Betaflight basics

Modes, rates, failsafe — and the 5 settings every new pilot must verify.

All APEXFPV drones ship pre-tuned on Betaflight 4.5+. This guide covers what runs underneath, what you can safely change, and what NEVER to touch on day one.

Flight modes

Modes are flight behaviors triggered by AUX channels (switches on your radio). Default APEXFPV setup uses 4 essential modes assigned to AUX1–AUX4.

ModeWhat it doesRecommended switch
ARMEnables motors. Safety lock — drone is dead until armed.AUX1, 2-pos, 1800 µs = ARM
ANGLESelf-leveling. Stick released = drone returns flat. Beginner mode.AUX2, 3-pos low
HORIZONSelf-leveling under 30° tilt + acro past it. Transition mode.AUX2, 3-pos mid
ACRO (default)No leveling. Pure rate-based. Required for flips, rolls, freestyle.AUX2, 3-pos high (no mode = ACRO)
BEEPERTriggers buzzer to locate crashed drone.AUX3, momentary
GPS RESCUEFoldApe LR with GM8 GPS only — auto return-to-home on switch flip.AUX4, 2-pos

How to assign: Betaflight Configurator → Modes tab → click Add Range → pick AUX channel + range (e.g. 1800–2100 µs for switch high).

Rates — sticks to angular velocity

Rates control how aggressive the drone reacts to your stick movement. Measured in deg/sec. Higher = faster spin. APEXFPV default rates are tuned for "feel like a 5-inch freestyle build" out of the box.

FoldApe4 LR

  • TypeActual
  • Roll/Pitch RC Rate1.00
  • Roll/Pitch Rate0.70
  • Yaw RC Rate1.00
  • Max angular vel~580 °/s

BabyApe II

  • TypeActual
  • Roll/Pitch RC Rate1.10
  • Roll/Pitch Rate0.72
  • Yaw RC Rate1.00
  • Max angular vel~640 °/s

SpeedyBee Master 5 V2

  • TypeActual
  • Roll/Pitch RC Rate1.20
  • Roll/Pitch Rate0.78
  • Yaw RC Rate1.00
  • Max angular vel~720 °/s

New pilot tip: Don't change rates in your first 50 flights. Memorize the default feel first. Then lower RC Rate by 0.10 if too twitchy, or raise it by 0.10 if too sluggish.

Failsafe — what happens when link drops

Failsafe is the most critical safety feature. It defines drone behavior when the radio signal is lost (out of range, battery dead, antenna fail). NEVER fly without testing failsafe first.

StageTriggerAction
Stage 1RX signal lost ~1 secHold last RC values OR set custom values (Betaflight Failsafe tab)
Stage 2Stage 1 timeout ~3 secDrop (kill motors), Land (slow descent), or GPS Rescue (FoldApe LR)

APEXFPV defaults:

  • FoldApe4 LR (long range) → Stage 2 = GPS Rescue → returns to Home position automatically
  • BabyApe II (freestyle) → Stage 2 = Drop → kills motors instantly, falls where it was
  • SpeedyBee Master 5 V2 (freestyle) → Stage 2 = Drop

Bench test (every new build): Power drone (NO PROPS), arm, throttle 0%. Power radio off. Within 4 seconds, motors should stop spinning OR drone should command return-to-home (GPS Rescue case).

The 5 settings every new pilot MUST verify

Before your first flight, open Betaflight Configurator and verify these 5 settings. APEXFPV ships with sane defaults but radios, regions, and pilot preferences vary.

  1. Receiver protocol = CRSF (ELRS)

    Configuration tab → Receiver section → Receiver Mode = Serial. Serial Receiver Provider = CRSF. Ports tab → UART2 (FoldApe / BabyApe) or UART1 (Master 5 V2) → Serial RX checked.

    CLI: set serialrx_provider = CRSF

  2. Arm switch — angle limit + minimum throttle

    Configuration tab → Maximum Angle for Arming = 25° (prevents arming on uneven surface). Min Throttle Check = 1050 µs. Modes tab → ARM range 1800–2100 µs on AUX1.

  3. Failsafe — Stage 2 action

    Failsafe tab → Stage 2 → Drop (freestyle) or GPS Rescue (FoldApe LR with GM8 GPS lock). Throttle = 1000. Test on bench WITHOUT PROPS before first flight.

    CLI: set failsafe_throttle = 1000

  4. Motor direction — DShot beacon test

    Motors tab → check "I understand the risks" → spin each motor at 5–10% — verify CW/CCW match the diagram (front-left CW, front-right CCW, etc.). Wrong direction? CLI: set motor_direction_inverted = ON per motor or use BLHeli Configurator.

  5. Battery voltage thresholds + warnings

    Power & Battery tab → Min Cell Voltage = 3.30 V, Warning Cell Voltage = 3.50 V. Voltage scale = 110 (default for most APEXFPV FCs). LiPo never below 3.30 V to preserve cells. Warning beeper on any cell < 3.50 V.

    CLI: set vbat_min_cell_voltage = 330
Don't touch (yet): PIDs, filters, Dynamic Notch, RPM Filter, motor idle, anti-gravity, throttle limits. APEXFPV pre-tunes these per-build for the exact motor/ESC/frame combo. Tweaking without understanding will degrade flight quality and may cause oscillations or burn motors.