SPECTRE OPERATING MANUAL.

These figures apply to the WUDFLY reference configuration.

Changes to electronics, battery, printed weight or component position may change the aircraft's CG and flight behaviour.

For the first flights, choose a large, clear area free from trees, buildings, people and other obstacles.

Give yourself plenty of room to launch, climb, make wide circuits and approach for landing.

Before powering the aircraft, check:

• wings are fully seated;
• carbon spar is fitted;
• wing-retaining hardware is secure;
• airframe is undamaged;
• motors are secure;
• propellers are undamaged;
• elevons move freely;
• battery is secure;
• CG is correct.

The reference mechanical starting point is approximately 1.2 mm of upward elevon reflex at the elevon root, matched on both sides.

Control direction

Check:

Pitch up
Both elevons move up.

Pitch down
Both elevons move down.

Roll right
Right elevon moves up, left elevon moves down.

Roll left
Left elevon moves up, right elevon moves down.

Yaw right
Left motor increases relative thrust.

Yaw left
Right motor increases relative thrust.

Also check that stabilisation moves the controls in the correct direction when the aircraft is physically tilted.

SPECTRE uses:

Elevons → pitch + roll
Differential thrust → yaw

SPECTRE should be considered a two-stick aircraft.

Use roll and yaw together when turning.

Stabilised / Angle Mode

In Stabilised mode:

ROLL STICK → commands bank angle
PITCH STICK → commands pitch angle
YAW STICK → commands yaw through differential thrust
THROTTLE → controls motor power

When the roll and pitch sticks return to centre, INAV returns the aircraft towards level flight.

This makes Stabilised mode useful for:

• launching;
• initial familiarisation;
• relaxed cruising;
• recovery when you want additional assistance.

Yaw still matters

SPECTRE's wing geometry naturally produces proverse yaw as the aircraft rolls into a turn.

The aircraft naturally wants to coordinate the turn.

The flight controller does not know that this naturally generated yaw is desirable. If you command roll while leaving the yaw stick centred, the yaw controller can interpret some of this movement as unwanted yaw and attempt to oppose it.

For this reason:

RIGHT TURN → right roll + right yaw

LEFT TURN → left roll + left yaw

The yaw input does not normally need to be large.

Think of the yaw stick as assisting the aircraft's natural turn and telling the flight controller that the yaw is intentional, rather than using it like a conventional rudder to force the nose around.

Simple rule

Roll sets the bank.
Yaw coordinates the turn.
Pitch controls the flight path.

Acro Mode

In Acro:

ROLL STICK → commands roll rate
PITCH STICK → commands pitch rate
YAW STICK → commands yaw rate through differential thrust
THROTTLE → controls motor power

When the sticks return to centre, INAV stops commanding rotation rather than returning the aircraft to level.

The aircraft therefore remains in approximately its existing attitude until you command something else or aerodynamic forces change it.

The same turning technique applies:

Use roll and yaw together.

The supplied INAV configuration has Fixed Wing Auto Launch enabled.

There is no separate launch-mode switch required.

Power-up

Place SPECTRE level and still before connecting the battery.

Allow INAV to initialise before moving the aircraft.

Check:

• receiver connected;
• video working;
• battery voltage correct;
• elevons working;
• stabilisation direction correct;
• flight mode selected.

Keep the throttle fully down until you are ready to prepare the launch.

Launch Sequence

For the first flight, use Stabilised / Angle mode.

Launch into the wind whenever practical.

1. Arm

With the aircraft level, the area clear and throttle fully down:

ARM SPECTRE.

Auto Launch is now waiting.

2. Raise the throttle

When ready to launch, move the throttle to approximately:

MID THROTTLE

This becomes the throttle command SPECTRE transitions towards after the automatic launch sequence.

Keep hands, clothing and cables clear of both propellers.

3. Wake the motors

Give the aircraft a quick deliberate yaw wiggle.

The motors will begin spinning at low idle.

The wiggle does not launch the aircraft.

It simply prepares the motors.

Once the props are spinning steadily, SPECTRE is ready to throw.

4. Launch

Face into the wind.

Hold SPECTRE securely from the rear of the fuselage, behind the propellers.

Give the aircraft a:

gentle, positive forward toss

Do not throw it hard.

Do not throw it sharply upward.

The launch detection activates when the aircraft is thrown.

INAV then brings the motors up and controls the initial climb.

The supplied configuration targets approximately a 22° launch climb.

Let the aircraft do the work.

5. Transition

The automatic launch phase runs for approximately the first second after launch.

INAV then transitions smoothly into the selected flight mode and your commanded throttle.

At this point you have normal control.

For the first launch:

TOSS → LET IT CLIMB → BUILD AIRSPEED → THEN TURN

Do not immediately make large stick inputs after release.

Keep the first flight simple.

Climb to a comfortable altitude and make several large circuits.

Get familiar with:

• throttle response;
• coordinated turns;
• climb and descent;
• speed changes;
• approach behaviour.

Do not immediately test:

• maximum speed;
• maximum-rate manoeuvres;
• low-level aerobatics;
• proximity flying.

There is plenty of time for that later.

Try Acro

If you are already comfortable flying FPV aircraft in Acro, you do not need to remain in Stabilised mode for long.

Once safely airborne with plenty of altitude, switch briefly into Acro mode and see how the aircraft feels.

This is also a useful check of the natural aircraft setup.

Stabilised mode can compensate for an aircraft that is slightly out of trim or balance. Acro gives you a more direct indication of whether the aircraft naturally feels correct.

With SPECTRE built correctly using the reference configuration and battery position, this should normally be uneventful.

It is simply a useful check.

Switch back to Stabilised mode whenever you want.

SPECTRE has a broad flight envelope.

There is no advantage in discovering all of it on the first battery.

A sensible progression is:

Circuits

↓

Slow + fast flight

↓

Acro

↓

Basic aerobatics

↓

Lower-level flying

↓

Proximity

Get comfortable with one stage before moving to the next.

Avoid combining:

an unfamiliar aircraft + an unfamiliar flight mode + a confined flying area

at the same time.

SPECTRE flies well and can be pushed hard once you know it.

The first few flights are about learning the aircraft, not finding its limits.

Cruise

At moderate throttle SPECTRE should settle naturally into stable forward flight.

Use small control inputs and allow the aircraft to maintain airspeed.

Avoid continually holding excessive pitch.

Turns

Use:

ROLL + YAW together

to enter the turn.

Use pitch as required to maintain the flight path.

As the turn finishes, reduce roll and yaw together.

The aircraft's natural proverse yaw and differential-thrust system work together to produce clean turns when the pilot gives matching yaw input.

SPECTRE can fly surprisingly slowly.

Its tractor propellers blow air directly over the inner wing, so throttle does more than simply increase forward speed.

Power also increases airflow over the wing.

This makes throttle particularly useful when flying slowly.

If SPECTRE begins sinking:

ADD POWER

and allow it to regain airspeed.

Do not simply keep pulling more pitch.

At low airspeed, increasing pitch increases angle of attack and can move the aircraft closer to the stall.

When slow:

• keep some power available;
• avoid sudden high-bank turns;
• use coordinated roll and yaw;
• use throttle to control sink;
• give yourself altitude while learning.

Land into the wind where practical.

Give yourself a long, clear approach.

Reduce speed progressively.

A small amount of power can be carried through the approach. Propeller wash over the inner wing gives useful control over sink rate.

Use:

THROTTLE → manage sink

PITCH → manage attitude and flight path

Avoid an aggressive high-angle flare.

Let SPECTRE settle onto the ground.

DISARM immediately after touchdown.

The reference aircraft uses 2S LiHV.

Validated batteries are:

750 mAh

Approximately 7 minutes of sport flying.

1000 mAh

Approximately 9 minutes of sport flying.

These are reference figures rather than guaranteed flight times.

Flight time changes with:

• throttle use;
• wind;
• flying style;
• battery condition;
• temperature.

Monitor battery voltage and land with adequate reserve.

Do not assume that because an individual component supports a higher voltage, the complete SPECTRE power system should be operated above 2S.

Do not troubleshoot a strange aircraft while flying low or close to obstacles.

If SPECTRE behaves unexpectedly:

GAIN SPACE

↓

MAINTAIN AIRSPEED

↓

SIMPLIFY THE FLIGHT

↓

LAND

If you notice unusual:

• oscillation;
• yaw;
• motor behaviour;
• control response;
• vibration;

land and inspect the aircraft.

After a hard landing or impact, check:

• propellers;
• motors and motor mounts;
• wing attachment;
• carbon spar;
• elevon hinges;
• pushrods;
• servos;
• printed structure;
• battery retention.

If something does not look right, fix it before flying again.

Before the next flight, inspect:

• propellers;
• motors;
• motor mounts;
• elevon hinges;
• pushrods;
• servos;
• wing retention;
• spar;
• printed structure;
• battery;
• ESC and motor temperature.

SPECTRE's primary airframe is printed from LW-PLA.

Avoid leaving it somewhere excessively hot, particularly inside a closed vehicle in direct sunlight.