AR636

[Nikom]

I just got a replacement rx the AR636 from Spektrum. My only concern is now is the SAFE option available in this rx?
I had SAFE in my old AR636A rx but is the 3 axses stabilisation the same as SAFE?

[xviper]

If it's an "open" 636, it'll be "empty" and must be programmed. AS3X can be programmed but SAFE may not be possible without a downloaded file. If they sent you an actual replacement for the model you have, then it's programmed just like the stock one you had. Hook it up to a smart phone APP or to your computer with the the APP to see what's on it. You won't be able to see if it has SAFE. Spektrum seems to hide that stuff from the end user. The only way to know is to put it into the plane and fly it. SAFE is NOT the same a AS3X. AS3X is the gyro stabilizer. SAFE is the feature that limits bank, pitch and possibly even yaw angles - ie, you cannot do a full roll or a loop.

[Nikom]

They didn’t send one like the one in my Viper. I’m pretty sure it’s an “open” AR636
and will connect to the programmer with the programmer cable soon. The one still in the Viper
is an AR636B. But let’s see if my new DX9 will fix the connection issue before i “swap”
the AR636B with the AR636.

Thank’s

[Nikom]

After connecting it to pc with Spektrum programmer
i could se safe select is installed on this ar636.

[scottnp]

I have an AR636A receiver out of a crashed Eflite Spitfire. I tried to install it in a similar tail dragger. At first SAFE and 3ASX seemed to work properly but then I noticed that in SAFE the elevator reaction to tilt the aircraft up and down was reverse to what it should have been. Tilting the wings work perfect with ailerons moving to level the aircraft. I mounted the receiver as close to CG as I could with ports facing forward. Any ideas other than reprogramming?

[Nikom]

Hard to say. I heard that safe select receivers from one specific plane won't work the same in a another plane. If you have the Spektrum programmer cable Maybe you could program safe with this?
Maybe others will chime in on this ?

[xviper]

I have an AR636A receiver out of a crashed Eflite Spitfire. I tried to install it in a similar tail dragger. At first SAFE and 3ASX seemed to work properly but then I noticed that in SAFE the elevator reaction to tilt the aircraft up and down was reverse to what it should have been. Tilting the wings work perfect with ailerons moving to level the aircraft. I mounted the receiver as close to CG as I could with ports facing forward. Any ideas other than reprogramming?

It's no longer necessary to place a gyro device at or even near the CG of a plane. It can be placed almost anywhere in the body of the plane, so that is not a factor in your case. Since the gyro response direction is incorrect for one of your control surfaces, your only choice is to go into the RX with the APP and reverse the gyro response (NOT stick response) direction for that axis (elevator in your case). Is the rudder gyro response OK? You can't just go into the TX and reverse that servo. Your problem is not "stick" response. It's "gyro" response. Not only is your SAFE response incorrect for that axis, your AS3X is also incorrect. If you fly it that way, it will drive itself into the ground.
PS. Make sure that the ports are supposed to face forward. In many (if not most) planes with 636 RXs, the ports face to the rear.

[N4Speed]

F-16 With AR636B

---

I bought an Eflight F-16 70 mm BNF, it came with an AR636B RX. I use SAFE mode when landing on windy days but when I put it in SAFE mode, it automatically applies some up elevator and I prefer if it didn't. I tried to use Forward Programming get rid of up elevator and also setup a master gain control but I get an error that says "Connection Failed". I get the same error on both my DX8 G2 and iX12 TXs.

I noticed on Horizon Hobby Website, it states that " The AR636B version of the AR636 is an OEM replacement item that does not have a remote receiver port or Xbus telemetry port. Beyond those differences, if you have this receiver new in package, not from some BNF or RTF aircraft, it will program exactly like the AR636 receivers."

Does this mean I can't use Forward Programming, since it's from a BNF plane? If so, are there any other way for me to get rid of up elevator when I chose SAFE mode?

I have the Spektrum programmer cable but not sure where in the App I can change this.

[xviper]

The programming cable may be the worst way to talk to the RX. I think that's why HH brought out the blue tooth device. It works much better. Usually, "connection failed" means you haven't turn the volume on the phone to max and even then, it may not be enough.
SAFE mode interprets the attitude of the plane in a different way. This UP elevator is not necessarily something that is programmed in and thus, may not be something you can program out. Where AS3X doesn't care where "level" is for a given plane, SAFE does. It may also have something to do with how the plane sits when you power it up. Failing to eliminate the UP elevator, you can always do a mix so that when you throw the switch to go into SAFE, it automatically dials some DOWN elevator. You'll have to experiment to see just how much DOWN you'll need to get it to where you're happy with it. What you see the elevator do on the bench may not be the same as what it does when flying when you throw the switch.

[mshagg]

The horizon/spektrum software doesnt expose the settings you need to eliminate that awful throttle/elevator mix (seriously i dont know why they insist on this, down elevator at low throttle on a jet? But anyway). AR636 has something similar to 'forward programming' but only for adjusting AS3X gains and only if they are set up as relative gains (by default they are set to absolute in their BNF models).

You'll need the SPMA3065 USB cable, the spektrum programmer software (from horizon) aka SPS and a third party application called SAFE Model Builder (should be able to find via google, it's hosted on a *different* forum) aka SMB

The workflow is to export the .srm configuration file using SPS, open that .srm file in SMB, eliminate the THR/ELE mix, save, then reimport the modified .srm back into SPS, which will then write it to the receiver.

Screenshot shows the relevant setting in SMB.

[xviper]

Wow! That was above my pay grade.

[Nikom]

Very useful info. However i was lucky to get a new AR636 from HH and after installing it i don’t have the up elevator in safe mode. I find the programmer cable and SPS to be very useful for Spektrum RX’es:)

[mshagg]

The humble 636 are incredibly powerful receivers when paired with the programming cable. It's better to think of them as 9 channel receivers with 6 output ports.

A colleague demonstrated the value of this thinking when he installed a second AR636 in an Eflite EC1500 cargo plane. With three duplicate outputs + three additional channels he was able to set up full span flaps, full span ailerons and - the piece de resistance - differential thrust with AS3X (stabilised yaw) on the motors. The results were out of this world.

https://www.youtube.com/watch?v=cobqaBBc3CA

[Nikom]

Incredible flying👍 I find the rx 636 rx to be good receivers.

[N4Speed]

xviper & mshagg thank you so much for your input!! Great info!

I will try the mixing solution 1st as a quick fix, however, I downloaded SAFE Model Builder and will start experimenting. It looks like an excellent solution for those of us who have HH BNF models and can’t use Forward programming. I found this thread very useful for using SAFE Model Builder. Go to post#4 to download SAFE Model Builder.

[Tilehtin]

Hi guys, can I use my Frsky usb S.port tool with Spektrum AR636A receiver if I load Spektrum App?

[Fletch88]

It's no longer necessary to place a gyro device at or even near the CG of a plane. It can be placed almost anywhere in the body of the plane, so that is not a factor in your case. Since the gyro response direction is incorrect for one of your control surfaces, your only choice is to go into the RX with the APP and reverse the gyro response (NOT stick response) direction for that axis (elevator in your case). Is the rudder gyro response OK? You can't just go into the TX and reverse that servo. Your problem is not "stick" response. It's "gyro" response. Not only is your SAFE response incorrect for that axis, your AS3X is also incorrect. If you fly it that way, it will drive itself into the ground.
PS. Make sure that the ports are supposed to face forward. In many (if not most) planes with 636 RXs, the ports face to the rear.

Viper, you say it does NOT have to be perfectly in center of fuse any longer? I have 630 mounted on side of fuse in FL warty and have only flown once with what seemed like very nose heavy condition. Kept FM 1 wide open no AS3X or anything. Only got 2mins in as I never felt comfortable flying with CG where it was. Came in no flaps very much hotter than I wanted and ended up doing the bounce and snapping nose gear upper hardened pin. I know previous gyro installs always said must be in center of fuse as close to CG as possible


Thanks,
Fletch

[Fletch88]

It's no longer necessary to place a gyro device at or even near the CG of a plane. It can be placed almost anywhere in the body of the plane, so that is not a factor in your case. Since the gyro response direction is incorrect for one of your control surfaces, your only choice is to go into the RX with the APP and reverse the gyro response (NOT stick response) direction for that axis (elevator in your case). Is the rudder gyro response OK? You can't just go into the TX and reverse that servo. Your problem is not "stick" response. It's "gyro" response. Not only is your SAFE response incorrect for that axis, your AS3X is also incorrect. If you fly it that way, it will drive itself into the ground.
PS. Make sure that the ports are supposed to face forward. In many (if not most) planes with 636 RXs, the ports face to the rear.

Viper, you say it does NOT have to be perfectly in center of fuse any longer? I have 630 mounted on side of fuse in FL warty and have only flown once with what seemed like very nose heavy condition. Kept FM 1 wide open no AS3X or anything. Only got 2mins in as I never felt comfortable flying with CG where it was. Came in no flaps very much hotter than I wanted and ended up doing the bounce and snapping nose gear upper hardened pin. I know previous gyro installs always said must be in center of fuse as close to CG as possible


Thanks,
Fletch

[xviper]

Viper, you say it does NOT have to be perfectly in center of fuse any longer? I have 630 mounted on side of fuse in FL warty and have only flown once with what seemed like very nose heavy condition. Kept FM 1 wide open no AS3X or anything. Only got 2mins in as I never felt comfortable flying with CG where it was. Came in no flaps very much hotter than I wanted and ended up doing the bounce and snapping nose gear upper hardened pin. I know previous gyro installs always said must be in center of fuse as close to CG as possible


Thanks,
Fletch

A gyro isn't going to fix an improper CG placement, nor has it anything to do with how it lands or whether not flaps are involved. The plane needs to fly OK and trimmed properly before activating any gyro. A gyro responds and acts upon NON-stick inputted changes. Most gyros are superseded by stick inputs.
Of course gyro manuals will generally tell you about the "proper" placement of the device. That's the "ideal" situation, but there are many planes that come with gyros out of the box and they are NOT placed anywhere near the center line at the CG. They work very well.

[Jtmasters68]

Ive been scrolling around here and cant find an exact answer. Can the ar636 be used with an older dsmx dx6i tx? And i found an ar630 i believe, too. I want gyro stabilization receiver in a new pnp dynam bf110. What are some options? Thank you