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New Futaba sv servos

Old 10-17-2013, 07:21 AM
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apereira
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Default New Futaba sv servos

I am writing this as I had a lot of trouble finding about the new servos, specially those replacing the BLS153 for my new byplane, even talking to Futaba or Towerhobbies Tech was not 100% clear but it helped, but the answers were always an assumption, so now I have them in hand and I can confirm what I tried to figure out.

In my opinion this are the best servos ever, talking about the technology that is, and the options they offer, I used JR radios and servos for over 24 years before going back to Futaba which was my first radio and can't be happier.

So, the sv, are:

High Voltage but they operate from 6V up to 7.4, why 7.4? no clue, Lipo bateries are 8.4 fully charged, and most regulators I've seen are 7.2 obviously. As not many people use 4.8V I think is the norm to go from 6V up. So almost anything can power this servos from 5 cells Nicd up.

Serial Bus.2, here is what I was trying to figure out, and the clear answer is, this is a smart servo, so, if at power up the servo senses SBus signals then it goes to SBus, but if it senses regular channel signal, then it goes to regular signal processing, and this happens only at power up, but how cool is that?, you can disconnect this servo from a Sbus and simply connect it to a regular channel and it will work just as a regular servo, so, anyone can try SBus, and if not convinced simply plug in to the corresponding channel and it is set, even at the field. This is the question I had as I am using SBus for the four ailerons, and regular connections for rudder, elev and throttle, so you can even mix the system any way you want. Note, the Tx must always be on first, or the servo might not work otherwise.

The servo has soft start which is very useful, and it has many programmable parameters, but the fact you can use this type of servos in any configuration possible of regular or HV and regular or SBus is what makes them so nice to me, and you do not need to program anything on them if you do not have a SBus radio or programmer, this servos you can plug in an FM Rx and it will be like a normal servo.

Again, I do not know if I was the only one asking this but just in case I share what I think it was the most important doubts I had.

Regars
Old 10-17-2013, 09:46 AM
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JAS
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I started using the 175sv on the rudders of my bipes before the worlds and didn't realize it had the soft start for a few weeks lol. I have since changed the Epic over to the 171sv's on ailerons and 175sv on the rudder. Next is to order up some 173sv's for bipe wings and stabs on both. I'm running them on my 14mz with a 6208 HV Rx and a 6v regulated lipo. I just replaced the previous servos and that was it.
Old 10-17-2013, 10:33 AM
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soft start???explain please what you use that for, I know what to use it for at a el.motor but a servo you want it to move fast! I have also started to look for some new servoes and its so many to chose from ...its a headache!!
Old 10-17-2013, 10:55 AM
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Hi,
On initial power up they centre slowly I believe.
Old 10-17-2013, 12:56 PM
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Dansy
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Originally Posted by serious power View Post
Hi,
On initial power up they centre slowly I believe.
That is correct....same as JR soft start
Old 10-17-2013, 03:25 PM
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apereira
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exactly on the soft start, the programming is to extensive to list.
Old 10-17-2013, 10:21 PM
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Has some one found some good ones ??I'm looking for some new servoes for a monoplane 2m, have looked at specs and speed and power is wery good at some off them but dont know what to try!
Old 10-18-2013, 04:02 AM
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apereira
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I am using 173sv which are the same as the BLS153 for aileron and elevators on the Accuracy Bipe and 175sv for the rudder 100 and 290oz respectively. I got most of the information from the Futaba page in Japan, that is the best information so far.

Check Jason's set up on monoplanes above.
Old 10-18-2013, 04:24 AM
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serious power
 
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Originally Posted by apereira View Post
I am using 173sv which are the same as the BLS153 for aileron and elevators on the Accuracy Bipe and 175sv for the rudder 100 and 290oz respectively. I got most of the information from the Futaba page in Japan, that is the best information so far.

Check Jason's set up on monoplanes above.
Hi,
That is almost 30Kg/cm torque on aileron !
Do you think that will be enough .

Brian
Old 10-18-2013, 05:20 AM
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apereira
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You are right!! do you think I should go with the 175 on the ailerons? I might not make weight.....

The mini servos of today are very powerful the 153 is an exceptional servo, will see on the 173...
Old 10-18-2013, 06:26 AM
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Honestly though I think 10Kg of torque is more than enough on aileron.

Brian
Old 10-18-2013, 07:04 AM
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I really think the 173 will be enough on ailrons even on a monoplane , gives you 7.6 kg on 7,4 V ...how is the gears on this ..thight? and the 171 on rudder 11,8 kg should be plenty even for F schedule on elevators i really dont find any need for some big kg I have flown with a gyro servo once didnt had any problems with that
Old 10-18-2013, 07:50 AM
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Hi Rune,
Yes absolutely.
It's all about weight (inertia and momentum) and flight loads.
I do not mean the 5Kg.
More like; if you have very heavy wings or very light wings, etc.
Even with the rudder - eg; at high alpha, blow-back is not as big an issue as we might perceive as the rudder is in the 'shadow' of the fuz,, .
The rudder and elevator moments are huge on F3A planes.
I suppose starting and stopping snaps is the main load criteria to consider and again weight distribution is the main consideration.

Brian
Old 10-18-2013, 07:55 AM
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I also think if you run a 2s dont know if you have to regulate it (?) then you have from 8.4 and down you will have even more power from the servoes.
Old 10-18-2013, 08:18 AM
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TimBle
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these servos run off packs with nominal voltage of
4.8V (4celll Nicad / Nimh)
6.0V (5cell NiCad / Nimh)
6.6V LiFe
7.4 LiPO

these are not the voltage limits!

Soft start is a reduced servo power and speed at start up so the servo returns to centre slowly to protect the linkage. Very nice on a Large scale.
You can set the deadband,
set the neutral point i.e. the centre so that if you have servo arms that just won't centre on the spline you don't need to use sub trim to centre them. This has the advantag that the servo will still have the same degree of throw either side of centre whereas subtrim tends to shorten one direction of throw slightly.

Yes they are S.Bus 2 so they will work on any port of a S.bus 2 RX or a S.bus rx and work on conventional Rx as well.
Explore the S-link software to see more features.

Love em, BLS 172 and 3172SV
Old 10-18-2013, 09:35 AM
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Brian,

Is not the torque, is the servo size, the wings are made for those servos.

Rune,

Unregulated LiPo voltage will cause the response to vary depending on Battery voltage, a 7.2V Reg will keep all servos as the same performance.

Regards guys
Old 10-18-2013, 01:00 PM
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I am also using a 171 sv on rudder on a monoplane with no problems in the F sequence. My brother has the same exact plane and setup except with the 175 sv on rudder and we cant feel a difference between the two in flight. Plus the 171 is only 48 grams or so.

Caglia
Old 10-18-2013, 02:34 PM
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I am also using a 171 sv on rudder on a monoplane with no problems in the F sequence. My brother has the same exact plane and setup except with the 175 sv on rudder and we cant feel a difference between the two in flight. Plus the 171 is only 48 grams or so.

Caglia
I think your into some there , we dont need the servo power that they need (do they) on the imac machines ..we dont need 250kg servo power on throtel..ehh just a joke...but what we need is precise fast and sloop free servoes, its not a bad thing if they not weigh over 50 gr each

Last edited by RuneG; 10-18-2013 at 02:38 PM.
Old 10-19-2013, 06:44 AM
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Are they available yet, cause they are not posted on FutabaUSA's site yet and Tower doesn't have them? I have a new airframe on the way and would consider using these over the BLS (which I haven't used yet). I'm still using 9650's and 9351's and 9156's. However, for the new airframe I am planning on using the BLS or the SAVOX BLS servos.

Bill
Old 10-19-2013, 07:53 AM
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Yes, Bill, Tower has them, they are just not listed yet.
Go to http://www.rc.futaba.co.jp they list them all , then just search the model you want in Tower.

Regards
Old 10-19-2013, 07:56 AM
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Here is the Tower link

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LNDNSX

Omni has them as well

http://www3.omnimodels.com/cgi-bin/w...I=FUTM0137&P=7
Old 10-19-2013, 08:22 AM
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Kool,....

Thanks guys. I searched Tower yesterday and it only listed one SV servo. I will check the links, much appreciated.

Bill
Old 10-19-2013, 10:01 AM
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Quick question if I may,

These servos are listed as requiring a 7.4 volt supply, which is essentially a 2s Lipo. Fully charged lipo RX packs are at 8.4V, but they drop down quickly when you start pulling a lot of current out of them, so a freshly charged lipo shouldn't be a problem.

However, suppose that I want to use the BEC on my new Mezon controller to keep my RX lipo pack charged at 8.4V, and also supply redundant power to my receiver at 8.4V. Would this be a problem for these new HV SV servos?

I know that I could regulate my BEC down to 7.4V, but then my RX lipo pack wouldn't be kept fully charged, so there is potential benefit in setting the BEC at the highest voltage.

Brenner ...
Old 10-19-2013, 10:13 AM
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Brenner,
From Futaba,

Notes from the Tech Department[TABLE]
[TR]
[TD]

This is the Futaba BLS174HV S-Bus Programmable High-Torque/High Speed Servo.FEATURES: Ideal for airplane aileronsHigh voltage, may be used with 2S LiPo packsDual ball bearingsWater sealedOne year limited warranty through Hobby Services beginning at date ofpurchase


Brian
[/TD]
[/TR]
[/TABLE]
Old 10-19-2013, 11:11 AM
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apereira
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On the Japanese page it says, the servos are to be used directly to a 2S Lipo, so no problems there with no regulator. The 7.4V, what I found, is that it is the voltage at which the Torque is measured for specs, not the maximum voltage the servo can take. You say something that answer itself, no battery has 8.4V once it is conected(well sort of what you said), my opinion only is, the receiver temperature will be thing to consider. I am personally going to use an Emcotec dual Batt SW with regulated voltage to 7.2V, but I already wrote them to ask for a higher voltage version if possible, and, at the same time, realized that it might not me feasable, as they (Emcoted and PowerBox) use linear regulators, so the output voltage should not be higher than the battery nominal voltage as the do not increase voltage during regulation.

Regards

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