Review: FRSKY S8R Receiver

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Review: FRSKY S8R Receiver

Post by Rob Thomson » Tue Mar 07, 2017 9:31 am

The Frsky S8R receiver is a convenient fully integrated 8-channel frsky receiver with built in flight stabilisation. In this review I run through initial setup and in-flight performance of the receiver so you can see how well it performs out the box.
A big thanks to Bang Good for providing me the sample for reviewing.
This review is written by Rob Thomson from openrcforums.com

Unboxing
Whats in the box:
  • S8R Receiver
    Double Sided Mounting Tape
    2 Jumpers
    Manual
The receiver is packaged well and in the same way that all frsky receivers are packaged. You could easily mistake the receiver for an X8R as it looks identical in all bar the label on the front.

Product Specification & Overview
  • S8R (8CH/16CH receiver with built-in 3-axis gyro and 3-axis acceleration)
    46.47x26.78x14.12mm(L x W x H)
    Weight: 14g
    Number of Channels: 16CH (1-8ch from conventional channel output, 1-16ch from SBUS port)
    With RSSI PWM output on board: PWM voltage output (0~3.3V), 100HZ, 1500±500us
    Operating Voltage Range: 4.0~10V
    Operating Range: full range
    Gyroscope Measurement Range ±2000dps
    Accelerometer Measurement Range: ±4g
    Compability: Frsky Taranis X9D Plus/X9E/Horus X12S/XJT in D16 mode
frsky_s8r.jpg
The receiver is a compact 46.47x26.78x14.12mm with a weight of just 14g. Compared to my previous setups with a separate receiver & stabiliser this is small.

My plan is to install it in a Wingnetic flying wing – a good test model as its robust, quick and nimble.

Binding
I chose to bind the receiver up to my Frsky Horus. This process proved to be relatively painless.

My receiver did not have any indication of what firmware was installed so I simply went ahead and tried to bind in D16 mode. This did not work.

5 minutes later I had downloaded the latest firmware from:

http://www.frsky-rc.com/download/view.p ... rmware-S8R

and reflashed the firmware to the LBT mode used on my EU radio.
Success. The receiver bound as expected. Happy days.

Channel Order

Looking at the S8R manual it became apparent that it would be important to setup my channel orders correctly for the stabiliser function to work as expected. The receiver expects the channels mixers to be sent in the following order:
  • CH1: AILERON 1
    CH2: ELEVATOR
    CH3: THROTTLE
    CH4: RUDDER
    CH5: AILERON 2
    CH6: ELEVATOR 2
    CH7: AUX1
    CH8: AUX2
    CH9: GYRO GAIN
    CH10: 3 POS FLIGHT MODE
    CH11: 3 POS FLIGHT MODE
To keep thing simple to start with I simply enabled CH1 to CH4 on the mixer and tested server response. As expected everything just worked.

At this point, I jiggled the receiver to see if stabilisation was active. Nothing. No servo movement occurred so I concluded that with CH10 & CH11 outputting a signal round 1500ms that the stabiliser was turned off.

Flight Modes
The receiver supports a comprehensive range of flight modes that are set using two 3 position switches.
  • Stabilisation (CH10 SWITCH DOWN, CH11 SWITCH MID)
    Auto Level (CH10 SWITCH DOWN, CH11 SWITCH DOWN)
    Hover (CH10 SWITCH DOWN, CH11 SWITCH UP)
    Knife Edge (CH10 SWITCH UP, CH11 SWITCH MID)
    Off CH10 SWITCH MID)
Setup of my flight modes caused a little mid of head scratching. I feel the FrSky manual needs a little bit of attention in this regard. The manual essentially lists exactly the items shown above in a table, however everything is so abbreviated it can take a bit of thought to understand how it works. I would have thought that a pictorial diagram would have made a bit more sense.

As an curve ball – there is no easy way to tell what flight mode the receiver is in – so you need to check very carefully to make sure your setup is correct prior to flying.

Note: I will be suggesting to the opentx team that a lua widget or similar is created to automatically show the receivers flight mode on the horus/Taranis display.


Configuration of Stability functions
One of the great things about the S8R is that you can remotely configure it by using either the STK adapter on yoru PC, or a LUA script on the radio. So no need to try get at the stabiliser when its buried inside your model!

PC
I started by configuring the receiver using the STK adapter from my PC.
unnamed1.png
Unfortunately, I did not have much success with this. I found the PC interface worked – but to be very sluggish. I was not clear at any point if it was actually talking to the receiver at all! That being said – it is entirely possible that I had a driver issue. I did not spend any time trying to debug this and moved straight on to using the LUA scripts.

LUA
Included by default on the opentx sdcard is a folder called S6R. While not specifically for the S8R, it is identical and works to configure the receiver.
IMG_20170306_044142.jpg
This process proved to be painless. I executed the lua script and immediately was presented with a 3 step wizard to help me setup the receiver.
IMG_20170306_044133.jpg
As can be seen in the screen shots above this is very self-explanatory and should not cause any confusion to a seasoned rc pilot.
The ability to configure the receiver from the radio is fantastic. This makes setup at the field an absolute breeze.

Issues & Problems
During setup I had a couple of issues. Some I resolved – Some I just skipped over and worked around.
  • Stabilise Mode would not work: This was very confusing at first. I simply could not get the stabilised mode to enable. All the others worked – but not this one. I eventually worked out that I needed to setup a mix on CH9 for gain control. I assume that opentx was sending no data on this channel by default – so the flight control software would not enable. I assigned CH9 to a POT.
    LUA script RX/Orientation: The lua script allows you to set the receiver orientation in the model. No mater what I did I could not get the receiver to pick up this change, despite it saving to to the radio. I suspect maybe a script issue or firmware issue. It is likely that I had the desktop pc app talking I could have fixed it. Regardless I simply skipped over the problem and changed the way I was locating my receiver.
Flight Testing
I spent an hour today flying my wingnetic with the S8R receiver/stabiliser installed.

As expected - no real vices.
  • Stabilise mode works great - Super smooth. The ability to dial in the gain using a slider is a winner!
    Auto Level - well. it works. bit boring on the wingnetic so I wont be using it again!
    Hover/Prop hang - it does a reasonable job on the wingnetic. But with no rudder on the model it tends to fall out on the yaw access
    Knife edge - i did not try. without the rudder on the model their would have been no point.
Where can I buy the receiver?

The receiver can be purchased from all good frsky distributors. I received mine from Bang Good. Their individual product pages are shown below.

Frsky S8R
http://www.banggood.com/search/frsky-s8 ... =hehuishan
FrSky STK
http://www.banggood.com/search/frsky-st ... =hehuishan


General Opinion

I am really happy with the receiver. It does more than I want it to do. I would certainly consider getting another for my next model.
Slope Soaring, FPV, and pretty much anything 'high tech'
...........if you think it should be in the wiki.. ask me for wiki access, then go add it!

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Re: Review: FRSKY S8R Receiver

Post by MikeB » Tue Mar 07, 2017 10:06 am

General discussion on the S6R/S8R is here: viewtopic.php?f=7&t=9291.
Configuration "over the air" is supported on ersky9x.
There may be some confusion over AUX1 and AUX2 on channels 7 and 8. These should probably be called AUX3 and AUX4.
When using the configuration tools (computer/LUA/ersky9x/sportset) the check boxes labelled AUX1 and AUX2 change the function ov channels 5 and 6. If AUX1 is checked, then channel 5 becomes a general purpose servo output instead of a second aileron output. If AUX2 is checked, then channel 6 becomes a general purpose servo output instead of a second elevator output.

Channel 12 is used to initiate "self-check" mode. When this mode is run, immediately after it finishes, you "teach" the S8R the physical channel limits by moving all the controls to their limits.

Mike.
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Re: Review: FRSKY S8R Receiver

Post by Rob Thomson » Tue Mar 07, 2017 8:37 pm

Thanks Mike

Some usefull extra info :)
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Re: Review: FRSKY S8R Receiver

Post by OctavioS » Fri Mar 10, 2017 4:14 pm

I wonder if this receiver is suitable for helicopter, since it has 3 axis gyro stabilization?
3 x - 9X TX with 9xtreme board;
Turnigy 9XRpro ;
Frsky Taranis & Taranis +;
Horus x10s;
Horus x12s.
Too much radios? Yes too much damn radios. No more please.

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Re: Review: FRSKY S8R Receiver

Post by Kilrah » Fri Mar 10, 2017 6:02 pm

No. Its software can't be configured for heli use.


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Re: Review: FRSKY S8R Receiver

Post by OctavioS » Mon Mar 13, 2017 7:51 pm

hmm, ok. thx.
3 x - 9X TX with 9xtreme board;
Turnigy 9XRpro ;
Frsky Taranis & Taranis +;
Horus x10s;
Horus x12s.
Too much radios? Yes too much damn radios. No more please.

"Sometimes you just have to take a leap and build your wings on the way down."

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Re: Review: FRSKY S8R Receiver

Post by KKong99 » Mon Dec 04, 2017 12:13 am

Any chance would you mind sharing your setup for the RX and TX? I have the same setup but for the life of me can't get anything to function the way it's described. I managed to get off or auto recover but nothing more.
Cheers
Kealan

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Re: Review: FRSKY S8R Receiver

Post by MikeB » Mon Dec 04, 2017 9:31 am

If the S8R is a recent purchase, then the firmware will likely include "convenience mode" hat is enabled by default. This uses channels 10 and 12 (yes 12 not 11) in a completely different way to configure operation.
How to use this mode is not described in the manual.
I suggest turning "convenience mode" off (disable it) if it is enabled.

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Re: Review: FRSKY S8R Receiver

Post by KKong99 » Sat Dec 09, 2017 9:10 pm

Thanks for the info. Its actually S6R but i'm sure firmware is identical. I'll try channel 12 and see what happens. I don't have a "convenience mode" but there is a "Quick mode" so i'd assume that's the same thing. I tried unselecting "quick mode" but I loose the auto recover all together. Huge lack of instructions from the manufacture as far as i'm concerned. Ill play with it abit and report back.
Cheers
Kealan

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Re: Review: FRSKY S8R Receiver

Post by MikeB » Sat Dec 09, 2017 10:56 pm

Yes "Convenience mode" is also know as "Quick mode".
For a normal aircraft, I use these settings ("Quick Mode" off):

CH10: +100% HALF switch(!SC^)
CH11: +100% HALF switch(L4)
CH12: +100% HALF switch(!SDv)
with L4 set to:
1-shot SCv 1.5

With switch SC up, I have normal mode, with SC in the middle I have stabilise mode, and with SC down I have auto-level for 1.5 seconds, then it reverts to stabilise mode. I do this because I don't like flying in auto-level mode, but 1.5 seconds is enough to get the 'plane level.

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Re: Review: FRSKY S8R Receiver

Post by KKong99 » Sun Dec 10, 2017 10:43 pm

Thanks for the help. Think I got it. Ch.10 is running flight modes between manual, stabilized, and auto. Ch.12 is -100% or 0 runs modes +100% seems to lock into auto recover. 2 things I found. I need quick mode on for it too work. 2nd make sure gain is above zero for stabilization, If at zero it does nothing.

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Re: Review: FRSKY S8R Receiver

Post by KKong99 » Mon Dec 11, 2017 1:24 am

StilL can't get things right. Though I was good too go and just before launch my elevator would move about 5% travel total. Tried changing channels and it's not the servo but the port so back to the drawing board

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Re: Review: FRSKY S8R Receiver

Post by KKong99 » Mon Dec 11, 2017 4:46 am

Well got it working now, hopefully next weekend I can try again. The receiver is screwed. ch.2 has something wrong. tried rebooting to default, loaded a new model and still the same result. Put new receiver in plane and looks good so far. I have a drone I have been having problems with that I put a X6R in recently and I have a feeling that receiver is having problems too. Not sure what is going on with FrSky but lack on literature, problematic receivers, not very impressed I have enough other problems like staying in the air. Thanks for the help Mike, never would have got it figured without your knowledge.

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Re: Review: FRSKY S8R Receiver

Post by bob195558 » Mon Dec 11, 2017 11:43 am

KKong99 wrote:
Mon Dec 11, 2017 4:46 am
I have a drone, I have been having problems with that,
I put a X6R in recently and I have a feeling that receiver is having problems too.
Hi KKong99,
With your drone, are you saying it was flying OK with a different receiver ? :?:

Bob B.
ErSky9x on Taranis, Sky9x, 9Xtreme, Er9x on 9x with Smartieparts Programmer with TelemetrEZ Board
3D Printing: (http://openrcforums.com/forum/viewforum.php?f=85)

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Re: Review: FRSKY S8R Receiver

Post by KKong99 » Mon Dec 11, 2017 1:14 pm

its always been problems from day one so I cant say it was flying ok. Last time flying I was running a turnigy setup without using the gyro (wish i knew that) and it was ok until 1 esc went. I have since changed it too a 4in1 esc and a X6R receiver and was working in the house. Soon as I went outside id get maybe 30' away and the whole unit shuts down like it looses range. I have yet to confirm the problem.

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Re: Review: FRSKY S8R Receiver

Post by drummaker » Mon Jan 15, 2018 2:47 pm

Does anyone know of a way to bind the S8R in non telemetry mode?

IE no telemetry from receiver...
This would make it work with redundancy bus

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Re: Review: FRSKY S8R Receiver

Post by MikeB » Mon Jan 15, 2018 5:30 pm

What Tx and firmware?
Very recently, both ersky9x and openTx include "bind options" that allow disabling the telemetry in the Rx at bind time. This works with recent firmware for the X8R, I'd need to test to see if it works on the S6R/S8R.

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Re: Review: FRSKY S8R Receiver

Post by MikeB » Mon Jan 15, 2018 6:48 pm

I just tried this having made sure the Tx had the latest firmware on the XJT module and the S8R always sent telemetry, so the current answer seems to be you can't disable telemetry on the S8R.
Since telemetry over SPort is used on the S8R to configure the stabilising parameters, perhaps this is not so surprising as you very likely don't want to disable that option.

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Re: Review: FRSKY S8R Receiver

Post by punkindrublik » Mon Feb 05, 2018 12:30 am

I REALLY wish they'd update the GUI/Firmware so you can turn the Rx sideways. I have a few projects where sideways would be a much easier installation. Seems like a big oversight and such an easy fix.

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Re: Review: FRSKY S8R Receiver

Post by MikeB » Mon Feb 05, 2018 2:52 pm

Unless you want "hover" or "knife edge" you may mount the Rx sideways (across the fuselage). I checked this out on the bench a while ago, all you need to do is plug the aileron servo into the ELE output and the elevator servo into the AIL output!

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Re: Review: FRSKY S8R Receiver

Post by punkindrublik » Tue Feb 06, 2018 11:54 pm

MikeB wrote:
Mon Feb 05, 2018 2:52 pm
Unless you want "hover" or "knife edge" you may mount the Rx sideways (across the fuselage). I checked this out on the bench a while ago, all you need to do is plug the aileron servo into the ELE output and the elevator servo into the AIL output!

Mike
Doesn't work for a wing installation with elevon mixing :(

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Re: Review: FRSKY S8R Receiver

Post by MikeB » Wed Feb 07, 2018 1:01 am

I thought I also checked that would work as well.
Put the Rx into "auto-level" mode and adjust the AIL and ELE output directions so the elevons respond correctly, reversing the outputs as required. If you can't get that to work, swap the servo connections, then you should be able to get it correct.
Then you have to adjust the Tx so the AIL and ELE signals are sent on the required channels, quite possibly ELE on channel 1 and AIL on channel 2.

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Re: Review: FRSKY S8R Receiver

Post by punkindrublik » Wed Feb 07, 2018 1:53 am

MikeB wrote:
Wed Feb 07, 2018 1:01 am
I thought I also checked that would work as well.
Put the Rx into "auto-level" mode and adjust the AIL and ELE output directions so the elevons respond correctly, reversing the outputs as required. If you can't get that to work, swap the servo connections, then you should be able to get it correct.
Then you have to adjust the Tx so the AIL and ELE signals are sent on the required channels, quite possibly ELE on channel 1 and AIL on channel 2.

Mike
I'm 99% sure I checked every possible combo and just couldn't get elevator/aileron to react correctly. I'll try again in the next few evenings and report back.

Thanks Mike

Brian

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