH more than when you were commanding them by stick movement. They will be moving tiny amounts, so you need, or could need, digital resolution. Digital servos draw more current than analog ones. That plus the FBL controller, means more current demand on the BEC. So, it would be nice to increase the BEC voltage to reduce currrent demand, so it would be nice if the servos could run at 6V, and it would be nice if the BEC could be programmed to output 6V. So maybe we need a different ESC, or an esc + a separate BEC....

So please, don't forget the BEC question or you will have only solved half the problem. If the ESC's BEC overheats, then the thermal protection will turn the ESC off, meaning no more power to the rx and KaBoom goes the heli, and maybe someone gets hurt....

Don't feel bad, we're all learning, the hard (or expensive) way...
Ciao,
Bob

[7.62x51]

My setup includes MKS DS92 for the cyclic and MKS DS95i for the tail.
I'm using the Koby BEC at 6.0v having a pretty quick heli and never had any issue.

[mattks]

I am using the koby 55

First thing I changed as the stock Hirobo one went into thermal shutdown twice on the very first battery.

Will try find mks servos in south Africa. They seem to be the answer. Apparently the aus distributor does not use the 3156 any more but rather the mks servos.


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[gratefulfrog]

You could look at Savox they are relatively cheap and good performers. I have them on 3 of my helis, on my Logo 400SE I have 127MG's on cyclic and 1290MG on the tail. They are relatively cheap and can stand up to huge amounts of work.

The investment in a separate BEC is only around $20 and may save you a lot of crashing... I use the Castle Creations CC BEC which is programmable via Castle-link (as are their ESCs). I set it to 6V.

My feeling is that there is so much effort spent building a heli and so much money as well, that a little extra for absolute peace of mind is well worth it.

Hope this helps!
Ciao,
Bob

[mattks]

Thanks Bob

Will look at my options this weekend at my lhs and hopefully report back on Monday with good news.


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[gouki74]

Originally Posted by 7.62x51

My setup includes MKS DS92 for the cyclic and MKS DS95i for the tail.
I'm using the Koby BEC at 6.0v having a pretty quick heli and never had any issue.

are you using a flybarless embla? i saw the mks92 with a big label saying for flybarred heli only. is it ok to use it on a fbl heli?

[gouki74]

Originally Posted by mattks

After getting a nice new canopy from one of my friends at my club and flying my embla successfully for 3 weeks this time round it is down again. Aileron servo burnt out again. So far this is the 3rd aileron servo gone. First 2 resulted in minor crashes costing me skids. This time as I was lifting of noticed it was not feeling right so shut it down. Went to check, aileron servo dead again.

All links/swash/head running smooth no binding

My setup is as follows
Kontronik koby 55 esc
Using Hyperion 3s 2600's

The bec delivering 5,5v on full battery and no load





Sent from my iPad using Tapatalk HD

i did see the manual saying it can accomodate 2200-2500mah 3s lipos. what c rating are your hyperion lipos? how is the fit inside the canopy? thanks!

[7.62x51]

Originally Posted by gouki74

are you using a flybarless embla? i saw the mks92 with a big label saying for flybarred heli only. is it ok to use it on a fbl heli?

My EMBLA is flybarred.

MKS92 with a label only for fbl? where?

[gouki74]

at the back of the box mine says for flybar heli in bold letters. i'm planning on going fbl and now i'm having 2nd thoughts about it

[7.62x51]

I, honestly, didn't notice it.
But, they're digital, fast and have good torque; so i wonder where's the limit to using 'em in a fbl configuration..

[gouki74]

then fbl it is! i'm excited about it since it will be my first fbl set up

[gratefulfrog]

Originally Posted by 7.62x51

I, honestly, didn't notice it.
But, they're digital, fast and have good torque; so i wonder where's the limit to using 'em in a fbl configuration..

It may be a heat dissipation problem? Due they have metal gears and metal case? In FBL, all the servos are gyro commanded, so they are constantly moving, thus creating more heat and load on the electrical circuit.

The warning may only mean, "if these servos fail on a fbl heli, then don't try to sue us cause we warned you."

I wouldn't go with servos that are specifically marked "not for this"... a heli is too expensive and repairs take too much time to experiment and try to skimp and save...

That's my 2 euro-cents!
Ciao,
Bob

[toyturbo]

Look into getting MKS DS92A+ servos for cylcic, they are the flybarless version of the DS92's and have a bigger motor to better handle the demands of a fbl heli. Or you can splurge and get DS95's and call it a day!

[gouki74]

too late the mks ds92's arrived last week. the middle case looks to be metal, aluminum probably

[mattks]

Ok. Finally go my new servos. Mks ds95 for cyclics and mks ds95i for tail.

The Hyperion I am using are only 25c

I ave now upgraded to the kontronik motor for the embla.

Will let y'all know how it flies this coming weekend


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[Luigi_tuga]

That servo setup will make you love the Embla

[mattks]

You are 100% on the button there luigi. She flying really nicely now.

Very smooth servos.

My final setup now as follows:
Kontronik Kira 400-38 motor
Kontronik koby 55 esc
Futaba gy750
Mks ds95 cyclics/collective
Mks ds95i tail
Sab main blades

Flying really well now. Sport flying I am getting 7 minutes and putting back 1900mah back into my Hyperion 2600's


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