Arrows Hobby L-39 50mm EDF PNP Complete Assembly Guide

PNP version: Power system (EDF fan, motor, 30A ESC, servos, optional Vector gyro) pre-installed factory side. You only assemble airframe, wiring & radio setup.

Things you need

• Fuselage, one-piece main wing, horizontal stabilizer, nose cowl, screws (2.0��12mm), elevator pushrod, clevis, decals
  Buy separately

1. 4-channel RC transmitter + receiver
2. 3S 11.1V LiPo battery (1300�C2200mAh, 30C+, XT60 plug)
3. Foam-safe medium CA glue (DO NOT use regular super glue �� it melts EPO foam)
4. Small screwdriver
5. LiPo charger

Step 1: Inspect all parts first

• EDF fan spins freely, no rubbing
• All 3 servos (aileron ��2, elevator ��1) work
• No cracks on foam airframe
• ESC cable is XT60

Step 2: Install Horizontal Stabilizer (Tailplane)

1. Dry-fit the horizontal stabilizer into the rear fuselage slot to confirm alignment.
2. Apply foam-safe CA glue evenly on mating surfaces of stabilizer and fuselage.
3. Slide stabilizer fully into position; hold firmly 2�C3 mins until glue sets.
4. Connect elevator pushrod:
   • Power radio, set transmitter sticks to neutral center
   • Attach clevis to elevator control horn; lock clevis pin

? Keep control surface perfectly level at neutral.

Step 3: Mount Main Wing

1. Open fuselage battery hatch. Locate the aileron servo Y-harness inside fuselage.
2. Plug the two aileron servo wires from the wing into the Y-harness. Route wires neatly into fuselage cavity.
3. Lower the one-piece wing onto fuselage mounting saddle.
4. Secure wing with 4�� included KA2.0��12mm screws (tighten evenly, do not over-torque to crush foam).

Step 4: Fit Nose Cowl

1. Dry test fit nose cone / cowl.
2. Apply foam-safe CA glue on the contact flange between cowl and fuselage.
3. Push cowl into place, align seams, hold until cured.

Step 5: Radio Wiring (Critical Step)

• CH1 Aileron
• CH2 Elevator
• CH3 Throttle (EDF fan)

If you have the Vector Stabilizer Gyro version, follow the gyro wiring diagram included; gyro unit sits between receiver and servo harness.

Step 6: Battery Installation

1. Remove magnetic battery hatch.
2. Stick hook & loop tape: loop side onto LiPo battery, hook side inside fuselage bay.
3. Slide battery into compartment (internal size: 160��40��40 mm).
4. Secure battery with built-in fabric strap.

Move battery forward/back slightly to tune CG balance.

Step 7: Center of Gravity (CG Balance �C DO NOT SKIP!)

1. Support aircraft gently under both wing roots with fingertips.
2. Plane should hang slightly nose-down (mild forward balance).

• Nose drops too much �� shift battery rearward
• Tail drops �� shift battery forward
  Bad CG = unstable flight, easy crash!

Step 8: Control Surface Travel & Trim Setup

• Ailerons: level
• Elevator: level
  Recommended throw (factory default):
• Aileron: 12�C14mm deflection
• Elevator: 14�C16mm deflection

Start low rates for first flight! Increase expo (20�C30%) for smoother jet handling.

Step 9: Pre-Flight Safety Checklist

1. Throttle stick to minimum/low position before connecting LiPo. ESC has safe start; will not arm if throttle high.
2. Test all controls: Aileron left/right, Elevator up/down, throttle response.
3. Check EDF fan rotation: Make sure fan spins the correct direction. Reverse motor wires if airflow blows forward (wrong rotation = zero thrust).
4. Check all clevises, screws are tight.
5. Check no wiring blocks control surfaces.

?? Flight Notes

• This model has no landing gear �� hand launch only, belly land
• Always launch at ?�C? throttle; maintain speed, jets stall easily at low speed
• Fly on open field away from crowds
• If equipped with Vector gyro: Test gyro mode on ground first, gain low for maiden flight

Official Manual Download