[NSRCA-discussion] Futaba S9155 Hi Torque servos

Tue Jul 11 06:43:20 AKDT 2006

Thanks Jim / Chad,

You have given me something to think about.

Peter

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Jim Woodward
Sent: Wednesday, 12 July 2006 12:35 AM
To: 'NSRCA Mailing List'
Subject: Re: [NSRCA-discussion] Futaba S9155 Hi Torque servos

Peter,

I sold my model to Billy Meadows.  I know Jason flew it and I think liked
the way it flew & snapped.  I thought that for the Impact, you needed to use
about 20 degrees of aileron or more to get snaps to look good.  My first
setup with the model allowed for about 15 degrees and that was not enough.
I then changed it to get in the 20 degree range. Some medium rudder and
medium amount of elevator come to mind as being OK to use.  My Impact had
different timing than the Aggressor.  It seemed to want to overrotate, where
as my Aggressor has the 'stop on a dime' feel to the snaps.  

I would try an experimental setup where you have at least 20 deg of aileron
on tap for snap trials, with about 25-30 deg rudder and 10 deg elevator
(just throwing out numbers).  I used the stock phenolic rudder control horn
that came with the kit. Have an extra rudder servo horn around were you can
move in the cables to maybe 1/2" or 5/8" at most out from the center of the
servo horn.  Use high ATVs such that the "most" rudder travel you get is
like 30-35 degrees of throw.  This should be a huge change and deliver more
power to the surface.  If you like the direction of the change, then
fine-tune the throw up so you have enough for stall turns/spins.  My bet is
that you will really like the way the rudder response improves overall
flight, but maybe think you need more for stall turns.  With more torque
going to the surface, you may need to increase expo.

Make a big enough change so that you will definitely see/feel it.  If you
think you have problems to work out, don't try for a small change - go for a
big change and see if that is what you need.

Jim W.

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Peter Pennisi
Sent: Tuesday, July 11, 2006 10:09 AM
To: 'NSRCA Mailing List'
Subject: Re: [NSRCA-discussion] Futaba S9155 Hi Torque servos

Jim,

Thanks for the detail. You have identified a number of valid points in your
email which I need to investigate further on my current model.

I must admit that I have had a struggle trying to get comfortable with the
rudder on the Impact. My problem is that I cannot seem to get a consistent
feel through my control system especially through the 8 pointer and the
reverse knife edge. Some days I pull of some blinders and most other days I
swear I will take up old-timers. I have tried all amounts of expo and have
settled on -60% for most flight modes. My cables are fairly tight so that
might be worth a try. My control setups are such that the cables are exactly
parallel between servo horn and rudder horn. The distance between them is
55mm to ensure my mechanical setup is symmetrical.

I know you were flying an Impact for a while. How did you find snapping the
model to the left? Snapping to the right is quite good, snapping to the left
is a struggle - never had this problem with my previous model so I don't
think it is me.  Any suggestions! 

Thanks,

Peter 

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Jim Woodward
Sent: Tuesday, 11 July 2006 11:33 PM
To: 'NSRCA Mailing List'
Subject: Re: [NSRCA-discussion] Futaba S9155 Hi Torque servos

The 9152 is my favorite rudder servo, but I was concerned on weight so I
went with the 9155. Flying the two Aggressors back to back, I decided the
fault of the 9152 setup was too tight rudder cables which made the rudder
very sensitive around neutral regardless of how much expo was used (if I
didn't fly for a while, the rudder inputs would really show).  Flying the
9155, the rudder was too soft - however, loved the seemless rudder inputs
around neutral it had over the 9152.  To get them to match, I moved the 9155
setup control horns out to the 7/8" mark, and used the wheel like I
mentioned previously.  On the 9152 setup, I moved the control horns in to
about 5/8" from the control surface and loosened the cables 1 turn each side
- still using the large horn the 9152 servo comes with.  The 9152 plane
flies with a little less actual throw than the 9155 setup.  With the 9155,
left rudder is full-swing (35 deg) for all flight barring snaps, and Right
rudder is about 30 deg for normal flight, 35 spin/stall turn. (snaps 30 deg
both sides).  Now, I can fly both planes back to back and it is best of both
worlds - plenty of torque, nice suppleness.  In retrospect, you don't need
everything the 9152 offers - but you need to get EVERYTHIING out of the 9155
setup to get the power needed for P/F07.  I think it's a valid comparison as
both planes are identical aerodynamically.

Thanks,
Jim W.

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of ppennisi
Sent: Tuesday, July 11, 2006 9:10 AM
To: 'NSRCA Mailing List'
Subject: Re: [NSRCA-discussion] Futaba S9155 Hi Torque servos

Hi Jim,

Thanks for the response (Chad as well). I hadn't forgotten about the
response you sent some time ago about the 9152 servo. The size of the unit
put me of a little due to the way I have the current servo mounted. 

The 9155 is more or less the same dimensions as the S9151 which I would like
to replace. 

The size of the rudder on the Impact I am currently flying is quite large
and I do believe I get a bit of blow back flying in wind as speed tends to
be higher. I always feel I am running out of rudder in some of the roller
manoeuvrers.

Thanks again,

Peter.

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Jim Woodward
Sent: Tuesday, 11 July 2006 10:59 PM
To: 'NSRCA Mailing List'
Subject: Re: [NSRCA-discussion] Futaba S9155 Hi Torque servos

Hi Peter,

I'm using this same servo on rudder, 6.0V regulator, 2400 Li-ion - zero
problems.  I use a long control horn on the rudder (cable attach point is
7/8" from surface of rudder on each side), and a Futaba large servo wheel
with the holes drilled about 1/8" inside the standard wheel holes.  With
this setup, the rolling loop/integration stuff is easy and nice.  Total
rudder travel on high rate is 35 degrees, ATV/AFR is high too.  Rudder is
very smooth and supple, but with plenty of power too.  I use -90% expo on
the 9WCII.

Thanks,
Jim W.

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of ppennisi
Sent: Tuesday, July 11, 2006 8:34 AM
To: 'NSRCA Mailing List'
Subject: [NSRCA-discussion] Futaba S9155 Hi Torque servos

I am thinking of purchasing some of the new Futaba S9155 servos for rudder
use on F3A models. Information taken from Tower's website state that it
should only be used in 6 volt NiCad powered systems.

Does anyone see any problems using this servo in a regulated 5.6 volt
environment using a Duralite regulator and 2 cell 2350 mah Lithium Ion
supply.  

Here is the information taken from their site

This is the Futaba S9155 Digital High Torque Metal Gear Servo.
                           with J Connector.
                      Designed for aircraft applications
            This servo requires high-current draw from batteries.
                         Use 6V NiCd batteries only.

FEATURES: Coreless motor, see COMMENTS
          Digitally enhanced microprocessors cut in half the response time
            from transmitter input to servo reaction
          Center of case is metal
          One year warranty

INCLUDES: One S9155 Digital High Torque Servo with J Connector
          Round servo wheel 1.8" (45mm) diameter
          Four point servo wheel 1.5" (38.5mm) diameter
          Six point servo wheel 1.2" (32mm) diameter
          Four rubber grommets
          Four metal eyelets
          Four 2x11mm mounting screws
          3x8mm horn set screw

SPECS:    Speed:        0.13 sec/60 deg @ 6.0V
          Torque:       192 oz-in @ 6.0V
          Length:       1.57"  (40mm)
          Width:        0.79"  (20mm)
          Height:       1.44"  (36mm)
          Weight:       2.15oz (61g)
          Power Supply: 6V required

COMMENTS: S9155 Digital Servo Precautions,
           -It is best to avoid long leads and Y-harnesses especially with
            standard grade wires. If problems are encountered, consider
using
            heavy duty wire such as Futaba's Heavy Duty Series or Hobbico's
            Pro Series, minimizing lead lengths, and/or removing
Y-harnesses.
           -Current Drain: This digital servo is specially designed for
high-
            torque or high-speed, therefore very high current drain is
normal
            at startup. For ultimate performance when using this servo
please
            review the following points.
              1. Radio systems with the Battery Fail Safe function have a
                 higher cut-off voltage setting which will cause shorter
                 operation time.
              2. When installing the servo, please check pushrod linkage to
                 make sure there is no binding in order to prevent excessive
                 power consumption and decrease the life of the motor and
                 battery.

         A note on Coreless motors: conventional servo motors have a steel
           core armature wrapped with wire that spins inside the magnets. In
           a Coreless design, the armature uses a thin wire mesh that forms
a
           cup that spins around the outside of the magnet eliminating the
           heavy steel core. This design results in smoother operation and
           faster response time.

         This digital servo cannot be used with any AM transmitters
including
           the following Futaba models as the servo neutral signal is:
1310us.
           CONQUEST AM, FG Series (T4FG, T5FGK,T6FG, T6FGK, T7FGK), New
Terra-
           top, T3EGX, T3PGE, T2NL, T2LGX, T2FR, T2PK series.

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