AIRCRAFT OPERATING INSTRUCTIONS – VIRUS 912 S-LSA GLIDER
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and initial climb! Having lifted off the ground, gently push the stick forward just a bit to accelerate. At
some 90 km/ h (50 kts) set flaps to 1st stage, at 110 km/h (60 kts) set them to neutral.
Climb
A comfortable setting for climb is flaps in neutral position, speed of 70 kts (130 km/h) at or slightly below
5500 RPM. In summer time or when outside temperature exceeds 30°C you should consider climbing at
some 85 kts (160 km/h) to provide more airflow to the engine radiators. Trim the aircraft for comfortable
stick forces.
Cruise
Passing through 85 kts (160 km/h), set flaps to negative position (handle full down). A comfortable cruise
setting is 5300 engine RPM. As the Virus is sensitive to flap settings, especially when it comes to fuel
efficiency, ALWAYS use negative stage of flaps beyond 85 kts (160 km/h) and neutral for level flight below
70 kts (130 km/h).
Cruising fast, do not kick-in rudder for turns! Above 85 kts (160 km/h) the rudder becomes almost
insignificant in comparison to aileron deflections when it comes to making a turn. Cruising fast, it is
extremely important to fly coordinated (ball in the middle) as this increases efficiency and de-creases
side-pressure onto vertical tail surfaces. Also, pay attention to turbulence. If you hit turbulence at speeds
greater than VRA, reduce power immediately and pull the nose up to reduce speed. If flying a traffic
pattern, keep flaps in neutral position and set engine power so that airspeed does not exceed 80 kts.
Descent
Descending with the Virus is the stage of flight where the most care should be taken. As the aircraft is
essentially a glider, it is very slippery and builds up speed very fast. Start the descent by reducing throttle
and keep your speed below V
A
. During initial descent it is recommended you trim for a 10 kts lower
speed than the one you decided to descent at. Do this for safety. In case you hit turbulence simply
release forward pressure on the stick and the aircraft will slow down. Also, keep in mind that you need
to begin your descent quite some time before reaching your destination. A comfortable rate of descent
is 500 fpm (2.5 m/s). So it takes you some 2 minutes for a 1000 ft (300 m) drop. At 105 kts (200 km/h)
this means 3.6 NM for each 1000 ft drop.
Entering the traffic pattern the aircraft must be slowing down. In order to do this, hold your altitude and
reduce throttle to idle. When going below 80 kts (150 km/h), set flaps to neutral position. Set proper
engine RPM to maintain speed of 70 kts (130 km/h). Trim the aircraft for comfortable stick forces. Before
turning to base-leg, reduce power to idle and set flaps to 1st stage at 60 kts (110 km/h). Once out of the
turn, reduce speed towards 55 kts (100 km/h). Power remains idle from the point of turning base all the
way to touch-down. If you plan your approach this way, you will always be on the safe side - even if your
engine fails, you will still be able to safely reach the runway!
Turn to final at 55 kts (100 km/h). When in runway heading, set flaps to 2nd stage. Operate the air-brakes
to obtain the desired descent path (if applicable).
How to determine how much airbrakes you need for a certain airspeed?
Open them half-way and observe the runway. If the runway threshold is moving up, you are dropping too
fast - retract the airbrakes a little. If the runway threshold is disappearing below your aircraft, you are
dropping too slowly - extend airbrakes further. When working on airbrakes, it is important to keep the
airspeed/pitch angle constant throughout final all the way to flare! The airbrakes will not impact your
speed, just rate (angle) of descent. For pilots who are not used to operating airbrakes but throttle
