Last week I was faced with a new AR636 challenge. I removed a locked-down AR636 receiver with SAFE® from V900, an E-flite speed plane. I wanted to make it fly my new EDF jet, the Freewing Mirage 2000 Tiger Meet. It would be a breeze to reprogram the AR636 today, presumably, with the advent of AS3X® firmware 2.27 made available in April 2018.
I honestly thought it would take me an hour to reprogram the receiver to fly a delta wing, given the new receiver firmware and upgraded programming apps, since I last looked into the AR636. I thought I would fire up the programming app, and change the aircraft type from normal to elevon. I thought I could then set AS3X rate gains, while keeping SAFE panic and self-leveling. Surely Spektrum documentation had caught up in the last three year, right?
In 2016 I wrote an article titled Salvage and Reprogram the AR636A Receiver from Eflite Planes with SAFE®. You’ll find it by simply googling for “reprogram AR636A”. It’s the first hit. This article on an obscure topic is read three times more than my second most popular article, on Peeled Extreme, an ordinary beef tenderloin from Costco.
I wrote that 2016 article after I failed to find clear explanations around these mysterious AR636A receivers that came with Bind-N-Fly Horizon Hobby planes. When I finally figured them out, I decided to put together a simple guide for the next person. Now everyone can learn to reprogram AS3X dual rates and expos on their AR636A, with a mobile app and a programming cable, without losing SAFE.
Similarly, I am again sharing what I leaned, after hacking the AR636 to fly my new delta wing.
Table of Contents
- My new problem
- AS3X® terminology
- AS3X® features
- SAFE® leverages AS3X
- Open stock AR636 vs BNF AR636A
- Upgrading between major firmware versions
- The big picture
- How to tweak rate gain, dual rate and expo on an AR636A
- How to use AR636A on a non-E-flite plane, “without” SAFE
- How to use AR636/A on a different SAFE plane from E-flite
- How to use AR636/A on a non-E-flite plane, “with” SAFE
My new problem
You cannot easily take an AR636 that is pre-programmed with SAFE for aircraft wing type X (say normal aileron and tail), and reconfigure it for another wing type Y (say a delta wing with elevons), without losing SAFE in the process.
No one has done this before. Or at least no one had clearly documented how to do this online before. It took me some time to figure out how to do this. Thus this sequel to the 2016 article.
The only physical tool I needed was the Transmitter/Receiver USB Programming Cable (SPMA3065). This time I would be using the PC app Spektrum Programmer, a more powerful version of the mobile one. That said, the audio jack-based AS3X programming cable is still useful, for tweaking rate gains at the field, if you are able to find this discontinued item today. It has now been replaced by the Bluetooth programming module.
While I use the example of teaching the AR636 to fly a delta wing, the text explains basic concepts that Spektrum neglects to elucidate. I learned much from this rcgroups.com thread on Experimenting with SAFE Settings on AR636. Mark (mdmyers), SystemsGuy, Flightengr and many other dedicated fans reversed engineered SRM and SAFE parameters. I found the SAFE Model Builder written by Flightengr to be essential for anyone attempting similar feats. Long-running discussions on the same topics can be found on these threads: AS3X (rcgroups), SAFE (rcgroups) and AR636 (wattflyer).
If you found this article, and you have read so far, then you must be researching for a solution to the same problem. Read on.