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Aug 05, 2016, 12:00 PM
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Best servos for RES


The new F3B RES class seems to be having a lot of us contemplating the limits of a 2m glider. In the old days, we built a gentle lady as light as possible with the smallest servos we find. Even then a 14 ounce/inch servo was all we get. With these new RES gliders, and the latest micro servos one has to wonder how much torque you really need. We also have the advantage of updated pushrod technology. So, what are the best arose to use in this new RES class?
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Aug 05, 2016, 12:19 PM
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I think if you have a single spoiler a 5G servo is fine. If you have split servos two 3G servos are fine. For the rudder and elevator you can use 5-9 gram servos. I like X08s for almost everything but you could use something smaller.

In my XRES I used pushrods but you could easily use pull springs if you are crazy about weight.
Aug 05, 2016, 01:49 PM
LJH
LJH
Moths do not fly inverted
LJH's Avatar
For my RESoholic I believe I am going to go with the S3114's on the tail (have to measure the servo mount) and the Power HD DSP-33's on the spoilers. I may a torsion bar set up for the first time on this plane.

Cheers,
Jim
Aug 05, 2016, 03:39 PM
supreme being of leisure
ZAGNUT's Avatar
i have a bunch of the S3110 micros which i believe are the older 4.8v only version of the 3114. dead nuts reliable even after numerous crashes. after first few flights the gears do develop a bit of slop but probably no worse than any other micro.

also use a bunch of the powerHD DSM44 that are digital with metal gears. same torque as the futabas but lighter and faster. also reliable but NOISY!
Aug 06, 2016, 01:31 AM
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slowmatch's Avatar
Emax ES08A II's for me, they are ridiculously priced and seem good quality for the money. They are recommended for the Slite by Seta-tech. They are 8g but I also have some metal gear ones at about 12g.

Spoilers will be 4.5g ES9051 for a single, or I may try two of the little 2.5g ES9251's for twin spoilers.
Aug 06, 2016, 01:46 AM
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"...updated pushrod technology..."
Aug 06, 2016, 04:16 PM
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Carbon fiber?
Aug 06, 2016, 04:21 PM
supreme being of leisure
ZAGNUT's Avatar
carbon fiber, pull-spring, proper geometry....a far cry from the old nyrods bent to suit that needed a full size servo just to overcome the drag.
Aug 07, 2016, 08:23 PM
Registered User
I will share what I've learned in building a fleet of 2-meter RES birds.

I have used Hitec HS-65s almost exclusively for rudder/elevator for this reason only: I had some, and they fit the servo tray exactly.

For the Slites, I also used HS-65s, but had to do some shimming because the fuselage isn't all that deep. For my own Slite, I use MKS6100s. Again, they fit, and I had some (which translates into: NO COST).

Other servos that will do the rudder/elevator job:
Futaba S3114 - cheap, capable, never had one fail in a DLG ever.
Dymond D47 - cute as a bug, and totally capable in the "P" version (avoid the "S" version)
- Order from the dealer, and get eleven for the price of ten
= Which is good, because often, one out of ten is dead in the box. But I've never had one fail in flight. Ever.
MKS6100 - expensive, they will jack your car if needed. And, suck your battery dry.
Dymond D60 - great servos, I use them in DLGs for ailerons all the time .
- Order from the dealer, and get eleven for the price of ten.
- No, I've never had a bad one. Ever.
Hyperion 09s - great, but perhaps no longer available.
KST08 - pretty good, in the V3 version. Avoid older versions altogether.
JR-188HV - I've had good fortune with these in DLGs. But, use 2S power.
JR DS285 - I've got one probably 15 years old, as reliable as a pet rock. But, $60?

Spoiler servos:
Dymond D47s - total overkill, no matter the spoiler size.
Blue Bird BMS-303 - tiny, but it will move a spoiler.
Whatever Josef supplies with the PuRES or Slite (I have no idea where he gets them, I cannot get them in the US)
DSM-44 - advertised as a D47 surrogate, it isn't. But it should move a spoiler.

I will be installing D47s in the spoilers of the X-RES on the boards now - but ONLY because I have them (translation: they fit, and they are already paid for).

For the next build (RESoholic? or ANDREaS?) I intend to use a pair of Futaba S3114s in one, and a pair of D47s in the other. These ships have gentle handling and dynamics, and servos are one way to save weight, even in the nose. Unless, of course, I don't have any on hand, in which case to next pair of HS-65s in my spares box will go in, instead. Because, after all, they (1) fit; and they (2) will be already paid for.

Finally, here is my overall criteria for servo selection:
1.: Do they advertise at least 20 ounce-inches of torque?
2.: Do they fit?
3.: Can I afford them (my personal limit is $40, sometimes, but not at others).

I am sure there are many, many servos out there that meet these criteria, even if I have not listed them.

Yours, Greg
Last edited by glidermang; Aug 07, 2016 at 08:32 PM.
Aug 08, 2016, 12:27 PM
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craigrrr's Avatar
Servo choice is a lot about your investment in your RES.
I build almost all of my planes, so I don't want to gamble much.
And, if you buy already assembled high cost planes, reliable servos are also a good idea.

Flight time is also a factor. I have over 600 hours on my favorite RES, so reliablity is important.

But, on the other hand, I am a cheapskate. I suspect that JR servos are the highest quality; but they are expensive and I only own one (rudder servo in my favorite RES).

I prefer using digital servos everywhere. They have a higher holding torque than dynamic torque. For example Hyperion says its digital servos have a holding torque that is twice its dynamic torque.
This would be especially advantageous for flaps.

In a RES the rudder servo is critical and the the elevator servo is also very important.

In my many years of RC flying, I have only had two servo failures. Unfortunately they were both rudder servos on RES planes. These two servos were both from the same company, a respected name brand, but low end analog servos.

When a rudder servo fails it is devastating. One instance resulted in a serious crash of my favorite RES. The other instance I was able to fly the airplane home because it was upwind and I was able to fly it intermittently upside down to do 180 degree direction changes.

So, at the moment, I prefer Hyperion digitals for rudder and elevator and cheap Hitec HS-55 for spoilers.

For most big 3 meter planes I use Hyperion DS13-TMB for rudder and elevator.
But I plan on using DS09-AMD for a lighter 3 meter plane (Introduction F5J) that I just ordered.

Craig
Aug 10, 2016, 05:29 AM
Sarven Bedikoglu
sarvenn's Avatar
I use Hitec HS-5055MG for both rudder and elevator.
I prefer HS-55 for spoiler.
I also tried HS-5065MG for both rudder and elevator as well and loved them.
Comparig 5055 and 5065, 5055 is a little bit slower and rarely you may want to have faster response from your servo (spot landing elevator push, fast zooms, gusty wind conditions while landing etc.)
I always try to choose more robust gears like metal or carbonite (like HS-65HB) not all plastic gears.
My friend Philip (Kolb) also had suggested JR DS285.
Aug 10, 2016, 08:07 AM
Flying = Falling (Slowly)
dharban's Avatar
As I have posted elsewhere I am experimenting with a lightweight motor/prop/spinner/esc combination that weighs 45 gms for a powered variant of these F3-RES planes. It will run on a 250 2S Lipo pack. (My intent is to have a conventional fuselage and an epower fuselage.

I have also been experimenting with the Taranis system. I recently purchased a couple of Frsky C2110 servos and the Frsky X4S receiver. The servos have metal cases and gears and weigh 9 gms. They are SBUS systems which will simplify and reduce wiring weight and they will run on 7.4 volts, allowing direct LiPo usage. The servos are supposed to be good for 22 oz-in at 7.4 volts.

My plan is to install the radio in the wing (I had an eSupra where this proved very satisfactory) to simplify installation and wiring.

I don't know if this will be any good or not, but we will see.

Happy Landings.

Don

BTW: The servos are 26 dollars apiece as is the receiver.
Aug 10, 2016, 08:14 AM
Pro Bro #829
steener's Avatar
Id like to hear your thoughts on these after you have time to play with them. I was contemplating using them in my Xres but couldnt find any feedback.
Aug 10, 2016, 09:23 AM
Registered User
Dead ringers for KST08s. I am interested also. I haven't seen them before, but they are the right size and spec for a DLG. Please let us know how they go along.

I use Taranis also.

Yours, Greg
Aug 12, 2016, 11:55 AM
I just want to go fly!
walter3rd's Avatar
I usually am kinda cheap and purchase servos that are name brand but still run around 12-15 dollars s pop. So far so good. I agree the rudder servo is so important.


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