The micro light aircraft SD-4 Viper is a two-seat, low wing monoplane of all-metal
structure with the side-by-side seat arrangement and aerodynamic control.
The fuselage has a semi-monocoque latticework construction formed with spars
and duralumin covers. The tail fin is an integral part of the fuselage. The engine
section is separated from the crew compartment by a steel fire-resistant wall.
The wing is of an all-metal, rectangular-shaped monospar construction provided
with an auxiliary spar. It is equipped with an aileron, a slotted landing flap
controllable electrically in three positions and a fuel tank. The wing ends are
terminated with composite wing tips.
The empennage is of a conventional structure. The horizontal tail unit consists
of stabilizer with right and left elevators which are connected by means of
control. The elevator is provided with a balance tab controllable electrically.
The vertical tail unit is taper-shaped and constructed of a tail fin and a rudder.
The cockpit with side-by-side seating is covered by transparent or tinted canopy
that offers incredible visibility. The canopy is detachable upwards and backwards.
Two-point canopy lock is controllable by two stand-alone handles mounted on both
sides of cockpit. The cabin is equipped with two intake openings on both sides of
fuselage and is vented by ram air over the instrument panel without airflow regulation.
The landing gear is of the tricycle type. The main landing gear is constructed of
composite springs. The wheels are equipped with hydraulic disc brakes which
are controlled by control lever located on the middle panel between pilots´ seats.
The steerable nose wheel is springloaded by rubber ligaments. The landing gear
wheels are equipped with wheel fairings.
It features a conventional dual control system. The elevator and ailerons are
tied-rod operated, the rudder is cableoperated.
Viper SD-4 is delivered with three-point safety harnesses.
The fuel system consists of two integrated lock-in fuel tanks installed in the
wings and provided with a fuel cock and draining valve, distribution piping,
a master fuel valve, a filter, and an electric charger fuel pump.
It is possible to use fixed or adjustable propeller. The propeller must be compatible
with the engine so that it would not limit the performance of the aircraft in the
The aircraft is powered by ROTAX 912 ULS/S-four-stroke, four-cylinder type
boxer, the cylinder heads are liquid cooled and the cylinders are air- cooled.
The engine is equipped with a reducer and two carburettors.
Engine: 4-Takt Rotax 912 ULS/S, 100hp
Wing span: 8,5m
Maximum take off weight: 450kg
Cruising speed: 200km/h
Stall speed: 65km/h
Climb rate: 6,5m/s
Practical ceiling: 5000m
Take off distance: 220m
Landing distance: 250m
Tank volume: 70l