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Aug 16, 2015, 08:27 AM
Better SAFE than sorry!
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Transmitter Setups for Horizon SAFE Airplane Receivers

The posts in this blog entry contain transmitter setups for the Horizon Hobby airplane receivers with SAFE (Sensor Assisted Flight Envelope). The setups are based on the original SAFE receiver from the Apprentice S 15e, but many of the other SAFE-equipped planes from HH use the same basic transmitter setup (three flight modes on the Gear channel, channel 5, and a push-button feature on the Aux1 channel, channel 6). I have used this setup successfully with the Sport Cub S, the Habu S receiver, and the Sportsman S+ with SAFE+. The exact features of each transmitter setting - primarily the push-button - may vary, in which case you may need to change the voice callouts to better fit the actual features. I would speculate that Horizon is making all of these SAFE models consistent so that their inexpensive transmitters included in the Ready-To-Fly packages can be programmed one way for many models.

SAFE Select: See post # 6 below for setting up SAFE Select receivers. Those are much simpler than the other SAFE receivers.

The setups are provided as SPM files, but each one is also accompanied by a PDF file that explains what the aircraft is looking for from the transmitter and how to set that up on the transmitter, step by step. I think it's important to understand how the transmitter works, and that understanding enables you to change the setup to your liking. You can't learn that simply by loading an SPM file!

NOTICE FOR Mini Apprentice S: The new 2016 Mini Apprentice S has a very similar setup as the previous SAFE aircraft, but the Aux1 channel should be left on NORMAL direction, NOT REVERSED! If you use any of the information below for the Mini Apprentice S, that's one change you'll have to correct in the transmitter setup. Panic is activated by a signal of -100% on that plane, not +100% like the others.
Last edited by flightengr; Jul 03, 2016 at 07:42 AM.
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Aug 16, 2015, 08:31 AM
Better SAFE than sorry!
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Gen2 Transmitters

Here are files for the Gen2 (new DX6/7/8/9/18) transmitters.

The SPM file has the flight modes on Switch B, a throttle hold mode (overrides throttle as a safety switch) on Switch H, and dual rates/expo on Switch F.
Last edited by flightengr; Feb 03, 2016 at 07:21 AM.
Aug 16, 2015, 08:35 AM
Better SAFE than sorry!
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Original DX8 and DX7s

Here's a similar thing for the original DX8.

The SPM file has the flight modes on the F Mode switch, throttle hold on the Mix switch, and dual rates on the AIL D/R switch.

The setup process for the DX7s would be very similar, although you'd want to set up the FLAP switch for the flight modes instead of F MODE, as FLAP is the only three-position switch on the DX7s. Unfortunately, the DX7s will not read the DX8's SPM file.
Last edited by flightengr; Feb 03, 2016 at 07:23 AM.
Dec 05, 2015, 04:31 PM
Better SAFE than sorry!
Thread OP


Here's a snippet from the Corsair S manual for the DX6i. The Corsair S receiver and the Apprentice S receiver both work the same way from the transmitter's perspective.
Jun 29, 2016, 05:47 PM
Better SAFE than sorry!
Thread OP

Counteract the Apprentice S Built-In Mix

The Apprentice S receiver has a slight mix of THR > ELE in Beginner Mode. As you raise the throttle, the receiver will also add up elevator gradually, to the point where it's adding about 20% up elevator when the throttle is at 100%.

You can add a mix on your transmitter to counteract that effect. With this mix active, you essentially nullify the receiver's mix and the elevator will no longer move in response to throttle.
On a Gen2 transmitter, go to the Function Menu > Mixing. Scroll down to the first available mix (most likely "P-Mix 1") and select it. Then choose "Normal" as the type as opposed to "Curve". On other transmitter models, go into your Mixing function and find the first available mix you can edit.

At that point, you want to set up something like this:

Mix 1
Rate: 10% 0%
Offset: -100%
Switch: Switch B (if that's the one you used for the flight modes)
Position: 0 box should be black (selected), 1 and 2 should be light (not selected)

The screen shot below is from a DX9. On my transmitter setup, I'm using the Flight Mode feature of the transmitter to display the flight mode name all the time. (How to do that is in my writeup above.) So I'm using "Flight Mode" as the switch for the mix. If you're not using the Flight Mode feature, then use the switch you have assigned to the Gear channel to change flight modes on the transmitter (such as Switch B, or maybe Switch D...)

You can test the mix without the airplane just to get an idea of whether it's moving things in the correct direction. Set up the mix, and then go back to the Function menu and choose Monitor. Then watch what happens to ELE as you move THR up. You want to see the value of ELE go up a little bit as THR goes up. You can also try checking the other switch positions to ensure that nothing happens on ELE when you move THR in the other modes.
Last edited by flightengr; Jul 17, 2016 at 06:41 AM.
Jul 03, 2016, 07:39 AM
Better SAFE than sorry!
Thread OP

SAFE Select

The SAFE Select receivers behave like normal AR636 receivers for the most part. Rather than having three SAFE flight modes, there are only two modes - "SAFE on" and "SAFE off". When SAFE is on, it has self-level capabilities similar to Beginner Mode on most of the other SAFE receivers. It has the bank angle limits set to a larger angle, similar to Intermediate Mode on the other receivers. When SAFE is off, there are no self-level or bank angle limit features, turning the receiver into a normal AR636 with AS3X.

The transmitter setup is very simple for SAFE Select. First, you start with a normal, default Acro (Airplane) new model. The first 6 channels are set up to control the plane directly. If the plane has flaps, they should be connected to channel 6 (Aux1) to work with the transmitter's built-in flap system. If you have an additional feature on your plane such as retracts, that would go on channel 5 (Gear).

You can choose whether SAFE is on or off permanently during the bind process. If you bind your transmitter to the receiver in the typical way, SAFE will be off. If you change up the order of the last two steps, you can bind with SAFE turned on.

Bind with SAFE off:
  1. Insert bind plug in receiver.
  2. Power up plane/receiver.
  3. Bind transmitter to receiver.
  4. Remove bind plug.

Bind with SAFE on:
  1. Insert bind plug in receiver.
  2. Power up plane/receiver.
  3. REMOVE BIND PLUG. (The receiver will stay in bind mode!)
  4. Bind transmitter to receiver.

Optionally, you can associate a switch on your transmitter to turning the SAFE on and off on demand during flight. The switch can be on any channel from 5 to 9 (Gear, Aux1 to Aux4).

To go ahead with this process, you must bind the transmitter such that the receiver has SAFE turned on.

If you have a 6-channel transmitter, you'll need to use either channel 5 (Gear) or 6 (Aux1). If you have a transmitter with 7 or more channels, you can use channel 7 (Aux2) and keep all 6 of the primary channels open for connecting flaps, retracts, or whatever.

To assign a switch to SAFE on/off, first you'll need to assign a switch to a radio channel. I'll use Aux2 for this explanation, but with a 6-channel transmitter, you should instead use Gear or Aux1.

On a newer Gen 2 transmitter, go to the System Menu > Channel Assign menu option. Skip the first screen (Rx Port Assignments) and choose Next to get to Channel Input Config. Associate a switch of your choice with Aux2. On an older transmitter, go to the System Menu > Switch Select menu option to associate a switch with Aux2.

The manual for planes equipped with SAFE Select mentions that the travel on the Aux2 channel should be 100% in both the positive and negative directions. This will be set for you by default with a new Acro model, so you don't need to worry about changing that.

Next, make sure your transmitter is on HIGH RATES. The special stick movement you need to put the receiver in the switch learning mode won't work on low rates. You can go back to low rates after you're done with this process.

With the plane on and SAFE turned on, you can now teach the receiver which channel/switch will turn SAFE on and off.

Move both transmitter sticks to the lower, inside corners. (Left stick to the lower-right corner, and right stick to the lower-left corner.) This works whether your transmitter is set up for Mode 1 or Mode 2.

While holding the sticks in that position, flip your switch fully back and forth 5 times. If you're using a three-position switch, then that means switching from position 0 to 2 to 0 and so on. It won't work if you only flip it as far as position 1.

If you have succeeded, the flight control surfaces will move to acknowledge the change.

There are a couple of ways to test which mode you're in (on or off). One way is to pick up the plane and move it around. When SAFE is on, you can roll the plane side to side or pitch the nose up and down, and the ailerons or elevator will move accordingly and HOLD their positions in an attempt to make the plane fly back to a level flight position. When SAFE is off, AS3X will move the control surfaces around if you're moving the plane, but the control surfaces will go back to center as soon as the movement stops. AS3X reacts to sudden unintended acceleration (such as wind) but doesn't try to control the plane otherwise.

Another test: If the plane is a tail-dragger, then with the plane just sitting on the ground in it's normal stance, the elevator should be even with the horizontal stabilizer when SAFE is off, but when SAFE is on the elevator will drop to try to level out the plane. Because it's a tail-dragger, SAFE notices that the nose is pitched up in the air and wants to straighten the plane out.

Advanced Information: If you'd like to do some programming on the transmitter with respect to the SAFE on/off switch, you'll need to know that a value of +100% turns SAFE on, and values of -100% and 0% both turn SAFE off. The threshold between on and off is somewhere between 0% and +100%.
Last edited by flightengr; Jul 06, 2017 at 01:49 PM.

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