How to choose transmitter and receiver for Flyfans SU‑57 Twin 70mm EDF Jet (PNP)

This jet has retractable landing gear + gear doors, flaps, airbrake, navigation lights, twin EDFs, ailerons, elevator, rudder.

1. Channel requirement (most critical)

• Minimum: 7‑8 channels
• Recommended: 10+ channels (to control landing‑gear doors, flaps, air‑brake, optional scale lights independently)
• Functions channel allocation reference:

1. Aileron
2. Elevator
3. Throttle (both ESCs are on same throttle channel via internal harness, you only need one throttle channel for twin fans)
4. Rudder
5. Retract landing gear
6. Flaps
7. Air‑brake
8. Optional: Scale lights / gear‑door sequencing

⚠️ Do NOT buy a 6‑channel radio, you will run out of channels for flaps, retracts & airbrake.

The airframe has an internal distribution harness board (Flyfans standard for their twin‑EDF jets). It accepts standard PWM servo plugs. It also works with SBUS if you want to use a serial‑bus receiver (no extra decoder needed for the stock harness).

2. Transmitter (TX) selection guidelines

Must‑have radio features for this EDF jet:

1. Computer‑programmable model memory
2. Dual rates & Expo (essential for fast jet; low rates for takeoff/landing, high rates for aerobatics)
3. Mixing capability (you will need elevator‑to‑flap compensation when deploying flaps to counter pitch‑up)
4. At least 2‑3 3‑position switches for flaps, airbrake, retracts

Radio system protocol choices (pick one ecosystem, TX & RX must match protocol)

1. Budget entry‑level
   • Flysky FS‑i6X (10‑ch, AFHDS‑2A) – good starter option
2. Mid‑range, highly recommended for EDF jets
   • Radiomaster TX12 / TX16S (ELRS 2.4G) – excellent range, future‑proof for other jets
   • FrSky QX7 (ACCST / ACCESS)
3. Premium
   • Futaba, Spektrum

ELRS is strongly recommended for fast EDF jets: lower latency, better long‑range reliability at high‑speed passes.

3. Receiver (RX) selection rules

Two options for this Flyfans jet:

Option A: PWM receiver (simple plug‑and‑play into stock harness)

• Need at least 8 physical PWM channels.
• Disadvantage: more wires inside fuselage.

Option B: SBUS / CRSF serial bus receiver (preferred)

• Smaller, lighter, less wiring inside the crowded fuselage of SU‑57.

Important: The stock Flyfans internal harness has a dedicated SBUS input socket on its distribution board! You just plug the SBUS wire from your receiver directly to this socket, no SBUS‑to‑PWM decoder needed.

• If you go ELRS: get an ELRS RX with SBUS output (e.g. Radiomaster ER6‑G, ER8G)
• If FrSky: R‑XSR, G‑RX8R
• If Flysky: iA6B / iA10B (i‑BUS)

Receiver mounting tips for SU‑57:

• Mount the receiver away from the twin EDF motors, ESC power wires and LiPo battery (high current creates RF noise).
• Orient antennas at ~90° to each other; do not lay antennas along carbon spars.

4. Key radio setup after binding

1. Flap‑to‑elevator mix: add elevator compensation (small up elevator) when flaps deployed to stop the jet pitching up violently on landing approach.
2. Set dual rates & expo:
   • Low rates for take‑off and landing (60‑70 % travel, expo 25‑35 %)
   • High rates for aerobatic flight (85‑100 % travel)
3. Servo reverse: carefully reverse channels on your transmitter (do NOT reverse servos mechanically)
4. Retract travel speed: slow down retract servo speed on your transmitter menu to avoid stripping the plastic retract gears (very common failure point on this model).

5. Typical recommended complete radio setups

• Budget build: Flysky i6X + iA10B (i‑BUS)
• Best all‑round: Radiomaster TX16S MKII ELRS + ER8G SBUS receiver
• FrSky option: Taranis QX7 ACCESS + G‑RX8R

Common mistakes to avoid

1. Buying a 6‑channel radio – not enough channels for retracts, flaps, airbrake
2. Using a tiny micro receiver placed right next to the EDF motors, causing signal glitches
3. Running retracts at full servo speed (strip plastic retract gears easily)
4. Forgetting to program the flap‑elevator mix (the jet will pitch sharply when you drop flaps for landing)